Preroll udpate

This reverts commit 98f5cbe309.

.gitea/workflows/ci.yml

@@ -59,7 +59,7 @@ jobs:
         shell: powershell
         run: cmake --build --preset build-debug
 
-      - name: Run Native Tests
+      - name: Run Native Tests And Shader Validation
         shell: powershell
         run: cmake --build --preset build-debug --target RUN_TESTS
 

CMakeLists.txt

@@ -31,7 +31,7 @@ if(NOT EXISTS "${SLANG_LICENSE_FILE}")
 endif()
 
 set(APP_SOURCES
-	"${APP_DIR}/DeckLinkAPI_i.c"
+	"${APP_DIR}/videoio/decklink/DeckLinkAPI_i.c"
 	"${APP_DIR}/control/ControlServer.cpp"
 	"${APP_DIR}/control/ControlServer.h"
 	"${APP_DIR}/control/OscServer.cpp"
@@ -40,48 +40,56 @@ set(APP_SOURCES
 	"${APP_DIR}/control/RuntimeControlBridge.h"
 	"${APP_DIR}/control/RuntimeServices.cpp"
 	"${APP_DIR}/control/RuntimeServices.h"
-	"${APP_DIR}/decklink/DeckLinkDisplayMode.cpp"
-	"${APP_DIR}/decklink/DeckLinkDisplayMode.h"
-	"${APP_DIR}/decklink/DeckLinkFrameTransfer.cpp"
-	"${APP_DIR}/decklink/DeckLinkFrameTransfer.h"
-	"${APP_DIR}/decklink/DeckLinkSession.cpp"
-	"${APP_DIR}/decklink/DeckLinkSession.h"
-	"${APP_DIR}/decklink/DeckLinkVideoIOFormat.cpp"
-	"${APP_DIR}/decklink/DeckLinkVideoIOFormat.h"
-	"${APP_DIR}/gl/GLExtensions.cpp"
-	"${APP_DIR}/gl/GLExtensions.h"
-	"${APP_DIR}/gl/GlobalParamsBuffer.cpp"
-	"${APP_DIR}/gl/GlobalParamsBuffer.h"
-	"${APP_DIR}/gl/GlRenderConstants.h"
-	"${APP_DIR}/gl/GlScopedObjects.h"
-	"${APP_DIR}/gl/GlShaderSources.cpp"
-	"${APP_DIR}/gl/GlShaderSources.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkAPI_h.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkDisplayMode.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkDisplayMode.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkFrameTransfer.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkFrameTransfer.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkSession.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkSession.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.h"
+	"${APP_DIR}/gl/renderer/GLExtensions.cpp"
+	"${APP_DIR}/gl/renderer/GLExtensions.h"
+	"${APP_DIR}/gl/shader/GlobalParamsBuffer.cpp"
+	"${APP_DIR}/gl/shader/GlobalParamsBuffer.h"
+	"${APP_DIR}/gl/renderer/GlRenderConstants.h"
+	"${APP_DIR}/gl/renderer/GlScopedObjects.h"
+	"${APP_DIR}/gl/shader/GlShaderSources.cpp"
+	"${APP_DIR}/gl/shader/GlShaderSources.h"
 	"${APP_DIR}/gl/OpenGLComposite.cpp"
 	"${APP_DIR}/gl/OpenGLComposite.h"
 	"${APP_DIR}/gl/OpenGLCompositeRuntimeControls.cpp"
-	"${APP_DIR}/gl/OpenGLRenderPass.cpp"
-	"${APP_DIR}/gl/OpenGLRenderPass.h"
-	"${APP_DIR}/gl/OpenGLRenderer.cpp"
-	"${APP_DIR}/gl/OpenGLRenderer.h"
-	"${APP_DIR}/gl/OpenGLVideoIOBridge.cpp"
-	"${APP_DIR}/gl/OpenGLVideoIOBridge.h"
-	"${APP_DIR}/gl/OpenGLShaderPrograms.cpp"
-	"${APP_DIR}/gl/OpenGLShaderPrograms.h"
-	"${APP_DIR}/gl/PngScreenshotWriter.cpp"
-	"${APP_DIR}/gl/PngScreenshotWriter.h"
-	"${APP_DIR}/gl/ShaderProgramCompiler.cpp"
-	"${APP_DIR}/gl/ShaderProgramCompiler.h"
-	"${APP_DIR}/gl/ShaderBuildQueue.cpp"
-	"${APP_DIR}/gl/ShaderBuildQueue.h"
-	"${APP_DIR}/gl/ShaderTextureBindings.cpp"
-	"${APP_DIR}/gl/ShaderTextureBindings.h"
-	"${APP_DIR}/gl/Std140Buffer.h"
-	"${APP_DIR}/gl/TextRasterizer.cpp"
-	"${APP_DIR}/gl/TextRasterizer.h"
-	"${APP_DIR}/gl/TextureAssetLoader.cpp"
-	"${APP_DIR}/gl/TextureAssetLoader.h"
-	"${APP_DIR}/gl/TemporalHistoryBuffers.cpp"
-	"${APP_DIR}/gl/TemporalHistoryBuffers.h"
+	"${APP_DIR}/gl/pipeline/OpenGLRenderPass.cpp"
+	"${APP_DIR}/gl/pipeline/OpenGLRenderPass.h"
+	"${APP_DIR}/gl/pipeline/OpenGLRenderPipeline.cpp"
+	"${APP_DIR}/gl/pipeline/OpenGLRenderPipeline.h"
+	"${APP_DIR}/gl/pipeline/RenderPassDescriptor.h"
+	"${APP_DIR}/gl/pipeline/ShaderFeedbackBuffers.cpp"
+	"${APP_DIR}/gl/pipeline/ShaderFeedbackBuffers.h"
+	"${APP_DIR}/gl/renderer/OpenGLRenderer.cpp"
+	"${APP_DIR}/gl/renderer/OpenGLRenderer.h"
+	"${APP_DIR}/gl/renderer/RenderTargetPool.cpp"
+	"${APP_DIR}/gl/renderer/RenderTargetPool.h"
+	"${APP_DIR}/gl/pipeline/OpenGLVideoIOBridge.cpp"
+	"${APP_DIR}/gl/pipeline/OpenGLVideoIOBridge.h"
+	"${APP_DIR}/gl/shader/OpenGLShaderPrograms.cpp"
+	"${APP_DIR}/gl/shader/OpenGLShaderPrograms.h"
+	"${APP_DIR}/gl/pipeline/PngScreenshotWriter.cpp"
+	"${APP_DIR}/gl/pipeline/PngScreenshotWriter.h"
+	"${APP_DIR}/gl/shader/ShaderProgramCompiler.cpp"
+	"${APP_DIR}/gl/shader/ShaderProgramCompiler.h"
+	"${APP_DIR}/gl/shader/ShaderBuildQueue.cpp"
+	"${APP_DIR}/gl/shader/ShaderBuildQueue.h"
+	"${APP_DIR}/gl/shader/ShaderTextureBindings.cpp"
+	"${APP_DIR}/gl/shader/ShaderTextureBindings.h"
+	"${APP_DIR}/gl/shader/Std140Buffer.h"
+	"${APP_DIR}/gl/shader/TextRasterizer.cpp"
+	"${APP_DIR}/gl/shader/TextRasterizer.h"
+	"${APP_DIR}/gl/shader/TextureAssetLoader.cpp"
+	"${APP_DIR}/gl/shader/TextureAssetLoader.h"
+	"${APP_DIR}/gl/pipeline/TemporalHistoryBuffers.cpp"
+	"${APP_DIR}/gl/pipeline/TemporalHistoryBuffers.h"
 	"${APP_DIR}/LoopThroughWithOpenGLCompositing.cpp"
 	"${APP_DIR}/LoopThroughWithOpenGLCompositing.h"
 	"${APP_DIR}/LoopThroughWithOpenGLCompositing.rc"
@@ -116,12 +124,15 @@ add_executable(LoopThroughWithOpenGLCompositing WIN32 ${APP_SOURCES})
 target_include_directories(LoopThroughWithOpenGLCompositing PRIVATE
 	"${APP_DIR}"
 	"${APP_DIR}/control"
-	"${APP_DIR}/decklink"
 	"${APP_DIR}/gl"
+	"${APP_DIR}/gl/pipeline"
+	"${APP_DIR}/gl/renderer"
+	"${APP_DIR}/gl/shader"
 	"${APP_DIR}/platform"
 	"${APP_DIR}/runtime"
 	"${APP_DIR}/shader"
 	"${APP_DIR}/videoio"
+	"${APP_DIR}/videoio/decklink"
 )
 
 target_link_libraries(LoopThroughWithOpenGLCompositing PRIVATE
@@ -202,6 +213,7 @@ add_executable(Std140BufferTests
 target_include_directories(Std140BufferTests PRIVATE
 	"${APP_DIR}"
 	"${APP_DIR}/gl"
+	"${APP_DIR}/gl/shader"
 )
 
 if(MSVC)
@@ -228,6 +240,29 @@ endif()
 
 add_test(NAME ShaderPackageRegistryTests COMMAND ShaderPackageRegistryTests)
 
+add_executable(ShaderSlangValidationTests
+	"${APP_DIR}/runtime/RuntimeJson.cpp"
+	"${APP_DIR}/shader/ShaderCompiler.cpp"
+	"${APP_DIR}/shader/ShaderPackageRegistry.cpp"
+	"${CMAKE_CURRENT_SOURCE_DIR}/tests/ShaderSlangValidationTests.cpp"
+)
+
+target_include_directories(ShaderSlangValidationTests PRIVATE
+	"${APP_DIR}"
+	"${APP_DIR}/platform"
+	"${APP_DIR}/runtime"
+	"${APP_DIR}/shader"
+)
+
+if(MSVC)
+	target_compile_options(ShaderSlangValidationTests PRIVATE /W3)
+endif()
+
+add_test(NAME ShaderSlangValidationTests COMMAND ShaderSlangValidationTests)
+set_tests_properties(ShaderSlangValidationTests PROPERTIES
+	ENVIRONMENT "SLANG_ROOT=${SLANG_ROOT}"
+)
+
 add_executable(OscServerTests
 	"${APP_DIR}/control/OscServer.cpp"
 	"${CMAKE_CURRENT_SOURCE_DIR}/tests/OscServerTests.cpp"
@@ -250,15 +285,15 @@ endif()
 add_test(NAME OscServerTests COMMAND OscServerTests)
 
 add_executable(VideoIOFormatTests
-	"${APP_DIR}/decklink/DeckLinkVideoIOFormat.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.cpp"
 	"${APP_DIR}/videoio/VideoIOFormat.cpp"
 	"${CMAKE_CURRENT_SOURCE_DIR}/tests/VideoIOFormatTests.cpp"
 )
 
 target_include_directories(VideoIOFormatTests PRIVATE
 	"${APP_DIR}"
-	"${APP_DIR}/decklink"
 	"${APP_DIR}/videoio"
+	"${APP_DIR}/videoio/decklink"
 )
 
 if(MSVC)
@@ -274,8 +309,8 @@ add_executable(VideoPlayoutSchedulerTests
 
 target_include_directories(VideoPlayoutSchedulerTests PRIVATE
 	"${APP_DIR}"
-	"${APP_DIR}/decklink"
 	"${APP_DIR}/videoio"
+	"${APP_DIR}/videoio/decklink"
 )
 
 if(MSVC)
@@ -291,8 +326,8 @@ add_executable(VideoIODeviceFakeTests
 
 target_include_directories(VideoIODeviceFakeTests PRIVATE
 	"${APP_DIR}"
-	"${APP_DIR}/decklink"
 	"${APP_DIR}/videoio"
+	"${APP_DIR}/videoio/decklink"
 )
 
 if(MSVC)
@@ -314,7 +349,7 @@ install(FILES "${SLANG_LICENSE_FILE}"
 	RENAME "SLANG_LICENSE.txt"
 )
 
-install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/SHADER_CONTRACT.md"
+install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/shaders/SHADER_CONTRACT.md"
 	DESTINATION "."
 )
 

OSC/Test.json

@@ -36,7 +36,7 @@
     "preArgs": "",
     "typeTags": "",
     "decimals": 2,
-    "target": "127.0.0.1:9000",
+    "target": "192.168.1.46:9000",
     "ignoreDefaults": false,
     "bypass": false,
     "onCreate": "",
@@ -53,8 +53,8 @@
         "visible": true,
         "interaction": true,
         "comments": "XY control for Fisheye Reproject pan and tilt.",
-        "width": 420,
-        "height": 420,
+        "width": 460,
+        "height": 250,
         "expand": false,
         "colorText": "auto",
         "colorWidget": "auto",
@@ -70,14 +70,14 @@
         "css": "",
         "pips": true,
         "snap": false,
-        "spring": false,
+        "spring": true,
         "rangeX": {
-          "min": -60,
-          "max": 60
+          "min": -1,
+          "max": 1
         },
         "rangeY": {
-          "min": 45,
-          "max": -45
+          "min": 1,
+          "max": -1
         },
         "logScaleX": false,
         "logScaleY": false,
@@ -94,13 +94,13 @@
         "address": "/VideoShaderToys/fisheye-reproject/xy",
         "preArgs": "",
         "typeTags": "",
-        "decimals": "2f",
-        "target": "127.0.0.1:9000",
+        "decimals": "3f",
+        "target": "192.168.1.46:9000",
         "ignoreDefaults": false,
         "bypass": true,
-        "onCreate": "",
-        "onValue": "var pan = Array.isArray(value) ? Number(value[0]) : 0;\nvar tilt = Array.isArray(value) ? Number(value[1]) : 0;\nsend('127.0.0.1:9000', '/VideoShaderToys/fisheye-reproject/panDegrees', {type: 'f', value: pan});\nsend('127.0.0.1:9000', '/VideoShaderToys/fisheye-reproject/tiltDegrees', {type: 'f', value: tilt});",
-        "onTouch": "",
+        "onCreate": "var state = globalThis.__fisheyePanTiltStick = globalThis.__fisheyePanTiltStick || {};\nstate.target = '192.168.1.46:9000';\nstate.panAddress = '/VideoShaderToys/fisheye-reproject/panDegrees';\nstate.tiltAddress = '/VideoShaderToys/fisheye-reproject/tiltDegrees';\nstate.minPan = -60;\nstate.maxPan = 60;\nstate.minTilt = -45;\nstate.maxTilt = 45;\nstate.pan = 0;\nstate.tilt = 0;\nstate.stickX = 0;\nstate.stickY = 0;\nstate.tickMs = 16;\nstate.stepPan = 0.75;\nstate.stepTilt = 0.75;\nstate.deadzone = 0.14;\nstate.applyCurve = function(input) {\n  var amount = Math.abs(input);\n  if (amount <= state.deadzone) {\n    return 0;\n  }\n  var normalized = (amount - state.deadzone) / (1 - state.deadzone);\n  var softened = normalized * normalized * (3 - (2 * normalized));\n  return (input < 0 ? -1 : 1) * softened;\n};\nif (state.timer) {\n  clearInterval(state.timer);\n  state.timer = null;\n}",
+        "onValue": "var state = globalThis.__fisheyePanTiltStick = globalThis.__fisheyePanTiltStick || {};\nvar stickX = Array.isArray(value) ? Number(value[0]) : 0;\nvar stickY = Array.isArray(value) ? Number(value[1]) : 0;\nstate.stickX = isFinite(stickX) ? state.applyCurve(stickX) : 0;\nstate.stickY = isFinite(stickY) ? state.applyCurve(stickY) : 0;",
+        "onTouch": "var state = globalThis.__fisheyePanTiltStick = globalThis.__fisheyePanTiltStick || {};\nif (value) {\n  if (!state.timer) {\n    state.timer = setInterval(function() {\n      if (!state.stickX && !state.stickY) {\n        return;\n      }\n      state.pan = Math.max(state.minPan, Math.min(state.maxPan, state.pan + (state.stickX * state.stepPan)));\n      state.tilt = Math.max(state.minTilt, Math.min(state.maxTilt, state.tilt + (state.stickY * state.stepTilt)));\n      send(state.target, state.panAddress, {type: 'f', value: state.pan});\n      send(state.target, state.tiltAddress, {type: 'f', value: state.tilt});\n    }, state.tickMs);\n  }\n} else {\n  state.stickX = 0;\n  state.stickY = 0;\n  if (state.timer) {\n    clearInterval(state.timer);\n    state.timer = null;\n  }\n}",
         "pointSize": 20,
         "ephemeral": false,
         "label": "",
@@ -121,7 +121,7 @@
         "interaction": true,
         "comments": "",
         "width": 90,
-        "height": 420,
+        "height": 250,
         "expand": false,
         "colorText": "auto",
         "colorWidget": "auto",
@@ -144,90 +144,29 @@
         "gradient": [],
         "snap": false,
         "touchZone": "all",
-        "spring": false,
+        "spring": true,
         "doubleTap": false,
         "range": {
-          "min": 100,
-          "max": 10
+          "min": -1,
+          "max": 1
         },
         "logScale": false,
         "sensitivity": 1,
         "steps": "",
         "origin": "auto",
-        "value": "",
-        "default": 90,
+        "value": 0,
+        "default": 0,
         "linkId": "",
         "address": "/VideoShaderToys/fisheye-reproject/virtualFovDegrees",
         "preArgs": "",
         "typeTags": "",
-        "decimals": 2,
-        "target": "127.0.0.1:9000",
-        "ignoreDefaults": false,
-        "bypass": false,
-        "onCreate": "",
-        "onValue": "",
-        "onTouch": ""
-      },
-      {
-        "type": "xy",
-        "top": 700,
-        "left": 190,
-        "lock": false,
-        "id": "Pan Pad",
-        "visible": true,
-        "interaction": true,
-        "comments": "",
-        "width": "auto",
-        "height": "auto",
-        "expand": false,
-        "colorText": "auto",
-        "colorWidget": "auto",
-        "colorStroke": "auto",
-        "colorFill": "auto",
-        "alphaStroke": "auto",
-        "alphaFillOff": "auto",
-        "alphaFillOn": "auto",
-        "lineWidth": "auto",
-        "borderRadius": "auto",
-        "padding": "auto",
-        "html": "",
-        "css": "",
-        "pointSize": 20,
-        "ephemeral": false,
-        "pips": true,
-        "label": "",
-        "snap": false,
-        "spring": false,
-        "rangeX": {
-          "min": -1,
-          "max": 1
-        },
-        "rangeY": {
-          "min": -1,
-          "max": 1
-        },
-        "logScaleX": false,
-        "logScaleY": false,
-        "stepsX": false,
-        "stepsY": false,
-        "clipX": "",
-        "clipY": "",
-        "axisLock": "",
-        "doubleTap": false,
-        "sensitivity": 1,
-        "value": "",
-        "default": "",
-        "linkId": "",
-        "address": "/VideoShaderToys/video-transform/pan",
-        "preArgs": "",
-        "typeTags": "",
-        "decimals": 2,
-        "target": "",
+        "decimals": "3f",
+        "target": "192.168.1.46:9000",
         "ignoreDefaults": false,
         "bypass": true,
-        "onCreate": "",
-        "onValue": "var x = Array.isArray(value) ? Number(value[0]) : 0;\nvar y = Array.isArray(value) ? Number(value[1]) : 0;\nsend('127.0.0.1:9000', '/VideoShaderToys/video-transform/pan', {type: 'f', value: x}, {type: 'f', value: y});",
-        "onTouch": ""
+        "onCreate": "var state = globalThis.__fisheyeFovStick = globalThis.__fisheyeFovStick || {};\nstate.target = '192.168.1.46:9000';\nstate.address = '/VideoShaderToys/fisheye-reproject/virtualFovDegrees';\nstate.minFov = 10;\nstate.maxFov = 100;\nstate.fov = 90;\nstate.stick = 0;\nstate.tickMs = 16;\nstate.stepFov = 0.6;\nstate.deadzone = 0.14;\nstate.applyCurve = function(input) {\n  var amount = Math.abs(input);\n  if (amount <= state.deadzone) {\n    return 0;\n  }\n  var normalized = (amount - state.deadzone) / (1 - state.deadzone);\n  var softened = normalized * normalized * (3 - (2 * normalized));\n  return (input < 0 ? -1 : 1) * softened;\n};\nif (state.timer) {\n  clearInterval(state.timer);\n  state.timer = null;\n}",
+        "onValue": "var state = globalThis.__fisheyeFovStick = globalThis.__fisheyeFovStick || {};\nvar stick = Number(value);\nstate.stick = isFinite(stick) ? state.applyCurve(stick) : 0;",
+        "onTouch": "var state = globalThis.__fisheyeFovStick = globalThis.__fisheyeFovStick || {};\nif (value) {\n  if (!state.timer) {\n    state.timer = setInterval(function() {\n      if (!state.stick) {\n        return;\n      }\n      state.fov = Math.max(state.minFov, Math.min(state.maxFov, state.fov - (state.stick * state.stepFov)));\n      send(state.target, state.address, {type: 'f', value: state.fov});\n    }, state.tickMs);\n  }\n} else {\n  state.stick = 0;\n  if (state.timer) {\n    clearInterval(state.timer);\n    state.timer = null;\n  }\n}"
       }
     ],
     "tabs": []

README.md

@@ -1,8 +1,8 @@
 # Video Shader
 
-Native video shader host with an OpenGL/DeckLink render path, Slang shader packages, and a local React control UI.
+Native video shader host with an OpenGL render path, pluggable video I/O boundary, DeckLink backend, Slang shader packages, and a local React control UI.
 
-The app loads shader packages from `shaders/`, compiles Slang to GLSL at runtime, renders a configurable layer stack, and exposes a browser-based control surface over a local HTTP/WebSocket server.
+The app loads shader packages from `shaders/`, compiles Slang to GLSL at runtime, renders a configurable layer stack, and exposes a browser-based control surface over a local HTTP/WebSocket server. Shader compilation is prepared off the frame path where possible, then committed on the render thread so editing shader files does not block video output for the whole compile.
 
 ## Repository Layout
 
@@ -15,12 +15,20 @@ The app loads shader packages from `shaders/`, compiles Slang to GLSL at runtime
 - `tests/`: focused native tests for pure runtime logic.
 - `.gitea/workflows/ci.yml`: Gitea Actions CI for Windows native tests and Ubuntu UI build.
 
+Native app internals are grouped by boundary:
+
+- `videoio/`: backend-neutral video I/O contracts, formats, and playout timing.
+- `videoio/decklink/`: DeckLink-specific device adapter, callbacks, and SDK bindings.
+- `gl/renderer/`: low-level OpenGL resources and extension helpers.
+- `gl/pipeline/`: frame pipeline, render passes, video I/O bridge, preview/readback, and screenshots.
+- `gl/shader/`: shader compilation, texture/text assets, UBO packing, and shader program ownership.
+
 ## Requirements
 
 - Windows with Visual Studio 2022 C++ tooling.
 - CMake 3.24 or newer.
 - Node.js and npm for the control UI.
-- Blackmagic Desktop Video drivers and a DeckLink device.
+- Blackmagic Desktop Video drivers and a DeckLink device for the current production video I/O backend.
 - Slang binary release with `slangc.exe`, `slang-compiler.dll`, `slang-glslang.dll`, and `LICENSE`.
 
 Default expected Slang path:
@@ -54,6 +62,14 @@ npm run build
 
 The native app serves `ui/dist` when it exists, otherwise it falls back to the source UI directory during development.
 
+The control UI provides:
+
+- A searchable shader library for adding layers.
+- Compact parameter rows with inline descriptions and OSC copy controls.
+- Stack save/recall presets.
+- Manual shader reload.
+- Screenshot capture from the final output render target.
+
 ## Package
 
 Build the UI, build the native Release target, then install into a portable runtime folder:
@@ -77,6 +93,8 @@ dist/VideoShader/
   shaders/
   3rdParty/slang/bin/
   ui/dist/
+  docs/
+  SHADER_CONTRACT.md
   runtime/templates/
   third_party_notices/
 ```
@@ -111,6 +129,9 @@ Current native test coverage includes:
 - JSON parsing and serialization.
 - Parameter normalization and preset filename safety.
 - Shader manifest parsing, temporal manifest validation, and package registry scanning.
+- Video I/O format helpers, v210/Ay10 row-byte math, v210 pack/unpack math, playout scheduler timing, and fake backend contract coverage.
+- OSC packet parsing.
+- Slang validation for every available shader package.
 
 ## Runtime Configuration
 
@@ -120,7 +141,9 @@ Current native test coverage includes:
 {
   "shaderLibrary": "shaders",
   "serverPort": 8080,
+  "oscBindAddress": "127.0.0.1",
   "oscPort": 9000,
+  "oscSmoothing": 0.18,
   "inputVideoFormat": "1080p",
   "inputFrameRate": "59.94",
   "outputVideoFormat": "1080p",
@@ -131,7 +154,7 @@ Current native test coverage includes:
 }
 ```
 
-`inputVideoFormat`/`inputFrameRate` select the DeckLink capture mode. `outputVideoFormat`/`outputFrameRate` select the playout mode. The shader stack runs at input resolution and the final rendered frame is scaled once into the configured output mode. Common examples include `720p`/`50`, `720p`/`59.94`, `1080i`/`50`, `1080i`/`59.94`, `1080p`/`25`, `1080p`/`50`, `1080p`/`59.94`, and `2160p`/`59.94`, depending on card support.
+`inputVideoFormat`/`inputFrameRate` select the video capture mode. `outputVideoFormat`/`outputFrameRate` select the playout mode. With the current DeckLink backend, supported modes depend on the installed card and driver. The shader stack runs at input resolution and the final rendered frame is scaled once into the configured output mode. Common examples include `720p`/`50`, `720p`/`59.94`, `1080i`/`50`, `1080i`/`59.94`, `1080p`/`25`, `1080p`/`50`, `1080p`/`59.94`, and `2160p`/`59.94`.
 
 Legacy `videoFormat` and `frameRate` keys are still accepted and apply to both input and output unless the explicit input/output keys are present.
 
@@ -170,7 +193,11 @@ http://127.0.0.1:<serverPort>/docs
 
 Use those docs to inspect the `/api/state`, layer control, stack preset, and reload endpoints. Live state updates are also sent over the `/ws` WebSocket.
 
-The control UI also has a Screenshot button. It queues a capture of the final output render target and writes a PNG under:
+The control UI has a **Reload shaders** button. It rescans `shaders/`, re-reads manifests, queues shader compilation, refreshes shader availability/errors, and keeps the previous working shader stack running if a changed shader fails to compile.
+
+Each parameter row also includes a small **OSC** button. Clicking it copies that parameter's OSC route to the clipboard.
+
+The control UI also has a **Screenshot** button. It queues a capture of the final output render target and writes a PNG under:
 
 ```text
 runtime/screenshots/
@@ -178,13 +205,13 @@ runtime/screenshots/
 
 ## OSC Control
 
-The native host also listens for local OSC parameter control on the configured `oscPort`:
+The native host also listens for OSC parameter control on the configured `oscBindAddress` and `oscPort`:
 
 ```text
 /VideoShaderToys/{LayerNameOrID}/{ParameterNameOrID}
 ```
 
-For example, `/VideoShaderToys/VHS/intensity` updates the `intensity` parameter on the first matching `VHS` layer. The listener accepts float, integer, string, and boolean OSC values, and validates them through the same shader parameter path as the REST API. See `docs/OSC_CONTROL.md` for details.
+For example, `/VideoShaderToys/VHS/intensity` updates the `intensity` parameter on the first matching `VHS` layer. The listener accepts float, integer, string, and boolean OSC values, and validates them through the same shader parameter path as the REST API. OSC updates are coalesced and applied once per render tick, UI state broadcasts are throttled, and OSC-driven parameter changes are not autosaved to `runtime/runtime_state.json`. `oscSmoothing` adds a small per-frame easing amount for numeric OSC controls such as floats, `vec2`, and `color`, while booleans, enums, text, and triggers stay immediate. The default bind address is `127.0.0.1`; set `oscBindAddress` to `0.0.0.0` to accept OSC on all IPv4 interfaces. See `docs/OSC_CONTROL.md` for details.
 
 ## Shader Packages
 
@@ -194,10 +221,11 @@ Each shader package lives under:
 shaders/<id>/
   shader.json
   shader.slang
+  optional-extra-pass.slang
   optional-font-or-texture-assets
 ```
 
-See `SHADER_CONTRACT.md` for the manifest schema, parameter types, texture assets, font/text assets, temporal history support, and the Slang entry point contract. `shaders/text-overlay/` is the reference live text package and bundles Roboto Regular with its OFL license.
+See `SHADER_CONTRACT.md` for the manifest schema, parameter types, texture assets, font/text assets, temporal history support, optional render-pass declarations, and the Slang entry point contract. `shaders/text-overlay/` is the reference live text package and bundles Roboto Regular with its OFL license. Broken shader packages are shown as unavailable in the selector with their error text instead of preventing the app from launching.
 
 ## Generated Files
 
@@ -208,6 +236,7 @@ Runtime-generated files are intentionally ignored:
 - `runtime/shader_cache/active_shader.frag`
 - `runtime/runtime_state.json` autosaved latest stack and parameter state.
 - `runtime/stack_presets/*.json`
+- `runtime/screenshots/*.png` screenshots captured from the final output render target.
 
 Only `runtime/templates/` and `runtime/README.md` are tracked.
 
@@ -236,16 +265,16 @@ If `SLANG_ROOT` is not set, the workflow falls back to the repo-local default un
 
 - Audio.
 - Genlock.
-- Find a better UI library for react.
 - Logs.
-- Continue source cleanup/refactoring. Pass 2 done
+- Add more video I/O backends now that the DeckLink path is behind `videoio/`.
 - Support a separate sound shader `.slang` file in shader packages. (https://www.shadertoy.com/view/XsBXWt)
-- Add WebView2
-- move to MSDF, typography rasterisation
-- better shader search UI, pass 1
-- More comprehensive greenscreen shader
-- linear compositing?
-- compute shaders or a small 1x1 or nx1 RGBA16f render target for abritary data store
+- Add WebView2 for an embedded native control surface.
+- MSDF typography rasterisation
+- More shader-library organisation and filtering as the built-in library grows.
+- Optional linear-light compositing mode.
+- compute shaders or a small 1x1 or nx1 RGBA16f render target for arbitrary data storage
 - allow shaders to read other shaders data store based on name? or output over OSC
-- Mipmappong for shader declared textures
-- Multipass for shaders at request
+- Mipmapping for shader-declared textures
+- Anotate included shaders
+- allow 3 vector exposed controls
+- add nearest sampling to the extra shader pass

apps/LoopThroughWithOpenGLCompositing/LoopThroughWithOpenGLCompositing.cpp

@@ -531,7 +531,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 				if (!sInteractiveResize && pOpenGLComposite)
 				{
 					wglMakeCurrent(hDC, hRC);
-					pOpenGLComposite->paintGL();
+					pOpenGLComposite->paintGL(true);
 					wglMakeCurrent( NULL, NULL );
 					RaiseStatusControls(sStatusStrip);
 				}

apps/LoopThroughWithOpenGLCompositing/LoopThroughWithOpenGLCompositing.vcxproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
@@ -89,7 +89,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <Optimization>Disabled</Optimization>
-      <AdditionalIncludeDirectories>.;control;decklink;gl;videoio;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>.;control;gl;gl\pipeline;gl\renderer;gl\shader;videoio;videoio\decklink;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
@@ -111,7 +111,7 @@
     </Midl>
     <ClCompile>
       <Optimization>Disabled</Optimization>
-      <AdditionalIncludeDirectories>.;control;decklink;gl;videoio;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>.;control;gl;gl\pipeline;gl\renderer;gl\shader;videoio;videoio\decklink;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
@@ -131,7 +131,7 @@
     <ClCompile>
       <Optimization>MaxSpeed</Optimization>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <AdditionalIncludeDirectories>.;control;decklink;gl;videoio;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>.;control;gl;gl\pipeline;gl\renderer;gl\shader;videoio;videoio\decklink;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <FunctionLevelLinking>true</FunctionLevelLinking>
@@ -156,7 +156,7 @@
     <ClCompile>
       <Optimization>MaxSpeed</Optimization>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <AdditionalIncludeDirectories>.;control;decklink;gl;videoio;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>.;control;gl;gl\pipeline;gl\renderer;gl\shader;videoio;videoio\decklink;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <FunctionLevelLinking>true</FunctionLevelLinking>
@@ -175,47 +175,52 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClCompile Include="gl\GLExtensions.cpp" />
+    <ClCompile Include="gl\renderer\GLExtensions.cpp" />
     <ClCompile Include="LoopThroughWithOpenGLCompositing.cpp" />
     <ClCompile Include="gl\OpenGLComposite.cpp" />
-    <ClCompile Include="gl\OpenGLRenderPass.cpp" />
-    <ClCompile Include="gl\OpenGLRenderer.cpp" />
-    <ClCompile Include="gl\OpenGLShaderPrograms.cpp" />
-    <ClCompile Include="gl\PngScreenshotWriter.cpp" />
-    <ClCompile Include="gl\ShaderBuildQueue.cpp" />
-    <ClCompile Include="gl\TemporalHistoryBuffers.cpp" />
-    <ClCompile Include="gl\OpenGLVideoIOBridge.cpp" />
+    <ClCompile Include="gl\pipeline\OpenGLRenderPass.cpp" />
+    <ClCompile Include="gl\pipeline\OpenGLRenderPipeline.cpp" />
+    <ClCompile Include="gl\renderer\OpenGLRenderer.cpp" />
+    <ClCompile Include="gl\renderer\RenderTargetPool.cpp" />
+    <ClCompile Include="gl\shader\OpenGLShaderPrograms.cpp" />
+    <ClCompile Include="gl\pipeline\PngScreenshotWriter.cpp" />
+    <ClCompile Include="gl\shader\ShaderBuildQueue.cpp" />
+    <ClCompile Include="gl\pipeline\TemporalHistoryBuffers.cpp" />
+    <ClCompile Include="gl\pipeline\OpenGLVideoIOBridge.cpp" />
     <ClCompile Include="stdafx.cpp">
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Create</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Create</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Create</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Create</PrecompiledHeader>
     </ClCompile>
-    <ClCompile Include="DeckLinkAPI_i.c" />
+    <ClCompile Include="videoio\decklink\DeckLinkAPI_i.c" />
     <ClCompile Include="control\RuntimeServices.cpp" />
-    <ClCompile Include="decklink\DeckLinkSession.cpp" />
-    <ClCompile Include="decklink\DeckLinkVideoIOFormat.cpp" />
+    <ClCompile Include="videoio\decklink\DeckLinkSession.cpp" />
+    <ClCompile Include="videoio\decklink\DeckLinkVideoIOFormat.cpp" />
     <ClCompile Include="runtime\RuntimeClock.cpp" />
     <ClCompile Include="videoio\VideoIOFormat.cpp" />
     <ClCompile Include="videoio\VideoPlayoutScheduler.cpp" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="gl\GLExtensions.h" />
+    <ClInclude Include="gl\renderer\GLExtensions.h" />
     <ClInclude Include="LoopThroughWithOpenGLCompositing.h" />
     <ClInclude Include="gl\OpenGLComposite.h" />
-    <ClInclude Include="gl\OpenGLRenderPass.h" />
-    <ClInclude Include="gl\OpenGLRenderer.h" />
-    <ClInclude Include="gl\OpenGLShaderPrograms.h" />
-    <ClInclude Include="gl\PngScreenshotWriter.h" />
-    <ClInclude Include="gl\ShaderBuildQueue.h" />
-    <ClInclude Include="gl\TemporalHistoryBuffers.h" />
-    <ClInclude Include="gl\OpenGLVideoIOBridge.h" />
+    <ClInclude Include="gl\pipeline\OpenGLRenderPass.h" />
+    <ClInclude Include="gl\pipeline\OpenGLRenderPipeline.h" />
+    <ClInclude Include="gl\pipeline\RenderPassDescriptor.h" />
+    <ClInclude Include="gl\renderer\OpenGLRenderer.h" />
+    <ClInclude Include="gl\renderer\RenderTargetPool.h" />
+    <ClInclude Include="gl\shader\OpenGLShaderPrograms.h" />
+    <ClInclude Include="gl\pipeline\PngScreenshotWriter.h" />
+    <ClInclude Include="gl\shader\ShaderBuildQueue.h" />
+    <ClInclude Include="gl\pipeline\TemporalHistoryBuffers.h" />
+    <ClInclude Include="gl\pipeline\OpenGLVideoIOBridge.h" />
     <ClInclude Include="resource.h" />
     <ClInclude Include="stdafx.h" />
     <ClInclude Include="targetver.h" />
     <ClInclude Include="control\RuntimeServices.h" />
-    <ClInclude Include="decklink\DeckLinkSession.h" />
-    <ClInclude Include="decklink\DeckLinkVideoIOFormat.h" />
+    <ClInclude Include="videoio\decklink\DeckLinkSession.h" />
+    <ClInclude Include="videoio\decklink\DeckLinkVideoIOFormat.h" />
     <ClInclude Include="runtime\RuntimeClock.h" />
     <ClInclude Include="videoio\VideoIOFormat.h" />
     <ClInclude Include="videoio\VideoIOTypes.h" />

apps/LoopThroughWithOpenGLCompositing/LoopThroughWithOpenGLCompositing.vcxproj.filters

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
     <Filter Include="Source Files">
@@ -18,7 +18,7 @@
     </Filter>
   </ItemGroup>
   <ItemGroup>
-    <ClCompile Include="gl\GLExtensions.cpp">
+    <ClCompile Include="gl\renderer\GLExtensions.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="LoopThroughWithOpenGLCompositing.cpp">
@@ -27,40 +27,46 @@
     <ClCompile Include="gl\OpenGLComposite.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\OpenGLRenderPass.cpp">
+    <ClCompile Include="gl\pipeline\OpenGLRenderPass.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\OpenGLRenderer.cpp">
+    <ClCompile Include="gl\pipeline\OpenGLRenderPipeline.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\OpenGLShaderPrograms.cpp">
+    <ClCompile Include="gl\renderer\OpenGLRenderer.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\PngScreenshotWriter.cpp">
+    <ClCompile Include="gl\renderer\RenderTargetPool.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\ShaderBuildQueue.cpp">
+    <ClCompile Include="gl\shader\OpenGLShaderPrograms.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\TemporalHistoryBuffers.cpp">
+    <ClCompile Include="gl\pipeline\PngScreenshotWriter.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="gl\OpenGLVideoIOBridge.cpp">
+    <ClCompile Include="gl\shader\ShaderBuildQueue.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="gl\pipeline\TemporalHistoryBuffers.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="gl\pipeline\OpenGLVideoIOBridge.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="stdafx.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="DeckLinkAPI_i.c">
+    <ClCompile Include="videoio\decklink\DeckLinkAPI_i.c">
       <Filter>DeckLink API</Filter>
     </ClCompile>
     <ClCompile Include="control\RuntimeServices.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="decklink\DeckLinkSession.cpp">
+    <ClCompile Include="videoio\decklink\DeckLinkSession.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="decklink\DeckLinkVideoIOFormat.cpp">
+    <ClCompile Include="videoio\decklink\DeckLinkVideoIOFormat.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="runtime\RuntimeClock.cpp">
@@ -74,7 +80,7 @@
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="gl\GLExtensions.h">
+    <ClInclude Include="gl\renderer\GLExtensions.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="LoopThroughWithOpenGLCompositing.h">
@@ -83,25 +89,34 @@
     <ClInclude Include="gl\OpenGLComposite.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\OpenGLRenderPass.h">
+    <ClInclude Include="gl\pipeline\OpenGLRenderPass.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\OpenGLRenderer.h">
+    <ClInclude Include="gl\pipeline\OpenGLRenderPipeline.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\OpenGLShaderPrograms.h">
+    <ClInclude Include="gl\pipeline\RenderPassDescriptor.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\PngScreenshotWriter.h">
+    <ClInclude Include="gl\renderer\OpenGLRenderer.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\ShaderBuildQueue.h">
+    <ClInclude Include="gl\renderer\RenderTargetPool.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\TemporalHistoryBuffers.h">
+    <ClInclude Include="gl\shader\OpenGLShaderPrograms.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="gl\OpenGLVideoIOBridge.h">
+    <ClInclude Include="gl\pipeline\PngScreenshotWriter.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="gl\shader\ShaderBuildQueue.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="gl\pipeline\TemporalHistoryBuffers.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="gl\pipeline\OpenGLVideoIOBridge.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="resource.h">
@@ -116,10 +131,10 @@
     <ClInclude Include="control\RuntimeServices.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="decklink\DeckLinkSession.h">
+    <ClInclude Include="videoio\decklink\DeckLinkSession.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="decklink\DeckLinkVideoIOFormat.h">
+    <ClInclude Include="videoio\decklink\DeckLinkVideoIOFormat.h">
       <Filter>Header Files</Filter>
     </ClInclude>
     <ClInclude Include="runtime\RuntimeClock.h">

apps/LoopThroughWithOpenGLCompositing/control/ControlServer.cpp

@@ -17,6 +17,7 @@
 namespace
 {
 constexpr DWORD kStateBroadcastIntervalMs = 250;
+constexpr DWORD kStateBroadcastThrottleMs = 50;
 
 bool InitializeWinsock(std::string& error)
 {
@@ -75,7 +76,7 @@ std::string GuessContentType(const std::filesystem::path& assetPath)
 }
 
 ControlServer::ControlServer()
-	: mPort(0), mRunning(false)
+	: mPort(0), mRunning(false), mBroadcastPending(false)
 {
 }
 
@@ -161,10 +162,16 @@ void ControlServer::Stop()
 
 void ControlServer::BroadcastState()
 {
+	mBroadcastPending = false;
 	std::lock_guard<std::mutex> lock(mMutex);
 	BroadcastStateLocked();
 }
 
+void ControlServer::RequestBroadcastState()
+{
+	mBroadcastPending = true;
+}
+
 void ControlServer::ServerLoop()
 {
 	DWORD lastStateBroadcastMs = GetTickCount();
@@ -173,7 +180,12 @@ void ControlServer::ServerLoop()
 		TryAcceptClient();
 
 		const DWORD nowMs = GetTickCount();
-		if (nowMs - lastStateBroadcastMs >= kStateBroadcastIntervalMs)
+		if (mBroadcastPending && nowMs - lastStateBroadcastMs >= kStateBroadcastThrottleMs)
+		{
+			BroadcastState();
+			lastStateBroadcastMs = nowMs;
+		}
+		else if (nowMs - lastStateBroadcastMs >= kStateBroadcastIntervalMs)
 		{
 			BroadcastState();
 			lastStateBroadcastMs = nowMs;
@@ -469,6 +481,7 @@ bool ControlServer::HandleWebSocketUpgrade(UniqueSocket clientSocket, const Http
 		client.socket.reset(clientSocket.release());
 		client.websocket = true;
 		mClients.push_back(std::move(client));
+		mBroadcastPending = false;
 		BroadcastStateLocked();
 	}
 	return true;
@@ -501,6 +514,9 @@ bool ControlServer::SendWebSocketText(SOCKET clientSocket, const std::string& pa
 
 void ControlServer::BroadcastStateLocked()
 {
+	if (mClients.empty())
+		return;
+
 	const std::string stateMessage = mCallbacks.getStateJson ? mCallbacks.getStateJson() : "{}";
 	for (auto it = mClients.begin(); it != mClients.end();)
 	{

apps/LoopThroughWithOpenGLCompositing/control/ControlServer.h

@@ -41,6 +41,7 @@ public:
 	bool Start(const std::filesystem::path& uiRoot, const std::filesystem::path& docsRoot, unsigned short preferredPort, const Callbacks& callbacks, std::string& error);
 	void Stop();
 	void BroadcastState();
+	void RequestBroadcastState();
 
 	unsigned short GetPort() const { return mPort; }
 
@@ -100,6 +101,7 @@ private:
 	unsigned short mPort;
 	std::thread mThread;
 	std::atomic<bool> mRunning;
+	std::atomic<bool> mBroadcastPending;
 	mutable std::mutex mMutex;
 	std::vector<ClientConnection> mClients;
 };

apps/LoopThroughWithOpenGLCompositing/control/OscServer.cpp

@@ -55,7 +55,7 @@ OscServer::~OscServer()
 	Stop();
 }
 
-bool OscServer::Start(unsigned short port, const Callbacks& callbacks, std::string& error)
+bool OscServer::Start(const std::string& bindAddress, unsigned short port, const Callbacks& callbacks, std::string& error)
 {
 	if (port == 0)
 		return true;
@@ -78,11 +78,15 @@ bool OscServer::Start(unsigned short port, const Callbacks& callbacks, std::stri
 
 	sockaddr_in address = {};
 	address.sin_family = AF_INET;
-	address.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+	if (!TryParseBindAddress(bindAddress, address.sin_addr, error))
+	{
+		mSocket.reset();
+		return false;
+	}
 	address.sin_port = htons(static_cast<u_short>(port));
 	if (bind(mSocket.get(), reinterpret_cast<sockaddr*>(&address), sizeof(address)) != 0)
 	{
-		error = "Could not bind OSC listener to UDP port " + std::to_string(port) + ".";
+		error = "Could not bind OSC listener to " + bindAddress + ":" + std::to_string(port) + ".";
 		mSocket.reset();
 		return false;
 	}
@@ -92,6 +96,24 @@ bool OscServer::Start(unsigned short port, const Callbacks& callbacks, std::stri
 	return true;
 }
 
+bool OscServer::TryParseBindAddress(const std::string& bindAddress, in_addr& address, std::string& error)
+{
+	if (bindAddress.empty())
+	{
+		error = "OSC bind address must not be empty.";
+		return false;
+	}
+
+	address = {};
+	if (InetPtonA(AF_INET, bindAddress.c_str(), &address) != 1)
+	{
+		error = "Invalid OSC bind address '" + bindAddress + "'. Use an IPv4 address such as 127.0.0.1 or 0.0.0.0.";
+		return false;
+	}
+
+	return true;
+}
+
 void OscServer::Stop()
 {
 	mRunning = false;

apps/LoopThroughWithOpenGLCompositing/control/OscServer.h

@@ -20,7 +20,7 @@ public:
 	OscServer();
 	~OscServer();
 
-	bool Start(unsigned short port, const Callbacks& callbacks, std::string& error);
+	bool Start(const std::string& bindAddress, unsigned short port, const Callbacks& callbacks, std::string& error);
 	void Stop();
 
 	unsigned short GetPort() const { return mPort; }
@@ -37,6 +37,7 @@ private:
 	void ServerLoop();
 	bool DecodeMessage(const char* data, int byteCount, OscMessage& message, std::string& error) const;
 	bool DispatchMessage(const OscMessage& message, std::string& error) const;
+	static bool TryParseBindAddress(const std::string& bindAddress, in_addr& address, std::string& error);
 	static bool DecodeArgument(const char* data, int byteCount, int& offset, char valueType, std::string& valueJson);
 	static bool ReadPaddedString(const char* data, int byteCount, int& offset, std::string& value);
 	static bool ReadInt32(const char* data, int byteCount, int& offset, int& value);

apps/LoopThroughWithOpenGLCompositing/control/RuntimeControlBridge.cpp

@@ -4,10 +4,12 @@
 #include "OpenGLComposite.h"
 #include "OscServer.h"
 #include "RuntimeHost.h"
+#include "RuntimeServices.h"
 
 bool StartRuntimeControlServices(
 	OpenGLComposite& composite,
 	RuntimeHost& runtimeHost,
+	RuntimeServices& runtimeServices,
 	ControlServer& controlServer,
 	OscServer& oscServer,
 	std::string& error)
@@ -41,10 +43,10 @@ bool StartRuntimeControlServices(
 	runtimeHost.SetServerPort(controlServer.GetPort());
 
 	OscServer::Callbacks oscCallbacks;
-	oscCallbacks.updateParameter = [&composite](const std::string& layerKey, const std::string& parameterKey, const std::string& valueJson, std::string& actionError) {
-		return composite.UpdateLayerParameterByControlKeyJson(layerKey, parameterKey, valueJson, actionError);
+	oscCallbacks.updateParameter = [&runtimeServices](const std::string& layerKey, const std::string& parameterKey, const std::string& valueJson, std::string& actionError) {
+		return runtimeServices.QueueOscUpdate(layerKey, parameterKey, valueJson, actionError);
 	};
-	if (runtimeHost.GetOscPort() > 0 && !oscServer.Start(runtimeHost.GetOscPort(), oscCallbacks, error))
+	if (runtimeHost.GetOscPort() > 0 && !oscServer.Start(runtimeHost.GetOscBindAddress(), runtimeHost.GetOscPort(), oscCallbacks, error))
 		return false;
 
 	return true;

apps/LoopThroughWithOpenGLCompositing/control/RuntimeControlBridge.h

@@ -6,10 +6,12 @@ class ControlServer;
 class OpenGLComposite;
 class OscServer;
 class RuntimeHost;
+class RuntimeServices;
 
 bool StartRuntimeControlServices(
 	OpenGLComposite& composite,
 	RuntimeHost& runtimeHost,
+	RuntimeServices& runtimeServices,
 	ControlServer& controlServer,
 	OscServer& oscServer,
 	std::string& error);

apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.cpp

@@ -4,7 +4,6 @@
 #include "OscServer.h"
 #include "RuntimeControlBridge.h"
 #include "RuntimeHost.h"
-
 #include <windows.h>
 
 RuntimeServices::RuntimeServices() :
@@ -26,7 +25,7 @@ bool RuntimeServices::Start(OpenGLComposite& composite, RuntimeHost& runtimeHost
 {
 	Stop();
 
-	if (!StartRuntimeControlServices(composite, runtimeHost, *mControlServer, *mOscServer, error))
+	if (!StartRuntimeControlServices(composite, runtimeHost, *this, *mControlServer, *mOscServer, error))
 	{
 		Stop();
 		return false;
@@ -57,6 +56,108 @@ void RuntimeServices::BroadcastState()
 		mControlServer->BroadcastState();
 }
 
+void RuntimeServices::RequestBroadcastState()
+{
+	if (mControlServer)
+		mControlServer->RequestBroadcastState();
+}
+
+bool RuntimeServices::QueueOscUpdate(const std::string& layerKey, const std::string& parameterKey, const std::string& valueJson, std::string& error)
+{
+	(void)error;
+
+	PendingOscUpdate update;
+	update.layerKey = layerKey;
+	update.parameterKey = parameterKey;
+	update.valueJson = valueJson;
+
+	const std::string routeKey = layerKey + "\n" + parameterKey;
+	{
+		std::lock_guard<std::mutex> lock(mPendingOscMutex);
+		mPendingOscUpdates[routeKey] = std::move(update);
+	}
+	return true;
+}
+
+bool RuntimeServices::ApplyPendingOscUpdates(std::vector<AppliedOscUpdate>& appliedUpdates, std::string& error)
+{
+	appliedUpdates.clear();
+
+	std::map<std::string, PendingOscUpdate> pending;
+	{
+		std::lock_guard<std::mutex> lock(mPendingOscMutex);
+		if (mPendingOscUpdates.empty())
+			return true;
+		pending.swap(mPendingOscUpdates);
+	}
+
+	for (const auto& entry : pending)
+	{
+		JsonValue targetValue;
+		std::string parseError;
+		if (!ParseJson(entry.second.valueJson, targetValue, parseError))
+		{
+			OutputDebugStringA(("OSC queued value parse failed: " + parseError + "\n").c_str());
+			continue;
+		}
+
+		AppliedOscUpdate appliedUpdate;
+		appliedUpdate.routeKey = entry.first;
+		appliedUpdate.layerKey = entry.second.layerKey;
+		appliedUpdate.parameterKey = entry.second.parameterKey;
+		appliedUpdate.targetValue = targetValue;
+		appliedUpdates.push_back(std::move(appliedUpdate));
+	}
+
+	(void)error;
+	return true;
+}
+
+bool RuntimeServices::QueueOscCommit(const std::string& routeKey, const std::string& layerKey, const std::string& parameterKey, const JsonValue& value, uint64_t generation, std::string& error)
+{
+	(void)error;
+
+	PendingOscCommit commit;
+	commit.routeKey = routeKey;
+	commit.layerKey = layerKey;
+	commit.parameterKey = parameterKey;
+	commit.value = value;
+	commit.generation = generation;
+
+	{
+		std::lock_guard<std::mutex> lock(mPendingOscCommitMutex);
+		mPendingOscCommits[routeKey] = std::move(commit);
+	}
+	return true;
+}
+
+void RuntimeServices::ClearOscState()
+{
+	{
+		std::lock_guard<std::mutex> lock(mPendingOscMutex);
+		mPendingOscUpdates.clear();
+	}
+	{
+		std::lock_guard<std::mutex> lock(mPendingOscCommitMutex);
+		mPendingOscCommits.clear();
+	}
+	{
+		std::lock_guard<std::mutex> lock(mCompletedOscCommitMutex);
+		mCompletedOscCommits.clear();
+	}
+}
+
+void RuntimeServices::ConsumeCompletedOscCommits(std::vector<CompletedOscCommit>& completedCommits)
+{
+	completedCommits.clear();
+
+	std::lock_guard<std::mutex> lock(mCompletedOscCommitMutex);
+	if (mCompletedOscCommits.empty())
+		return;
+
+	completedCommits.swap(mCompletedOscCommits);
+}
+
 RuntimePollEvents RuntimeServices::ConsumePollEvents()
 {
 	RuntimePollEvents events;
@@ -94,6 +195,33 @@ void RuntimeServices::PollLoop(RuntimeHost& runtimeHost)
 {
 	while (mPollRunning)
 	{
+		std::map<std::string, PendingOscCommit> pendingCommits;
+		{
+			std::lock_guard<std::mutex> lock(mPendingOscCommitMutex);
+			pendingCommits.swap(mPendingOscCommits);
+		}
+		for (const auto& entry : pendingCommits)
+		{
+			std::string commitError;
+			if (runtimeHost.UpdateLayerParameterByControlKey(
+				entry.second.layerKey,
+				entry.second.parameterKey,
+				entry.second.value,
+				false,
+				commitError))
+			{
+				CompletedOscCommit completedCommit;
+				completedCommit.routeKey = entry.second.routeKey;
+				completedCommit.generation = entry.second.generation;
+				std::lock_guard<std::mutex> lock(mCompletedOscCommitMutex);
+				mCompletedOscCommits.push_back(std::move(completedCommit));
+			}
+			else if (!commitError.empty())
+			{
+				OutputDebugStringA(("OSC commit failed: " + commitError + "\n").c_str());
+			}
+		}
+
 		bool registryChanged = false;
 		bool reloadRequested = false;
 		std::string runtimeError;

apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.h

@@ -1,6 +1,10 @@
 #pragma once
 
+#include "RuntimeJson.h"
+#include "ShaderTypes.h"
+
 #include <atomic>
+#include <map>
 #include <memory>
 #include <mutex>
 #include <string>
@@ -22,6 +26,20 @@ struct RuntimePollEvents
 class RuntimeServices
 {
 public:
+	struct AppliedOscUpdate
+	{
+		std::string routeKey;
+		std::string layerKey;
+		std::string parameterKey;
+		JsonValue targetValue;
+	};
+
+	struct CompletedOscCommit
+	{
+		std::string routeKey;
+		uint64_t generation = 0;
+	};
+
 	RuntimeServices();
 	~RuntimeServices();
 
@@ -29,9 +47,31 @@ public:
 	void BeginPolling(RuntimeHost& runtimeHost);
 	void Stop();
 	void BroadcastState();
+	void RequestBroadcastState();
+	bool QueueOscUpdate(const std::string& layerKey, const std::string& parameterKey, const std::string& valueJson, std::string& error);
+	bool ApplyPendingOscUpdates(std::vector<AppliedOscUpdate>& appliedUpdates, std::string& error);
+	bool QueueOscCommit(const std::string& routeKey, const std::string& layerKey, const std::string& parameterKey, const JsonValue& value, uint64_t generation, std::string& error);
+	void ClearOscState();
+	void ConsumeCompletedOscCommits(std::vector<CompletedOscCommit>& completedCommits);
 	RuntimePollEvents ConsumePollEvents();
 
 private:
+	struct PendingOscUpdate
+	{
+		std::string layerKey;
+		std::string parameterKey;
+		std::string valueJson;
+	};
+
+	struct PendingOscCommit
+	{
+		std::string routeKey;
+		std::string layerKey;
+		std::string parameterKey;
+		JsonValue value;
+		uint64_t generation = 0;
+	};
+
 	void StartPolling(RuntimeHost& runtimeHost);
 	void StopPolling();
 	void PollLoop(RuntimeHost& runtimeHost);
@@ -45,4 +85,10 @@ private:
 	std::atomic<bool> mPollFailed;
 	std::mutex mPollErrorMutex;
 	std::string mPollError;
+	std::mutex mPendingOscMutex;
+	std::map<std::string, PendingOscUpdate> mPendingOscUpdates;
+	std::mutex mPendingOscCommitMutex;
+	std::map<std::string, PendingOscCommit> mPendingOscCommits;
+	std::mutex mCompletedOscCommitMutex;
+	std::vector<CompletedOscCommit> mCompletedOscCommits;
 };

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp

@@ -4,22 +4,97 @@
 #include "GLExtensions.h"
 #include "GlRenderConstants.h"
 #include "OpenGLRenderPass.h"
+#include "OpenGLRenderPipeline.h"
 #include "OpenGLShaderPrograms.h"
 #include "OpenGLVideoIOBridge.h"
 #include "PngScreenshotWriter.h"
+#include "RuntimeParameterUtils.h"
 #include "RuntimeServices.h"
 #include "ShaderBuildQueue.h"
 
 #include <algorithm>
+#include <cctype>
 #include <chrono>
+#include <cmath>
 #include <ctime>
 #include <filesystem>
 #include <iomanip>
 #include <memory>
+#include <set>
 #include <sstream>
 #include <string>
 #include <vector>
 
+namespace
+{
+constexpr auto kOscOverlayCommitDelay = std::chrono::milliseconds(150);
+constexpr double kOscSmoothingReferenceFps = 60.0;
+constexpr double kOscSmoothingMaxStepSeconds = 0.25;
+
+std::string SimplifyOscControlKey(const std::string& text)
+{
+	std::string simplified;
+	for (unsigned char ch : text)
+	{
+		if (std::isalnum(ch))
+			simplified.push_back(static_cast<char>(std::tolower(ch)));
+	}
+	return simplified;
+}
+
+bool MatchesOscControlKey(const std::string& candidate, const std::string& key)
+{
+	return candidate == key || SimplifyOscControlKey(candidate) == SimplifyOscControlKey(key);
+}
+
+double ClampOscAlpha(double value)
+{
+	return (std::max)(0.0, (std::min)(1.0, value));
+}
+
+double ComputeTimeBasedOscAlpha(double smoothing, double deltaSeconds)
+{
+	const double clampedSmoothing = ClampOscAlpha(smoothing);
+	if (clampedSmoothing <= 0.0)
+		return 0.0;
+	if (clampedSmoothing >= 1.0)
+		return 1.0;
+
+	const double clampedDeltaSeconds = (std::max)(0.0, (std::min)(kOscSmoothingMaxStepSeconds, deltaSeconds));
+	if (clampedDeltaSeconds <= 0.0)
+		return 0.0;
+
+	const double frameScale = clampedDeltaSeconds * kOscSmoothingReferenceFps;
+	return ClampOscAlpha(1.0 - std::pow(1.0 - clampedSmoothing, frameScale));
+}
+
+JsonValue BuildOscCommitValue(const ShaderParameterDefinition& definition, const ShaderParameterValue& value)
+{
+	switch (definition.type)
+	{
+	case ShaderParameterType::Boolean:
+		return JsonValue(value.booleanValue);
+	case ShaderParameterType::Enum:
+		return JsonValue(value.enumValue);
+	case ShaderParameterType::Text:
+		return JsonValue(value.textValue);
+	case ShaderParameterType::Trigger:
+	case ShaderParameterType::Float:
+		return JsonValue(value.numberValues.empty() ? 0.0 : value.numberValues.front());
+	case ShaderParameterType::Vec2:
+	case ShaderParameterType::Color:
+	{
+		JsonValue array = JsonValue::MakeArray();
+		for (double number : value.numberValues)
+			array.pushBack(JsonValue(number));
+		return array;
+	}
+	}
+
+	return JsonValue();
+}
+}
+
 OpenGLComposite::OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC) :
 	hGLWnd(hWnd), hGLDC(hDC), hGLRC(hRC),
 	mVideoIO(std::make_unique<DeckLinkSession>()),
@@ -29,16 +104,20 @@ OpenGLComposite::OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC) :
 {
 	InitializeCriticalSection(&pMutex);
 	mRuntimeHost = std::make_unique<RuntimeHost>();
+	mRenderPipeline = std::make_unique<OpenGLRenderPipeline>(
+		*mRenderer,
+		*mRuntimeHost,
+		[this]() { renderEffect(); },
+		[this]() { ProcessScreenshotRequest(); },
+		[this]() { paintGL(false); });
 	mVideoIOBridge = std::make_unique<OpenGLVideoIOBridge>(
 		*mVideoIO,
 		*mRenderer,
+		*mRenderPipeline,
 		*mRuntimeHost,
 		pMutex,
 		hGLDC,
-		hGLRC,
-		[this]() { renderEffect(); },
-		[this]() { ProcessScreenshotRequest(); },
-		[this]() { paintGL(); });
+		hGLRC);
 	mRenderPass = std::make_unique<OpenGLRenderPass>(*mRenderer);
 	mShaderPrograms = std::make_unique<OpenGLShaderPrograms>(*mRenderer, *mRuntimeHost);
 	mShaderBuildQueue = std::make_unique<ShaderBuildQueue>(*mRuntimeHost);
@@ -100,7 +179,8 @@ bool OpenGLComposite::InitVideoIO()
 		MessageBoxA(NULL, initFailureReason.c_str(), title, MB_OK | MB_ICONERROR);
 		return false;
 	}
-	if (!mVideoIO->SelectPreferredFormats(videoModes, initFailureReason))
+	const bool outputAlphaRequired = mRuntimeHost && mRuntimeHost->ExternalKeyingEnabled();
+	if (!mVideoIO->SelectPreferredFormats(videoModes, outputAlphaRequired, initFailureReason))
 		goto error;
 
 	if (! CheckOpenGLExtensions())
@@ -150,8 +230,26 @@ error:
 	return false;
 }
 
-void OpenGLComposite::paintGL()
+void OpenGLComposite::paintGL(bool force)
 {
+	if (!force)
+	{
+		if (IsIconic(hGLWnd))
+			return;
+
+		const unsigned previewFps = mRuntimeHost ? mRuntimeHost->GetPreviewFps() : 30u;
+		if (previewFps == 0)
+			return;
+
+		const auto now = std::chrono::steady_clock::now();
+		const auto minimumInterval = std::chrono::microseconds(1000000 / (previewFps == 0 ? 1u : previewFps));
+		if (mLastPreviewPresentTime != std::chrono::steady_clock::time_point() &&
+			now - mLastPreviewPresentTime < minimumInterval)
+		{
+			return;
+		}
+	}
+
 	if (!TryEnterCriticalSection(&pMutex))
 	{
 		ValidateRect(hGLWnd, NULL);
@@ -159,6 +257,7 @@ void OpenGLComposite::paintGL()
 	}
 
 	mRenderer->PresentToWindow(hGLDC, mVideoIO->OutputFrameWidth(), mVideoIO->OutputFrameHeight());
+	mLastPreviewPresentTime = std::chrono::steady_clock::now();
 	ValidateRect(hGLWnd, NULL);
 	LeaveCriticalSection(&pMutex);
 }
@@ -229,15 +328,6 @@ bool OpenGLComposite::InitOpenGLState()
 		return false;
 	}
 
-	if (!mShaderPrograms->CompileLayerPrograms(mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), sizeof(compilerErrorMessage), compilerErrorMessage))
-	{
-		MessageBoxA(NULL, compilerErrorMessage, "OpenGL shader failed to load or compile", MB_OK);
-		return false;
-	}
-	mCachedLayerRenderStates = mShaderPrograms->CommittedLayerStates();
-	mUseCommittedLayerStates = false;
-	mShaderPrograms->ResetTemporalHistoryState();
-
 	std::string rendererError;
 	if (!mRenderer->InitializeResources(
 		mVideoIO->InputFrameWidth(),
@@ -252,6 +342,17 @@ bool OpenGLComposite::InitOpenGLState()
 		return false;
 	}
 
+	if (!mShaderPrograms->CompileLayerPrograms(mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), sizeof(compilerErrorMessage), compilerErrorMessage))
+	{
+		MessageBoxA(NULL, compilerErrorMessage, "OpenGL shader failed to load or compile", MB_OK);
+		return false;
+	}
+	mCachedLayerRenderStates = mShaderPrograms->CommittedLayerStates();
+	mUseCommittedLayerStates = false;
+
+	mShaderPrograms->ResetTemporalHistoryState();
+	mShaderPrograms->ResetShaderFeedbackState();
+
 	broadcastRuntimeState();
 	mRuntimeServices->BeginPolling(*mRuntimeHost);
 	return true;
@@ -275,8 +376,9 @@ bool OpenGLComposite::Stop()
 	return true;
 }
 
-bool OpenGLComposite::ReloadShader()
+bool OpenGLComposite::ReloadShader(bool preserveFeedbackState)
 {
+	mPreserveFeedbackOnNextShaderBuild = preserveFeedbackState;
 	if (mRuntimeHost)
 	{
 		mRuntimeHost->SetCompileStatus(true, "Shader rebuild queued.");
@@ -297,25 +399,243 @@ bool OpenGLComposite::RequestScreenshot(std::string& error)
 void OpenGLComposite::renderEffect()
 {
 	ProcessRuntimePollResults();
+	std::vector<RuntimeServices::AppliedOscUpdate> appliedOscUpdates;
+	std::vector<RuntimeServices::CompletedOscCommit> completedOscCommits;
+	if (mRuntimeHost && mRuntimeServices)
+	{
+		std::string oscError;
+		if (!mRuntimeServices->ApplyPendingOscUpdates(appliedOscUpdates, oscError) && !oscError.empty())
+			OutputDebugStringA(("OSC apply failed: " + oscError + "\n").c_str());
+		mRuntimeServices->ConsumeCompletedOscCommits(completedOscCommits);
+	}
+
+	for (const RuntimeServices::CompletedOscCommit& completedCommit : completedOscCommits)
+	{
+		auto overlayIt = mOscOverlayStates.find(completedCommit.routeKey);
+		if (overlayIt == mOscOverlayStates.end())
+			continue;
+
+		OscOverlayState& overlay = overlayIt->second;
+		if (overlay.commitQueued &&
+			overlay.pendingCommitGeneration == completedCommit.generation &&
+			overlay.generation == completedCommit.generation)
+		{
+			mOscOverlayStates.erase(overlayIt);
+		}
+	}
+
+	std::set<std::string> pendingOscRouteKeys;
+	const auto oscNow = std::chrono::steady_clock::now();
+	for (const RuntimeServices::AppliedOscUpdate& update : appliedOscUpdates)
+	{
+		const std::string routeKey = update.routeKey;
+		auto overlayIt = mOscOverlayStates.find(routeKey);
+		if (overlayIt == mOscOverlayStates.end())
+		{
+			OscOverlayState overlay;
+			overlay.layerKey = update.layerKey;
+			overlay.parameterKey = update.parameterKey;
+			overlay.targetValue = update.targetValue;
+			overlay.lastUpdatedTime = oscNow;
+			overlay.lastAppliedTime = oscNow;
+			overlay.generation = 1;
+			mOscOverlayStates[routeKey] = std::move(overlay);
+		}
+		else
+		{
+			overlayIt->second.targetValue = update.targetValue;
+			overlayIt->second.lastUpdatedTime = oscNow;
+			overlayIt->second.generation += 1;
+			overlayIt->second.commitQueued = false;
+		}
+		pendingOscRouteKeys.insert(routeKey);
+	}
+
+	const auto applyOscOverlays = [&](std::vector<RuntimeRenderState>& states, bool allowCommit)
+	{
+		if (states.empty() || mOscOverlayStates.empty() || !mRuntimeHost)
+			return;
+
+		const double smoothing = ClampOscAlpha(mRuntimeHost->GetOscSmoothing());
+		std::vector<std::string> overlayKeysToRemove;
+		for (auto& item : mOscOverlayStates)
+		{
+			OscOverlayState& overlay = item.second;
+			auto stateIt = std::find_if(states.begin(), states.end(),
+				[&overlay](const RuntimeRenderState& state)
+				{
+					return MatchesOscControlKey(state.layerId, overlay.layerKey) ||
+						MatchesOscControlKey(state.shaderId, overlay.layerKey) ||
+						MatchesOscControlKey(state.shaderName, overlay.layerKey);
+				});
+			if (stateIt == states.end())
+				continue;
+
+			auto definitionIt = std::find_if(stateIt->parameterDefinitions.begin(), stateIt->parameterDefinitions.end(),
+				[&overlay](const ShaderParameterDefinition& definition)
+				{
+					return MatchesOscControlKey(definition.id, overlay.parameterKey) ||
+						MatchesOscControlKey(definition.label, overlay.parameterKey);
+				});
+			if (definitionIt == stateIt->parameterDefinitions.end())
+				continue;
+
+			if (definitionIt->type == ShaderParameterType::Trigger)
+			{
+				if (pendingOscRouteKeys.find(item.first) == pendingOscRouteKeys.end())
+					continue;
+
+				ShaderParameterValue& value = stateIt->parameterValues[definitionIt->id];
+				const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
+				const double triggerTime = stateIt->timeSeconds;
+				value.numberValues = { previousCount + 1.0, triggerTime };
+				overlayKeysToRemove.push_back(item.first);
+				continue;
+			}
+
+			ShaderParameterValue targetValue;
+			std::string normalizeError;
+			if (!NormalizeAndValidateParameterValue(*definitionIt, overlay.targetValue, targetValue, normalizeError))
+				continue;
+
+			const bool smoothable =
+				smoothing > 0.0 &&
+				(definitionIt->type == ShaderParameterType::Float ||
+					definitionIt->type == ShaderParameterType::Vec2 ||
+					definitionIt->type == ShaderParameterType::Color);
+			if (!smoothable)
+			{
+				overlay.currentValue = targetValue;
+				overlay.hasCurrentValue = true;
+				stateIt->parameterValues[definitionIt->id] = overlay.currentValue;
+				if (allowCommit &&
+					!overlay.commitQueued &&
+					oscNow - overlay.lastUpdatedTime >= kOscOverlayCommitDelay &&
+					mRuntimeServices)
+				{
+					std::string commitError;
+					if (mRuntimeServices->QueueOscCommit(item.first, overlay.layerKey, overlay.parameterKey, overlay.targetValue, overlay.generation, commitError))
+					{
+						overlay.pendingCommitGeneration = overlay.generation;
+						overlay.commitQueued = true;
+					}
+				}
+				continue;
+			}
+
+			if (!overlay.hasCurrentValue)
+			{
+				overlay.currentValue = DefaultValueForDefinition(*definitionIt);
+				auto currentIt = stateIt->parameterValues.find(definitionIt->id);
+				if (currentIt != stateIt->parameterValues.end())
+					overlay.currentValue = currentIt->second;
+				overlay.hasCurrentValue = true;
+			}
+
+			if (overlay.currentValue.numberValues.size() != targetValue.numberValues.size())
+				overlay.currentValue.numberValues = targetValue.numberValues;
+
+			double smoothingAlpha = smoothing;
+			if (overlay.lastAppliedTime != std::chrono::steady_clock::time_point())
+			{
+				const double deltaSeconds =
+					std::chrono::duration_cast<std::chrono::duration<double>>(oscNow - overlay.lastAppliedTime).count();
+				smoothingAlpha = ComputeTimeBasedOscAlpha(smoothing, deltaSeconds);
+			}
+			overlay.lastAppliedTime = oscNow;
+
+			ShaderParameterValue nextValue = targetValue;
+			bool converged = true;
+			for (std::size_t index = 0; index < targetValue.numberValues.size(); ++index)
+			{
+				const double currentNumber = overlay.currentValue.numberValues[index];
+				const double targetNumber = targetValue.numberValues[index];
+				const double delta = targetNumber - currentNumber;
+				double nextNumber = currentNumber + delta * smoothingAlpha;
+				if (std::fabs(delta) <= 0.0005)
+					nextNumber = targetNumber;
+				else
+					converged = false;
+				nextValue.numberValues[index] = nextNumber;
+			}
+
+			if (converged)
+				nextValue.numberValues = targetValue.numberValues;
+
+			overlay.currentValue = nextValue;
+			overlay.hasCurrentValue = true;
+			stateIt->parameterValues[definitionIt->id] = overlay.currentValue;
+			if (allowCommit &&
+				converged &&
+				!overlay.commitQueued &&
+				oscNow - overlay.lastUpdatedTime >= kOscOverlayCommitDelay &&
+				mRuntimeServices)
+			{
+				std::string commitError;
+				JsonValue committedValue = BuildOscCommitValue(*definitionIt, overlay.currentValue);
+				if (mRuntimeServices->QueueOscCommit(item.first, overlay.layerKey, overlay.parameterKey, committedValue, overlay.generation, commitError))
+				{
+					overlay.pendingCommitGeneration = overlay.generation;
+					overlay.commitQueued = true;
+				}
+			}
+		}
+
+		for (const std::string& overlayKey : overlayKeysToRemove)
+			mOscOverlayStates.erase(overlayKey);
+	};
 
 	const bool hasInputSource = mVideoIO->HasInputSource();
 	std::vector<RuntimeRenderState> layerStates;
 	if (mUseCommittedLayerStates)
 	{
 		layerStates = mShaderPrograms->CommittedLayerStates();
+		applyOscOverlays(layerStates, false);
 		if (mRuntimeHost)
 			mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
 	}
 	else if (mRuntimeHost)
 	{
-		if (mRuntimeHost->TryGetLayerRenderStates(mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), layerStates))
+		const unsigned renderWidth = mVideoIO->InputFrameWidth();
+		const unsigned renderHeight = mVideoIO->InputFrameHeight();
+		const uint64_t renderStateVersion = mRuntimeHost->GetRenderStateVersion();
+		const uint64_t parameterStateVersion = mRuntimeHost->GetParameterStateVersion();
+		const bool renderStateCacheValid =
+			!mCachedLayerRenderStates.empty() &&
+			mCachedRenderStateVersion == renderStateVersion &&
+			mCachedRenderStateWidth == renderWidth &&
+			mCachedRenderStateHeight == renderHeight;
+
+		if (renderStateCacheValid)
 		{
-			mCachedLayerRenderStates = layerStates;
+			applyOscOverlays(mCachedLayerRenderStates, true);
+			if (mCachedParameterStateVersion != parameterStateVersion &&
+				mRuntimeHost->TryRefreshCachedLayerStates(mCachedLayerRenderStates))
+			{
+				mCachedParameterStateVersion = parameterStateVersion;
+				applyOscOverlays(mCachedLayerRenderStates, true);
+			}
+			layerStates = mCachedLayerRenderStates;
+			mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
 		}
 		else
 		{
-			layerStates = mCachedLayerRenderStates;
-			mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
+			if (mRuntimeHost->TryGetLayerRenderStates(renderWidth, renderHeight, layerStates))
+			{
+				mCachedLayerRenderStates = layerStates;
+				mCachedRenderStateVersion = renderStateVersion;
+				mCachedParameterStateVersion = parameterStateVersion;
+				mCachedRenderStateWidth = renderWidth;
+				mCachedRenderStateHeight = renderHeight;
+				applyOscOverlays(mCachedLayerRenderStates, true);
+				layerStates = mCachedLayerRenderStates;
+			}
+			else
+			{
+				applyOscOverlays(mCachedLayerRenderStates, true);
+				layerStates = mCachedLayerRenderStates;
+				mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
+			}
 		}
 	}
 	const unsigned historyCap = mRuntimeHost ? mRuntimeHost->GetMaxTemporalHistoryFrames() : 0;
@@ -330,8 +650,8 @@ void OpenGLComposite::renderEffect()
 		[this](const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error) {
 			return mShaderPrograms->UpdateTextBindingTexture(state, textBinding, error);
 		},
-		[this](const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength) {
-			return mShaderPrograms->UpdateGlobalParamsBuffer(state, availableSourceHistoryLength, availableTemporalHistoryLength);
+		[this](const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable) {
+			return mShaderPrograms->UpdateGlobalParamsBuffer(state, availableSourceHistoryLength, availableTemporalHistoryLength, feedbackAvailable);
 		});
 }
 
@@ -425,6 +745,7 @@ bool OpenGLComposite::ProcessRuntimePollResults()
 		{
 			mRuntimeHost->SetCompileStatus(false, compilerErrorMessage);
 			mUseCommittedLayerStates = true;
+			mPreserveFeedbackOnNextShaderBuild = false;
 			broadcastRuntimeState();
 			return false;
 		}
@@ -432,11 +753,15 @@ bool OpenGLComposite::ProcessRuntimePollResults()
 		mUseCommittedLayerStates = false;
 		mCachedLayerRenderStates = mShaderPrograms->CommittedLayerStates();
 		mShaderPrograms->ResetTemporalHistoryState();
+		if (!mPreserveFeedbackOnNextShaderBuild)
+			mShaderPrograms->ResetShaderFeedbackState();
+		mPreserveFeedbackOnNextShaderBuild = false;
 		broadcastRuntimeState();
 		return true;
 	}
 
 	mRuntimeHost->SetCompileStatus(true, "Shader rebuild queued.");
+	mPreserveFeedbackOnNextShaderBuild = false;
 	RequestShaderBuild();
 	broadcastRuntimeState();
 	return true;
@@ -462,6 +787,7 @@ void OpenGLComposite::broadcastRuntimeState()
 void OpenGLComposite::resetTemporalHistoryState()
 {
 	mShaderPrograms->ResetTemporalHistoryState();
+	mShaderPrograms->ResetShaderFeedbackState();
 }
 
 bool OpenGLComposite::CheckOpenGLExtensions()

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h

@@ -23,10 +23,12 @@
 #include <string>
 #include <vector>
 #include <deque>
+#include <chrono>
 
 class VideoIODevice;
 class OpenGLVideoIOBridge;
 class OpenGLRenderPass;
+class OpenGLRenderPipeline;
 class OpenGLShaderPrograms;
 class RuntimeServices;
 class ShaderBuildQueue;
@@ -42,7 +44,7 @@ public:
 	bool InitVideoIO();
 	bool Start();
 	bool Stop();
-	bool ReloadShader();
+	bool ReloadShader(bool preserveFeedbackState = false);
 	std::string GetRuntimeStateJson() const;
 	bool AddLayer(const std::string& shaderId, std::string& error);
 	bool RemoveLayer(const std::string& layerId, std::string& error);
@@ -58,18 +60,32 @@ public:
 	bool RequestScreenshot(std::string& error);
 	unsigned short GetControlServerPort() const;
 	unsigned short GetOscPort() const;
+	std::string GetOscBindAddress() const;
 	std::string GetControlUrl() const;
 	std::string GetDocsUrl() const;
 	std::string GetOscAddress() const;
 
 	void resizeGL(WORD width, WORD height);
-	void paintGL();
+	void paintGL(bool force = false);
 
 private:
 	void resizeWindow(int width, int height);
 	bool CheckOpenGLExtensions();
 	void PublishVideoIOStatus(const std::string& statusMessage);
 	using LayerProgram = OpenGLRenderer::LayerProgram;
+	struct OscOverlayState
+	{
+		std::string layerKey;
+		std::string parameterKey;
+		JsonValue targetValue;
+		ShaderParameterValue currentValue;
+		bool hasCurrentValue = false;
+		std::chrono::steady_clock::time_point lastUpdatedTime;
+		std::chrono::steady_clock::time_point lastAppliedTime;
+		uint64_t generation = 0;
+		uint64_t pendingCommitGeneration = 0;
+		bool commitQueued = false;
+	};
 
 	HWND									hGLWnd;
 	HDC										hGLDC;
@@ -81,12 +97,20 @@ private:
 	std::unique_ptr<RuntimeHost>				mRuntimeHost;
 	std::unique_ptr<OpenGLVideoIOBridge>		mVideoIOBridge;
 	std::unique_ptr<OpenGLRenderPass>		mRenderPass;
+	std::unique_ptr<OpenGLRenderPipeline>	mRenderPipeline;
 	std::unique_ptr<OpenGLShaderPrograms>	mShaderPrograms;
 	std::unique_ptr<ShaderBuildQueue>		mShaderBuildQueue;
 	std::unique_ptr<RuntimeServices>		mRuntimeServices;
 	std::vector<RuntimeRenderState>			mCachedLayerRenderStates;
+	uint64_t								mCachedRenderStateVersion = 0;
+	uint64_t								mCachedParameterStateVersion = 0;
+	unsigned								mCachedRenderStateWidth = 0;
+	unsigned								mCachedRenderStateHeight = 0;
+	std::map<std::string, OscOverlayState>	mOscOverlayStates;
 	std::atomic<bool>						mUseCommittedLayerStates;
 	std::atomic<bool>						mScreenshotRequested;
+	std::chrono::steady_clock::time_point	mLastPreviewPresentTime;
+	bool									mPreserveFeedbackOnNextShaderBuild = false;
 
 	bool InitOpenGLState();
 	void renderEffect();

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLCompositeRuntimeControls.cpp

@@ -1,4 +1,5 @@
 #include "OpenGLComposite.h"
+#include "RuntimeServices.h"
 
 std::string OpenGLComposite::GetRuntimeStateJson() const
 {
@@ -15,6 +16,11 @@ unsigned short OpenGLComposite::GetOscPort() const
 	return mRuntimeHost ? mRuntimeHost->GetOscPort() : 0;
 }
 
+std::string OpenGLComposite::GetOscBindAddress() const
+{
+	return mRuntimeHost ? mRuntimeHost->GetOscBindAddress() : "127.0.0.1";
+}
+
 std::string OpenGLComposite::GetControlUrl() const
 {
 	return "http://127.0.0.1:" + std::to_string(GetControlServerPort()) + "/";
@@ -27,7 +33,7 @@ std::string OpenGLComposite::GetDocsUrl() const
 
 std::string OpenGLComposite::GetOscAddress() const
 {
-	return "udp://127.0.0.1:" + std::to_string(GetOscPort()) + " /VideoShaderToys/{Layer}/{Parameter}";
+	return "udp://" + GetOscBindAddress() + ":" + std::to_string(GetOscPort()) + " /VideoShaderToys/{Layer}/{Parameter}";
 }
 
 bool OpenGLComposite::AddLayer(const std::string& shaderId, std::string& error)
@@ -35,7 +41,7 @@ bool OpenGLComposite::AddLayer(const std::string& shaderId, std::string& error)
 	if (!mRuntimeHost->AddLayer(shaderId, error))
 		return false;
 
-	ReloadShader();
+	ReloadShader(true);
 	broadcastRuntimeState();
 	return true;
 }
@@ -45,7 +51,7 @@ bool OpenGLComposite::RemoveLayer(const std::string& layerId, std::string& error
 	if (!mRuntimeHost->RemoveLayer(layerId, error))
 		return false;
 
-	ReloadShader();
+	ReloadShader(true);
 	broadcastRuntimeState();
 	return true;
 }
@@ -55,7 +61,7 @@ bool OpenGLComposite::MoveLayer(const std::string& layerId, int direction, std::
 	if (!mRuntimeHost->MoveLayer(layerId, direction, error))
 		return false;
 
-	ReloadShader();
+	ReloadShader(true);
 	broadcastRuntimeState();
 	return true;
 }
@@ -65,7 +71,7 @@ bool OpenGLComposite::MoveLayerToIndex(const std::string& layerId, std::size_t t
 	if (!mRuntimeHost->MoveLayerToIndex(layerId, targetIndex, error))
 		return false;
 
-	ReloadShader();
+	ReloadShader(true);
 	broadcastRuntimeState();
 	return true;
 }
@@ -121,6 +127,11 @@ bool OpenGLComposite::ResetLayerParameters(const std::string& layerId, std::stri
 	if (!mRuntimeHost->ResetLayerParameters(layerId, error))
 		return false;
 
+	mOscOverlayStates.clear();
+	if (mRuntimeServices)
+		mRuntimeServices->ClearOscState();
+	resetTemporalHistoryState();
+
 	broadcastRuntimeState();
 	return true;
 }

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLRenderPass.cpp

@@ -1,169 +0,0 @@
-#include "OpenGLRenderPass.h"
-
-#include "GlRenderConstants.h"
-
-OpenGLRenderPass::OpenGLRenderPass(OpenGLRenderer& renderer) :
-	mRenderer(renderer)
-{
-}
-
-void OpenGLRenderPass::Render(
-	bool hasInputSource,
-	const std::vector<RuntimeRenderState>& layerStates,
-	unsigned inputFrameWidth,
-	unsigned inputFrameHeight,
-	unsigned captureTextureWidth,
-	VideoIOPixelFormat inputPixelFormat,
-	unsigned historyCap,
-	const TextBindingUpdater& updateTextBinding,
-	const GlobalParamsUpdater& updateGlobalParams)
-{
-	glDisable(GL_SCISSOR_TEST);
-	glDisable(GL_BLEND);
-	glDisable(GL_DEPTH_TEST);
-	if (hasInputSource)
-	{
-		RenderDecodePass(inputFrameWidth, inputFrameHeight, captureTextureWidth, inputPixelFormat);
-	}
-	else
-	{
-		glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
-		glViewport(0, 0, inputFrameWidth, inputFrameHeight);
-		glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-		glClear(GL_COLOR_BUFFER_BIT);
-	}
-
-	std::vector<LayerProgram>& layerPrograms = mRenderer.LayerPrograms();
-	if (layerStates.empty() || layerPrograms.empty())
-	{
-		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
-		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
-		glBlitFramebuffer(0, 0, inputFrameWidth, inputFrameHeight, 0, 0, inputFrameWidth, inputFrameHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
-		glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
-	}
-	else
-	{
-		GLuint sourceTexture = mRenderer.DecodedTexture();
-		GLuint sourceFrameBuffer = mRenderer.DecodeFramebuffer();
-		for (std::size_t index = 0; index < layerStates.size() && index < layerPrograms.size(); ++index)
-		{
-			const std::size_t remaining = layerStates.size() - index;
-			const bool writeToMain = (remaining % 2) == 1;
-			RenderShaderProgram(
-				sourceTexture,
-				writeToMain ? mRenderer.CompositeFramebuffer() : mRenderer.LayerTempFramebuffer(),
-				layerPrograms[index],
-				layerStates[index],
-				inputFrameWidth,
-				inputFrameHeight,
-				historyCap,
-				updateTextBinding,
-				updateGlobalParams);
-			if (layerStates[index].temporalHistorySource == TemporalHistorySource::PreLayerInput)
-				mRenderer.TemporalHistory().PushPreLayerFramebuffer(layerStates[index].layerId, sourceFrameBuffer, inputFrameWidth, inputFrameHeight);
-			sourceTexture = writeToMain ? mRenderer.CompositeTexture() : mRenderer.LayerTempTexture();
-			sourceFrameBuffer = writeToMain ? mRenderer.CompositeFramebuffer() : mRenderer.LayerTempFramebuffer();
-		}
-	}
-
-	mRenderer.TemporalHistory().PushSourceFramebuffer(mRenderer.DecodeFramebuffer(), inputFrameWidth, inputFrameHeight);
-}
-
-void OpenGLRenderPass::RenderDecodePass(unsigned inputFrameWidth, unsigned inputFrameHeight, unsigned captureTextureWidth, VideoIOPixelFormat inputPixelFormat)
-{
-	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
-	glViewport(0, 0, inputFrameWidth, inputFrameHeight);
-	glClear(GL_COLOR_BUFFER_BIT);
-	glActiveTexture(GL_TEXTURE0 + kPackedVideoTextureUnit);
-	glBindTexture(GL_TEXTURE_2D, mRenderer.CaptureTexture());
-	glBindVertexArray(mRenderer.FullscreenVertexArray());
-	glUseProgram(mRenderer.DecodeProgram());
-
-	const GLint packedResolutionLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uPackedVideoResolution");
-	const GLint decodedResolutionLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uDecodedVideoResolution");
-	const GLint inputPixelFormatLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uInputPixelFormat");
-	if (packedResolutionLocation >= 0)
-		glUniform2f(packedResolutionLocation, static_cast<float>(captureTextureWidth), static_cast<float>(inputFrameHeight));
-	if (decodedResolutionLocation >= 0)
-		glUniform2f(decodedResolutionLocation, static_cast<float>(inputFrameWidth), static_cast<float>(inputFrameHeight));
-	if (inputPixelFormatLocation >= 0)
-		glUniform1i(inputPixelFormatLocation, inputPixelFormat == VideoIOPixelFormat::V210 ? 1 : 0);
-
-	glDrawArrays(GL_TRIANGLES, 0, 3);
-
-	glUseProgram(0);
-	glBindVertexArray(0);
-	glBindTexture(GL_TEXTURE_2D, 0);
-	glActiveTexture(GL_TEXTURE0);
-}
-
-void OpenGLRenderPass::RenderShaderProgram(
-	GLuint sourceTexture,
-	GLuint destinationFrameBuffer,
-	LayerProgram& layerProgram,
-	const RuntimeRenderState& state,
-	unsigned inputFrameWidth,
-	unsigned inputFrameHeight,
-	unsigned historyCap,
-	const TextBindingUpdater& updateTextBinding,
-	const GlobalParamsUpdater& updateGlobalParams)
-{
-	for (LayerProgram::TextBinding& textBinding : layerProgram.textBindings)
-	{
-		std::string textError;
-		if (!updateTextBinding(state, textBinding, textError))
-			OutputDebugStringA((textError + "\n").c_str());
-	}
-
-	glBindFramebuffer(GL_FRAMEBUFFER, destinationFrameBuffer);
-	glViewport(0, 0, inputFrameWidth, inputFrameHeight);
-	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-	glActiveTexture(GL_TEXTURE0 + kDecodedVideoTextureUnit);
-	glBindTexture(GL_TEXTURE_2D, sourceTexture);
-	mRenderer.TemporalHistory().BindSamplers(state, sourceTexture, historyCap);
-	BindLayerTextureAssets(layerProgram);
-	glBindVertexArray(mRenderer.FullscreenVertexArray());
-	glUseProgram(layerProgram.program);
-	updateGlobalParams(state, mRenderer.TemporalHistory().SourceAvailableCount(), mRenderer.TemporalHistory().AvailableCountForLayer(state.layerId));
-	glDrawArrays(GL_TRIANGLES, 0, 3);
-	glUseProgram(0);
-	glBindVertexArray(0);
-	UnbindLayerTextureAssets(layerProgram, historyCap);
-}
-
-void OpenGLRenderPass::BindLayerTextureAssets(const LayerProgram& layerProgram)
-{
-	const GLuint shaderTextureBase = layerProgram.shaderTextureBase != 0 ? layerProgram.shaderTextureBase : kSourceHistoryTextureUnitBase;
-	for (std::size_t index = 0; index < layerProgram.textureBindings.size(); ++index)
-	{
-		glActiveTexture(GL_TEXTURE0 + shaderTextureBase + static_cast<GLuint>(index));
-		glBindTexture(GL_TEXTURE_2D, layerProgram.textureBindings[index].texture);
-	}
-	const GLuint textTextureBase = shaderTextureBase + static_cast<GLuint>(layerProgram.textureBindings.size());
-	for (std::size_t index = 0; index < layerProgram.textBindings.size(); ++index)
-	{
-		glActiveTexture(GL_TEXTURE0 + textTextureBase + static_cast<GLuint>(index));
-		glBindTexture(GL_TEXTURE_2D, layerProgram.textBindings[index].texture);
-	}
-	glActiveTexture(GL_TEXTURE0);
-}
-
-void OpenGLRenderPass::UnbindLayerTextureAssets(const LayerProgram& layerProgram, unsigned historyCap)
-{
-	for (unsigned index = 0; index < historyCap; ++index)
-	{
-		glActiveTexture(GL_TEXTURE0 + kSourceHistoryTextureUnitBase + index);
-		glBindTexture(GL_TEXTURE_2D, 0);
-		glActiveTexture(GL_TEXTURE0 + kSourceHistoryTextureUnitBase + historyCap + index);
-		glBindTexture(GL_TEXTURE_2D, 0);
-	}
-	const GLuint shaderTextureBase = layerProgram.shaderTextureBase != 0 ? layerProgram.shaderTextureBase : kSourceHistoryTextureUnitBase;
-	for (std::size_t index = 0; index < layerProgram.textureBindings.size() + layerProgram.textBindings.size(); ++index)
-	{
-		glActiveTexture(GL_TEXTURE0 + shaderTextureBase + static_cast<GLuint>(index));
-		glBindTexture(GL_TEXTURE_2D, 0);
-	}
-	glActiveTexture(GL_TEXTURE0 + kDecodedVideoTextureUnit);
-	glBindTexture(GL_TEXTURE_2D, 0);
-	glActiveTexture(GL_TEXTURE0);
-}

apps/LoopThroughWithOpenGLCompositing/gl/ShaderProgramCompiler.cpp

@@ -1,244 +0,0 @@
-#include "ShaderProgramCompiler.h"
-
-#include "GlRenderConstants.h"
-#include "GlScopedObjects.h"
-#include "GlShaderSources.h"
-
-#include <cstring>
-#include <vector>
-
-namespace
-{
-void CopyErrorMessage(const std::string& message, int errorMessageSize, char* errorMessage)
-{
-	if (!errorMessage || errorMessageSize <= 0)
-		return;
-
-	strncpy_s(errorMessage, errorMessageSize, message.c_str(), _TRUNCATE);
-}
-}
-
-ShaderProgramCompiler::ShaderProgramCompiler(OpenGLRenderer& renderer, RuntimeHost& runtimeHost, ShaderTextureBindings& textureBindings) :
-	mRenderer(renderer),
-	mRuntimeHost(runtimeHost),
-	mTextureBindings(textureBindings)
-{
-}
-
-bool ShaderProgramCompiler::CompileLayerProgram(const RuntimeRenderState& state, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
-{
-	std::string fragmentShaderSource;
-	std::string loadError;
-
-	if (!mRuntimeHost.BuildLayerFragmentShaderSource(state.layerId, fragmentShaderSource, loadError))
-	{
-		CopyErrorMessage(loadError, errorMessageSize, errorMessage);
-		return false;
-	}
-
-	return CompilePreparedLayerProgram(state, fragmentShaderSource, layerProgram, errorMessageSize, errorMessage);
-}
-
-bool ShaderProgramCompiler::CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::string& fragmentShaderSource, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
-{
-	GLsizei errorBufferSize = 0;
-	GLint compileResult = GL_FALSE;
-	GLint linkResult = GL_FALSE;
-	std::string loadError;
-	std::vector<LayerProgram::TextureBinding> textureBindings;
-	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
-	const char* fragmentSource = fragmentShaderSource.c_str();
-
-	ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
-	glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
-	glCompileShader(newVertexShader.get());
-	glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
-	glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
-	glCompileShader(newFragmentShader.get());
-	glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlProgram newProgram(glCreateProgram());
-	glAttachShader(newProgram.get(), newVertexShader.get());
-	glAttachShader(newProgram.get(), newFragmentShader.get());
-	glLinkProgram(newProgram.get());
-	glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
-	if (linkResult == GL_FALSE)
-	{
-		glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	for (const ShaderTextureAsset& textureAsset : state.textureAssets)
-	{
-		LayerProgram::TextureBinding textureBinding;
-		textureBinding.samplerName = textureAsset.id;
-		textureBinding.sourcePath = textureAsset.path;
-		if (!mTextureBindings.LoadTextureAsset(textureAsset, textureBinding.texture, loadError))
-		{
-			for (LayerProgram::TextureBinding& loadedTexture : textureBindings)
-			{
-				if (loadedTexture.texture != 0)
-					glDeleteTextures(1, &loadedTexture.texture);
-			}
-			CopyErrorMessage(loadError, errorMessageSize, errorMessage);
-			return false;
-		}
-		textureBindings.push_back(textureBinding);
-	}
-
-	std::vector<LayerProgram::TextBinding> textBindings;
-	mTextureBindings.CreateTextBindings(state, textBindings);
-
-	const GLuint globalParamsIndex = glGetUniformBlockIndex(newProgram.get(), "GlobalParams");
-	if (globalParamsIndex != GL_INVALID_INDEX)
-		glUniformBlockBinding(newProgram.get(), globalParamsIndex, kGlobalParamsBindingPoint);
-
-	const unsigned historyCap = mRuntimeHost.GetMaxTemporalHistoryFrames();
-	const GLuint shaderTextureBase = state.isTemporal ? kSourceHistoryTextureUnitBase + historyCap + historyCap : kSourceHistoryTextureUnitBase;
-	glUseProgram(newProgram.get());
-	const GLint videoInputLocation = glGetUniformLocation(newProgram.get(), "gVideoInput");
-	if (videoInputLocation >= 0)
-		glUniform1i(videoInputLocation, static_cast<GLint>(kDecodedVideoTextureUnit));
-	for (unsigned index = 0; index < historyCap; ++index)
-	{
-		const std::string sourceSamplerName = "gSourceHistory" + std::to_string(index);
-		const GLint sourceSamplerLocation = glGetUniformLocation(newProgram.get(), sourceSamplerName.c_str());
-		if (sourceSamplerLocation >= 0)
-			glUniform1i(sourceSamplerLocation, static_cast<GLint>(kSourceHistoryTextureUnitBase + index));
-
-		const std::string temporalSamplerName = "gTemporalHistory" + std::to_string(index);
-		const GLint temporalSamplerLocation = glGetUniformLocation(newProgram.get(), temporalSamplerName.c_str());
-		if (temporalSamplerLocation >= 0)
-			glUniform1i(temporalSamplerLocation, static_cast<GLint>(kSourceHistoryTextureUnitBase + historyCap + index));
-	}
-	for (std::size_t index = 0; index < textureBindings.size(); ++index)
-	{
-		const GLint textureSamplerLocation = mTextureBindings.FindSamplerUniformLocation(newProgram.get(), textureBindings[index].samplerName);
-		if (textureSamplerLocation >= 0)
-			glUniform1i(textureSamplerLocation, static_cast<GLint>(shaderTextureBase + static_cast<GLuint>(index)));
-	}
-	const GLuint textTextureBase = shaderTextureBase + static_cast<GLuint>(textureBindings.size());
-	for (std::size_t index = 0; index < textBindings.size(); ++index)
-	{
-		const GLint textSamplerLocation = mTextureBindings.FindSamplerUniformLocation(newProgram.get(), textBindings[index].samplerName);
-		if (textSamplerLocation >= 0)
-			glUniform1i(textSamplerLocation, static_cast<GLint>(textTextureBase + static_cast<GLuint>(index)));
-	}
-	glUseProgram(0);
-
-	layerProgram.layerId = state.layerId;
-	layerProgram.shaderId = state.shaderId;
-	layerProgram.shaderTextureBase = shaderTextureBase;
-	layerProgram.program = newProgram.release();
-	layerProgram.vertexShader = newVertexShader.release();
-	layerProgram.fragmentShader = newFragmentShader.release();
-	layerProgram.textureBindings.swap(textureBindings);
-	layerProgram.textBindings.swap(textBindings);
-	return true;
-}
-
-bool ShaderProgramCompiler::CompileDecodeShader(int errorMessageSize, char* errorMessage)
-{
-	GLsizei errorBufferSize = 0;
-	GLint compileResult = GL_FALSE;
-	GLint linkResult = GL_FALSE;
-	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
-	const char* fragmentSource = kDecodeFragmentShaderSource;
-
-	ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
-	glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
-	glCompileShader(newVertexShader.get());
-	glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
-	glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
-	glCompileShader(newFragmentShader.get());
-	glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlProgram newProgram(glCreateProgram());
-	glAttachShader(newProgram.get(), newVertexShader.get());
-	glAttachShader(newProgram.get(), newFragmentShader.get());
-	glLinkProgram(newProgram.get());
-	glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
-	if (linkResult == GL_FALSE)
-	{
-		glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	mRenderer.DestroyDecodeShaderProgram();
-	mRenderer.SetDecodeShaderProgram(newProgram.release(), newVertexShader.release(), newFragmentShader.release());
-	return true;
-}
-
-bool ShaderProgramCompiler::CompileOutputPackShader(int errorMessageSize, char* errorMessage)
-{
-	GLsizei errorBufferSize = 0;
-	GLint compileResult = GL_FALSE;
-	GLint linkResult = GL_FALSE;
-	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
-	const char* fragmentSource = kOutputPackFragmentShaderSource;
-
-	ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
-	glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
-	glCompileShader(newVertexShader.get());
-	glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
-	glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
-	glCompileShader(newFragmentShader.get());
-	glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
-	if (compileResult == GL_FALSE)
-	{
-		glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	ScopedGlProgram newProgram(glCreateProgram());
-	glAttachShader(newProgram.get(), newVertexShader.get());
-	glAttachShader(newProgram.get(), newFragmentShader.get());
-	glLinkProgram(newProgram.get());
-	glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
-	if (linkResult == GL_FALSE)
-	{
-		glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
-		return false;
-	}
-
-	glUseProgram(newProgram.get());
-	const GLint outputSamplerLocation = glGetUniformLocation(newProgram.get(), "uOutputRgb");
-	if (outputSamplerLocation >= 0)
-		glUniform1i(outputSamplerLocation, 0);
-	glUseProgram(0);
-
-	mRenderer.DestroyOutputPackShaderProgram();
-	mRenderer.SetOutputPackShaderProgram(newProgram.release(), newVertexShader.release(), newFragmentShader.release());
-	return true;
-}

apps/LoopThroughWithOpenGLCompositing/gl/ShaderTextureBindings.cpp

@@ -1,104 +0,0 @@
-#include "ShaderTextureBindings.h"
-
-#include "GlRenderConstants.h"
-#include "TextRasterizer.h"
-#include "TextureAssetLoader.h"
-
-#include <algorithm>
-#include <filesystem>
-
-namespace
-{
-std::string TextValueForBinding(const RuntimeRenderState& state, const std::string& parameterId)
-{
-	auto valueIt = state.parameterValues.find(parameterId);
-	return valueIt == state.parameterValues.end() ? std::string() : valueIt->second.textValue;
-}
-
-const ShaderFontAsset* FindFontAssetForParameter(const RuntimeRenderState& state, const ShaderParameterDefinition& definition)
-{
-	if (!definition.fontId.empty())
-	{
-		for (const ShaderFontAsset& fontAsset : state.fontAssets)
-		{
-			if (fontAsset.id == definition.fontId)
-				return &fontAsset;
-		}
-	}
-	return state.fontAssets.empty() ? nullptr : &state.fontAssets.front();
-}
-}
-
-bool ShaderTextureBindings::LoadTextureAsset(const ShaderTextureAsset& textureAsset, GLuint& textureId, std::string& error)
-{
-	return ::LoadTextureAsset(textureAsset, textureId, error);
-}
-
-void ShaderTextureBindings::CreateTextBindings(const RuntimeRenderState& state, std::vector<LayerProgram::TextBinding>& textBindings)
-{
-	for (const ShaderParameterDefinition& definition : state.parameterDefinitions)
-	{
-		if (definition.type != ShaderParameterType::Text)
-			continue;
-		LayerProgram::TextBinding textBinding;
-		textBinding.parameterId = definition.id;
-		textBinding.samplerName = definition.id + "Texture";
-		textBinding.fontId = definition.fontId;
-		glGenTextures(1, &textBinding.texture);
-		glBindTexture(GL_TEXTURE_2D, textBinding.texture);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-		std::vector<unsigned char> empty(static_cast<std::size_t>(kTextTextureWidth) * kTextTextureHeight * 4, 0);
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kTextTextureWidth, kTextTextureHeight, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, empty.data());
-		glBindTexture(GL_TEXTURE_2D, 0);
-		textBindings.push_back(textBinding);
-	}
-}
-
-bool ShaderTextureBindings::UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error)
-{
-	const std::string text = TextValueForBinding(state, textBinding.parameterId);
-	if (text == textBinding.renderedText && textBinding.renderedWidth == kTextTextureWidth && textBinding.renderedHeight == kTextTextureHeight)
-		return true;
-
-	auto definitionIt = std::find_if(state.parameterDefinitions.begin(), state.parameterDefinitions.end(),
-		[&textBinding](const ShaderParameterDefinition& definition) { return definition.id == textBinding.parameterId; });
-	if (definitionIt == state.parameterDefinitions.end())
-		return true;
-
-	const ShaderFontAsset* fontAsset = FindFontAssetForParameter(state, *definitionIt);
-	std::filesystem::path fontPath;
-	if (fontAsset)
-		fontPath = fontAsset->path;
-
-	std::vector<unsigned char> sdf;
-	if (!RasterizeTextSdf(text, fontPath, sdf, error))
-		return false;
-
-	GLint previousActiveTexture = 0;
-	GLint previousUnpackBuffer = 0;
-	glGetIntegerv(GL_ACTIVE_TEXTURE, &previousActiveTexture);
-	glGetIntegerv(GL_PIXEL_UNPACK_BUFFER_BINDING, &previousUnpackBuffer);
-	glActiveTexture(GL_TEXTURE0);
-	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
-	glBindTexture(GL_TEXTURE_2D, textBinding.texture);
-	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kTextTextureWidth, kTextTextureHeight, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, sdf.data());
-	glBindTexture(GL_TEXTURE_2D, 0);
-	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, static_cast<GLuint>(previousUnpackBuffer));
-	glActiveTexture(static_cast<GLenum>(previousActiveTexture));
-
-	textBinding.renderedText = text;
-	textBinding.renderedWidth = kTextTextureWidth;
-	textBinding.renderedHeight = kTextTextureHeight;
-	return true;
-}
-
-GLint ShaderTextureBindings::FindSamplerUniformLocation(GLuint program, const std::string& samplerName) const
-{
-	GLint location = glGetUniformLocation(program, samplerName.c_str());
-	if (location >= 0)
-		return location;
-	return glGetUniformLocation(program, (samplerName + "_0").c_str());
-}

apps/LoopThroughWithOpenGLCompositing/gl/ShaderTextureBindings.h

@@ -1,18 +0,0 @@
-#pragma once
-
-#include "OpenGLRenderer.h"
-#include "ShaderTypes.h"
-
-#include <string>
-#include <vector>
-
-class ShaderTextureBindings
-{
-public:
-	using LayerProgram = OpenGLRenderer::LayerProgram;
-
-	bool LoadTextureAsset(const ShaderTextureAsset& textureAsset, GLuint& textureId, std::string& error);
-	void CreateTextBindings(const RuntimeRenderState& state, std::vector<LayerProgram::TextBinding>& textBindings);
-	bool UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error);
-	GLint FindSamplerUniformLocation(GLuint program, const std::string& samplerName) const;
-};

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.cpp

@@ -0,0 +1,288 @@
+#include "OpenGLRenderPass.h"
+
+#include "GlRenderConstants.h"
+
+#include <map>
+
+OpenGLRenderPass::OpenGLRenderPass(OpenGLRenderer& renderer) :
+	mRenderer(renderer)
+{
+}
+
+void OpenGLRenderPass::Render(
+	bool hasInputSource,
+	const std::vector<RuntimeRenderState>& layerStates,
+	unsigned inputFrameWidth,
+	unsigned inputFrameHeight,
+	unsigned captureTextureWidth,
+	VideoIOPixelFormat inputPixelFormat,
+	unsigned historyCap,
+	const TextBindingUpdater& updateTextBinding,
+	const GlobalParamsUpdater& updateGlobalParams)
+{
+	glDisable(GL_SCISSOR_TEST);
+	glDisable(GL_BLEND);
+	glDisable(GL_DEPTH_TEST);
+	if (hasInputSource)
+	{
+		RenderDecodePass(inputFrameWidth, inputFrameHeight, captureTextureWidth, inputPixelFormat);
+	}
+	else
+	{
+		glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
+		glViewport(0, 0, inputFrameWidth, inputFrameHeight);
+		glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+		glClear(GL_COLOR_BUFFER_BIT);
+	}
+
+	std::vector<LayerProgram>& layerPrograms = mRenderer.LayerPrograms();
+	if (layerStates.empty() || layerPrograms.empty())
+	{
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
+		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
+		glBlitFramebuffer(0, 0, inputFrameWidth, inputFrameHeight, 0, 0, inputFrameWidth, inputFrameHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+		glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
+	}
+	else
+	{
+		const std::vector<RenderPassDescriptor>& passes = BuildLayerPassDescriptors(layerStates, layerPrograms);
+		for (const RenderPassDescriptor& pass : passes)
+		{
+			RenderLayerPass(
+				pass,
+				inputFrameWidth,
+				inputFrameHeight,
+				historyCap,
+				updateTextBinding,
+				updateGlobalParams);
+		}
+	}
+
+	mRenderer.TemporalHistory().PushSourceFramebuffer(mRenderer.DecodeFramebuffer(), inputFrameWidth, inputFrameHeight);
+	mRenderer.FeedbackBuffers().FinalizeFrame();
+}
+
+void OpenGLRenderPass::RenderDecodePass(unsigned inputFrameWidth, unsigned inputFrameHeight, unsigned captureTextureWidth, VideoIOPixelFormat inputPixelFormat)
+{
+	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.DecodeFramebuffer());
+	glViewport(0, 0, inputFrameWidth, inputFrameHeight);
+	glClear(GL_COLOR_BUFFER_BIT);
+	glActiveTexture(GL_TEXTURE0 + kPackedVideoTextureUnit);
+	glBindTexture(GL_TEXTURE_2D, mRenderer.CaptureTexture());
+	glBindVertexArray(mRenderer.FullscreenVertexArray());
+	glUseProgram(mRenderer.DecodeProgram());
+
+	const GLint packedResolutionLocation = mRenderer.DecodePackedResolutionLocation();
+	const GLint decodedResolutionLocation = mRenderer.DecodeDecodedResolutionLocation();
+	const GLint inputPixelFormatLocation = mRenderer.DecodeInputPixelFormatLocation();
+	if (packedResolutionLocation >= 0)
+		glUniform2f(packedResolutionLocation, static_cast<float>(captureTextureWidth), static_cast<float>(inputFrameHeight));
+	if (decodedResolutionLocation >= 0)
+		glUniform2f(decodedResolutionLocation, static_cast<float>(inputFrameWidth), static_cast<float>(inputFrameHeight));
+	if (inputPixelFormatLocation >= 0)
+		glUniform1i(inputPixelFormatLocation, inputPixelFormat == VideoIOPixelFormat::V210 ? 1 : 0);
+
+	glDrawArrays(GL_TRIANGLES, 0, 3);
+
+	glUseProgram(0);
+	glBindVertexArray(0);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glActiveTexture(GL_TEXTURE0);
+}
+
+std::vector<RenderPassDescriptor> OpenGLRenderPass::BuildLayerPassDescriptors(
+	const std::vector<RuntimeRenderState>& layerStates,
+	std::vector<LayerProgram>& layerPrograms) const
+{
+	// Flatten the layer stack into concrete GL passes. A layer may now contain
+	// several shader passes, but the outer stack still sees one visible output
+	// per layer.
+	std::vector<RenderPassDescriptor>& passes = mPassScratch;
+	passes.clear();
+	const std::size_t passCount = layerStates.size() < layerPrograms.size() ? layerStates.size() : layerPrograms.size();
+	std::size_t descriptorCount = 0;
+	for (std::size_t index = 0; index < passCount; ++index)
+		descriptorCount += layerPrograms[index].passes.size();
+	passes.reserve(descriptorCount);
+
+	GLuint sourceTexture = mRenderer.DecodedTexture();
+	GLuint sourceFramebuffer = mRenderer.DecodeFramebuffer();
+	for (std::size_t index = 0; index < passCount; ++index)
+	{
+		const RuntimeRenderState& state = layerStates[index];
+		LayerProgram& layerProgram = layerPrograms[index];
+		if (layerProgram.passes.empty())
+			continue;
+
+		// Preserve the original two-target layer ping-pong. Intermediate passes
+		// inside this layer are routed through pooled temporary targets instead.
+		const std::size_t remaining = layerStates.size() - index;
+		const bool writeToMain = (remaining % 2) == 1;
+		const GLuint layerOutputTexture = writeToMain ? mRenderer.CompositeTexture() : mRenderer.LayerTempTexture();
+		const GLuint layerOutputFramebuffer = writeToMain ? mRenderer.CompositeFramebuffer() : mRenderer.LayerTempFramebuffer();
+		const RenderPassOutputTarget layerOutputTarget = writeToMain ? RenderPassOutputTarget::Composite : RenderPassOutputTarget::LayerTemp;
+
+		const GLuint layerInputTexture = sourceTexture;
+		const GLuint layerInputFramebuffer = sourceFramebuffer;
+		GLuint previousPassTexture = layerInputTexture;
+		GLuint previousPassFramebuffer = layerInputFramebuffer;
+		std::map<std::string, std::pair<GLuint, GLuint>> namedOutputs;
+		std::size_t temporaryTargetIndex = 0;
+
+		for (std::size_t passIndex = 0; passIndex < layerProgram.passes.size(); ++passIndex)
+		{
+			PassProgram& passProgram = layerProgram.passes[passIndex];
+			const bool lastPassForLayer = passIndex + 1 == layerProgram.passes.size();
+			const std::string outputName = passProgram.outputName.empty() ? passProgram.passId : passProgram.outputName;
+			const bool writesLayerOutput = outputName == "layerOutput" || lastPassForLayer;
+
+			GLuint passSourceTexture = previousPassTexture;
+			GLuint passSourceFramebuffer = previousPassFramebuffer;
+			if (!passProgram.inputNames.empty())
+			{
+				// v1 multipass uses the first declared input as gVideoInput.
+				// Later inputs are parsed for forward compatibility.
+				const std::string& inputName = passProgram.inputNames.front();
+				if (inputName == "layerInput")
+				{
+					passSourceTexture = layerInputTexture;
+					passSourceFramebuffer = layerInputFramebuffer;
+				}
+				else if (inputName == "previousPass")
+				{
+					passSourceTexture = previousPassTexture;
+					passSourceFramebuffer = previousPassFramebuffer;
+				}
+				else
+				{
+					auto namedOutputIt = namedOutputs.find(inputName);
+					if (namedOutputIt != namedOutputs.end())
+					{
+						passSourceTexture = namedOutputIt->second.first;
+						passSourceFramebuffer = namedOutputIt->second.second;
+					}
+				}
+			}
+
+			GLuint passDestinationTexture = layerOutputTexture;
+			GLuint passDestinationFramebuffer = layerOutputFramebuffer;
+			RenderPassOutputTarget outputTarget = layerOutputTarget;
+			if (!writesLayerOutput)
+			{
+				// Temporary targets are reserved when the shader stack is
+				// committed, avoiding texture allocation during playback.
+				if (temporaryTargetIndex < mRenderer.TemporaryRenderTargetCount())
+				{
+					const RenderTarget& temporaryTarget = mRenderer.TemporaryRenderTarget(temporaryTargetIndex);
+					++temporaryTargetIndex;
+					passDestinationTexture = temporaryTarget.texture;
+					passDestinationFramebuffer = temporaryTarget.framebuffer;
+					outputTarget = RenderPassOutputTarget::Temporary;
+				}
+			}
+
+			RenderPassDescriptor pass;
+			pass.kind = RenderPassKind::LayerEffect;
+			pass.outputTarget = outputTarget;
+			pass.passIndex = passes.size();
+			pass.passId = passProgram.passId;
+			pass.layerId = state.layerId;
+			pass.shaderId = state.shaderId;
+			pass.layerInputTexture = layerInputTexture;
+			pass.sourceTexture = passSourceTexture;
+			pass.sourceFramebuffer = passIndex == 0 ? layerInputFramebuffer : passSourceFramebuffer;
+			pass.destinationTexture = passDestinationTexture;
+			pass.destinationFramebuffer = passDestinationFramebuffer;
+			pass.layerProgram = &layerProgram;
+			pass.passProgram = &passProgram;
+			pass.layerState = &state;
+			pass.capturePreLayerHistory = passIndex == 0 && state.temporalHistorySource == TemporalHistorySource::PreLayerInput;
+			pass.captureFeedbackWrite = state.feedback.enabled && passProgram.passId == state.feedback.writePassId;
+			passes.push_back(pass);
+
+			// A later pass can reference either the explicit output name or the
+			// pass id, which keeps small manifests pleasant to write.
+			namedOutputs[outputName] = std::make_pair(passDestinationTexture, passDestinationFramebuffer);
+			namedOutputs[passProgram.passId] = std::make_pair(passDestinationTexture, passDestinationFramebuffer);
+			previousPassTexture = passDestinationTexture;
+			previousPassFramebuffer = passDestinationFramebuffer;
+		}
+
+		sourceTexture = layerOutputTexture;
+		sourceFramebuffer = layerOutputFramebuffer;
+	}
+
+	return passes;
+}
+
+void OpenGLRenderPass::RenderLayerPass(
+	const RenderPassDescriptor& pass,
+	unsigned inputFrameWidth,
+	unsigned inputFrameHeight,
+	unsigned historyCap,
+	const TextBindingUpdater& updateTextBinding,
+	const GlobalParamsUpdater& updateGlobalParams)
+{
+	if (pass.passProgram == nullptr || pass.layerState == nullptr)
+		return;
+
+	RenderShaderProgram(
+		pass.layerInputTexture,
+		pass.sourceTexture,
+		pass.destinationFramebuffer,
+		*pass.passProgram,
+		*pass.layerState,
+		inputFrameWidth,
+		inputFrameHeight,
+		historyCap,
+		updateTextBinding,
+		updateGlobalParams);
+
+	if (pass.capturePreLayerHistory)
+		mRenderer.TemporalHistory().PushPreLayerFramebuffer(pass.layerId, pass.sourceFramebuffer, inputFrameWidth, inputFrameHeight);
+	if (pass.captureFeedbackWrite)
+		mRenderer.FeedbackBuffers().CaptureFeedbackFramebuffer(pass.layerId, pass.destinationFramebuffer, inputFrameWidth, inputFrameHeight);
+}
+
+void OpenGLRenderPass::RenderShaderProgram(
+	GLuint layerInputTexture,
+	GLuint sourceTexture,
+	GLuint destinationFrameBuffer,
+	PassProgram& passProgram,
+	const RuntimeRenderState& state,
+	unsigned inputFrameWidth,
+	unsigned inputFrameHeight,
+	unsigned historyCap,
+	const TextBindingUpdater& updateTextBinding,
+	const GlobalParamsUpdater& updateGlobalParams)
+{
+	for (LayerProgram::TextBinding& textBinding : passProgram.textBindings)
+	{
+		std::string textError;
+		if (!updateTextBinding(state, textBinding, textError))
+			OutputDebugStringA((textError + "\n").c_str());
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, destinationFrameBuffer);
+	glViewport(0, 0, inputFrameWidth, inputFrameHeight);
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+	const std::vector<GLuint> sourceHistoryTextures = mRenderer.TemporalHistory().ResolveSourceHistoryTextures(sourceTexture, state.isTemporal ? historyCap : 0);
+	const std::vector<GLuint> temporalHistoryTextures = mRenderer.TemporalHistory().ResolveTemporalHistoryTextures(state, sourceTexture, state.isTemporal ? historyCap : 0);
+	const GLuint feedbackTexture = mRenderer.FeedbackBuffers().ResolveReadTexture(state);
+	const ShaderTextureBindings::RuntimeTextureBindingPlan texturePlan =
+		mTextureBindings.BuildLayerRuntimeBindingPlan(passProgram, sourceTexture, layerInputTexture, state, feedbackTexture, sourceHistoryTextures, temporalHistoryTextures);
+	mTextureBindings.BindRuntimeTexturePlan(texturePlan);
+	glBindVertexArray(mRenderer.FullscreenVertexArray());
+	glUseProgram(passProgram.program);
+	// The UBO is shared by every pass in a layer; texture routing is what
+	// changes from pass to pass.
+	updateGlobalParams(
+		state,
+		mRenderer.TemporalHistory().SourceAvailableCount(),
+		mRenderer.TemporalHistory().AvailableCountForLayer(state.layerId),
+		mRenderer.FeedbackBuffers().FeedbackAvailable(state));
+	glDrawArrays(GL_TRIANGLES, 0, 3);
+	glUseProgram(0);
+	glBindVertexArray(0);
+	mTextureBindings.UnbindRuntimeTexturePlan(texturePlan);
+}

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include "OpenGLRenderer.h"
+#include "RenderPassDescriptor.h"
+#include "ShaderTextureBindings.h"
 #include "ShaderTypes.h"
 #include "VideoIOFormat.h"
 
@@ -12,8 +14,9 @@ class OpenGLRenderPass
 {
 public:
 	using LayerProgram = OpenGLRenderer::LayerProgram;
+	using PassProgram = OpenGLRenderer::LayerProgram::PassProgram;
 	using TextBindingUpdater = std::function<bool(const RuntimeRenderState&, LayerProgram::TextBinding&, std::string&)>;
-	using GlobalParamsUpdater = std::function<bool(const RuntimeRenderState&, unsigned, unsigned)>;
+	using GlobalParamsUpdater = std::function<bool(const RuntimeRenderState&, unsigned, unsigned, bool)>;
 
 	explicit OpenGLRenderPass(OpenGLRenderer& renderer);
 
@@ -30,18 +33,29 @@ public:
 
 private:
 	void RenderDecodePass(unsigned inputFrameWidth, unsigned inputFrameHeight, unsigned captureTextureWidth, VideoIOPixelFormat inputPixelFormat);
+	std::vector<RenderPassDescriptor> BuildLayerPassDescriptors(
+		const std::vector<RuntimeRenderState>& layerStates,
+		std::vector<LayerProgram>& layerPrograms) const;
+	void RenderLayerPass(
+		const RenderPassDescriptor& pass,
+		unsigned inputFrameWidth,
+		unsigned inputFrameHeight,
+		unsigned historyCap,
+		const TextBindingUpdater& updateTextBinding,
+		const GlobalParamsUpdater& updateGlobalParams);
 	void RenderShaderProgram(
+		GLuint layerInputTexture,
 		GLuint sourceTexture,
 		GLuint destinationFrameBuffer,
-		LayerProgram& layerProgram,
+		PassProgram& passProgram,
 		const RuntimeRenderState& state,
 		unsigned inputFrameWidth,
 		unsigned inputFrameHeight,
 		unsigned historyCap,
 		const TextBindingUpdater& updateTextBinding,
 		const GlobalParamsUpdater& updateGlobalParams);
-	void BindLayerTextureAssets(const LayerProgram& layerProgram);
-	void UnbindLayerTextureAssets(const LayerProgram& layerProgram, unsigned historyCap);
 
 	OpenGLRenderer& mRenderer;
+	ShaderTextureBindings mTextureBindings;
+	mutable std::vector<RenderPassDescriptor> mPassScratch;
 };

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp

@@ -0,0 +1,279 @@
+#include "OpenGLRenderPipeline.h"
+
+#include "OpenGLRenderer.h"
+#include "RuntimeHost.h"
+#include "VideoIOFormat.h"
+
+#include <cstring>
+
+#include <chrono>
+#include <gl/gl.h>
+
+OpenGLRenderPipeline::OpenGLRenderPipeline(
+	OpenGLRenderer& renderer,
+	RuntimeHost& runtimeHost,
+	RenderEffectCallback renderEffect,
+	OutputReadyCallback outputReady,
+	PaintCallback paint) :
+	mRenderer(renderer),
+	mRuntimeHost(runtimeHost),
+	mRenderEffect(renderEffect),
+	mOutputReady(outputReady),
+	mPaint(paint)
+{
+}
+
+OpenGLRenderPipeline::~OpenGLRenderPipeline()
+{
+	ResetAsyncReadbackState();
+}
+
+bool OpenGLRenderPipeline::RenderFrame(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame)
+{
+	const VideoIOState& state = context.videoState;
+
+	const auto renderStartTime = std::chrono::steady_clock::now();
+	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
+	mRenderEffect();
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mRenderer.OutputFramebuffer());
+	glBlitFramebuffer(0, 0, state.inputFrameSize.width, state.inputFrameSize.height, 0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.OutputFramebuffer());
+	if (mOutputReady)
+		mOutputReady();
+	if (state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10)
+		PackOutputFor10Bit(state);
+	glFlush();
+
+	const auto renderEndTime = std::chrono::steady_clock::now();
+	const double renderMilliseconds = std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(renderEndTime - renderStartTime).count();
+	mRuntimeHost.TrySetPerformanceStats(state.frameBudgetMilliseconds, renderMilliseconds);
+	mRuntimeHost.TryAdvanceFrame();
+
+	ReadOutputFrame(state, outputFrame);
+	if (mPaint)
+		mPaint();
+
+	return true;
+}
+
+void OpenGLRenderPipeline::PackOutputFor10Bit(const VideoIOState& state)
+{
+	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.OutputPackFramebuffer());
+	glViewport(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height);
+	glDisable(GL_SCISSOR_TEST);
+	glDisable(GL_BLEND);
+	glDisable(GL_DEPTH_TEST);
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, mRenderer.OutputTexture());
+	glBindVertexArray(mRenderer.FullscreenVertexArray());
+	glUseProgram(mRenderer.OutputPackProgram());
+
+	const GLint outputResolutionLocation = mRenderer.OutputPackResolutionLocation();
+	const GLint activeWordsLocation = mRenderer.OutputPackActiveWordsLocation();
+	const GLint packFormatLocation = mRenderer.OutputPackFormatLocation();
+	if (outputResolutionLocation >= 0)
+		glUniform2f(outputResolutionLocation, static_cast<float>(state.outputFrameSize.width), static_cast<float>(state.outputFrameSize.height));
+	if (activeWordsLocation >= 0)
+		glUniform1f(activeWordsLocation, static_cast<float>(ActiveV210WordsForWidth(state.outputFrameSize.width)));
+	if (packFormatLocation >= 0)
+		glUniform1i(packFormatLocation, state.outputPixelFormat == VideoIOPixelFormat::Yuva10 ? 2 : 1);
+
+	glDrawArrays(GL_TRIANGLES, 0, 3);
+	glUseProgram(0);
+	glBindVertexArray(0);
+	glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+bool OpenGLRenderPipeline::EnsureAsyncReadbackBuffers(std::size_t requiredBytes)
+{
+	if (requiredBytes == 0)
+		return false;
+
+	if (mAsyncReadbackBytes == requiredBytes && mAsyncReadbackSlots[0].pixelPackBuffer != 0)
+		return true;
+
+	ResetAsyncReadbackState();
+	mAsyncReadbackBytes = requiredBytes;
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+	{
+		glGenBuffers(1, &slot.pixelPackBuffer);
+		glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+		glBufferData(GL_PIXEL_PACK_BUFFER, static_cast<GLsizeiptr>(requiredBytes), nullptr, GL_STREAM_READ);
+		slot.sizeBytes = requiredBytes;
+		slot.inFlight = false;
+	}
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+	return true;
+}
+
+void OpenGLRenderPipeline::ResetAsyncReadbackState()
+{
+	FlushAsyncReadbackPipeline();
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+		slot.sizeBytes = 0;
+
+	if (mAsyncReadbackSlots[0].pixelPackBuffer != 0)
+	{
+		for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+		{
+			if (slot.pixelPackBuffer != 0)
+			{
+				glDeleteBuffers(1, &slot.pixelPackBuffer);
+				slot.pixelPackBuffer = 0;
+			}
+		}
+	}
+
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+	mAsyncReadbackBytes = 0;
+}
+
+void OpenGLRenderPipeline::FlushAsyncReadbackPipeline()
+{
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+	{
+		if (slot.fence != nullptr)
+		{
+			glDeleteSync(slot.fence);
+			slot.fence = nullptr;
+		}
+		slot.inFlight = false;
+	}
+
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+}
+
+void OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state)
+{
+	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
+	const std::size_t requiredBytes = static_cast<std::size_t>(state.outputFrameRowBytes) * state.outputFrameSize.height;
+	const GLenum format = usePackedOutput ? GL_RGBA : GL_BGRA;
+	const GLenum type = usePackedOutput ? GL_UNSIGNED_BYTE : GL_UNSIGNED_INT_8_8_8_8_REV;
+	const GLuint framebuffer = usePackedOutput ? mRenderer.OutputPackFramebuffer() : mRenderer.OutputFramebuffer();
+	const GLsizei readWidth = static_cast<GLsizei>(usePackedOutput ? state.outputPackTextureWidth : state.outputFrameSize.width);
+	const GLsizei readHeight = static_cast<GLsizei>(state.outputFrameSize.height);
+
+	if (requiredBytes == 0)
+		return;
+
+	if (mAsyncReadbackBytes != requiredBytes
+		|| mAsyncReadbackFormat != format
+		|| mAsyncReadbackType != type
+		|| mAsyncReadbackFramebuffer != framebuffer)
+	{
+		mAsyncReadbackFormat = format;
+		mAsyncReadbackType = type;
+		mAsyncReadbackFramebuffer = framebuffer;
+		if (!EnsureAsyncReadbackBuffers(requiredBytes))
+			return;
+	}
+
+	AsyncReadbackSlot& slot = mAsyncReadbackSlots[mAsyncReadbackWriteIndex];
+	if (slot.fence != nullptr)
+	{
+		glDeleteSync(slot.fence);
+		slot.fence = nullptr;
+	}
+
+	glPixelStorei(GL_PACK_ALIGNMENT, 4);
+	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	glBufferData(GL_PIXEL_PACK_BUFFER, static_cast<GLsizeiptr>(requiredBytes), nullptr, GL_STREAM_READ);
+	glReadPixels(0, 0, readWidth, readHeight, format, type, nullptr);
+	slot.fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
+	slot.inFlight = slot.fence != nullptr;
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+
+	mAsyncReadbackWriteIndex = (mAsyncReadbackWriteIndex + 1) % mAsyncReadbackSlots.size();
+}
+
+bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds)
+{
+	if (mAsyncReadbackBytes == 0 || outputFrame.bytes == nullptr)
+		return false;
+
+	AsyncReadbackSlot& slot = mAsyncReadbackSlots[mAsyncReadbackReadIndex];
+	if (!slot.inFlight || slot.fence == nullptr || slot.pixelPackBuffer == 0)
+		return false;
+
+	const GLenum waitFlags = timeoutNanoseconds > 0 ? GL_SYNC_FLUSH_COMMANDS_BIT : 0;
+	const GLenum waitResult = glClientWaitSync(slot.fence, waitFlags, timeoutNanoseconds);
+	if (waitResult != GL_ALREADY_SIGNALED && waitResult != GL_CONDITION_SATISFIED)
+		return false;
+
+	glDeleteSync(slot.fence);
+	slot.fence = nullptr;
+
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	void* mappedBytes = glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
+	if (mappedBytes == nullptr)
+	{
+		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+		slot.inFlight = false;
+		mAsyncReadbackReadIndex = (mAsyncReadbackReadIndex + 1) % mAsyncReadbackSlots.size();
+		return false;
+	}
+
+	std::memcpy(outputFrame.bytes, mappedBytes, slot.sizeBytes);
+	glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+
+	slot.inFlight = false;
+	mAsyncReadbackReadIndex = (mAsyncReadbackReadIndex + 1) % mAsyncReadbackSlots.size();
+	CacheOutputFrame(outputFrame);
+	return true;
+}
+
+void OpenGLRenderPipeline::CacheOutputFrame(const VideoIOOutputFrame& outputFrame)
+{
+	if (outputFrame.bytes == nullptr || outputFrame.height == 0 || outputFrame.rowBytes <= 0)
+		return;
+
+	const std::size_t byteCount = static_cast<std::size_t>(outputFrame.rowBytes) * outputFrame.height;
+	mCachedOutputFrame.resize(byteCount);
+	std::memcpy(mCachedOutputFrame.data(), outputFrame.bytes, byteCount);
+}
+
+void OpenGLRenderPipeline::ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes)
+{
+	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
+
+	glPixelStorei(GL_PACK_ALIGNMENT, 4);
+	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
+	if (usePackedOutput)
+	{
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputPackFramebuffer());
+		glReadPixels(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height, GL_RGBA, GL_UNSIGNED_BYTE, destinationBytes);
+	}
+	else
+	{
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputFramebuffer());
+		glReadPixels(0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, destinationBytes);
+	}
+}
+
+void OpenGLRenderPipeline::ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame)
+{
+	if (TryConsumeAsyncReadback(outputFrame, 500000))
+	{
+		QueueAsyncReadback(state);
+		return;
+	}
+
+	// If async readback misses the playout deadline, prefer a fresh synchronous
+	// frame over reusing stale cached output, then restart the async pipeline.
+	if (outputFrame.bytes != nullptr)
+	{
+		ReadOutputFrameSynchronously(state, outputFrame.bytes);
+		CacheOutputFrame(outputFrame);
+	}
+
+	FlushAsyncReadbackPipeline();
+	QueueAsyncReadback(state);
+}

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.h

@@ -0,0 +1,68 @@
+#pragma once
+
+#include "GLExtensions.h"
+#include "VideoIOTypes.h"
+
+#include <array>
+#include <functional>
+#include <vector>
+
+class OpenGLRenderer;
+class RuntimeHost;
+
+struct RenderPipelineFrameContext
+{
+	VideoIOState videoState;
+	VideoIOCompletion completion;
+};
+
+class OpenGLRenderPipeline
+{
+public:
+	using RenderEffectCallback = std::function<void()>;
+	using OutputReadyCallback = std::function<void()>;
+	using PaintCallback = std::function<void()>;
+
+	OpenGLRenderPipeline(
+		OpenGLRenderer& renderer,
+		RuntimeHost& runtimeHost,
+		RenderEffectCallback renderEffect,
+		OutputReadyCallback outputReady,
+		PaintCallback paint);
+	~OpenGLRenderPipeline();
+
+	bool RenderFrame(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame);
+
+private:
+	struct AsyncReadbackSlot
+	{
+		GLuint pixelPackBuffer = 0;
+		GLsync fence = nullptr;
+		std::size_t sizeBytes = 0;
+		bool inFlight = false;
+	};
+
+	bool EnsureAsyncReadbackBuffers(std::size_t requiredBytes);
+	void ResetAsyncReadbackState();
+	void FlushAsyncReadbackPipeline();
+	void QueueAsyncReadback(const VideoIOState& state);
+	bool TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds);
+	void CacheOutputFrame(const VideoIOOutputFrame& outputFrame);
+	void ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes);
+	void PackOutputFor10Bit(const VideoIOState& state);
+	void ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame);
+
+	OpenGLRenderer& mRenderer;
+	RuntimeHost& mRuntimeHost;
+	RenderEffectCallback mRenderEffect;
+	OutputReadyCallback mOutputReady;
+	PaintCallback mPaint;
+	std::array<AsyncReadbackSlot, 3> mAsyncReadbackSlots;
+	std::size_t mAsyncReadbackWriteIndex = 0;
+	std::size_t mAsyncReadbackReadIndex = 0;
+	std::size_t mAsyncReadbackBytes = 0;
+	GLenum mAsyncReadbackFormat = GL_BGRA;
+	GLenum mAsyncReadbackType = GL_UNSIGNED_INT_8_8_8_8_REV;
+	GLuint mAsyncReadbackFramebuffer = 0;
+	std::vector<unsigned char> mCachedOutputFrame;
+};

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp

@@ -9,22 +9,18 @@
 OpenGLVideoIOBridge::OpenGLVideoIOBridge(
 	VideoIODevice& videoIO,
 	OpenGLRenderer& renderer,
+	OpenGLRenderPipeline& renderPipeline,
 	RuntimeHost& runtimeHost,
 	CRITICAL_SECTION& mutex,
 	HDC hdc,
-	HGLRC hglrc,
-	RenderEffectCallback renderEffect,
-	OutputReadyCallback outputReady,
-	PaintCallback paint) :
+	HGLRC hglrc) :
 	mVideoIO(videoIO),
 	mRenderer(renderer),
+	mRenderPipeline(renderPipeline),
 	mRuntimeHost(runtimeHost),
 	mMutex(mutex),
 	mHdc(hdc),
-	mHglrc(hglrc),
-	mRenderEffect(renderEffect),
-	mOutputReady(outputReady),
-	mPaint(paint)
+	mHglrc(hglrc)
 {
 }
 
@@ -69,7 +65,10 @@ void OpenGLVideoIOBridge::VideoFrameArrived(const VideoIOFrame& inputFrame)
 
 	const long textureSize = inputFrame.rowBytes * static_cast<long>(inputFrame.height);
 
-	EnterCriticalSection(&mMutex);
+	// Never let input upload stall the playout/render callback. If the GL bridge
+	// is busy producing an output frame, skip this upload and use the next input.
+	if (!TryEnterCriticalSection(&mMutex))
+		return;
 
 	wglMakeCurrent(mHdc, mHglrc);		// make OpenGL context current in this thread
 
@@ -97,83 +96,29 @@ void OpenGLVideoIOBridge::PlayoutFrameCompleted(const VideoIOCompletion& complet
 {
 	RecordFramePacing(completion.result);
 
-	EnterCriticalSection(&mMutex);
-
 	VideoIOOutputFrame outputFrame;
 	if (!mVideoIO.BeginOutputFrame(outputFrame))
-	{
-		LeaveCriticalSection(&mMutex);
 		return;
-	}
 	const VideoIOState& state = mVideoIO.State();
 	RenderPipelineFrameContext frameContext;
 	frameContext.videoState = state;
 	frameContext.completion = completion;
 
+	EnterCriticalSection(&mMutex);
+
 	// make GL context current in this thread
 	wglMakeCurrent(mHdc, mHglrc);
 
-	// Draw the effect output to the off-screen framebuffer.
-	const auto renderStartTime = std::chrono::steady_clock::now();
-	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
-	mRenderEffect();
-	glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.CompositeFramebuffer());
-	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mRenderer.OutputFramebuffer());
-	glBlitFramebuffer(0, 0, state.inputFrameSize.width, state.inputFrameSize.height, 0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_COLOR_BUFFER_BIT, GL_LINEAR);
-	glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.OutputFramebuffer());
-	if (mOutputReady)
-		mOutputReady();
-	if (state.outputPixelFormat == VideoIOPixelFormat::V210)
-	{
-		glBindFramebuffer(GL_FRAMEBUFFER, mRenderer.OutputPackFramebuffer());
-		glViewport(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height);
-		glDisable(GL_SCISSOR_TEST);
-		glDisable(GL_BLEND);
-		glDisable(GL_DEPTH_TEST);
-		glActiveTexture(GL_TEXTURE0);
-		glBindTexture(GL_TEXTURE_2D, mRenderer.OutputTexture());
-		glBindVertexArray(mRenderer.FullscreenVertexArray());
-		glUseProgram(mRenderer.OutputPackProgram());
-		const GLint outputResolutionLocation = glGetUniformLocation(mRenderer.OutputPackProgram(), "uOutputVideoResolution");
-		const GLint activeWordsLocation = glGetUniformLocation(mRenderer.OutputPackProgram(), "uActiveV210Words");
-		if (outputResolutionLocation >= 0)
-			glUniform2f(outputResolutionLocation, static_cast<float>(state.outputFrameSize.width), static_cast<float>(state.outputFrameSize.height));
-		if (activeWordsLocation >= 0)
-			glUniform1f(activeWordsLocation, static_cast<float>(ActiveV210WordsForWidth(state.outputFrameSize.width)));
-		glDrawArrays(GL_TRIANGLES, 0, 3);
-		glUseProgram(0);
-		glBindVertexArray(0);
-		glBindTexture(GL_TEXTURE_2D, 0);
-	}
-	glFlush();
-	const auto renderEndTime = std::chrono::steady_clock::now();
-	const double frameBudgetMilliseconds = state.frameBudgetMilliseconds;
-	const double renderMilliseconds = std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(renderEndTime - renderStartTime).count();
-	mRuntimeHost.TrySetPerformanceStats(frameBudgetMilliseconds, renderMilliseconds);
-	mRuntimeHost.TryAdvanceFrame();
+	mRenderPipeline.RenderFrame(frameContext, outputFrame);
+	wglMakeCurrent(NULL, NULL);
 
-	glPixelStorei(GL_PACK_ALIGNMENT, 4);
-	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
-	if (state.outputPixelFormat == VideoIOPixelFormat::V210)
-	{
-		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputPackFramebuffer());
-		glReadPixels(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height, GL_RGBA, GL_UNSIGNED_BYTE, outputFrame.bytes);
-	}
-	else
-	{
-		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputFramebuffer());
-		glReadPixels(0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, outputFrame.bytes);
-	}
-	mPaint();
+	LeaveCriticalSection(&mMutex);
 
 	mVideoIO.EndOutputFrame(outputFrame);
 
 	mVideoIO.AccountForCompletionResult(completion.result);
 
-	// Schedule the next frame for playout
+	// Schedule the next frame for playout after the GL bridge is released so
+	// input uploads are not blocked by non-GL output bookkeeping.
 	mVideoIO.ScheduleOutputFrame(outputFrame);
-
-	wglMakeCurrent(NULL, NULL);
-
-	LeaveCriticalSection(&mMutex);
 }

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.h

@@ -1,39 +1,25 @@
 #pragma once
 
-#include "VideoIOTypes.h"
+#include "OpenGLRenderPipeline.h"
 
 #include <windows.h>
 
 #include <chrono>
-#include <functional>
 #include <cstdint>
 
-class OpenGLRenderer;
 class RuntimeHost;
 
-struct RenderPipelineFrameContext
-{
-	VideoIOState videoState;
-	VideoIOCompletion completion;
-};
-
 class OpenGLVideoIOBridge
 {
 public:
-	using RenderEffectCallback = std::function<void()>;
-	using OutputReadyCallback = std::function<void()>;
-	using PaintCallback = std::function<void()>;
-
 	OpenGLVideoIOBridge(
 		VideoIODevice& videoIO,
 		OpenGLRenderer& renderer,
+		OpenGLRenderPipeline& renderPipeline,
 		RuntimeHost& runtimeHost,
 		CRITICAL_SECTION& mutex,
 		HDC hdc,
-		HGLRC hglrc,
-		RenderEffectCallback renderEffect,
-		OutputReadyCallback outputReady,
-		PaintCallback paint);
+		HGLRC hglrc);
 
 	void VideoFrameArrived(const VideoIOFrame& inputFrame);
 	void PlayoutFrameCompleted(const VideoIOCompletion& completion);
@@ -43,13 +29,11 @@ private:
 
 	VideoIODevice& mVideoIO;
 	OpenGLRenderer& mRenderer;
+	OpenGLRenderPipeline& mRenderPipeline;
 	RuntimeHost& mRuntimeHost;
 	CRITICAL_SECTION& mMutex;
 	HDC mHdc;
 	HGLRC mHglrc;
-	RenderEffectCallback mRenderEffect;
-	OutputReadyCallback mOutputReady;
-	PaintCallback mPaint;
 	std::chrono::steady_clock::time_point mLastPlayoutCompletionTime;
 	double mCompletionIntervalMilliseconds = 0.0;
 	double mSmoothedCompletionIntervalMilliseconds = 0.0;

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/RenderPassDescriptor.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include "OpenGLRenderer.h"
+#include "ShaderTypes.h"
+
+#include <gl/gl.h>
+
+#include <cstddef>
+#include <string>
+
+enum class RenderPassKind
+{
+	LayerEffect
+};
+
+enum class RenderPassOutputTarget
+{
+	Temporary,
+	LayerTemp,
+	Composite
+};
+
+struct RenderPassDescriptor
+{
+	RenderPassKind kind = RenderPassKind::LayerEffect;
+	RenderPassOutputTarget outputTarget = RenderPassOutputTarget::Composite;
+	std::size_t passIndex = 0;
+	std::string passId;
+	std::string layerId;
+	std::string shaderId;
+	GLuint layerInputTexture = 0;
+	GLuint sourceTexture = 0;
+	GLuint sourceFramebuffer = 0;
+	GLuint destinationTexture = 0;
+	GLuint destinationFramebuffer = 0;
+	OpenGLRenderer::LayerProgram* layerProgram = nullptr;
+	OpenGLRenderer::LayerProgram::PassProgram* passProgram = nullptr;
+	const RuntimeRenderState* layerState = nullptr;
+	bool capturePreLayerHistory = false;
+	bool captureFeedbackWrite = false;
+};

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/ShaderFeedbackBuffers.cpp

@@ -0,0 +1,202 @@
+#include "ShaderFeedbackBuffers.h"
+
+#include <set>
+
+namespace
+{
+void ConfigureFeedbackTexture(unsigned frameWidth, unsigned frameHeight)
+{
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, frameWidth, frameHeight, 0, GL_RGBA, GL_FLOAT, NULL);
+}
+}
+
+bool ShaderFeedbackBuffers::EnsureResources(const std::vector<RuntimeRenderState>& layerStates, unsigned frameWidth, unsigned frameHeight, std::string& error)
+{
+	if (!EnsureZeroTexture())
+	{
+		error = "Failed to initialize shader feedback fallback texture.";
+		return false;
+	}
+
+	std::set<std::string> requiredLayerIds;
+	for (const RuntimeRenderState& state : layerStates)
+	{
+		if (!state.feedback.enabled)
+			continue;
+
+		requiredLayerIds.insert(state.layerId);
+		auto surfaceIt = mSurfacesByLayerId.find(state.layerId);
+		if (surfaceIt == mSurfacesByLayerId.end() ||
+			surfaceIt->second.width != frameWidth ||
+			surfaceIt->second.height != frameHeight)
+		{
+			Surface replacement;
+			if (!CreateSurface(replacement, frameWidth, frameHeight, error))
+				return false;
+			mSurfacesByLayerId[state.layerId] = std::move(replacement);
+		}
+	}
+
+	for (auto it = mSurfacesByLayerId.begin(); it != mSurfacesByLayerId.end();)
+	{
+		if (requiredLayerIds.find(it->first) == requiredLayerIds.end())
+		{
+			DestroySurface(it->second);
+			it = mSurfacesByLayerId.erase(it);
+		}
+		else
+		{
+			++it;
+		}
+	}
+
+	return true;
+}
+
+void ShaderFeedbackBuffers::DestroyResources()
+{
+	for (auto& entry : mSurfacesByLayerId)
+		DestroySurface(entry.second);
+	mSurfacesByLayerId.clear();
+
+	if (mZeroTexture != 0)
+	{
+		glDeleteTextures(1, &mZeroTexture);
+		mZeroTexture = 0;
+	}
+}
+
+void ShaderFeedbackBuffers::ResetState()
+{
+	for (auto& entry : mSurfacesByLayerId)
+		ClearSurfaceState(entry.second);
+}
+
+GLuint ShaderFeedbackBuffers::ResolveReadTexture(const RuntimeRenderState& state) const
+{
+	if (!state.feedback.enabled)
+		return mZeroTexture;
+
+	auto surfaceIt = mSurfacesByLayerId.find(state.layerId);
+	if (surfaceIt == mSurfacesByLayerId.end() || !surfaceIt->second.hasData)
+		return mZeroTexture;
+
+	return surfaceIt->second.slots[surfaceIt->second.readIndex].texture != 0
+		? surfaceIt->second.slots[surfaceIt->second.readIndex].texture
+		: mZeroTexture;
+}
+
+bool ShaderFeedbackBuffers::FeedbackAvailable(const RuntimeRenderState& state) const
+{
+	if (!state.feedback.enabled)
+		return false;
+
+	auto surfaceIt = mSurfacesByLayerId.find(state.layerId);
+	return surfaceIt != mSurfacesByLayerId.end() && surfaceIt->second.hasData;
+}
+
+void ShaderFeedbackBuffers::CaptureFeedbackFramebuffer(const std::string& layerId, GLuint sourceFramebuffer, unsigned frameWidth, unsigned frameHeight)
+{
+	auto surfaceIt = mSurfacesByLayerId.find(layerId);
+	if (surfaceIt == mSurfacesByLayerId.end())
+		return;
+
+	Surface& surface = surfaceIt->second;
+	const unsigned writeIndex = 1u - surface.readIndex;
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, sourceFramebuffer);
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, surface.slots[writeIndex].framebuffer);
+	glBlitFramebuffer(0, 0, frameWidth, frameHeight, 0, 0, frameWidth, frameHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+	surface.pendingWrite = true;
+}
+
+void ShaderFeedbackBuffers::FinalizeFrame()
+{
+	for (auto& entry : mSurfacesByLayerId)
+	{
+		Surface& surface = entry.second;
+		if (!surface.pendingWrite)
+			continue;
+
+		surface.readIndex = 1u - surface.readIndex;
+		surface.hasData = true;
+		surface.pendingWrite = false;
+	}
+}
+
+bool ShaderFeedbackBuffers::EnsureZeroTexture()
+{
+	if (mZeroTexture != 0)
+		return true;
+
+	glGenTextures(1, &mZeroTexture);
+	glBindTexture(GL_TEXTURE_2D, mZeroTexture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	const float zeroPixel[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, 1, 1, 0, GL_RGBA, GL_FLOAT, zeroPixel);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	return mZeroTexture != 0;
+}
+
+bool ShaderFeedbackBuffers::CreateSurface(Surface& surface, unsigned frameWidth, unsigned frameHeight, std::string& error)
+{
+	DestroySurface(surface);
+
+	surface.width = frameWidth;
+	surface.height = frameHeight;
+	for (Slot& slot : surface.slots)
+	{
+		glGenTextures(1, &slot.texture);
+		glBindTexture(GL_TEXTURE_2D, slot.texture);
+		ConfigureFeedbackTexture(frameWidth, frameHeight);
+
+		glGenFramebuffers(1, &slot.framebuffer);
+		glBindFramebuffer(GL_FRAMEBUFFER, slot.framebuffer);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, slot.texture, 0);
+		if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+		{
+			error = "Failed to initialize a shader feedback framebuffer.";
+			glBindFramebuffer(GL_FRAMEBUFFER, 0);
+			glBindTexture(GL_TEXTURE_2D, 0);
+			DestroySurface(surface);
+			return false;
+		}
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	ClearSurfaceState(surface);
+	return true;
+}
+
+void ShaderFeedbackBuffers::DestroySurface(Surface& surface)
+{
+	for (Slot& slot : surface.slots)
+	{
+		if (slot.framebuffer != 0)
+			glDeleteFramebuffers(1, &slot.framebuffer);
+		if (slot.texture != 0)
+			glDeleteTextures(1, &slot.texture);
+		slot.framebuffer = 0;
+		slot.texture = 0;
+	}
+
+	surface.width = 0;
+	surface.height = 0;
+	surface.readIndex = 0;
+	surface.hasData = false;
+	surface.pendingWrite = false;
+}
+
+void ShaderFeedbackBuffers::ClearSurfaceState(Surface& surface)
+{
+	surface.readIndex = 0;
+	surface.hasData = false;
+	surface.pendingWrite = false;
+}

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/ShaderFeedbackBuffers.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "GLExtensions.h"
+#include "ShaderTypes.h"
+
+#include <map>
+#include <string>
+#include <vector>
+
+class ShaderFeedbackBuffers
+{
+public:
+	struct Slot
+	{
+		GLuint texture = 0;
+		GLuint framebuffer = 0;
+	};
+
+	struct Surface
+	{
+		Slot slots[2];
+		unsigned width = 0;
+		unsigned height = 0;
+		unsigned readIndex = 0;
+		bool hasData = false;
+		bool pendingWrite = false;
+	};
+
+	bool EnsureResources(const std::vector<RuntimeRenderState>& layerStates, unsigned frameWidth, unsigned frameHeight, std::string& error);
+	void DestroyResources();
+	void ResetState();
+	GLuint ResolveReadTexture(const RuntimeRenderState& state) const;
+	bool FeedbackAvailable(const RuntimeRenderState& state) const;
+	void CaptureFeedbackFramebuffer(const std::string& layerId, GLuint sourceFramebuffer, unsigned frameWidth, unsigned frameHeight);
+	void FinalizeFrame();
+
+private:
+	bool EnsureZeroTexture();
+	bool CreateSurface(Surface& surface, unsigned frameWidth, unsigned frameHeight, std::string& error);
+	void DestroySurface(Surface& surface);
+	void ClearSurfaceState(Surface& surface);
+
+private:
+	std::map<std::string, Surface> mSurfacesByLayerId;
+	GLuint mZeroTexture = 0;
+};

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/TemporalHistoryBuffers.cpp

@@ -19,7 +19,8 @@ bool TemporalHistoryBuffers::ValidateTextureUnitBudget(const std::vector<Runtime
 				++textTextureCount;
 		}
 		const unsigned totalShaderTextures = static_cast<unsigned>(state.textureAssets.size()) + textTextureCount;
-		const unsigned layerRequiredUnits = kSourceHistoryTextureUnitBase + (state.isTemporal ? historyCap + historyCap : 0u) + totalShaderTextures;
+		const unsigned feedbackTextureCount = state.feedback.enabled ? 1u : 0u;
+		const unsigned layerRequiredUnits = kSourceHistoryTextureUnitBase + (state.isTemporal ? historyCap + historyCap : 0u) + feedbackTextureCount + totalShaderTextures;
 		if (layerRequiredUnits > requiredUnits)
 			requiredUnits = layerRequiredUnits;
 	}
@@ -212,6 +213,29 @@ void TemporalHistoryBuffers::BindSamplers(const RuntimeRenderState& state, GLuin
 	glActiveTexture(GL_TEXTURE0);
 }
 
+std::vector<GLuint> TemporalHistoryBuffers::ResolveSourceHistoryTextures(GLuint fallbackTexture, unsigned historyCap) const
+{
+	std::vector<GLuint> textures;
+	textures.reserve(historyCap);
+	for (unsigned index = 0; index < historyCap; ++index)
+		textures.push_back(ResolveTexture(sourceHistoryRing, fallbackTexture, index));
+	return textures;
+}
+
+std::vector<GLuint> TemporalHistoryBuffers::ResolveTemporalHistoryTextures(const RuntimeRenderState& state, GLuint fallbackTexture, unsigned historyCap) const
+{
+	const Ring* temporalRing = nullptr;
+	auto it = preLayerHistoryByLayerId.find(state.layerId);
+	if (it != preLayerHistoryByLayerId.end())
+		temporalRing = &it->second;
+
+	std::vector<GLuint> textures;
+	textures.reserve(historyCap);
+	for (unsigned index = 0; index < historyCap; ++index)
+		textures.push_back(temporalRing ? ResolveTexture(*temporalRing, fallbackTexture, index) : fallbackTexture);
+	return textures;
+}
+
 GLuint TemporalHistoryBuffers::ResolveTexture(const Ring& ring, GLuint fallbackTexture, std::size_t framesAgo) const
 {
 	if (ring.filledCount == 0 || ring.slots.empty())

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/TemporalHistoryBuffers.h

@@ -40,6 +40,8 @@ public:
 	void PushSourceFramebuffer(GLuint sourceFramebuffer, unsigned frameWidth, unsigned frameHeight);
 	void PushPreLayerFramebuffer(const std::string& layerId, GLuint sourceFramebuffer, unsigned frameWidth, unsigned frameHeight);
 	void BindSamplers(const RuntimeRenderState& state, GLuint currentSourceTexture, unsigned historyCap);
+	std::vector<GLuint> ResolveSourceHistoryTextures(GLuint fallbackTexture, unsigned historyCap) const;
+	std::vector<GLuint> ResolveTemporalHistoryTextures(const RuntimeRenderState& state, GLuint fallbackTexture, unsigned historyCap) const;
 	GLuint ResolveTexture(const Ring& ring, GLuint fallbackTexture, std::size_t framesAgo) const;
 	unsigned SourceAvailableCount() const;
 	unsigned AvailableCountForLayer(const std::string& layerId) const;

apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.cpp

@@ -62,6 +62,8 @@ PFNGLGENBUFFERSPROC glGenBuffers;
 PFNGLDELETEBUFFERSPROC glDeleteBuffers;
 PFNGLBINDBUFFERPROC glBindBuffer;
 PFNGLBUFFERDATAPROC glBufferData;
+PFNGLMAPBUFFERPROC glMapBuffer;
+PFNGLUNMAPBUFFERPROC glUnmapBuffer;
 PFNGLBUFFERSUBDATAPROC glBufferSubData;
 PFNGLBINDBUFFERBASEPROC glBindBufferBase;
 PFNGLACTIVETEXTUREPROC glActiveTexture;
@@ -131,6 +133,8 @@ bool ResolveGLExtensions()
 	glDeleteBuffers = (PFNGLDELETEBUFFERSPROC) wglGetProcAddress("glDeleteBuffers");
 	glBindBuffer = (PFNGLBINDBUFFERPROC) wglGetProcAddress("glBindBuffer");
 	glBufferData = (PFNGLBUFFERDATAPROC) wglGetProcAddress("glBufferData");
+	glMapBuffer = (PFNGLMAPBUFFERPROC) wglGetProcAddress("glMapBuffer");
+	glUnmapBuffer = (PFNGLUNMAPBUFFERPROC) wglGetProcAddress("glUnmapBuffer");
 	glBufferSubData = (PFNGLBUFFERSUBDATAPROC) wglGetProcAddress("glBufferSubData");
 	glBindBufferBase = (PFNGLBINDBUFFERBASEPROC) wglGetProcAddress("glBindBufferBase");
 	glActiveTexture = (PFNGLACTIVETEXTUREPROC) wglGetProcAddress("glActiveTexture");
@@ -176,6 +180,8 @@ bool ResolveGLExtensions()
 			&& glDeleteBuffers
 			&& glBindBuffer
 			&& glBufferData
+			&& glMapBuffer
+			&& glUnmapBuffer
 			&& glBufferSubData
 			&& glBindBufferBase
 			&& glActiveTexture

apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.h

@@ -89,6 +89,11 @@
 #define GL_EXTERNAL_VIRTUAL_MEMORY_BUFFER_AMD	0x9160
 #define GL_SYNC_GPU_COMMANDS_COMPLETE			0x9117
 #define GL_SYNC_FLUSH_COMMANDS_BIT				0x00000001
+#define GL_ALREADY_SIGNALED						0x911A
+#define GL_TIMEOUT_EXPIRED						0x911B
+#define GL_CONDITION_SATISFIED					0x911C
+#define GL_WAIT_FAILED							0x911D
+#define GL_READ_ONLY							0x88B8
 
 typedef struct __GLsync *GLsync;
 typedef unsigned __int64 GLuint64;
@@ -100,6 +105,8 @@ typedef void (APIENTRYP PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
 typedef void (APIENTRYP PFNGLDELETEBUFFERSPROC) (GLsizei n, const GLuint *buffers);
 typedef void (APIENTRYP PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
 typedef void (APIENTRYP PFNGLBUFFERDATAPROC) (GLenum target, GLsizeiptr size, const GLvoid *data, GLenum usage);
+typedef GLvoid* (APIENTRYP PFNGLMAPBUFFERPROC) (GLenum target, GLenum access);
+typedef GLboolean (APIENTRYP PFNGLUNMAPBUFFERPROC) (GLenum target);
 typedef void (APIENTRYP PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
 typedef void (APIENTRYP PFNGLCOMPILESHADERPROC) (GLuint shader);
 typedef GLuint (APIENTRYP PFNGLCREATEPROGRAMPROC) (void);
@@ -159,6 +166,8 @@ extern PFNGLGENBUFFERSPROC glGenBuffers;
 extern PFNGLDELETEBUFFERSPROC glDeleteBuffers;
 extern PFNGLBINDBUFFERPROC glBindBuffer;
 extern PFNGLBUFFERDATAPROC glBufferData;
+extern PFNGLMAPBUFFERPROC glMapBuffer;
+extern PFNGLUNMAPBUFFERPROC glUnmapBuffer;
 extern PFNGLBUFFERSUBDATAPROC glBufferSubData;
 extern PFNGLBINDBUFFERBASEPROC glBindBufferBase;
 extern PFNGLACTIVETEXTUREPROC glActiveTexture;

apps/LoopThroughWithOpenGLCompositing/gl/renderer/GlRenderConstants.h

@@ -2,8 +2,9 @@
 
 #include <gl/gl.h>
 
+constexpr GLuint kLayerInputTextureUnit = 0;
 constexpr GLuint kDecodedVideoTextureUnit = 1;
 constexpr GLuint kSourceHistoryTextureUnitBase = 2;
 constexpr GLuint kPackedVideoTextureUnit = 2;
 constexpr GLuint kGlobalParamsBindingPoint = 0;
-constexpr unsigned kPrerollFrameCount = 8;
+constexpr unsigned kPrerollFrameCount = 12;

apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.cpp

@@ -12,15 +12,6 @@ namespace
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 	}
-
-	void ConfigureDisplayFrameTexture(unsigned width, unsigned height)
-	{
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, width, height, 0, GL_RGBA, GL_FLOAT, NULL);
-	}
 }
 
 bool OpenGLRenderer::InitializeResources(unsigned inputFrameWidth, unsigned inputFrameHeight, unsigned captureTextureWidth, unsigned outputFrameWidth, unsigned outputFrameHeight, unsigned outputPackTextureWidth, std::string& error)
@@ -35,80 +26,32 @@ bool OpenGLRenderer::InitializeResources(unsigned inputFrameWidth, unsigned inpu
 	ConfigureByteFrameTexture(captureTextureWidth, inputFrameHeight);
 	glBindTexture(GL_TEXTURE_2D, 0);
 
-	glGenTextures(1, &mDecodedTexture);
-	glBindTexture(GL_TEXTURE_2D, mDecodedTexture);
-	ConfigureDisplayFrameTexture(inputFrameWidth, inputFrameHeight);
-	glBindTexture(GL_TEXTURE_2D, 0);
-
-	glGenTextures(1, &mLayerTempTexture);
-	glBindTexture(GL_TEXTURE_2D, mLayerTempTexture);
-	ConfigureDisplayFrameTexture(inputFrameWidth, inputFrameHeight);
-	glBindTexture(GL_TEXTURE_2D, 0);
-
-	glGenFramebuffers(1, &mDecodeFrameBuf);
-	glGenFramebuffers(1, &mLayerTempFrameBuf);
-	glGenFramebuffers(1, &mIdFrameBuf);
-	glGenFramebuffers(1, &mOutputFrameBuf);
-	glGenFramebuffers(1, &mOutputPackFrameBuf);
 	glGenRenderbuffers(1, &mIdColorBuf);
 	glGenRenderbuffers(1, &mIdDepthBuf);
 	glGenVertexArrays(1, &mFullscreenVAO);
 	glGenBuffers(1, &mGlobalParamsUBO);
 
-	glBindFramebuffer(GL_FRAMEBUFFER, mDecodeFrameBuf);
-	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mDecodedTexture, 0);
-	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
-	{
-		error = "Cannot initialize decode framebuffer.";
+	if (!mRenderTargets.Create(RenderTargetId::Decoded, inputFrameWidth, inputFrameHeight, GL_RGBA16F, GL_RGBA, GL_FLOAT, "decode", error))
 		return false;
-	}
-
-	glBindFramebuffer(GL_FRAMEBUFFER, mLayerTempFrameBuf);
-	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mLayerTempTexture, 0);
-	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
-	{
-		error = "Cannot initialize layer framebuffer.";
+	if (!mRenderTargets.Create(RenderTargetId::LayerTemp, inputFrameWidth, inputFrameHeight, GL_RGBA16F, GL_RGBA, GL_FLOAT, "layer", error))
+		return false;
+	if (!mRenderTargets.Create(RenderTargetId::Composite, inputFrameWidth, inputFrameHeight, GL_RGBA16F, GL_RGBA, GL_FLOAT, "composite", error))
 		return false;
-	}
-
-	glBindFramebuffer(GL_FRAMEBUFFER, mIdFrameBuf);
-	glGenTextures(1, &mFBOTexture);
-	glBindTexture(GL_TEXTURE_2D, mFBOTexture);
-	ConfigureDisplayFrameTexture(inputFrameWidth, inputFrameHeight);
 
+	glBindFramebuffer(GL_FRAMEBUFFER, CompositeFramebuffer());
 	glBindRenderbuffer(GL_RENDERBUFFER, mIdDepthBuf);
 	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, inputFrameWidth, inputFrameHeight);
 	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER, mIdDepthBuf);
-	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mFBOTexture, 0);
 	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
 	{
 		error = "Cannot initialize framebuffer.";
 		return false;
 	}
 
-	glGenTextures(1, &mOutputTexture);
-	glBindTexture(GL_TEXTURE_2D, mOutputTexture);
-	ConfigureDisplayFrameTexture(outputFrameWidth, outputFrameHeight);
-
-	glBindFramebuffer(GL_FRAMEBUFFER, mOutputFrameBuf);
-	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mOutputTexture, 0);
-	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
-	{
-		error = "Cannot initialize output framebuffer.";
+	if (!mRenderTargets.Create(RenderTargetId::Output, outputFrameWidth, outputFrameHeight, GL_RGBA16F, GL_RGBA, GL_FLOAT, "output", error))
 		return false;
-	}
-
-	glGenTextures(1, &mOutputPackTexture);
-	glBindTexture(GL_TEXTURE_2D, mOutputPackTexture);
-	ConfigureByteFrameTexture(outputPackTextureWidth, outputFrameHeight);
-
-	glBindFramebuffer(GL_FRAMEBUFFER, mOutputPackFrameBuf);
-	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mOutputPackTexture, 0);
-	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
-	{
-		error = "Cannot initialize output pack framebuffer.";
+	if (!mRenderTargets.Create(RenderTargetId::OutputPack, outputPackTextureWidth, outputFrameHeight, GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE, "output pack", error))
 		return false;
-	}
 
 	glBindTexture(GL_TEXTURE_2D, 0);
 	glBindRenderbuffer(GL_RENDERBUFFER, 0);
@@ -120,6 +63,7 @@ bool OpenGLRenderer::InitializeResources(unsigned inputFrameWidth, unsigned inpu
 	glBindBufferBase(GL_UNIFORM_BUFFER, kGlobalParamsBindingPoint, mGlobalParamsUBO);
 	glBindBuffer(GL_UNIFORM_BUFFER, 0);
 
+	mResourcesInitialized = true;
 	return true;
 }
 
@@ -128,6 +72,9 @@ void OpenGLRenderer::SetDecodeShaderProgram(GLuint program, GLuint vertexShader,
 	mDecodeProgram = program;
 	mDecodeVertexShader = vertexShader;
 	mDecodeFragmentShader = fragmentShader;
+	mDecodePackedResolutionLocation = program != 0 ? glGetUniformLocation(program, "uPackedVideoResolution") : -1;
+	mDecodeDecodedResolutionLocation = program != 0 ? glGetUniformLocation(program, "uDecodedVideoResolution") : -1;
+	mDecodeInputPixelFormatLocation = program != 0 ? glGetUniformLocation(program, "uInputPixelFormat") : -1;
 }
 
 void OpenGLRenderer::SetOutputPackShaderProgram(GLuint program, GLuint vertexShader, GLuint fragmentShader)
@@ -135,6 +82,14 @@ void OpenGLRenderer::SetOutputPackShaderProgram(GLuint program, GLuint vertexSha
 	mOutputPackProgram = program;
 	mOutputPackVertexShader = vertexShader;
 	mOutputPackFragmentShader = fragmentShader;
+	mOutputPackResolutionLocation = program != 0 ? glGetUniformLocation(program, "uOutputVideoResolution") : -1;
+	mOutputPackActiveWordsLocation = program != 0 ? glGetUniformLocation(program, "uActiveV210Words") : -1;
+	mOutputPackFormatLocation = program != 0 ? glGetUniformLocation(program, "uOutputPackFormat") : -1;
+}
+
+bool OpenGLRenderer::ReserveTemporaryRenderTargets(std::size_t count, unsigned width, unsigned height, std::string& error)
+{
+	return mRenderTargets.ReserveTemporaryTargets(count, width, height, GL_RGBA16F, GL_RGBA, GL_FLOAT, error);
 }
 
 void OpenGLRenderer::ResizeView(int width, int height)
@@ -169,7 +124,7 @@ void OpenGLRenderer::PresentToWindow(HDC hdc, unsigned outputFrameWidth, unsigne
 		}
 	}
 
-	glBindFramebuffer(GL_READ_FRAMEBUFFER, mOutputFrameBuf);
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, OutputFramebuffer());
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 	glDisable(GL_SCISSOR_TEST);
 	glViewport(0, 0, mViewWidth, mViewHeight);
@@ -186,54 +141,27 @@ void OpenGLRenderer::DestroyResources()
 		glDeleteVertexArrays(1, &mFullscreenVAO);
 	if (mGlobalParamsUBO != 0)
 		glDeleteBuffers(1, &mGlobalParamsUBO);
-	if (mDecodeFrameBuf != 0)
-		glDeleteFramebuffers(1, &mDecodeFrameBuf);
-	if (mLayerTempFrameBuf != 0)
-		glDeleteFramebuffers(1, &mLayerTempFrameBuf);
-	if (mIdFrameBuf != 0)
-		glDeleteFramebuffers(1, &mIdFrameBuf);
-	if (mOutputFrameBuf != 0)
-		glDeleteFramebuffers(1, &mOutputFrameBuf);
-	if (mOutputPackFrameBuf != 0)
-		glDeleteFramebuffers(1, &mOutputPackFrameBuf);
 	if (mIdColorBuf != 0)
 		glDeleteRenderbuffers(1, &mIdColorBuf);
 	if (mIdDepthBuf != 0)
 		glDeleteRenderbuffers(1, &mIdDepthBuf);
 	if (mCaptureTexture != 0)
 		glDeleteTextures(1, &mCaptureTexture);
-	if (mDecodedTexture != 0)
-		glDeleteTextures(1, &mDecodedTexture);
-	if (mLayerTempTexture != 0)
-		glDeleteTextures(1, &mLayerTempTexture);
-	if (mFBOTexture != 0)
-		glDeleteTextures(1, &mFBOTexture);
-	if (mOutputTexture != 0)
-		glDeleteTextures(1, &mOutputTexture);
-	if (mOutputPackTexture != 0)
-		glDeleteTextures(1, &mOutputPackTexture);
 	if (mTextureUploadBuffer != 0)
 		glDeleteBuffers(1, &mTextureUploadBuffer);
+	mRenderTargets.Destroy();
 
 	mFullscreenVAO = 0;
 	mGlobalParamsUBO = 0;
-	mDecodeFrameBuf = 0;
-	mLayerTempFrameBuf = 0;
-	mIdFrameBuf = 0;
-	mOutputFrameBuf = 0;
-	mOutputPackFrameBuf = 0;
 	mIdColorBuf = 0;
 	mIdDepthBuf = 0;
 	mCaptureTexture = 0;
-	mDecodedTexture = 0;
-	mLayerTempTexture = 0;
-	mFBOTexture = 0;
-	mOutputTexture = 0;
-	mOutputPackTexture = 0;
 	mTextureUploadBuffer = 0;
 	mGlobalParamsUBOSize = 0;
+	mResourcesInitialized = false;
 
 	mTemporalHistory.DestroyResources();
+	mFeedbackBuffers.DestroyResources();
 	DestroyLayerPrograms();
 	DestroyDecodeShaderProgram();
 	DestroyOutputPackShaderProgram();
@@ -241,43 +169,47 @@ void OpenGLRenderer::DestroyResources()
 
 void OpenGLRenderer::DestroySingleLayerProgram(LayerProgram& layerProgram)
 {
-	for (LayerProgram::TextureBinding& binding : layerProgram.textureBindings)
+	for (LayerProgram::PassProgram& passProgram : layerProgram.passes)
 	{
-		if (binding.texture != 0)
+		for (LayerProgram::TextureBinding& binding : passProgram.textureBindings)
 		{
-			glDeleteTextures(1, &binding.texture);
-			binding.texture = 0;
+			if (binding.texture != 0)
+			{
+				glDeleteTextures(1, &binding.texture);
+				binding.texture = 0;
+			}
+		}
+		passProgram.textureBindings.clear();
+
+		for (LayerProgram::TextBinding& binding : passProgram.textBindings)
+		{
+			if (binding.texture != 0)
+			{
+				glDeleteTextures(1, &binding.texture);
+				binding.texture = 0;
+			}
+		}
+		passProgram.textBindings.clear();
+
+		if (passProgram.program != 0)
+		{
+			glDeleteProgram(passProgram.program);
+			passProgram.program = 0;
+		}
+
+		if (passProgram.fragmentShader != 0)
+		{
+			glDeleteShader(passProgram.fragmentShader);
+			passProgram.fragmentShader = 0;
+		}
+
+		if (passProgram.vertexShader != 0)
+		{
+			glDeleteShader(passProgram.vertexShader);
+			passProgram.vertexShader = 0;
 		}
 	}
-	layerProgram.textureBindings.clear();
-
-	for (LayerProgram::TextBinding& binding : layerProgram.textBindings)
-	{
-		if (binding.texture != 0)
-		{
-			glDeleteTextures(1, &binding.texture);
-			binding.texture = 0;
-		}
-	}
-	layerProgram.textBindings.clear();
-
-	if (layerProgram.program != 0)
-	{
-		glDeleteProgram(layerProgram.program);
-		layerProgram.program = 0;
-	}
-
-	if (layerProgram.fragmentShader != 0)
-	{
-		glDeleteShader(layerProgram.fragmentShader);
-		layerProgram.fragmentShader = 0;
-	}
-
-	if (layerProgram.vertexShader != 0)
-	{
-		glDeleteShader(layerProgram.vertexShader);
-		layerProgram.vertexShader = 0;
-	}
+	layerProgram.passes.clear();
 }
 
 void OpenGLRenderer::DestroyLayerPrograms()
@@ -294,6 +226,9 @@ void OpenGLRenderer::DestroyDecodeShaderProgram()
 		glDeleteProgram(mDecodeProgram);
 		mDecodeProgram = 0;
 	}
+	mDecodePackedResolutionLocation = -1;
+	mDecodeDecodedResolutionLocation = -1;
+	mDecodeInputPixelFormatLocation = -1;
 
 	if (mDecodeFragmentShader != 0)
 	{
@@ -315,6 +250,9 @@ void OpenGLRenderer::DestroyOutputPackShaderProgram()
 		glDeleteProgram(mOutputPackProgram);
 		mOutputPackProgram = 0;
 	}
+	mOutputPackResolutionLocation = -1;
+	mOutputPackActiveWordsLocation = -1;
+	mOutputPackFormatLocation = -1;
 
 	if (mOutputPackFragmentShader != 0)
 	{

apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include "GLExtensions.h"
+#include "RenderTargetPool.h"
+#include "ShaderFeedbackBuffers.h"
 #include "ShaderTypes.h"
 #include "TemporalHistoryBuffers.h"
 
@@ -36,37 +38,58 @@ public:
 
 		std::string layerId;
 		std::string shaderId;
-		GLuint shaderTextureBase = 0;
-		GLuint program = 0;
-		GLuint vertexShader = 0;
-		GLuint fragmentShader = 0;
-		std::vector<TextureBinding> textureBindings;
-		std::vector<TextBinding> textBindings;
+
+		struct PassProgram
+		{
+			std::string passId;
+			std::vector<std::string> inputNames;
+			std::string outputName;
+			GLuint shaderTextureBase = 0;
+			GLuint program = 0;
+			GLuint vertexShader = 0;
+			GLuint fragmentShader = 0;
+			std::vector<TextureBinding> textureBindings;
+			std::vector<TextBinding> textBindings;
+		};
+
+		std::vector<PassProgram> passes;
 	};
 
 	GLuint CaptureTexture() const { return mCaptureTexture; }
-	GLuint DecodedTexture() const { return mDecodedTexture; }
-	GLuint LayerTempTexture() const { return mLayerTempTexture; }
-	GLuint CompositeTexture() const { return mFBOTexture; }
-	GLuint OutputTexture() const { return mOutputTexture; }
-	GLuint OutputPackTexture() const { return mOutputPackTexture; }
+	GLuint DecodedTexture() const { return mRenderTargets.Texture(RenderTargetId::Decoded); }
+	GLuint LayerTempTexture() const { return mRenderTargets.Texture(RenderTargetId::LayerTemp); }
+	GLuint CompositeTexture() const { return mRenderTargets.Texture(RenderTargetId::Composite); }
+	GLuint OutputTexture() const { return mRenderTargets.Texture(RenderTargetId::Output); }
+	GLuint OutputPackTexture() const { return mRenderTargets.Texture(RenderTargetId::OutputPack); }
 	GLuint TextureUploadBuffer() const { return mTextureUploadBuffer; }
-	GLuint DecodeFramebuffer() const { return mDecodeFrameBuf; }
-	GLuint LayerTempFramebuffer() const { return mLayerTempFrameBuf; }
-	GLuint CompositeFramebuffer() const { return mIdFrameBuf; }
-	GLuint OutputFramebuffer() const { return mOutputFrameBuf; }
-	GLuint OutputPackFramebuffer() const { return mOutputPackFrameBuf; }
+	GLuint DecodeFramebuffer() const { return mRenderTargets.Framebuffer(RenderTargetId::Decoded); }
+	GLuint LayerTempFramebuffer() const { return mRenderTargets.Framebuffer(RenderTargetId::LayerTemp); }
+	GLuint CompositeFramebuffer() const { return mRenderTargets.Framebuffer(RenderTargetId::Composite); }
+	GLuint OutputFramebuffer() const { return mRenderTargets.Framebuffer(RenderTargetId::Output); }
+	GLuint OutputPackFramebuffer() const { return mRenderTargets.Framebuffer(RenderTargetId::OutputPack); }
 	GLuint FullscreenVertexArray() const { return mFullscreenVAO; }
 	GLuint GlobalParamsUBO() const { return mGlobalParamsUBO; }
 	GLuint DecodeProgram() const { return mDecodeProgram; }
 	GLuint OutputPackProgram() const { return mOutputPackProgram; }
+	GLint DecodePackedResolutionLocation() const { return mDecodePackedResolutionLocation; }
+	GLint DecodeDecodedResolutionLocation() const { return mDecodeDecodedResolutionLocation; }
+	GLint DecodeInputPixelFormatLocation() const { return mDecodeInputPixelFormatLocation; }
+	GLint OutputPackResolutionLocation() const { return mOutputPackResolutionLocation; }
+	GLint OutputPackActiveWordsLocation() const { return mOutputPackActiveWordsLocation; }
+	GLint OutputPackFormatLocation() const { return mOutputPackFormatLocation; }
 	GLsizeiptr GlobalParamsUBOSize() const { return mGlobalParamsUBOSize; }
 	void SetGlobalParamsUBOSize(GLsizeiptr size) { mGlobalParamsUBOSize = size; }
+	bool ResourcesInitialized() const { return mResourcesInitialized; }
 	void ReplaceLayerPrograms(std::vector<LayerProgram>& newPrograms) { mLayerPrograms.swap(newPrograms); }
 	std::vector<LayerProgram>& LayerPrograms() { return mLayerPrograms; }
 	const std::vector<LayerProgram>& LayerPrograms() const { return mLayerPrograms; }
+	bool ReserveTemporaryRenderTargets(std::size_t count, unsigned width, unsigned height, std::string& error);
+	const RenderTarget& TemporaryRenderTarget(std::size_t index) const { return mRenderTargets.TemporaryTarget(index); }
+	std::size_t TemporaryRenderTargetCount() const { return mRenderTargets.TemporaryTargetCount(); }
 	TemporalHistoryBuffers& TemporalHistory() { return mTemporalHistory; }
 	const TemporalHistoryBuffers& TemporalHistory() const { return mTemporalHistory; }
+	ShaderFeedbackBuffers& FeedbackBuffers() { return mFeedbackBuffers; }
+	const ShaderFeedbackBuffers& FeedbackBuffers() const { return mFeedbackBuffers; }
 	void SetDecodeShaderProgram(GLuint program, GLuint vertexShader, GLuint fragmentShader);
 	void SetOutputPackShaderProgram(GLuint program, GLuint vertexShader, GLuint fragmentShader);
 	bool InitializeResources(unsigned inputFrameWidth, unsigned inputFrameHeight, unsigned captureTextureWidth, unsigned outputFrameWidth, unsigned outputFrameHeight, unsigned outputPackTextureWidth, std::string& error);
@@ -80,17 +103,7 @@ public:
 
 private:
 	GLuint mCaptureTexture = 0;
-	GLuint mDecodedTexture = 0;
-	GLuint mLayerTempTexture = 0;
-	GLuint mFBOTexture = 0;
-	GLuint mOutputTexture = 0;
-	GLuint mOutputPackTexture = 0;
 	GLuint mTextureUploadBuffer = 0;
-	GLuint mDecodeFrameBuf = 0;
-	GLuint mLayerTempFrameBuf = 0;
-	GLuint mIdFrameBuf = 0;
-	GLuint mOutputFrameBuf = 0;
-	GLuint mOutputPackFrameBuf = 0;
 	GLuint mIdColorBuf = 0;
 	GLuint mIdDepthBuf = 0;
 	GLuint mFullscreenVAO = 0;
@@ -98,12 +111,21 @@ private:
 	GLuint mDecodeProgram = 0;
 	GLuint mDecodeVertexShader = 0;
 	GLuint mDecodeFragmentShader = 0;
+	GLint mDecodePackedResolutionLocation = -1;
+	GLint mDecodeDecodedResolutionLocation = -1;
+	GLint mDecodeInputPixelFormatLocation = -1;
 	GLuint mOutputPackProgram = 0;
 	GLuint mOutputPackVertexShader = 0;
 	GLuint mOutputPackFragmentShader = 0;
+	GLint mOutputPackResolutionLocation = -1;
+	GLint mOutputPackActiveWordsLocation = -1;
+	GLint mOutputPackFormatLocation = -1;
 	GLsizeiptr mGlobalParamsUBOSize = 0;
+	bool mResourcesInitialized = false;
 	int mViewWidth = 0;
 	int mViewHeight = 0;
 	std::vector<LayerProgram> mLayerPrograms;
+	RenderTargetPool mRenderTargets;
 	TemporalHistoryBuffers mTemporalHistory;
+	ShaderFeedbackBuffers mFeedbackBuffers;
 };

apps/LoopThroughWithOpenGLCompositing/gl/renderer/RenderTargetPool.cpp

@@ -0,0 +1,136 @@
+#include "RenderTargetPool.h"
+
+#include <cstddef>
+
+namespace
+{
+	void ConfigureRenderTargetTexture(
+		unsigned width,
+		unsigned height,
+		GLenum internalFormat,
+		GLenum pixelFormat,
+		GLenum pixelType)
+	{
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+		glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, width, height, 0, pixelFormat, pixelType, NULL);
+	}
+}
+
+bool RenderTargetPool::Create(
+	RenderTargetId id,
+	unsigned width,
+	unsigned height,
+	GLenum internalFormat,
+	GLenum pixelFormat,
+	GLenum pixelType,
+	const char* errorPrefix,
+	std::string& error)
+{
+	RenderTarget& target = mTargets[TargetIndex(id)];
+	if (target.texture != 0 || target.framebuffer != 0)
+	{
+		error = std::string(errorPrefix) + " render target was already initialized.";
+		return false;
+	}
+
+	glGenTextures(1, &target.texture);
+	glBindTexture(GL_TEXTURE_2D, target.texture);
+	ConfigureRenderTargetTexture(width, height, internalFormat, pixelFormat, pixelType);
+	glBindTexture(GL_TEXTURE_2D, 0);
+
+	glGenFramebuffers(1, &target.framebuffer);
+	glBindFramebuffer(GL_FRAMEBUFFER, target.framebuffer);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, target.texture, 0);
+	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+	{
+		error = std::string("Cannot initialize ") + errorPrefix + " framebuffer.";
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
+		return false;
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	target.width = width;
+	target.height = height;
+	target.internalFormat = internalFormat;
+	target.pixelFormat = pixelFormat;
+	target.pixelType = pixelType;
+	return true;
+}
+
+bool RenderTargetPool::ReserveTemporaryTargets(
+	std::size_t count,
+	unsigned width,
+	unsigned height,
+	GLenum internalFormat,
+	GLenum pixelFormat,
+	GLenum pixelType,
+	std::string& error)
+{
+	if (mTemporaryTargets.size() == count)
+		return true;
+
+	DestroyTemporaryTargets();
+
+	mTemporaryTargets.resize(count);
+	for (std::size_t index = 0; index < mTemporaryTargets.size(); ++index)
+	{
+		RenderTarget& target = mTemporaryTargets[index];
+		glGenTextures(1, &target.texture);
+		glBindTexture(GL_TEXTURE_2D, target.texture);
+		ConfigureRenderTargetTexture(width, height, internalFormat, pixelFormat, pixelType);
+		glBindTexture(GL_TEXTURE_2D, 0);
+
+		glGenFramebuffers(1, &target.framebuffer);
+		glBindFramebuffer(GL_FRAMEBUFFER, target.framebuffer);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, target.texture, 0);
+		if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+		{
+			error = "Cannot initialize temporary render target.";
+			glBindFramebuffer(GL_FRAMEBUFFER, 0);
+			return false;
+		}
+
+		target.width = width;
+		target.height = height;
+		target.internalFormat = internalFormat;
+		target.pixelFormat = pixelFormat;
+		target.pixelType = pixelType;
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	return true;
+}
+
+void RenderTargetPool::DestroyTemporaryTargets()
+{
+	for (RenderTarget& target : mTemporaryTargets)
+	{
+		if (target.framebuffer != 0)
+			glDeleteFramebuffers(1, &target.framebuffer);
+		if (target.texture != 0)
+			glDeleteTextures(1, &target.texture);
+	}
+	mTemporaryTargets.clear();
+}
+
+void RenderTargetPool::Destroy()
+{
+	for (RenderTarget& target : mTargets)
+	{
+		if (target.framebuffer != 0)
+			glDeleteFramebuffers(1, &target.framebuffer);
+		if (target.texture != 0)
+			glDeleteTextures(1, &target.texture);
+		target = RenderTarget();
+	}
+
+	DestroyTemporaryTargets();
+}
+
+const RenderTarget& RenderTargetPool::Target(RenderTargetId id) const
+{
+	return mTargets[TargetIndex(id)];
+}

apps/LoopThroughWithOpenGLCompositing/gl/renderer/RenderTargetPool.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#include "GLExtensions.h"
+
+#include <array>
+#include <string>
+#include <vector>
+
+enum class RenderTargetId
+{
+	Decoded,
+	LayerTemp,
+	Composite,
+	Output,
+	OutputPack,
+	Count
+};
+
+struct RenderTarget
+{
+	GLuint texture = 0;
+	GLuint framebuffer = 0;
+	unsigned width = 0;
+	unsigned height = 0;
+	GLenum internalFormat = GL_RGBA8;
+	GLenum pixelFormat = GL_RGBA;
+	GLenum pixelType = GL_UNSIGNED_BYTE;
+};
+
+class RenderTargetPool
+{
+public:
+	bool Create(
+		RenderTargetId id,
+		unsigned width,
+		unsigned height,
+		GLenum internalFormat,
+		GLenum pixelFormat,
+		GLenum pixelType,
+		const char* errorPrefix,
+		std::string& error);
+	bool ReserveTemporaryTargets(
+		std::size_t count,
+		unsigned width,
+		unsigned height,
+		GLenum internalFormat,
+		GLenum pixelFormat,
+		GLenum pixelType,
+		std::string& error);
+	void DestroyTemporaryTargets();
+	void Destroy();
+
+	GLuint Texture(RenderTargetId id) const { return Target(id).texture; }
+	GLuint Framebuffer(RenderTargetId id) const { return Target(id).framebuffer; }
+	const RenderTarget& Target(RenderTargetId id) const;
+	const RenderTarget& TemporaryTarget(std::size_t index) const { return mTemporaryTargets[index]; }
+	std::size_t TemporaryTargetCount() const { return mTemporaryTargets.size(); }
+
+private:
+	static std::size_t TargetIndex(RenderTargetId id) { return static_cast<std::size_t>(id); }
+
+	std::array<RenderTarget, static_cast<std::size_t>(RenderTargetId::Count)> mTargets;
+	std::vector<RenderTarget> mTemporaryTargets;
+};

apps/LoopThroughWithOpenGLCompositing/gl/shader/GlShaderSources.cpp

@@ -90,12 +90,17 @@ const char* kOutputPackFragmentShaderSource =
 	"layout(binding = 0) uniform sampler2D uOutputRgb;\n"
 	"uniform vec2 uOutputVideoResolution;\n"
 	"uniform float uActiveV210Words;\n"
+	"uniform int uOutputPackFormat;\n"
 	"in vec2 vTexCoord;\n"
 	"layout(location = 0) out vec4 fragColor;\n"
-	"vec3 rgbAt(int x, int y)\n"
+	"vec4 rgbaAt(int x, int y)\n"
 	"{\n"
 	"	ivec2 size = ivec2(max(uOutputVideoResolution, vec2(1.0, 1.0)));\n"
-	"	return clamp(texelFetch(uOutputRgb, ivec2(clamp(x, 0, size.x - 1), clamp(y, 0, size.y - 1)), 0).rgb, vec3(0.0), vec3(1.0));\n"
+	"	return clamp(texelFetch(uOutputRgb, ivec2(clamp(x, 0, size.x - 1), clamp(y, 0, size.y - 1)), 0), vec4(0.0), vec4(1.0));\n"
+	"}\n"
+	"vec3 rgbAt(int x, int y)\n"
+	"{\n"
+	"	return rgbaAt(x, y).rgb;\n"
 	"}\n"
 	"vec3 rgbToLegalYcbcr10(vec3 rgb)\n"
 	"{\n"
@@ -112,9 +117,35 @@ const char* kOutputPackFragmentShaderSource =
 	"{\n"
 	"	return vec4(float(word & 255u), float((word >> 8) & 255u), float((word >> 16) & 255u), float((word >> 24) & 255u)) / 255.0;\n"
 	"}\n"
+	"vec4 bigEndianWordToBytes(uint word)\n"
+	"{\n"
+	"	return vec4(float((word >> 24) & 255u), float((word >> 16) & 255u), float((word >> 8) & 255u), float(word & 255u)) / 255.0;\n"
+	"}\n"
+	"vec4 packAy10Word(ivec2 outCoord)\n"
+	"{\n"
+	"	ivec2 size = ivec2(max(uOutputVideoResolution, vec2(1.0, 1.0)));\n"
+	"	if (outCoord.x >= size.x)\n"
+	"		return vec4(0.0);\n"
+	"	int pixelBase = (outCoord.x / 2) * 2;\n"
+	"	int y = outCoord.y;\n"
+	"	vec4 rgba0 = rgbaAt(pixelBase + 0, y);\n"
+	"	vec4 rgba1 = rgbaAt(pixelBase + 1, y);\n"
+	"	vec3 c0 = rgbToLegalYcbcr10(rgba0.rgb);\n"
+	"	vec3 c1 = rgbToLegalYcbcr10(rgba1.rgb);\n"
+	"	float chroma = (outCoord.x & 1) == 0 ? round((c0.y + c1.y) * 0.5) : round((c0.z + c1.z) * 0.5);\n"
+	"	float alpha = round(clamp(((outCoord.x & 1) == 0 ? rgba0.a : rgba1.a), 0.0, 1.0) * 1023.0);\n"
+	"	float luma = (outCoord.x & 1) == 0 ? c0.x : c1.x;\n"
+	"	uint word = ((uint(luma) & 1023u) << 22) | ((uint(chroma) & 1023u) << 12) | ((uint(alpha) & 1023u) << 2);\n"
+	"	return bigEndianWordToBytes(word);\n"
+	"}\n"
 	"void main()\n"
 	"{\n"
 	"	ivec2 outCoord = ivec2(gl_FragCoord.xy);\n"
+	"	if (uOutputPackFormat == 2)\n"
+	"	{\n"
+	"		fragColor = packAy10Word(outCoord);\n"
+	"		return;\n"
+	"	}\n"
 	"	if (float(outCoord.x) >= uActiveV210Words)\n"
 	"	{\n"
 	"		fragColor = vec4(0.0);\n"

apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.cpp

@@ -10,9 +10,10 @@ GlobalParamsBuffer::GlobalParamsBuffer(OpenGLRenderer& renderer) :
 {
 }
 
-bool GlobalParamsBuffer::Update(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength)
+bool GlobalParamsBuffer::Update(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable)
 {
-	std::vector<unsigned char> buffer;
+	std::vector<unsigned char>& buffer = mScratchBuffer;
+	buffer.clear();
 	buffer.reserve(512);
 
 	AppendStd140Float(buffer, static_cast<float>(state.timeSeconds));
@@ -32,6 +33,7 @@ bool GlobalParamsBuffer::Update(const RuntimeRenderState& state, unsigned availa
 		: 0u;
 	AppendStd140Int(buffer, static_cast<int>(effectiveSourceHistoryLength));
 	AppendStd140Int(buffer, static_cast<int>(effectiveTemporalHistoryLength));
+	AppendStd140Int(buffer, feedbackAvailable ? 1 : 0);
 
 	for (const ShaderParameterDefinition& definition : state.parameterDefinitions)
 	{

apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.h

@@ -3,13 +3,16 @@
 #include "OpenGLRenderer.h"
 #include "ShaderTypes.h"
 
+#include <vector>
+
 class GlobalParamsBuffer
 {
 public:
 	explicit GlobalParamsBuffer(OpenGLRenderer& renderer);
 
-	bool Update(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength);
+	bool Update(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable);
 
 private:
 	OpenGLRenderer& mRenderer;
+	std::vector<unsigned char> mScratchBuffer;
 };

apps/LoopThroughWithOpenGLCompositing/gl/shader/OpenGLShaderPrograms.cpp

@@ -13,6 +13,20 @@ void CopyErrorMessage(const std::string& message, int errorMessageSize, char* er
 
 	strncpy_s(errorMessage, errorMessageSize, message.c_str(), _TRUNCATE);
 }
+
+std::size_t RequiredTemporaryRenderTargets(const std::vector<OpenGLRenderer::LayerProgram>& layerPrograms)
+{
+	// Only one layer renders at a time, so the pool needs to cover the widest
+	// layer, not the sum of every intermediate pass in the stack.
+	std::size_t requiredTargets = 0;
+	for (const OpenGLRenderer::LayerProgram& layerProgram : layerPrograms)
+	{
+		const std::size_t internalPasses = layerProgram.passes.size() > 0 ? layerProgram.passes.size() - 1 : 0;
+		if (internalPasses > requiredTargets)
+			requiredTargets = internalPasses;
+	}
+	return requiredTargets;
+}
 }
 
 OpenGLShaderPrograms::OpenGLShaderPrograms(OpenGLRenderer& renderer, RuntimeHost& runtimeHost) :
@@ -38,7 +52,15 @@ bool OpenGLShaderPrograms::CompileLayerPrograms(unsigned inputFrameWidth, unsign
 		CopyErrorMessage(temporalError, errorMessageSize, errorMessage);
 		return false;
 	}
+	if (mRenderer.ResourcesInitialized() &&
+		!mRenderer.FeedbackBuffers().EnsureResources(layerStates, inputFrameWidth, inputFrameHeight, temporalError))
+	{
+		CopyErrorMessage(temporalError, errorMessageSize, errorMessage);
+		return false;
+	}
 
+	// Initial startup still compiles synchronously; auto-reload uses the build
+	// queue so Slang/file work stays off the playback path.
 	std::vector<LayerProgram> newPrograms;
 	newPrograms.reserve(layerStates.size());
 
@@ -54,6 +76,15 @@ bool OpenGLShaderPrograms::CompileLayerPrograms(unsigned inputFrameWidth, unsign
 		newPrograms.push_back(layerProgram);
 	}
 
+	std::string targetError;
+	if (!mRenderer.ReserveTemporaryRenderTargets(RequiredTemporaryRenderTargets(newPrograms), inputFrameWidth, inputFrameHeight, targetError))
+	{
+		for (LayerProgram& program : newPrograms)
+			DestroySingleLayerProgram(program);
+		CopyErrorMessage(targetError, errorMessageSize, errorMessage);
+		return false;
+	}
+
 	DestroyLayerPrograms();
 	mRenderer.ReplaceLayerPrograms(newPrograms);
 	mCommittedLayerStates = layerStates;
@@ -84,14 +115,22 @@ bool OpenGLShaderPrograms::CommitPreparedLayerPrograms(const PreparedShaderBuild
 		CopyErrorMessage(temporalError, errorMessageSize, errorMessage);
 		return false;
 	}
+	if (mRenderer.ResourcesInitialized() &&
+		!mRenderer.FeedbackBuffers().EnsureResources(preparedBuild.layerStates, inputFrameWidth, inputFrameHeight, temporalError))
+	{
+		CopyErrorMessage(temporalError, errorMessageSize, errorMessage);
+		return false;
+	}
 
+	// The prepared build already contains GLSL text for each pass. This commit
+	// step performs the short GL work on the render thread.
 	std::vector<LayerProgram> newPrograms;
 	newPrograms.reserve(preparedBuild.layers.size());
 
 	for (const PreparedLayerShader& preparedLayer : preparedBuild.layers)
 	{
 		LayerProgram layerProgram;
-		if (!mCompiler.CompilePreparedLayerProgram(preparedLayer.state, preparedLayer.fragmentShaderSource, layerProgram, errorMessageSize, errorMessage))
+		if (!mCompiler.CompilePreparedLayerProgram(preparedLayer.state, preparedLayer.passes, layerProgram, errorMessageSize, errorMessage))
 		{
 			for (LayerProgram& program : newPrograms)
 				DestroySingleLayerProgram(program);
@@ -100,6 +139,15 @@ bool OpenGLShaderPrograms::CommitPreparedLayerPrograms(const PreparedShaderBuild
 		newPrograms.push_back(layerProgram);
 	}
 
+	std::string targetError;
+	if (!mRenderer.ReserveTemporaryRenderTargets(RequiredTemporaryRenderTargets(newPrograms), inputFrameWidth, inputFrameHeight, targetError))
+	{
+		for (LayerProgram& program : newPrograms)
+			DestroySingleLayerProgram(program);
+		CopyErrorMessage(targetError, errorMessageSize, errorMessage);
+		return false;
+	}
+
 	DestroyLayerPrograms();
 	mRenderer.ReplaceLayerPrograms(newPrograms);
 	mCommittedLayerStates = preparedBuild.layerStates;
@@ -140,12 +188,17 @@ void OpenGLShaderPrograms::ResetTemporalHistoryState()
 	mRenderer.TemporalHistory().ResetState();
 }
 
+void OpenGLShaderPrograms::ResetShaderFeedbackState()
+{
+	mRenderer.FeedbackBuffers().ResetState();
+}
+
 bool OpenGLShaderPrograms::UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error)
 {
 	return mTextureBindings.UpdateTextBindingTexture(state, textBinding, error);
 }
 
-bool OpenGLShaderPrograms::UpdateGlobalParamsBuffer(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength)
+bool OpenGLShaderPrograms::UpdateGlobalParamsBuffer(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable)
 {
-	return mGlobalParamsBuffer.Update(state, availableSourceHistoryLength, availableTemporalHistoryLength);
+	return mGlobalParamsBuffer.Update(state, availableSourceHistoryLength, availableTemporalHistoryLength, feedbackAvailable);
 }

apps/LoopThroughWithOpenGLCompositing/gl/shader/OpenGLShaderPrograms.h

@@ -25,9 +25,10 @@ public:
 	void DestroySingleLayerProgram(LayerProgram& layerProgram);
 	void DestroyDecodeShaderProgram();
 	void ResetTemporalHistoryState();
+	void ResetShaderFeedbackState();
 	const std::vector<RuntimeRenderState>& CommittedLayerStates() const { return mCommittedLayerStates; }
 	bool UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error);
-	bool UpdateGlobalParamsBuffer(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength);
+	bool UpdateGlobalParamsBuffer(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable);
 
 private:
 	OpenGLRenderer& mRenderer;

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderBuildQueue.cpp

@@ -120,7 +120,7 @@ PreparedShaderBuild ShaderBuildQueue::Build(uint64_t generation, unsigned output
 	{
 		PreparedLayerShader layer;
 		layer.state = state;
-		if (!mRuntimeHost.BuildLayerFragmentShaderSource(state.layerId, layer.fragmentShaderSource, build.message))
+		if (!mRuntimeHost.BuildLayerPassFragmentShaderSources(state.layerId, layer.passes, build.message))
 		{
 			build.succeeded = false;
 			return build;

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderBuildQueue.h

@@ -14,7 +14,7 @@ class RuntimeHost;
 struct PreparedLayerShader
 {
 	RuntimeRenderState state;
-	std::string fragmentShaderSource;
+	std::vector<ShaderPassBuildSource> passes;
 };
 
 struct PreparedShaderBuild

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderProgramCompiler.cpp

@@ -0,0 +1,233 @@
+#include "ShaderProgramCompiler.h"
+
+#include "GlRenderConstants.h"
+#include "GlScopedObjects.h"
+#include "GlShaderSources.h"
+
+#include <cstring>
+#include <utility>
+#include <vector>
+
+namespace
+{
+void CopyErrorMessage(const std::string& message, int errorMessageSize, char* errorMessage)
+{
+	if (!errorMessage || errorMessageSize <= 0)
+		return;
+
+	strncpy_s(errorMessage, errorMessageSize, message.c_str(), _TRUNCATE);
+}
+}
+
+ShaderProgramCompiler::ShaderProgramCompiler(OpenGLRenderer& renderer, RuntimeHost& runtimeHost, ShaderTextureBindings& textureBindings) :
+	mRenderer(renderer),
+	mRuntimeHost(runtimeHost),
+	mTextureBindings(textureBindings)
+{
+}
+
+bool ShaderProgramCompiler::CompileLayerProgram(const RuntimeRenderState& state, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
+{
+	std::vector<ShaderPassBuildSource> passSources;
+	std::string loadError;
+
+	if (!mRuntimeHost.BuildLayerPassFragmentShaderSources(state.layerId, passSources, loadError))
+	{
+		CopyErrorMessage(loadError, errorMessageSize, errorMessage);
+		return false;
+	}
+
+	return CompilePreparedLayerProgram(state, passSources, layerProgram, errorMessageSize, errorMessage);
+}
+
+bool ShaderProgramCompiler::CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::vector<ShaderPassBuildSource>& passSources, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
+{
+	GLsizei errorBufferSize = 0;
+	std::string loadError;
+	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
+
+	layerProgram.layerId = state.layerId;
+	layerProgram.shaderId = state.shaderId;
+	layerProgram.passes.clear();
+
+	for (const auto& passSource : passSources)
+	{
+		GLint compileResult = GL_FALSE;
+		GLint linkResult = GL_FALSE;
+		const char* fragmentSource = passSource.fragmentShaderSource.c_str();
+
+		ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
+		glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
+		glCompileShader(newVertexShader.get());
+		glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
+		if (compileResult == GL_FALSE)
+		{
+			glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+			mRenderer.DestroySingleLayerProgram(layerProgram);
+			return false;
+		}
+
+		ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
+		glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
+		glCompileShader(newFragmentShader.get());
+		glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
+		if (compileResult == GL_FALSE)
+		{
+			glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+			mRenderer.DestroySingleLayerProgram(layerProgram);
+			return false;
+		}
+
+		ScopedGlProgram newProgram(glCreateProgram());
+		glAttachShader(newProgram.get(), newVertexShader.get());
+		glAttachShader(newProgram.get(), newFragmentShader.get());
+		glLinkProgram(newProgram.get());
+		glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
+		if (linkResult == GL_FALSE)
+		{
+			glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
+			mRenderer.DestroySingleLayerProgram(layerProgram);
+			return false;
+		}
+
+		std::vector<LayerProgram::TextureBinding> textureBindings;
+		for (const ShaderTextureAsset& textureAsset : state.textureAssets)
+		{
+			LayerProgram::TextureBinding textureBinding;
+			textureBinding.samplerName = textureAsset.id;
+			textureBinding.sourcePath = textureAsset.path;
+			if (!mTextureBindings.LoadTextureAsset(textureAsset, textureBinding.texture, loadError))
+			{
+				for (LayerProgram::TextureBinding& loadedTexture : textureBindings)
+				{
+					if (loadedTexture.texture != 0)
+						glDeleteTextures(1, &loadedTexture.texture);
+				}
+				CopyErrorMessage(loadError, errorMessageSize, errorMessage);
+				mRenderer.DestroySingleLayerProgram(layerProgram);
+				return false;
+			}
+			textureBindings.push_back(textureBinding);
+		}
+
+		std::vector<LayerProgram::TextBinding> textBindings;
+		mTextureBindings.CreateTextBindings(state, textBindings);
+
+		PassProgram passProgram;
+		passProgram.passId = passSource.passId;
+		passProgram.inputNames = passSource.inputNames;
+		passProgram.outputName = passSource.outputName;
+		passProgram.shaderTextureBase = mTextureBindings.ResolveShaderTextureBase(state, mRuntimeHost.GetMaxTemporalHistoryFrames());
+		passProgram.textureBindings.swap(textureBindings);
+		passProgram.textBindings.swap(textBindings);
+
+		const GLuint globalParamsIndex = glGetUniformBlockIndex(newProgram.get(), "GlobalParams");
+		if (globalParamsIndex != GL_INVALID_INDEX)
+			glUniformBlockBinding(newProgram.get(), globalParamsIndex, kGlobalParamsBindingPoint);
+
+		const unsigned historyCap = mRuntimeHost.GetMaxTemporalHistoryFrames();
+		glUseProgram(newProgram.get());
+		mTextureBindings.AssignLayerSamplerUniforms(newProgram.get(), state, passProgram, historyCap);
+		glUseProgram(0);
+
+		passProgram.program = newProgram.release();
+		passProgram.vertexShader = newVertexShader.release();
+		passProgram.fragmentShader = newFragmentShader.release();
+		layerProgram.passes.push_back(std::move(passProgram));
+	}
+	return true;
+}
+
+bool ShaderProgramCompiler::CompileDecodeShader(int errorMessageSize, char* errorMessage)
+{
+	GLsizei errorBufferSize = 0;
+	GLint compileResult = GL_FALSE;
+	GLint linkResult = GL_FALSE;
+	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
+	const char* fragmentSource = kDecodeFragmentShaderSource;
+
+	ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
+	glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
+	glCompileShader(newVertexShader.get());
+	glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
+	if (compileResult == GL_FALSE)
+	{
+		glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
+	glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
+	glCompileShader(newFragmentShader.get());
+	glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
+	if (compileResult == GL_FALSE)
+	{
+		glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	ScopedGlProgram newProgram(glCreateProgram());
+	glAttachShader(newProgram.get(), newVertexShader.get());
+	glAttachShader(newProgram.get(), newFragmentShader.get());
+	glLinkProgram(newProgram.get());
+	glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
+	if (linkResult == GL_FALSE)
+	{
+		glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	mRenderer.DestroyDecodeShaderProgram();
+	mRenderer.SetDecodeShaderProgram(newProgram.release(), newVertexShader.release(), newFragmentShader.release());
+	return true;
+}
+
+bool ShaderProgramCompiler::CompileOutputPackShader(int errorMessageSize, char* errorMessage)
+{
+	GLsizei errorBufferSize = 0;
+	GLint compileResult = GL_FALSE;
+	GLint linkResult = GL_FALSE;
+	const char* vertexSource = kFullscreenTriangleVertexShaderSource;
+	const char* fragmentSource = kOutputPackFragmentShaderSource;
+
+	ScopedGlShader newVertexShader(glCreateShader(GL_VERTEX_SHADER));
+	glShaderSource(newVertexShader.get(), 1, (const GLchar**)&vertexSource, NULL);
+	glCompileShader(newVertexShader.get());
+	glGetShaderiv(newVertexShader.get(), GL_COMPILE_STATUS, &compileResult);
+	if (compileResult == GL_FALSE)
+	{
+		glGetShaderInfoLog(newVertexShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	ScopedGlShader newFragmentShader(glCreateShader(GL_FRAGMENT_SHADER));
+	glShaderSource(newFragmentShader.get(), 1, (const GLchar**)&fragmentSource, NULL);
+	glCompileShader(newFragmentShader.get());
+	glGetShaderiv(newFragmentShader.get(), GL_COMPILE_STATUS, &compileResult);
+	if (compileResult == GL_FALSE)
+	{
+		glGetShaderInfoLog(newFragmentShader.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	ScopedGlProgram newProgram(glCreateProgram());
+	glAttachShader(newProgram.get(), newVertexShader.get());
+	glAttachShader(newProgram.get(), newFragmentShader.get());
+	glLinkProgram(newProgram.get());
+	glGetProgramiv(newProgram.get(), GL_LINK_STATUS, &linkResult);
+	if (linkResult == GL_FALSE)
+	{
+		glGetProgramInfoLog(newProgram.get(), errorMessageSize, &errorBufferSize, errorMessage);
+		return false;
+	}
+
+	glUseProgram(newProgram.get());
+	const GLint outputSamplerLocation = glGetUniformLocation(newProgram.get(), "uOutputRgb");
+	if (outputSamplerLocation >= 0)
+		glUniform1i(outputSamplerLocation, 0);
+	glUseProgram(0);
+
+	mRenderer.DestroyOutputPackShaderProgram();
+	mRenderer.SetOutputPackShaderProgram(newProgram.release(), newVertexShader.release(), newFragmentShader.release());
+	return true;
+}

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderProgramCompiler.h

@@ -5,16 +5,18 @@
 #include "ShaderTextureBindings.h"
 
 #include <string>
+#include <vector>
 
 class ShaderProgramCompiler
 {
 public:
 	using LayerProgram = OpenGLRenderer::LayerProgram;
+	using PassProgram = OpenGLRenderer::LayerProgram::PassProgram;
 
 	ShaderProgramCompiler(OpenGLRenderer& renderer, RuntimeHost& runtimeHost, ShaderTextureBindings& textureBindings);
 
 	bool CompileLayerProgram(const RuntimeRenderState& state, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage);
-	bool CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::string& fragmentShaderSource, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage);
+	bool CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::vector<ShaderPassBuildSource>& passSources, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage);
 	bool CompileDecodeShader(int errorMessageSize, char* errorMessage);
 	bool CompileOutputPackShader(int errorMessageSize, char* errorMessage);
 

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderTextureBindings.cpp

@@ -0,0 +1,256 @@
+#include "ShaderTextureBindings.h"
+
+#include "GlRenderConstants.h"
+#include "TextRasterizer.h"
+#include "TextureAssetLoader.h"
+
+#include <algorithm>
+#include <filesystem>
+
+namespace
+{
+std::string TextValueForBinding(const RuntimeRenderState& state, const std::string& parameterId)
+{
+	auto valueIt = state.parameterValues.find(parameterId);
+	return valueIt == state.parameterValues.end() ? std::string() : valueIt->second.textValue;
+}
+
+const ShaderFontAsset* FindFontAssetForParameter(const RuntimeRenderState& state, const ShaderParameterDefinition& definition)
+{
+	if (!definition.fontId.empty())
+	{
+		for (const ShaderFontAsset& fontAsset : state.fontAssets)
+		{
+			if (fontAsset.id == definition.fontId)
+				return &fontAsset;
+		}
+	}
+	return state.fontAssets.empty() ? nullptr : &state.fontAssets.front();
+}
+}
+
+bool ShaderTextureBindings::LoadTextureAsset(const ShaderTextureAsset& textureAsset, GLuint& textureId, std::string& error)
+{
+	return ::LoadTextureAsset(textureAsset, textureId, error);
+}
+
+void ShaderTextureBindings::CreateTextBindings(const RuntimeRenderState& state, std::vector<LayerProgram::TextBinding>& textBindings)
+{
+	for (const ShaderParameterDefinition& definition : state.parameterDefinitions)
+	{
+		if (definition.type != ShaderParameterType::Text)
+			continue;
+		LayerProgram::TextBinding textBinding;
+		textBinding.parameterId = definition.id;
+		textBinding.samplerName = definition.id + "Texture";
+		textBinding.fontId = definition.fontId;
+		glGenTextures(1, &textBinding.texture);
+		glBindTexture(GL_TEXTURE_2D, textBinding.texture);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+		std::vector<unsigned char> empty(static_cast<std::size_t>(kTextTextureWidth) * kTextTextureHeight * 4, 0);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kTextTextureWidth, kTextTextureHeight, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, empty.data());
+		glBindTexture(GL_TEXTURE_2D, 0);
+		textBindings.push_back(textBinding);
+	}
+}
+
+bool ShaderTextureBindings::UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error)
+{
+	const std::string text = TextValueForBinding(state, textBinding.parameterId);
+	if (text == textBinding.renderedText && textBinding.renderedWidth == kTextTextureWidth && textBinding.renderedHeight == kTextTextureHeight)
+		return true;
+
+	auto definitionIt = std::find_if(state.parameterDefinitions.begin(), state.parameterDefinitions.end(),
+		[&textBinding](const ShaderParameterDefinition& definition) { return definition.id == textBinding.parameterId; });
+	if (definitionIt == state.parameterDefinitions.end())
+		return true;
+
+	const ShaderFontAsset* fontAsset = FindFontAssetForParameter(state, *definitionIt);
+	std::filesystem::path fontPath;
+	if (fontAsset)
+		fontPath = fontAsset->path;
+
+	std::vector<unsigned char> sdf;
+	if (!RasterizeTextSdf(text, fontPath, sdf, error))
+		return false;
+
+	GLint previousActiveTexture = 0;
+	GLint previousUnpackBuffer = 0;
+	glGetIntegerv(GL_ACTIVE_TEXTURE, &previousActiveTexture);
+	glGetIntegerv(GL_PIXEL_UNPACK_BUFFER_BINDING, &previousUnpackBuffer);
+	glActiveTexture(GL_TEXTURE0);
+	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
+	glBindTexture(GL_TEXTURE_2D, textBinding.texture);
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kTextTextureWidth, kTextTextureHeight, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, sdf.data());
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, static_cast<GLuint>(previousUnpackBuffer));
+	glActiveTexture(static_cast<GLenum>(previousActiveTexture));
+
+	textBinding.renderedText = text;
+	textBinding.renderedWidth = kTextTextureWidth;
+	textBinding.renderedHeight = kTextTextureHeight;
+	return true;
+}
+
+GLint ShaderTextureBindings::FindSamplerUniformLocation(GLuint program, const std::string& samplerName) const
+{
+	GLint location = glGetUniformLocation(program, samplerName.c_str());
+	if (location >= 0)
+		return location;
+	return glGetUniformLocation(program, (samplerName + "_0").c_str());
+}
+
+GLuint ShaderTextureBindings::ResolveFeedbackTextureUnit(const RuntimeRenderState& state, unsigned historyCap) const
+{
+	return state.isTemporal ? kSourceHistoryTextureUnitBase + historyCap + historyCap : kSourceHistoryTextureUnitBase;
+}
+
+GLuint ShaderTextureBindings::ResolveShaderTextureBase(const RuntimeRenderState& state, unsigned historyCap) const
+{
+	return ResolveFeedbackTextureUnit(state, historyCap) + (state.feedback.enabled ? 1u : 0u);
+}
+
+void ShaderTextureBindings::AssignLayerSamplerUniforms(GLuint program, const RuntimeRenderState& state, const PassProgram& passProgram, unsigned historyCap) const
+{
+	const GLuint shaderTextureBase = ResolveShaderTextureBase(state, historyCap);
+
+	const GLint layerInputLocation = FindSamplerUniformLocation(program, "gLayerInput");
+	if (layerInputLocation >= 0)
+		glUniform1i(layerInputLocation, static_cast<GLint>(kLayerInputTextureUnit));
+
+	const GLint videoInputLocation = FindSamplerUniformLocation(program, "gVideoInput");
+	if (videoInputLocation >= 0)
+		glUniform1i(videoInputLocation, static_cast<GLint>(kDecodedVideoTextureUnit));
+
+	for (unsigned index = 0; index < historyCap; ++index)
+	{
+		const std::string sourceSamplerName = "gSourceHistory" + std::to_string(index);
+		const GLint sourceSamplerLocation = glGetUniformLocation(program, sourceSamplerName.c_str());
+		if (sourceSamplerLocation >= 0)
+			glUniform1i(sourceSamplerLocation, static_cast<GLint>(kSourceHistoryTextureUnitBase + index));
+
+		const std::string temporalSamplerName = "gTemporalHistory" + std::to_string(index);
+		const GLint temporalSamplerLocation = glGetUniformLocation(program, temporalSamplerName.c_str());
+		if (temporalSamplerLocation >= 0)
+			glUniform1i(temporalSamplerLocation, static_cast<GLint>(kSourceHistoryTextureUnitBase + historyCap + index));
+	}
+
+	if (state.feedback.enabled)
+	{
+		const GLint feedbackSamplerLocation = FindSamplerUniformLocation(program, "gFeedbackState");
+		if (feedbackSamplerLocation >= 0)
+			glUniform1i(feedbackSamplerLocation, static_cast<GLint>(ResolveFeedbackTextureUnit(state, historyCap)));
+	}
+
+	for (std::size_t index = 0; index < passProgram.textureBindings.size(); ++index)
+	{
+		const GLint textureSamplerLocation = FindSamplerUniformLocation(program, passProgram.textureBindings[index].samplerName);
+		if (textureSamplerLocation >= 0)
+			glUniform1i(textureSamplerLocation, static_cast<GLint>(shaderTextureBase + static_cast<GLuint>(index)));
+	}
+
+	const GLuint textTextureBase = shaderTextureBase + static_cast<GLuint>(passProgram.textureBindings.size());
+	for (std::size_t index = 0; index < passProgram.textBindings.size(); ++index)
+	{
+		const GLint textSamplerLocation = FindSamplerUniformLocation(program, passProgram.textBindings[index].samplerName);
+		if (textSamplerLocation >= 0)
+			glUniform1i(textSamplerLocation, static_cast<GLint>(textTextureBase + static_cast<GLuint>(index)));
+	}
+}
+
+ShaderTextureBindings::RuntimeTextureBindingPlan ShaderTextureBindings::BuildLayerRuntimeBindingPlan(
+	const PassProgram& passProgram,
+	GLuint layerInputTexture,
+	GLuint originalLayerInputTexture,
+	const RuntimeRenderState& state,
+	GLuint feedbackTexture,
+	const std::vector<GLuint>& sourceHistoryTextures,
+	const std::vector<GLuint>& temporalHistoryTextures) const
+{
+	RuntimeTextureBindingPlan plan;
+	plan.bindings.push_back({ "originalLayerInput", "gLayerInput", originalLayerInputTexture, kLayerInputTextureUnit });
+	plan.bindings.push_back({ "layerInput", "gVideoInput", layerInputTexture, kDecodedVideoTextureUnit });
+
+	for (std::size_t index = 0; index < sourceHistoryTextures.size(); ++index)
+	{
+		plan.bindings.push_back({
+			"sourceHistory",
+			"gSourceHistory" + std::to_string(index),
+			sourceHistoryTextures[index],
+			kSourceHistoryTextureUnitBase + static_cast<GLuint>(index)
+		});
+	}
+
+	const GLuint temporalBase = kSourceHistoryTextureUnitBase + static_cast<GLuint>(sourceHistoryTextures.size());
+	for (std::size_t index = 0; index < temporalHistoryTextures.size(); ++index)
+	{
+		plan.bindings.push_back({
+			"temporalHistory",
+			"gTemporalHistory" + std::to_string(index),
+			temporalHistoryTextures[index],
+			temporalBase + static_cast<GLuint>(index)
+		});
+	}
+
+	const GLuint feedbackTextureUnit = ResolveFeedbackTextureUnit(state, static_cast<unsigned>(sourceHistoryTextures.size()));
+	if (state.feedback.enabled)
+	{
+		plan.bindings.push_back({
+			"feedbackState",
+			"gFeedbackState",
+			feedbackTexture,
+			feedbackTextureUnit
+		});
+	}
+
+	const GLuint shaderTextureBase = passProgram.shaderTextureBase != 0
+		? passProgram.shaderTextureBase
+		: feedbackTextureUnit + (state.feedback.enabled ? 1u : 0u);
+	for (std::size_t index = 0; index < passProgram.textureBindings.size(); ++index)
+	{
+		const LayerProgram::TextureBinding& textureBinding = passProgram.textureBindings[index];
+		plan.bindings.push_back({
+			"shaderTexture",
+			textureBinding.samplerName,
+			textureBinding.texture,
+			shaderTextureBase + static_cast<GLuint>(index)
+		});
+	}
+
+	const GLuint textTextureBase = shaderTextureBase + static_cast<GLuint>(passProgram.textureBindings.size());
+	for (std::size_t index = 0; index < passProgram.textBindings.size(); ++index)
+	{
+		const LayerProgram::TextBinding& textBinding = passProgram.textBindings[index];
+		plan.bindings.push_back({
+			"textTexture",
+			textBinding.samplerName,
+			textBinding.texture,
+			textTextureBase + static_cast<GLuint>(index)
+		});
+	}
+
+	return plan;
+}
+
+void ShaderTextureBindings::BindRuntimeTexturePlan(const RuntimeTextureBindingPlan& plan) const
+{
+	for (const RuntimeTextureBinding& binding : plan.bindings)
+	{
+		glActiveTexture(GL_TEXTURE0 + binding.textureUnit);
+		glBindTexture(GL_TEXTURE_2D, binding.texture);
+	}
+	glActiveTexture(GL_TEXTURE0);
+}
+
+void ShaderTextureBindings::UnbindRuntimeTexturePlan(const RuntimeTextureBindingPlan& plan) const
+{
+	for (const RuntimeTextureBinding& binding : plan.bindings)
+	{
+		glActiveTexture(GL_TEXTURE0 + binding.textureUnit);
+		glBindTexture(GL_TEXTURE_2D, 0);
+	}
+	glActiveTexture(GL_TEXTURE0);
+}

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderTextureBindings.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include "OpenGLRenderer.h"
+#include "ShaderTypes.h"
+
+#include <string>
+#include <vector>
+
+class ShaderTextureBindings
+{
+public:
+	using LayerProgram = OpenGLRenderer::LayerProgram;
+	using PassProgram = OpenGLRenderer::LayerProgram::PassProgram;
+
+	struct RuntimeTextureBinding
+	{
+		std::string semanticName;
+		std::string samplerName;
+		GLuint texture = 0;
+		GLuint textureUnit = 0;
+	};
+
+	struct RuntimeTextureBindingPlan
+	{
+		std::vector<RuntimeTextureBinding> bindings;
+	};
+
+	bool LoadTextureAsset(const ShaderTextureAsset& textureAsset, GLuint& textureId, std::string& error);
+	void CreateTextBindings(const RuntimeRenderState& state, std::vector<LayerProgram::TextBinding>& textBindings);
+	bool UpdateTextBindingTexture(const RuntimeRenderState& state, LayerProgram::TextBinding& textBinding, std::string& error);
+	GLint FindSamplerUniformLocation(GLuint program, const std::string& samplerName) const;
+	GLuint ResolveFeedbackTextureUnit(const RuntimeRenderState& state, unsigned historyCap) const;
+	GLuint ResolveShaderTextureBase(const RuntimeRenderState& state, unsigned historyCap) const;
+	void AssignLayerSamplerUniforms(GLuint program, const RuntimeRenderState& state, const PassProgram& passProgram, unsigned historyCap) const;
+	RuntimeTextureBindingPlan BuildLayerRuntimeBindingPlan(
+		const PassProgram& passProgram,
+		GLuint layerInputTexture,
+		GLuint originalLayerInputTexture,
+		const RuntimeRenderState& state,
+		GLuint feedbackTexture,
+		const std::vector<GLuint>& sourceHistoryTextures,
+		const std::vector<GLuint>& temporalHistoryTextures) const;
+	void BindRuntimeTexturePlan(const RuntimeTextureBindingPlan& plan) const;
+	void UnbindRuntimeTexturePlan(const RuntimeTextureBindingPlan& plan) const;
+};

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.cpp

@@ -33,6 +33,11 @@ bool IsFiniteNumber(double value)
 	return std::isfinite(value) != 0;
 }
 
+double Clamp01(double value)
+{
+	return std::max(0.0, std::min(1.0, value));
+}
+
 std::string ToLowerCopy(std::string text)
 {
 	std::transform(text.begin(), text.end(), text.begin(),
@@ -56,6 +61,20 @@ bool MatchesControlKey(const std::string& candidate, const std::string& key)
 	return candidate == key || SimplifyControlKey(candidate) == SimplifyControlKey(key);
 }
 
+bool JsonValueContainsOnlyNumbers(const JsonValue& value)
+{
+	if (!value.isArray())
+		return false;
+
+	for (const JsonValue& item : value.asArray())
+	{
+		if (!item.isNumber() || !IsFiniteNumber(item.asNumber()))
+			return false;
+	}
+
+	return true;
+}
+
 double GenerateStartupRandom()
 {
 	std::random_device randomDevice;
@@ -82,17 +101,6 @@ bool TryParseLayerIdNumber(const std::string& layerId, uint64_t& number)
 	return true;
 }
 
-std::vector<double> JsonArrayToNumbers(const JsonValue& value)
-{
-	std::vector<double> numbers;
-	for (const JsonValue& item : value.asArray())
-	{
-		if (item.isNumber())
-			numbers.push_back(item.asNumber());
-	}
-	return numbers;
-}
-
 bool LooksLikePackagedRuntimeRoot(const std::filesystem::path& candidate)
 {
 	return std::filesystem::exists(candidate / "config" / "runtime-host.json") &&
@@ -629,6 +637,9 @@ bool ParseParameterDefinition(const JsonValue& parameterJson, ShaderParameterDef
 	if (!ValidateShaderIdentifier(definition.id, "parameters[].id", manifestPath, error))
 		return false;
 
+	if (!OptionalStringField(parameterJson, "description", definition.description, "", manifestPath, error))
+		return false;
+
 	if (!ParseParameterDefault(parameterJson, definition, manifestPath, error) ||
 		!ParseParameterNumberField(parameterJson, "min", definition.minNumbers, manifestPath, error) ||
 		!ParseParameterNumberField(parameterJson, "max", definition.maxNumbers, manifestPath, error) ||
@@ -849,6 +860,8 @@ bool RuntimeHost::PollFileChanges(bool& registryChanged, bool& reloadRequested,
 		}
 
 		reloadRequested = mReloadRequested;
+		if (registryChanged || reloadRequested)
+			MarkRenderStateDirtyLocked();
 		return true;
 	}
 	catch (const std::exception& exception)
@@ -892,6 +905,7 @@ bool RuntimeHost::AddLayer(const std::string& shaderId, std::string& error)
 	EnsureLayerDefaultsLocked(layer, shaderIt->second);
 	mPersistentState.layers.push_back(layer);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -908,6 +922,7 @@ bool RuntimeHost::RemoveLayer(const std::string& layerId, std::string& error)
 
 	mPersistentState.layers.erase(it);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -929,6 +944,7 @@ bool RuntimeHost::MoveLayer(const std::string& layerId, int direction, std::stri
 
 	std::swap(mPersistentState.layers[index], mPersistentState.layers[newIndex]);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -957,6 +973,7 @@ bool RuntimeHost::MoveLayerToIndex(const std::string& layerId, std::size_t targe
 	mPersistentState.layers.erase(mPersistentState.layers.begin() + static_cast<std::ptrdiff_t>(sourceIndex));
 	mPersistentState.layers.insert(mPersistentState.layers.begin() + static_cast<std::ptrdiff_t>(targetIndex), movedLayer);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -972,6 +989,7 @@ bool RuntimeHost::SetLayerBypass(const std::string& layerId, bool bypassed, std:
 
 	layer->bypass = bypassed;
 	mReloadRequested = true;
+	MarkParameterStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -996,6 +1014,7 @@ bool RuntimeHost::SetLayerShader(const std::string& layerId, const std::string&
 	layer->parameterValues.clear();
 	EnsureLayerDefaultsLocked(*layer, shaderIt->second);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -1032,6 +1051,7 @@ bool RuntimeHost::UpdateLayerParameter(const std::string& layerId, const std::st
 		const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
 		const double triggerTime = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mStartTime).count();
 		value.numberValues = { previousCount + 1.0, triggerTime };
+		MarkParameterStateDirtyLocked();
 		return true;
 	}
 
@@ -1040,10 +1060,16 @@ bool RuntimeHost::UpdateLayerParameter(const std::string& layerId, const std::st
 		return false;
 
 	layer->parameterValues[parameterId] = normalized;
+	MarkParameterStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
 bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& newValue, std::string& error)
+{
+	return UpdateLayerParameterByControlKey(layerKey, parameterKey, newValue, true, error);
+}
+
+bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& newValue, bool persistState, std::string& error)
 {
 	std::lock_guard<std::mutex> lock(mMutex);
 
@@ -1087,6 +1113,7 @@ bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey,
 		const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
 		const double triggerTime = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mStartTime).count();
 		value.numberValues = { previousCount + 1.0, triggerTime };
+		MarkParameterStateDirtyLocked();
 		return true;
 	}
 
@@ -1095,7 +1122,141 @@ bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey,
 		return false;
 
 	matchedLayer->parameterValues[parameterIt->id] = normalized;
-	return SavePersistentState(error);
+	MarkParameterStateDirtyLocked();
+	return !persistState || SavePersistentState(error);
+}
+
+bool RuntimeHost::ApplyOscTargetByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& targetValue, double smoothingAmount, bool& keepApplying, std::string& resolvedLayerId, std::string& resolvedParameterId, ShaderParameterValue& appliedValue, std::string& error)
+{
+	keepApplying = false;
+	resolvedLayerId.clear();
+	resolvedParameterId.clear();
+	appliedValue = ShaderParameterValue();
+
+	std::lock_guard<std::mutex> lock(mMutex);
+
+	LayerPersistentState* matchedLayer = nullptr;
+	const ShaderPackage* matchedPackage = nullptr;
+	for (LayerPersistentState& layer : mPersistentState.layers)
+	{
+		auto shaderIt = mPackagesById.find(layer.shaderId);
+		if (shaderIt == mPackagesById.end())
+			continue;
+
+		if (MatchesControlKey(layer.id, layerKey) || MatchesControlKey(shaderIt->second.id, layerKey) ||
+			MatchesControlKey(shaderIt->second.displayName, layerKey))
+		{
+			matchedLayer = &layer;
+			matchedPackage = &shaderIt->second;
+			break;
+		}
+	}
+
+	if (!matchedLayer || !matchedPackage)
+	{
+		error = "Unknown OSC layer key: " + layerKey;
+		return false;
+	}
+
+	resolvedLayerId = matchedLayer->id;
+
+	const auto parameterIt = std::find_if(matchedPackage->parameters.begin(), matchedPackage->parameters.end(),
+		[&parameterKey](const ShaderParameterDefinition& definition)
+		{
+			return MatchesControlKey(definition.id, parameterKey) || MatchesControlKey(definition.label, parameterKey);
+		});
+	if (parameterIt == matchedPackage->parameters.end())
+	{
+		error = "Unknown OSC parameter key: " + parameterKey;
+		return false;
+	}
+
+	resolvedParameterId = parameterIt->id;
+
+	if (parameterIt->type == ShaderParameterType::Trigger)
+	{
+		ShaderParameterValue& value = matchedLayer->parameterValues[parameterIt->id];
+		const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
+		const double triggerTime = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mStartTime).count();
+		value.numberValues = { previousCount + 1.0, triggerTime };
+		MarkParameterStateDirtyLocked();
+		appliedValue = value;
+		return true;
+	}
+
+	ShaderParameterValue normalizedTarget;
+	if (!NormalizeAndValidateValue(*parameterIt, targetValue, normalizedTarget, error))
+		return false;
+
+	const bool smoothableType =
+		parameterIt->type == ShaderParameterType::Float ||
+		parameterIt->type == ShaderParameterType::Vec2 ||
+		parameterIt->type == ShaderParameterType::Color;
+	const bool smoothableInput = targetValue.isNumber() || JsonValueContainsOnlyNumbers(targetValue);
+	const double alpha = Clamp01(smoothingAmount);
+
+	if (!smoothableType || !smoothableInput || alpha <= 0.0)
+	{
+		matchedLayer->parameterValues[parameterIt->id] = normalizedTarget;
+		MarkParameterStateDirtyLocked();
+		appliedValue = normalizedTarget;
+		return true;
+	}
+
+	ShaderParameterValue currentValue = DefaultValueForDefinition(*parameterIt);
+	auto currentIt = matchedLayer->parameterValues.find(parameterIt->id);
+	if (currentIt != matchedLayer->parameterValues.end())
+		currentValue = currentIt->second;
+
+	ShaderParameterValue nextValue = normalizedTarget;
+	nextValue.numberValues = normalizedTarget.numberValues;
+
+	if (currentValue.numberValues.size() != normalizedTarget.numberValues.size())
+		currentValue.numberValues = normalizedTarget.numberValues;
+
+	bool changed = false;
+	bool converged = true;
+	for (std::size_t index = 0; index < normalizedTarget.numberValues.size(); ++index)
+	{
+		const double currentNumber = currentValue.numberValues[index];
+		const double targetNumber = normalizedTarget.numberValues[index];
+		const double delta = targetNumber - currentNumber;
+		double nextNumber = currentNumber + delta * alpha;
+
+		if (std::fabs(delta) <= 0.0005)
+		{
+			nextNumber = targetNumber;
+		}
+		else
+		{
+			converged = false;
+		}
+
+		if (std::fabs(nextNumber - currentNumber) > 0.0000001)
+			changed = true;
+
+		nextValue.numberValues[index] = nextNumber;
+	}
+
+	if (!converged)
+	{
+		keepApplying = true;
+	}
+	else
+	{
+		nextValue.numberValues = normalizedTarget.numberValues;
+	}
+
+	if (!changed && !keepApplying)
+	{
+		appliedValue = matchedLayer->parameterValues[parameterIt->id];
+		return true;
+	}
+
+	matchedLayer->parameterValues[parameterIt->id] = nextValue;
+	MarkParameterStateDirtyLocked();
+	appliedValue = nextValue;
+	return true;
 }
 
 bool RuntimeHost::ResetLayerParameters(const std::string& layerId, std::string& error)
@@ -1118,6 +1279,7 @@ bool RuntimeHost::ResetLayerParameters(const std::string& layerId, std::string&
 
 	layer->parameterValues.clear();
 	EnsureLayerDefaultsLocked(*layer, shaderIt->second);
+	MarkParameterStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -1177,6 +1339,7 @@ bool RuntimeHost::LoadStackPreset(const std::string& presetName, std::string& er
 
 	mPersistentState.layers = nextLayers;
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }
 
@@ -1205,10 +1368,27 @@ bool RuntimeHost::TrySetSignalStatus(bool hasSignal, unsigned width, unsigned he
 
 void RuntimeHost::SetSignalStatusLocked(bool hasSignal, unsigned width, unsigned height, const std::string& modeName)
 {
+	const bool changed = mHasSignal != hasSignal ||
+		mSignalWidth != width ||
+		mSignalHeight != height ||
+		mSignalModeName != modeName;
 	mHasSignal = hasSignal;
 	mSignalWidth = width;
 	mSignalHeight = height;
 	mSignalModeName = modeName;
+	if (changed)
+		MarkRenderStateDirtyLocked();
+}
+
+void RuntimeHost::MarkRenderStateDirtyLocked()
+{
+	mRenderStateVersion.fetch_add(1, std::memory_order_relaxed);
+	mParameterStateVersion.fetch_add(1, std::memory_order_relaxed);
+}
+
+void RuntimeHost::MarkParameterStateDirtyLocked()
+{
+	mParameterStateVersion.fetch_add(1, std::memory_order_relaxed);
 }
 
 void RuntimeHost::SetDeckLinkOutputStatus(const std::string& modelName, bool supportsInternalKeying, bool supportsExternalKeying,
@@ -1300,7 +1480,7 @@ bool RuntimeHost::TryAdvanceFrame()
 	return true;
 }
 
-bool RuntimeHost::BuildLayerFragmentShaderSource(const std::string& layerId, std::string& fragmentShaderSource, std::string& error)
+bool RuntimeHost::BuildLayerPassFragmentShaderSources(const std::string& layerId, std::vector<ShaderPassBuildSource>& passSources, std::string& error)
 {
 	try
 	{
@@ -1324,16 +1504,30 @@ bool RuntimeHost::BuildLayerFragmentShaderSource(const std::string& layerId, std
 		}
 
 		ShaderCompiler compiler(mRepoRoot, mWrapperPath, mGeneratedGlslPath, mPatchedGlslPath, mConfig.maxTemporalHistoryFrames);
-		return compiler.BuildLayerFragmentShaderSource(shaderPackage, fragmentShaderSource, error);
+		// Compile every declared pass while the caller remains backend-neutral.
+		// The GL layer decides how the resulting pass sources are routed.
+		passSources.clear();
+		passSources.reserve(shaderPackage.passes.size());
+		for (const ShaderPassDefinition& pass : shaderPackage.passes)
+		{
+			ShaderPassBuildSource passSource;
+			passSource.passId = pass.id;
+			passSource.inputNames = pass.inputNames;
+			passSource.outputName = pass.outputName;
+			if (!compiler.BuildPassFragmentShaderSource(shaderPackage, pass, passSource.fragmentShaderSource, error))
+				return false;
+			passSources.push_back(std::move(passSource));
+		}
+		return true;
 	}
 	catch (const std::exception& exception)
 	{
-		error = std::string("RuntimeHost::BuildLayerFragmentShaderSource exception: ") + exception.what();
+		error = std::string("RuntimeHost::BuildLayerPassFragmentShaderSources exception: ") + exception.what();
 		return false;
 	}
 	catch (...)
 	{
-		error = "RuntimeHost::BuildLayerFragmentShaderSource threw a non-standard exception.";
+		error = "RuntimeHost::BuildLayerPassFragmentShaderSources threw a non-standard exception.";
 		return false;
 	}
 }
@@ -1357,6 +1551,34 @@ bool RuntimeHost::TryGetLayerRenderStates(unsigned outputWidth, unsigned outputH
 	return true;
 }
 
+bool RuntimeHost::TryRefreshCachedLayerStates(std::vector<RuntimeRenderState>& states) const
+{
+	std::unique_lock<std::mutex> lock(mMutex, std::try_to_lock);
+	if (!lock.owns_lock())
+		return false;
+
+	for (RuntimeRenderState& state : states)
+	{
+		const auto layerIt = std::find_if(mPersistentState.layers.begin(), mPersistentState.layers.end(),
+			[&state](const LayerPersistentState& layer) { return layer.id == state.layerId; });
+		if (layerIt == mPersistentState.layers.end())
+			continue;
+
+		state.bypass = layerIt->bypass ? 1.0 : 0.0;
+		state.parameterValues.clear();
+		for (const ShaderParameterDefinition& definition : state.parameterDefinitions)
+		{
+			ShaderParameterValue value = DefaultValueForDefinition(definition);
+			auto valueIt = layerIt->parameterValues.find(definition.id);
+			if (valueIt != layerIt->parameterValues.end())
+				value = valueIt->second;
+			state.parameterValues[definition.id] = value;
+		}
+	}
+
+	return true;
+}
+
 void RuntimeHost::RefreshDynamicRenderStateFields(std::vector<RuntimeRenderState>& states) const
 {
 	const RuntimeClockSnapshot clock = GetRuntimeClockSnapshot();
@@ -1384,6 +1606,7 @@ void RuntimeHost::BuildLayerRenderStatesLocked(unsigned outputWidth, unsigned ou
 		RuntimeRenderState state;
 		state.layerId = layer.id;
 		state.shaderId = layer.shaderId;
+		state.shaderName = shaderIt->second.displayName;
 		state.mixAmount = 1.0;
 		state.bypass = layer.bypass ? 1.0 : 0.0;
 		state.inputWidth = mSignalWidth;
@@ -1397,6 +1620,7 @@ void RuntimeHost::BuildLayerRenderStatesLocked(unsigned outputWidth, unsigned ou
 		state.temporalHistorySource = shaderIt->second.temporal.historySource;
 		state.requestedTemporalHistoryLength = shaderIt->second.temporal.requestedHistoryLength;
 		state.effectiveTemporalHistoryLength = shaderIt->second.temporal.effectiveHistoryLength;
+		state.feedback = shaderIt->second.feedback;
 
 		for (const ShaderParameterDefinition& definition : shaderIt->second.parameters)
 		{
@@ -1443,6 +1667,10 @@ bool RuntimeHost::LoadConfig(std::string& error)
 		mConfig.serverPort = static_cast<unsigned short>(serverPortValue->asNumber(mConfig.serverPort));
 	if (const JsonValue* oscPortValue = configJson.find("oscPort"))
 		mConfig.oscPort = static_cast<unsigned short>(oscPortValue->asNumber(mConfig.oscPort));
+	if (const JsonValue* oscBindAddressValue = configJson.find("oscBindAddress"))
+		mConfig.oscBindAddress = oscBindAddressValue->asString();
+	if (const JsonValue* oscSmoothingValue = configJson.find("oscSmoothing"))
+		mConfig.oscSmoothing = Clamp01(oscSmoothingValue->asNumber(mConfig.oscSmoothing));
 	if (const JsonValue* autoReloadValue = configJson.find("autoReload"))
 		mConfig.autoReload = autoReloadValue->asBoolean(mConfig.autoReload);
 	if (const JsonValue* maxTemporalHistoryFramesValue = configJson.find("maxTemporalHistoryFrames"))
@@ -1450,6 +1678,11 @@ bool RuntimeHost::LoadConfig(std::string& error)
 		const double configuredValue = maxTemporalHistoryFramesValue->asNumber(static_cast<double>(mConfig.maxTemporalHistoryFrames));
 		mConfig.maxTemporalHistoryFrames = configuredValue <= 0.0 ? 0u : static_cast<unsigned>(configuredValue);
 	}
+	if (const JsonValue* previewFpsValue = configJson.find("previewFps"))
+	{
+		const double configuredValue = previewFpsValue->asNumber(static_cast<double>(mConfig.previewFps));
+		mConfig.previewFps = configuredValue <= 0.0 ? 0u : static_cast<unsigned>(configuredValue);
+	}
 	if (const JsonValue* enableExternalKeyingValue = configJson.find("enableExternalKeying"))
 		mConfig.enableExternalKeying = enableExternalKeyingValue->asBoolean(mConfig.enableExternalKeying);
 	if (const JsonValue* videoFormatValue = configJson.find("videoFormat"))
@@ -1668,42 +1901,11 @@ bool RuntimeHost::ScanShaderPackages(std::string& error)
 			++it;
 	}
 
+	MarkRenderStateDirtyLocked();
+
 	return true;
 }
 
-bool RuntimeHost::ParseShaderManifest(const std::filesystem::path& manifestPath, ShaderPackage& shaderPackage, std::string& error) const
-{
-	const std::string manifestText = ReadTextFile(manifestPath, error);
-	if (manifestText.empty())
-		return false;
-
-	JsonValue manifestJson;
-	if (!ParseJson(manifestText, manifestJson, error))
-		return false;
-	if (!manifestJson.isObject())
-	{
-		error = "Shader manifest root must be an object: " + manifestPath.string();
-		return false;
-	}
-
-	if (!ParseShaderMetadata(manifestJson, shaderPackage, manifestPath, error))
-		return false;
-
-	if (!std::filesystem::exists(shaderPackage.shaderPath))
-	{
-		error = "Shader source not found for package " + shaderPackage.id + ": " + shaderPackage.shaderPath.string();
-		return false;
-	}
-
-	shaderPackage.shaderWriteTime = std::filesystem::last_write_time(shaderPackage.shaderPath);
-	shaderPackage.manifestWriteTime = std::filesystem::last_write_time(shaderPackage.manifestPath);
-
-	return ParseTextureAssets(manifestJson, shaderPackage, manifestPath, error) &&
-		ParseFontAssets(manifestJson, shaderPackage, manifestPath, error) &&
-		ParseTemporalSettings(manifestJson, shaderPackage, mConfig.maxTemporalHistoryFrames, manifestPath, error) &&
-		ParseParameterDefinitions(manifestJson, shaderPackage, manifestPath, error);
-}
-
 bool RuntimeHost::NormalizeAndValidateValue(const ShaderParameterDefinition& definition, const JsonValue& value, ShaderParameterValue& normalizedValue, std::string& error) const
 {
 	return NormalizeAndValidateParameterValue(definition, value, normalizedValue, error);
@@ -1865,8 +2067,11 @@ JsonValue RuntimeHost::BuildStateValue() const
 	JsonValue app = JsonValue::MakeObject();
 	app.set("serverPort", JsonValue(static_cast<double>(mServerPort)));
 	app.set("oscPort", JsonValue(static_cast<double>(mConfig.oscPort)));
+	app.set("oscBindAddress", JsonValue(mConfig.oscBindAddress));
+	app.set("oscSmoothing", JsonValue(mConfig.oscSmoothing));
 	app.set("autoReload", JsonValue(mAutoReloadEnabled));
 	app.set("maxTemporalHistoryFrames", JsonValue(static_cast<double>(mConfig.maxTemporalHistoryFrames)));
+	app.set("previewFps", JsonValue(static_cast<double>(mConfig.previewFps)));
 	app.set("enableExternalKeying", JsonValue(mConfig.enableExternalKeying));
 	app.set("inputVideoFormat", JsonValue(mConfig.inputVideoFormat));
 	app.set("inputFrameRate", JsonValue(mConfig.inputFrameRate));
@@ -1943,6 +2148,13 @@ JsonValue RuntimeHost::BuildStateValue() const
 			temporal.set("effectiveHistoryLength", JsonValue(static_cast<double>(shaderIt->second.temporal.effectiveHistoryLength)));
 			shader.set("temporal", temporal);
 		}
+		if (status.available && shaderIt != mPackagesById.end() && shaderIt->second.feedback.enabled)
+		{
+			JsonValue feedback = JsonValue::MakeObject();
+			feedback.set("enabled", JsonValue(true));
+			feedback.set("writePass", JsonValue(shaderIt->second.feedback.writePassId));
+			shader.set("feedback", feedback);
+		}
 		shaderLibrary.pushBack(shader);
 	}
 	root.set("shaders", shaderLibrary);
@@ -1980,6 +2192,13 @@ JsonValue RuntimeHost::SerializeLayerStackLocked() const
 			temporal.set("effectiveHistoryLength", JsonValue(static_cast<double>(shaderIt->second.temporal.effectiveHistoryLength)));
 			layerValue.set("temporal", temporal);
 		}
+		if (shaderIt->second.feedback.enabled)
+		{
+			JsonValue feedback = JsonValue::MakeObject();
+			feedback.set("enabled", JsonValue(true));
+			feedback.set("writePass", JsonValue(shaderIt->second.feedback.writePassId));
+			layerValue.set("feedback", feedback);
+		}
 
 		JsonValue parameters = JsonValue::MakeArray();
 		for (const ShaderParameterDefinition& definition : shaderIt->second.parameters)
@@ -1987,6 +2206,8 @@ JsonValue RuntimeHost::SerializeLayerStackLocked() const
 			JsonValue parameter = JsonValue::MakeObject();
 			parameter.set("id", JsonValue(definition.id));
 			parameter.set("label", JsonValue(definition.label));
+			if (!definition.description.empty())
+				parameter.set("description", JsonValue(definition.description));
 			parameter.set("type", JsonValue(ShaderParameterTypeToString(definition.type)));
 			parameter.set("defaultValue", SerializeParameterValue(definition, DefaultValueForDefinition(definition)));
 

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.h

@@ -9,6 +9,7 @@
 #include <map>
 #include <mutex>
 #include <string>
+#include <utility>
 #include <vector>
 
 class RuntimeHost
@@ -30,6 +31,8 @@ public:
 	bool SetLayerShader(const std::string& layerId, const std::string& shaderId, std::string& error);
 	bool UpdateLayerParameter(const std::string& layerId, const std::string& parameterId, const JsonValue& newValue, std::string& error);
 	bool UpdateLayerParameterByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& newValue, std::string& error);
+	bool UpdateLayerParameterByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& newValue, bool persistState, std::string& error);
+	bool ApplyOscTargetByControlKey(const std::string& layerKey, const std::string& parameterKey, const JsonValue& targetValue, double smoothingAmount, bool& keepApplying, std::string& resolvedLayerId, std::string& resolvedParameterId, ShaderParameterValue& appliedValue, std::string& error);
 	bool ResetLayerParameters(const std::string& layerId, std::string& error);
 	bool SaveStackPreset(const std::string& presetName, std::string& error) const;
 	bool LoadStackPreset(const std::string& presetName, std::string& error);
@@ -50,11 +53,14 @@ public:
 	void AdvanceFrame();
 	bool TryAdvanceFrame();
 
-	bool BuildLayerFragmentShaderSource(const std::string& layerId, std::string& fragmentShaderSource, std::string& error);
+	bool BuildLayerPassFragmentShaderSources(const std::string& layerId, std::vector<ShaderPassBuildSource>& passSources, std::string& error);
 	std::vector<RuntimeRenderState> GetLayerRenderStates(unsigned outputWidth, unsigned outputHeight) const;
 	bool TryGetLayerRenderStates(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const;
+	bool TryRefreshCachedLayerStates(std::vector<RuntimeRenderState>& states) const;
 	void RefreshDynamicRenderStateFields(std::vector<RuntimeRenderState>& states) const;
 	std::string BuildStateJson() const;
+	uint64_t GetRenderStateVersion() const { return mRenderStateVersion.load(std::memory_order_relaxed); }
+	uint64_t GetParameterStateVersion() const { return mParameterStateVersion.load(std::memory_order_relaxed); }
 
 	const std::filesystem::path& GetRepoRoot() const { return mRepoRoot; }
 	const std::filesystem::path& GetUiRoot() const { return mUiRoot; }
@@ -62,7 +68,10 @@ public:
 	const std::filesystem::path& GetRuntimeRoot() const { return mRuntimeRoot; }
 	unsigned short GetServerPort() const { return mServerPort; }
 	unsigned short GetOscPort() const { return mConfig.oscPort; }
+	const std::string& GetOscBindAddress() const { return mConfig.oscBindAddress; }
+	double GetOscSmoothing() const { return mConfig.oscSmoothing; }
 	unsigned GetMaxTemporalHistoryFrames() const { return mConfig.maxTemporalHistoryFrames; }
+	unsigned GetPreviewFps() const { return mConfig.previewFps; }
 	bool ExternalKeyingEnabled() const { return mConfig.enableExternalKeying; }
 	const std::string& GetInputVideoFormat() const { return mConfig.inputVideoFormat; }
 	const std::string& GetInputFrameRate() const { return mConfig.inputFrameRate; }
@@ -77,8 +86,11 @@ private:
 		std::string shaderLibrary = "shaders";
 		unsigned short serverPort = 8080;
 		unsigned short oscPort = 9000;
+		std::string oscBindAddress = "127.0.0.1";
+		double oscSmoothing = 0.18;
 		bool autoReload = true;
 		unsigned maxTemporalHistoryFrames = 4;
+		unsigned previewFps = 30;
 		bool enableExternalKeying = false;
 		std::string inputVideoFormat = "1080p";
 		std::string inputFrameRate = "59.94";
@@ -115,7 +127,6 @@ private:
 	bool LoadPersistentState(std::string& error);
 	bool SavePersistentState(std::string& error) const;
 	bool ScanShaderPackages(std::string& error);
-	bool ParseShaderManifest(const std::filesystem::path& manifestPath, ShaderPackage& shaderPackage, std::string& error) const;
 	bool NormalizeAndValidateValue(const ShaderParameterDefinition& definition, const JsonValue& value, ShaderParameterValue& normalizedValue, std::string& error) const;
 	ShaderParameterValue DefaultValueForDefinition(const ShaderParameterDefinition& definition) const;
 	void EnsureLayerDefaultsLocked(LayerPersistentState& layerState, const ShaderPackage& shaderPackage) const;
@@ -135,6 +146,8 @@ private:
 	const LayerPersistentState* FindLayerById(const std::string& layerId) const;
 	std::string GenerateLayerId();
 	void SetSignalStatusLocked(bool hasSignal, unsigned width, unsigned height, const std::string& modeName);
+	void MarkRenderStateDirtyLocked();
+	void MarkParameterStateDirtyLocked();
 	void SetPerformanceStatsLocked(double frameBudgetMilliseconds, double renderMilliseconds);
 	void SetFramePacingStatsLocked(double completionIntervalMilliseconds, double smoothedCompletionIntervalMilliseconds,
 		double maxCompletionIntervalMilliseconds, uint64_t lateFrameCount, uint64_t droppedFrameCount, uint64_t flushedFrameCount);
@@ -179,6 +192,8 @@ private:
 	bool mAutoReloadEnabled;
 	std::chrono::steady_clock::time_point mStartTime;
 	std::chrono::steady_clock::time_point mLastScanTime;
-	std::atomic<uint64_t> mFrameCounter;
+	std::atomic<uint64_t> mFrameCounter{ 0 };
+	std::atomic<uint64_t> mRenderStateVersion{ 0 };
+	std::atomic<uint64_t> mParameterStateVersion{ 0 };
 	uint64_t mNextLayerId;
 };

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeJson.cpp

@@ -661,3 +661,14 @@ std::string SerializeJson(const JsonValue& value, bool pretty)
 	SerializeJsonImpl(value, output, pretty, 0);
 	return output.str();
 }
+
+std::vector<double> JsonArrayToNumbers(const JsonValue& value)
+{
+	std::vector<double> numbers;
+	for (const JsonValue& item : value.asArray())
+	{
+		if (item.isNumber())
+			numbers.push_back(item.asNumber());
+	}
+	return numbers;
+}

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeJson.h

@@ -62,3 +62,4 @@ private:
 
 bool ParseJson(const std::string& text, JsonValue& value, std::string& error);
 std::string SerializeJson(const JsonValue& value, bool pretty = false);
+std::vector<double> JsonArrayToNumbers(const JsonValue& value);

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeParameterUtils.cpp

@@ -26,17 +26,6 @@ bool IsFiniteNumber(double value)
 	return std::isfinite(value) != 0;
 }
 
-std::vector<double> JsonArrayToNumbers(const JsonValue& value)
-{
-	std::vector<double> numbers;
-	for (const JsonValue& item : value.asArray())
-	{
-		if (item.isNumber())
-			numbers.push_back(item.asNumber());
-	}
-	return numbers;
-}
-
 std::string NormalizeTextValue(const std::string& text, unsigned maxLength)
 {
 	std::string normalized;

apps/LoopThroughWithOpenGLCompositing/shader/ShaderCompiler.cpp

@@ -143,10 +143,10 @@ ShaderCompiler::ShaderCompiler(
 {
 }
 
-bool ShaderCompiler::BuildLayerFragmentShaderSource(const ShaderPackage& shaderPackage, std::string& fragmentShaderSource, std::string& error) const
+bool ShaderCompiler::BuildPassFragmentShaderSource(const ShaderPackage& shaderPackage, const ShaderPassDefinition& pass, std::string& fragmentShaderSource, std::string& error) const
 {
 	std::string wrapperSource;
-	if (!BuildWrapperSlangSource(shaderPackage, wrapperSource, error))
+	if (!BuildWrapperSlangSource(shaderPackage, pass, wrapperSource, error))
 		return false;
 	if (!WriteTextFile(mWrapperPath, wrapperSource, error))
 		return false;
@@ -167,7 +167,7 @@ bool ShaderCompiler::BuildLayerFragmentShaderSource(const ShaderPackage& shaderP
 	return true;
 }
 
-bool ShaderCompiler::BuildWrapperSlangSource(const ShaderPackage& shaderPackage, std::string& wrapperSource, std::string& error) const
+bool ShaderCompiler::BuildWrapperSlangSource(const ShaderPackage& shaderPackage, const ShaderPassDefinition& pass, std::string& wrapperSource, std::string& error) const
 {
 	const std::filesystem::path templatePath = mRepoRoot / "runtime" / "templates" / "shader_wrapper.slang.in";
 	wrapperSource = ReadTextFile(templatePath, error);
@@ -178,18 +178,35 @@ bool ShaderCompiler::BuildWrapperSlangSource(const ShaderPackage& shaderPackage,
 	const unsigned historySamplerCount = shaderPackage.temporal.enabled ? mMaxTemporalHistoryFrames : 0;
 	wrapperSource = ReplaceAll(wrapperSource, "{{SOURCE_HISTORY_SAMPLERS}}", BuildHistorySamplerDeclarations("gSourceHistory", historySamplerCount));
 	wrapperSource = ReplaceAll(wrapperSource, "{{TEMPORAL_HISTORY_SAMPLERS}}", BuildHistorySamplerDeclarations("gTemporalHistory", historySamplerCount));
+	wrapperSource = ReplaceAll(wrapperSource, "{{FEEDBACK_SAMPLER}}", shaderPackage.feedback.enabled ? "Sampler2D<float4> gFeedbackState;\n" : "");
+	wrapperSource = ReplaceAll(wrapperSource, "{{FEEDBACK_HELPER}}",
+		shaderPackage.feedback.enabled
+			? "float4 sampleFeedback(float2 tc)\n{\n\tif (gFeedbackAvailable <= 0)\n\t\treturn float4(0.0, 0.0, 0.0, 0.0);\n\treturn gFeedbackState.Sample(tc);\n}\n"
+			: "float4 sampleFeedback(float2 tc)\n{\n\treturn float4(0.0, 0.0, 0.0, 0.0);\n}\n");
 	wrapperSource = ReplaceAll(wrapperSource, "{{TEXTURE_SAMPLERS}}", BuildTextureSamplerDeclarations(shaderPackage.textureAssets));
 	wrapperSource = ReplaceAll(wrapperSource, "{{TEXT_SAMPLERS}}", BuildTextSamplerDeclarations(shaderPackage.parameters));
 	wrapperSource = ReplaceAll(wrapperSource, "{{TEXT_HELPERS}}", BuildTextHelpers(shaderPackage.parameters));
 	wrapperSource = ReplaceAll(wrapperSource, "{{SOURCE_HISTORY_SWITCH_CASES}}", BuildHistorySwitchCases("gSourceHistory", historySamplerCount));
 	wrapperSource = ReplaceAll(wrapperSource, "{{TEMPORAL_HISTORY_SWITCH_CASES}}", BuildHistorySwitchCases("gTemporalHistory", historySamplerCount));
-	wrapperSource = ReplaceAll(wrapperSource, "{{USER_SHADER_INCLUDE}}", shaderPackage.shaderPath.generic_string());
-	wrapperSource = ReplaceAll(wrapperSource, "{{ENTRY_POINT_CALL}}", shaderPackage.entryPoint + "(context)");
+	wrapperSource = ReplaceAll(wrapperSource, "{{USER_SHADER_INCLUDE}}", pass.sourcePath.generic_string());
+	wrapperSource = ReplaceAll(wrapperSource, "{{ENTRY_POINT_CALL}}", pass.entryPoint + "(context)");
 	return true;
 }
 
 bool ShaderCompiler::FindSlangCompiler(std::filesystem::path& compilerPath, std::string& error) const
 {
+	char slangRootBuffer[MAX_PATH] = {};
+	const DWORD slangRootLength = GetEnvironmentVariableA("SLANG_ROOT", slangRootBuffer, static_cast<DWORD>(sizeof(slangRootBuffer)));
+	if (slangRootLength > 0 && slangRootLength < sizeof(slangRootBuffer))
+	{
+		std::filesystem::path candidate = std::filesystem::path(slangRootBuffer) / "bin" / "slangc.exe";
+		if (std::filesystem::exists(candidate))
+		{
+			compilerPath = candidate;
+			return true;
+		}
+	}
+
 	std::filesystem::path thirdPartyRoot = mRepoRoot / "3rdParty";
 	if (!std::filesystem::exists(thirdPartyRoot))
 	{

apps/LoopThroughWithOpenGLCompositing/shader/ShaderCompiler.h

@@ -15,10 +15,10 @@ public:
 		const std::filesystem::path& patchedGlslPath,
 		unsigned maxTemporalHistoryFrames);
 
-	bool BuildLayerFragmentShaderSource(const ShaderPackage& shaderPackage, std::string& fragmentShaderSource, std::string& error) const;
+	bool BuildPassFragmentShaderSource(const ShaderPackage& shaderPackage, const ShaderPassDefinition& pass, std::string& fragmentShaderSource, std::string& error) const;
 
 private:
-	bool BuildWrapperSlangSource(const ShaderPackage& shaderPackage, std::string& wrapperSource, std::string& error) const;
+	bool BuildWrapperSlangSource(const ShaderPackage& shaderPackage, const ShaderPassDefinition& pass, std::string& wrapperSource, std::string& error) const;
 	bool FindSlangCompiler(std::filesystem::path& compilerPath, std::string& error) const;
 	bool RunSlangCompiler(const std::filesystem::path& wrapperPath, const std::filesystem::path& outputPath, std::string& error) const;
 	bool PatchGeneratedGlsl(std::string& shaderText, std::string& error) const;

apps/LoopThroughWithOpenGLCompositing/shader/ShaderPackageRegistry.cpp

@@ -29,17 +29,6 @@ bool IsFiniteNumber(double value)
 	return std::isfinite(value) != 0;
 }
 
-std::vector<double> JsonArrayToNumbers(const JsonValue& value)
-{
-	std::vector<double> numbers;
-	for (const JsonValue& item : value.asArray())
-	{
-		if (item.isNumber())
-			numbers.push_back(item.asNumber());
-	}
-	return numbers;
-}
-
 bool ParseShaderParameterType(const std::string& typeName, ShaderParameterType& type)
 {
 	if (typeName == "float")
@@ -250,6 +239,107 @@ bool ParseShaderMetadata(const JsonValue& manifestJson, ShaderPackage& shaderPac
 	return true;
 }
 
+bool ParsePassDefinitions(const JsonValue& manifestJson, ShaderPackage& shaderPackage, const std::filesystem::path& manifestPath, std::string& error)
+{
+	const JsonValue* passesValue = nullptr;
+	if (!OptionalArrayField(manifestJson, "passes", passesValue, manifestPath, error))
+		return false;
+
+	if (!passesValue)
+	{
+		// Existing shader packages are treated as a single implicit pass, so
+		// multipass support does not require manifest churn.
+		ShaderPassDefinition pass;
+		pass.id = "main";
+		pass.entryPoint = shaderPackage.entryPoint;
+		pass.sourcePath = shaderPackage.shaderPath;
+		pass.outputName = "layerOutput";
+		if (!std::filesystem::exists(pass.sourcePath))
+		{
+			error = "Shader source not found for package " + shaderPackage.id + ": " + pass.sourcePath.string();
+			return false;
+		}
+		pass.sourceWriteTime = std::filesystem::last_write_time(pass.sourcePath);
+		shaderPackage.passes.push_back(pass);
+		return true;
+	}
+
+	if (passesValue->asArray().empty())
+	{
+		error = "Shader manifest 'passes' field must not be empty in: " + ManifestPathMessage(manifestPath);
+		return false;
+	}
+
+	for (const JsonValue& passJson : passesValue->asArray())
+	{
+		if (!passJson.isObject())
+		{
+			error = "Shader pass entry must be an object in: " + ManifestPathMessage(manifestPath);
+			return false;
+		}
+
+		std::string passId;
+		std::string sourcePath;
+		if (!RequireNonEmptyStringField(passJson, "id", passId, manifestPath, error) ||
+			!RequireNonEmptyStringField(passJson, "source", sourcePath, manifestPath, error))
+		{
+			error = "Shader pass is missing required 'id' or 'source' in: " + ManifestPathMessage(manifestPath);
+			return false;
+		}
+		if (!ValidateShaderIdentifier(passId, "passes[].id", manifestPath, error))
+			return false;
+
+		for (const ShaderPassDefinition& existingPass : shaderPackage.passes)
+		{
+			if (existingPass.id == passId)
+			{
+				error = "Duplicate shader pass id '" + passId + "' in: " + ManifestPathMessage(manifestPath);
+				return false;
+			}
+		}
+
+		ShaderPassDefinition pass;
+		pass.id = passId;
+		pass.sourcePath = shaderPackage.directoryPath / sourcePath;
+		if (!OptionalStringField(passJson, "entryPoint", pass.entryPoint, shaderPackage.entryPoint, manifestPath, error) ||
+			!OptionalStringField(passJson, "output", pass.outputName, passId, manifestPath, error))
+		{
+			return false;
+		}
+		if (!ValidateShaderIdentifier(pass.entryPoint, "passes[].entryPoint", manifestPath, error))
+			return false;
+
+		const JsonValue* inputsValue = nullptr;
+		if (!OptionalArrayField(passJson, "inputs", inputsValue, manifestPath, error))
+			return false;
+		if (inputsValue)
+		{
+			for (const JsonValue& inputValue : inputsValue->asArray())
+			{
+				if (!inputValue.isString())
+				{
+					error = "Shader pass inputs must be strings in: " + ManifestPathMessage(manifestPath);
+					return false;
+				}
+				pass.inputNames.push_back(inputValue.asString());
+			}
+		}
+
+		// Keep source validation in the registry. Bad pass declarations then
+		// appear as unavailable shaders instead of failing at render time.
+		if (!std::filesystem::exists(pass.sourcePath))
+		{
+			error = "Shader pass source not found for package " + shaderPackage.id + ": " + pass.sourcePath.string();
+			return false;
+		}
+		pass.sourceWriteTime = std::filesystem::last_write_time(pass.sourcePath);
+		shaderPackage.passes.push_back(pass);
+	}
+
+	shaderPackage.shaderPath = shaderPackage.passes.front().sourcePath;
+	return true;
+}
+
 bool ParseTextureAssets(const JsonValue& manifestJson, ShaderPackage& shaderPackage, const std::filesystem::path& manifestPath, std::string& error)
 {
 	const JsonValue* texturesValue = nullptr;
@@ -383,6 +473,46 @@ bool ParseTemporalSettings(const JsonValue& manifestJson, ShaderPackage& shaderP
 	return true;
 }
 
+bool ParseFeedbackSettings(const JsonValue& manifestJson, ShaderPackage& shaderPackage, const std::filesystem::path& manifestPath, std::string& error)
+{
+	const JsonValue* feedbackValue = nullptr;
+	if (!OptionalObjectField(manifestJson, "feedback", feedbackValue, manifestPath, error))
+		return false;
+	if (!feedbackValue)
+		return true;
+
+	const JsonValue* enabledValue = feedbackValue->find("enabled");
+	if (!enabledValue || !enabledValue->asBoolean(false))
+		return true;
+
+	shaderPackage.feedback.enabled = true;
+	if (!OptionalStringField(*feedbackValue, "writePass", shaderPackage.feedback.writePassId, "", manifestPath, error))
+		return false;
+
+	if (shaderPackage.feedback.writePassId.empty())
+	{
+		if (shaderPackage.passes.empty())
+		{
+			error = "Feedback-enabled shader has no passes to target in: " + ManifestPathMessage(manifestPath);
+			return false;
+		}
+		shaderPackage.feedback.writePassId = shaderPackage.passes.back().id;
+	}
+
+	if (!ValidateShaderIdentifier(shaderPackage.feedback.writePassId, "feedback.writePass", manifestPath, error))
+		return false;
+
+	const auto passIt = std::find_if(shaderPackage.passes.begin(), shaderPackage.passes.end(),
+		[&shaderPackage](const ShaderPassDefinition& pass) { return pass.id == shaderPackage.feedback.writePassId; });
+	if (passIt == shaderPackage.passes.end())
+	{
+		error = "Feedback writePass '" + shaderPackage.feedback.writePassId + "' does not match any declared pass in: " + ManifestPathMessage(manifestPath);
+		return false;
+	}
+
+	return true;
+}
+
 bool ParseParameterNumberField(const JsonValue& parameterJson, const char* fieldName, std::vector<double>& values, const std::filesystem::path& manifestPath, std::string& error)
 {
 	if (const JsonValue* fieldValue = parameterJson.find(fieldName))
@@ -503,6 +633,9 @@ bool ParseParameterDefinition(const JsonValue& parameterJson, ShaderParameterDef
 	if (!ValidateShaderIdentifier(definition.id, "parameters[].id", manifestPath, error))
 		return false;
 
+	if (!OptionalStringField(parameterJson, "description", definition.description, "", manifestPath, error))
+		return false;
+
 	if (!ParseParameterDefault(parameterJson, definition, manifestPath, error) ||
 		!ParseParameterNumberField(parameterJson, "min", definition.minNumbers, manifestPath, error) ||
 		!ParseParameterNumberField(parameterJson, "max", definition.maxNumbers, manifestPath, error) ||
@@ -666,17 +799,20 @@ bool ShaderPackageRegistry::ParseManifest(const std::filesystem::path& manifestP
 	if (!ParseShaderMetadata(manifestJson, shaderPackage, manifestPath, error))
 		return false;
 
-	if (!std::filesystem::exists(shaderPackage.shaderPath))
-	{
-		error = "Shader source not found for package " + shaderPackage.id + ": " + shaderPackage.shaderPath.string();
+	if (!ParsePassDefinitions(manifestJson, shaderPackage, manifestPath, error))
 		return false;
-	}
 
-	shaderPackage.shaderWriteTime = std::filesystem::last_write_time(shaderPackage.shaderPath);
+	shaderPackage.shaderWriteTime = shaderPackage.passes.front().sourceWriteTime;
+	for (const ShaderPassDefinition& pass : shaderPackage.passes)
+	{
+		if (pass.sourceWriteTime > shaderPackage.shaderWriteTime)
+			shaderPackage.shaderWriteTime = pass.sourceWriteTime;
+	}
 	shaderPackage.manifestWriteTime = std::filesystem::last_write_time(shaderPackage.manifestPath);
 
 	return ParseTextureAssets(manifestJson, shaderPackage, manifestPath, error) &&
 		ParseFontAssets(manifestJson, shaderPackage, manifestPath, error) &&
 		ParseTemporalSettings(manifestJson, shaderPackage, mMaxTemporalHistoryFrames, manifestPath, error) &&
+		ParseFeedbackSettings(manifestJson, shaderPackage, manifestPath, error) &&
 		ParseParameterDefinitions(manifestJson, shaderPackage, manifestPath, error);
 }

apps/LoopThroughWithOpenGLCompositing/shader/ShaderTypes.h

@@ -26,6 +26,7 @@ struct ShaderParameterDefinition
 {
 	std::string id;
 	std::string label;
+	std::string description;
 	ShaderParameterType type = ShaderParameterType::Float;
 	std::vector<double> defaultNumbers;
 	std::vector<double> minNumbers;
@@ -62,6 +63,12 @@ struct TemporalSettings
 	unsigned effectiveHistoryLength = 0;
 };
 
+struct FeedbackSettings
+{
+	bool enabled = false;
+	std::string writePassId;
+};
+
 struct ShaderTextureAsset
 {
 	std::string id;
@@ -76,6 +83,24 @@ struct ShaderFontAsset
 	std::filesystem::file_time_type writeTime;
 };
 
+struct ShaderPassDefinition
+{
+	std::string id;
+	std::string entryPoint;
+	std::filesystem::path sourcePath;
+	std::filesystem::file_time_type sourceWriteTime;
+	std::vector<std::string> inputNames;
+	std::string outputName;
+};
+
+struct ShaderPassBuildSource
+{
+	std::string passId;
+	std::string fragmentShaderSource;
+	std::vector<std::string> inputNames;
+	std::string outputName;
+};
+
 struct ShaderPackage
 {
 	std::string id;
@@ -86,10 +111,12 @@ struct ShaderPackage
 	std::filesystem::path directoryPath;
 	std::filesystem::path shaderPath;
 	std::filesystem::path manifestPath;
+	std::vector<ShaderPassDefinition> passes;
 	std::vector<ShaderParameterDefinition> parameters;
 	std::vector<ShaderTextureAsset> textureAssets;
 	std::vector<ShaderFontAsset> fontAssets;
 	TemporalSettings temporal;
+	FeedbackSettings feedback;
 	std::filesystem::file_time_type shaderWriteTime;
 	std::filesystem::file_time_type manifestWriteTime;
 };
@@ -108,6 +135,7 @@ struct RuntimeRenderState
 {
 	std::string layerId;
 	std::string shaderId;
+	std::string shaderName;
 	std::vector<ShaderParameterDefinition> parameterDefinitions;
 	std::map<std::string, ShaderParameterValue> parameterValues;
 	std::vector<ShaderTextureAsset> textureAssets;
@@ -127,4 +155,5 @@ struct RuntimeRenderState
 	TemporalHistorySource temporalHistorySource = TemporalHistorySource::None;
 	unsigned requestedTemporalHistoryLength = 0;
 	unsigned effectiveTemporalHistoryLength = 0;
+	FeedbackSettings feedback;
 };

apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOFormat.cpp

@@ -54,6 +54,8 @@ const char* VideoIOPixelFormatName(VideoIOPixelFormat format)
 	{
 	case VideoIOPixelFormat::V210:
 		return "10-bit YUV v210";
+	case VideoIOPixelFormat::Yuva10:
+		return "10-bit YUVA Ay10";
 	case VideoIOPixelFormat::Bgra8:
 		return "8-bit BGRA";
 	case VideoIOPixelFormat::Uyvy8:
@@ -64,7 +66,7 @@ const char* VideoIOPixelFormatName(VideoIOPixelFormat format)
 
 bool VideoIOPixelFormatIsTenBit(VideoIOPixelFormat format)
 {
-	return format == VideoIOPixelFormat::V210;
+	return format == VideoIOPixelFormat::V210 || format == VideoIOPixelFormat::Yuva10;
 }
 
 VideoIOPixelFormat ChoosePreferredVideoIOFormat(bool tenBitSupported)
@@ -80,6 +82,8 @@ unsigned VideoIOBytesPerPixel(VideoIOPixelFormat format)
 		return 2u;
 	case VideoIOPixelFormat::Bgra8:
 		return 4u;
+	case VideoIOPixelFormat::Yuva10:
+		return 4u;
 	case VideoIOPixelFormat::V210:
 	default:
 		return 0u;
@@ -90,6 +94,8 @@ unsigned VideoIORowBytes(VideoIOPixelFormat format, unsigned frameWidth)
 {
 	if (format == VideoIOPixelFormat::V210)
 		return MinimumV210RowBytes(frameWidth);
+	if (format == VideoIOPixelFormat::Yuva10)
+		return MinimumYuva10RowBytes(frameWidth);
 	return frameWidth * VideoIOBytesPerPixel(format);
 }
 
@@ -103,6 +109,11 @@ unsigned MinimumV210RowBytes(unsigned frameWidth)
 	return ((frameWidth + 5u) / 6u) * 16u;
 }
 
+unsigned MinimumYuva10RowBytes(unsigned frameWidth)
+{
+	return ((frameWidth + 63u) / 64u) * 256u;
+}
+
 unsigned ActiveV210WordsForWidth(unsigned frameWidth)
 {
 	return ((frameWidth + 5u) / 6u) * 4u;

apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOFormat.h

@@ -7,6 +7,7 @@ enum class VideoIOPixelFormat
 {
 	Uyvy8,
 	V210,
+	Yuva10,
 	Bgra8
 };
 
@@ -31,6 +32,7 @@ unsigned VideoIOBytesPerPixel(VideoIOPixelFormat format);
 unsigned VideoIORowBytes(VideoIOPixelFormat format, unsigned frameWidth);
 unsigned PackedTextureWidthFromRowBytes(unsigned rowBytes);
 unsigned MinimumV210RowBytes(unsigned frameWidth);
+unsigned MinimumYuva10RowBytes(unsigned frameWidth);
 unsigned ActiveV210WordsForWidth(unsigned frameWidth);
 V210CodeValues Rec709RgbToLegalV210(float red, float green, float blue);
 std::array<uint8_t, 16> PackV210Block(const V210SixPixelBlock& block);

apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOTypes.h

@@ -95,7 +95,7 @@ public:
 	virtual ~VideoIODevice() = default;
 	virtual void ReleaseResources() = 0;
 	virtual bool DiscoverDevicesAndModes(const VideoFormatSelection& videoModes, std::string& error) = 0;
-	virtual bool SelectPreferredFormats(const VideoFormatSelection& videoModes, std::string& error) = 0;
+	virtual bool SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error) = 0;
 	virtual bool ConfigureInput(InputFrameCallback callback, const VideoFormat& inputVideoMode, std::string& error) = 0;
 	virtual bool ConfigureOutput(OutputFrameCallback callback, const VideoFormat& outputVideoMode, bool externalKeyingEnabled, std::string& error) = 0;
 	virtual bool Start() = 0;

apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp

@@ -223,7 +223,7 @@ bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoM
 	return true;
 }
 
-bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoModes, std::string& error)
+bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error)
 {
 	if (!output)
 	{
@@ -239,8 +239,15 @@ bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoMo
 		mState.formatStatusMessage += "DeckLink input does not report 10-bit YUV support for the configured mode; using 8-bit capture. ";
 
 	const bool outputTenBitSupported = OutputSupportsFormat(output, videoModes.output.displayMode, bmdFormat10BitYUV);
-	mState.outputPixelFormat = outputTenBitSupported ? VideoIOPixelFormat::V210 : VideoIOPixelFormat::Bgra8;
-	if (!outputTenBitSupported)
+	const bool outputTenBitYuvaSupported = OutputSupportsFormat(output, videoModes.output.displayMode, bmdFormat10BitYUVA);
+	mState.outputPixelFormat = outputAlphaRequired
+		? (outputTenBitYuvaSupported ? VideoIOPixelFormat::Yuva10 : VideoIOPixelFormat::Bgra8)
+		: (outputTenBitSupported ? VideoIOPixelFormat::V210 : VideoIOPixelFormat::Bgra8);
+	if (outputAlphaRequired && outputTenBitYuvaSupported)
+		mState.formatStatusMessage += "External keying requires alpha; using 10-bit YUVA output. ";
+	else if (outputAlphaRequired)
+		mState.formatStatusMessage += "External keying requires alpha, but DeckLink output does not report 10-bit YUVA support for the configured mode; using 8-bit BGRA output. ";
+	else if (!outputTenBitSupported)
 		mState.formatStatusMessage += "DeckLink output does not report 10-bit YUV support for the configured mode; using 8-bit BGRA output. ";
 
 	int deckLinkOutputRowBytes = 0;

apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.h

@@ -22,7 +22,7 @@ public:
 
 	void ReleaseResources() override;
 	bool DiscoverDevicesAndModes(const VideoFormatSelection& videoModes, std::string& error) override;
-	bool SelectPreferredFormats(const VideoFormatSelection& videoModes, std::string& error) override;
+	bool SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error) override;
 	bool ConfigureInput(InputFrameCallback callback, const VideoFormat& inputVideoMode, std::string& error) override;
 	bool ConfigureOutput(OutputFrameCallback callback, const VideoFormat& outputVideoMode, bool externalKeyingEnabled, std::string& error) override;
 	bool Start() override;

apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkVideoIOFormat.cpp

@@ -6,6 +6,8 @@ BMDPixelFormat DeckLinkPixelFormatForVideoIO(VideoIOPixelFormat format)
 	{
 	case VideoIOPixelFormat::V210:
 		return bmdFormat10BitYUV;
+	case VideoIOPixelFormat::Yuva10:
+		return bmdFormat10BitYUVA;
 	case VideoIOPixelFormat::Bgra8:
 		return bmdFormat8BitBGRA;
 	case VideoIOPixelFormat::Uyvy8:
@@ -18,6 +20,8 @@ VideoIOPixelFormat VideoIOPixelFormatFromDeckLink(BMDPixelFormat format)
 {
 	if (format == bmdFormat10BitYUV)
 		return VideoIOPixelFormat::V210;
+	if (format == bmdFormat10BitYUVA)
+		return VideoIOPixelFormat::Yuva10;
 	if (format == bmdFormat8BitBGRA)
 		return VideoIOPixelFormat::Bgra8;
 	return VideoIOPixelFormat::Uyvy8;

config/runtime-host.json

@@ -1,12 +1,15 @@
 {
   "shaderLibrary": "shaders",
   "serverPort": 8080,
+  "oscBindAddress": "0.0.0.0",
   "oscPort": 9000,
+  "oscSmoothing": 0.18,
   "inputVideoFormat": "1080p",
   "inputFrameRate": "59.94",
   "outputVideoFormat": "1080p",
   "outputFrameRate": "59.94",
   "autoReload": true,
   "maxTemporalHistoryFrames": 12,
+  "previewFps": 30,
   "enableExternalKeying": true
 }

docs/ARCHITECTURE_RESILIENCE_REVIEW.md

@@ -0,0 +1,638 @@
+# Architecture Resilience Review
+
+This note summarizes the main architectural improvements that would make the app more resilient during live use, especially around timing isolation, failure isolation, and recoverability.
+
+Phase checklist:
+
+- [ ] Define subsystem boundaries and target architecture
+- [ ] Introduce an internal event model
+- [ ] Split `RuntimeHost`
+- [ ] Make the render thread the sole GL owner
+- [ ] Refactor live state layering into an explicit composition model
+- [ ] Move persistence onto a background snapshot writer
+- [ ] Make DeckLink/backend lifecycle explicit with a state machine
+- [ ] Add structured health, telemetry, and operational reporting
+
+## Timing Review
+
+The recent OSC work removed several control-path stalls, but the app still has a few deeper timing characteristics that matter for live resilience:
+
+- output playout is still effectively render-on-demand from the DeckLink completion callback
+- output buffering and preroll are now larger, but the buffering model is still static and only loosely related to actual render cost
+- GPU readback is partly asynchronous, but the fallback path still returns to synchronous readback on any miss
+- preview presentation is still tied to the playout render path
+- background service timing still relies on coarse polling sleeps
+
+Those points are important because they affect not just average performance, but how the app behaves under brief spikes, device jitter, or load bursts.
+
+## Key Findings
+
+### 1. `RuntimeHost` is carrying too many responsibilities
+
+`RuntimeHost` currently acts as:
+
+- config store
+- persistent state store
+- live parameter/state authority
+- shader package registry owner
+- status/telemetry sink
+- control mutation entrypoint
+
+That makes it a single contention and failure domain. It is also why OSC and render timing issues repeatedly surfaced around shared state access.
+
+Relevant code:
+
+- [RuntimeHost.h](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.h:15)
+
+Recommended direction:
+
+- split persisted config/state from live render-facing state
+- separate status/telemetry updates from control mutation paths
+- make render consume snapshots rather than sharing a large mutable authority object
+
+### 2. OpenGL ownership is still centralized behind one shared lock
+
+Even after recent timing improvements, preview, input upload, and playout rendering still rely on one shared GL context protected by one `CRITICAL_SECTION`.
+
+Relevant code:
+
+- [OpenGLComposite.h](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h:93)
+- [OpenGLComposite.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp:253)
+- [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:70)
+
+This is still a central choke point and limits timing isolation.
+
+Recommended direction:
+
+- use one dedicated render thread as the sole GL owner
+- have input/output/control threads queue work instead of performing GL work directly
+- remove ad hoc GL use from callback threads
+
+### 3. Control flow is spread across polling and shared-memory patterns
+
+`RuntimeServices` currently mixes:
+
+- file polling
+- deferred OSC commit handling
+- control service orchestration
+
+OSC ingest, overlay application, and host sync are distributed across several components.
+
+Relevant code:
+
+- [RuntimeServices.h](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.h:26)
+- [RuntimeServices.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.cpp:178)
+
+Recommended direction:
+
+- introduce a small internal event pipeline or message bus
+- use typed events for OSC, reloads, persistence requests, and status changes
+- make timing ownership explicit per subsystem
+
+Example event types:
+
+- `OscParameterTargeted`
+- `RenderOverlaySettled`
+- `PersistStateRequested`
+- `ShaderReloadRequested`
+- `DeckLinkStatusChanged`
+
+### 4. Error handling is still heavily UI-coupled
+
+Failures are often surfaced via `MessageBoxA`, while background services mainly log with `OutputDebugStringA`.
+
+Relevant code:
+
+- [OpenGLComposite.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp:314)
+- [DeckLinkSession.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp:478)
+- [RuntimeServices.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.cpp:205)
+
+This is not ideal for a live system where modal dialogs and silent debug logging are both poor operational behavior.
+
+Recommended direction:
+
+- introduce structured in-app error reporting
+- define severity levels and counters
+- prefer degraded runtime states over modal failure handling where possible
+- add a rolling log file for operational troubleshooting
+
+### 5. Live OSC overlay and persisted state are still separate concepts without a formal model
+
+The current design works better now, but it still relies on hand-managed reconciliation between:
+
+- persisted parameter state in `RuntimeHost`
+- transient OSC overlay state in `OpenGLComposite`
+
+Relevant code:
+
+- [OpenGLComposite.h](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h:66)
+
+Recommended direction:
+
+Formalize three layers of state:
+
+- base persisted state
+- operator/UI committed state
+- transient live automation overlay
+
+Then render can always resolve:
+
+- `final = base + committed + transient`
+
+That avoids special-case sync behavior becoming scattered across the code.
+
+### 6. DeckLink lifecycle could be modeled more explicitly
+
+`DeckLinkSession` has a number of imperative calls, but startup, preroll, running, degraded, and stopped are not represented as an explicit state machine.
+
+Relevant code:
+
+- [DeckLinkSession.h](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.h:17)
+
+Recommended direction:
+
+- introduce explicit session states
+- define allowed transitions
+- centralize recovery behavior
+- make shutdown ordering and degraded-mode behavior more predictable
+
+Timing-specific additions:
+
+- separate "device callback received" from "render the next output frame" so output cadence is not driven directly by the completion callback thread
+- make playout headroom configurable and adaptive instead of using a fixed compile-time preroll count
+- track an explicit backend health state such as `running-steady`, `catching-up`, `late`, and `dropping`
+
+Relevant timing code:
+
+- [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:86)
+- [DeckLinkSession.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp:420)
+- [DeckLinkSession.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp:487)
+- [VideoPlayoutScheduler.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.cpp:26)
+
+Why this matters:
+
+- `PlayoutFrameCompleted()` currently begins an output frame, takes the shared GL path, renders, reads back, and schedules the next frame in one callback-driven flow.
+- `VideoPlayoutScheduler::AccountForCompletionResult()` currently reacts to both late and dropped frames by blindly advancing the schedule index by `2`, which is simple but not especially robust.
+- `kPrerollFrameCount` is now `12`, but `DeckLinkSession::ConfigureOutput()` still creates a fixed pool of `10` mutable output frames. That mismatch suggests the buffering model is not being sized from one coherent source of truth.
+
+Recommended direction:
+
+- move playout to a producer/consumer model where a render worker fills output buffers ahead of the DeckLink callback
+- define buffer-pool sizing from one policy object, for example: preroll depth, minimum spare buffers, and allowed catch-up depth
+- replace fixed "skip two frames" recovery with measured lag accounting based on actual scheduled-versus-completed position
+- expose playout latency as a runtime setting or policy, rather than burying it in a constant
+
+### 6a. The current playout timing model is still callback-coupled
+
+The app now has more headroom, but the next output frame is still produced directly in the scheduled-frame completion callback path.
+
+Relevant code:
+
+- [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:86)
+- [DeckLinkFrameTransfer.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkFrameTransfer.cpp:53)
+
+That means the completion callback is currently responsible for:
+
+- frame pacing accounting
+- acquiring the next output buffer
+- taking the GL critical section
+- rendering the composite
+- performing output readback
+- scheduling the next frame
+
+This works when the app is comfortably within budget, but it makes deadline misses much harder to absorb gracefully.
+
+Recommended direction:
+
+- make the DeckLink callback a lightweight notifier
+- have a dedicated playout worker or render worker keep an ahead-of-time queue of ready output frames
+- treat callback time as control-plane time, not render time
+
+### 6b. A producer/consumer playout model would be a better long-term fit
+
+The stronger architecture for this app is:
+
+- a render scheduler or dedicated render thread runs at the configured video cadence
+- rendering produces completed output frames ahead of need
+- those frames are placed into a bounded queue or ring buffer
+- the DeckLink side consumes already-prepared frames when callbacks indicate they are needed
+
+That is a better fit than callback-driven rendering because it separates:
+
+- render timing
+- GL ownership
+- output-device timing
+- latency policy
+
+In that model:
+
+- render is the producer
+- DeckLink is the timing consumer
+- the queue between them becomes the main place to manage latency versus resilience
+
+Why this is preferable:
+
+- brief callback jitter is less likely to become a visible dropped frame
+- render spikes can be absorbed by queue headroom instead of immediately missing output deadlines
+- latency becomes an explicit policy choice rather than an incidental side effect of callback timing
+- queue depth, underruns, stale-frame reuse, and catch-up behavior become measurable and tunable
+
+Recommended direction:
+
+- move toward a bounded producer/consumer playout queue
+- make queue depth and target headroom runtime policy, not compile-time constants
+- define explicit underrun behavior, for example:
+  - reuse newest completed frame
+  - reuse last scheduled frame
+  - output black or degraded frame
+- keep DeckLink callbacks limited to dequeue/schedule/accounting work wherever possible
+
+### 7. Persistence should be more asynchronous and debounced
+
+`SavePersistentState()` is still called directly from many update paths.
+
+Relevant code:
+
+- [RuntimeHost.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.cpp:1841)
+
+Recent OSC work already reduced this problem for live automation, but the broader architecture would still benefit from:
+
+- a debounced persistence queue
+- atomic write-behind snapshots
+- clear separation between state mutation and disk flush
+
+This improves both resilience and timing safety.
+
+### 8. Telemetry is useful, but still too coarse
+
+The app already records render timing and playout pacing, which is a good foundation.
+
+Relevant code:
+
+- [OpenGLRenderPipeline.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp:24)
+- [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:24)
+
+Recommended direction:
+
+Add lightweight tracing for:
+
+- input callback latency
+- input upload skip count
+- GL lock wait time
+- render queue depth
+- render time
+- pass build/compile latency
+- readback time
+- output scheduling lag
+- output queue depth
+- preroll depth versus spare-buffer depth
+- preview present cost and skipped-preview count
+- control queue depth
+- `RuntimeHost` lock contention
+
+That would make future tuning and failure diagnosis much easier.
+
+Timing-specific observations from the current code:
+
+- render time is captured as one total number in [OpenGLRenderPipeline.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp:24), but not split into draw, pack, readback wait, readback copy, or preview present
+- frame pacing stats are recorded in [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:17), but there is no explicit visibility into how much queued playout headroom remains
+- input uploads are intentionally skipped when the GL bridge is busy in [OpenGLVideoIOBridge.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp:60), but the app does not currently surface how often that is happening
+
+### 8a. Preview and playout are still too close together
+
+The desktop preview is rate-limited, but still presented from inside the render pipeline path.
+
+Relevant code:
+
+- [OpenGLRenderPipeline.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp:54)
+- [OpenGLComposite.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp:235)
+
+This means preview presentation can still consume time on the same path that is trying to meet output deadlines.
+
+Recommended direction:
+
+- treat preview as best-effort and entirely subordinate to playout
+- move preview present to a separate presentation schedule fed from the latest completed render
+- record preview skips and preview present cost independently from playout timing
+
+### 8b. Readback is improved, but still not fully deadline-safe
+
+The async readback path is a good step, but the miss path still falls back to synchronous `glReadPixels()` and then flushes the async pipeline.
+
+Relevant code:
+
+- [OpenGLRenderPipeline.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp:150)
+- [OpenGLRenderPipeline.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp:228)
+
+That means a single late GPU fence can push the app back onto the most timing-sensitive path exactly when it is already under pressure.
+
+Recommended direction:
+
+- increase readback instrumentation before changing policy again
+- consider deeper readback buffering or a true stale-frame reuse policy instead of immediate synchronous fallback
+- separate "freshest possible frame" policy from "never miss output deadline" policy and make that tradeoff explicit
+
+### 8c. Background control and file-watch timing are still coarse
+
+`RuntimeServices::PollLoop()` currently uses a `25 x Sleep(10)` loop, which gives it a coarse `~250 ms` cadence for file-watch polling and deferred OSC commit work.
+
+Relevant code:
+
+- [RuntimeServices.cpp](/c:/Users/Aiden/Documents/GitHub/video-shader-toys/apps/LoopThroughWithOpenGLCompositing/control/RuntimeServices.cpp:245)
+
+That is acceptable for non-critical background work, but it is still too blunt to be the long-term timing model for coordination-heavy runtime services.
+
+Recommended direction:
+
+- replace coarse sleep polling with waitable events or condition-variable driven wakeups where practical
+- isolate truly background work from latency-sensitive control reconciliation
+- add separate metrics for queue age, not just queue depth
+
+## Phased Roadmap
+
+This roadmap is ordered by architectural dependency rather than by “quick wins.” The goal is to move the app toward clearer ownership boundaries and safer live behavior without doing later work on top of foundations that are likely to change again.
+
+### Phase 1. Define subsystem boundaries and target architecture
+
+Before changing major internals, formalize the target responsibilities for each major part of the app.
+
+Target split:
+
+- `RuntimeStore`
+  - persisted config
+  - persisted layer stack
+  - preset persistence
+- `RuntimeSnapshot`
+  - render-facing immutable or near-immutable snapshots
+  - parameter values prepared for the render path
+- `ControlServices`
+  - OSC ingress
+  - web control ingress
+  - reload/file-watch requests
+  - commit/persist requests
+- `RenderEngine`
+  - sole owner of live GL rendering
+  - sole consumer of render snapshots plus transient overlays
+- `VideoBackend`
+  - DeckLink input/output lifecycle
+  - pacing and scheduling
+- `Health/Telemetry`
+  - logging
+  - counters
+  - timing traces
+  - degraded-state reporting
+
+Why this phase comes first:
+
+- it prevents later refactors from reintroducing responsibility overlap
+- it gives names to the seams the later phases will build around
+- it reduces the risk of replacing one monolith with several poorly-defined ones
+
+Suggested deliverables:
+
+- a short architecture diagram
+- a responsibility table for each subsystem
+- a list of allowed dependencies between subsystems
+
+### Phase 2. Introduce an internal event model
+
+Once subsystem boundaries are defined, introduce a typed event pipeline between them. This should happen before large state splits so the app has a stable coordination model.
+
+Example event families:
+
+- control events
+  - `OscParameterTargeted`
+  - `UiParameterCommitted`
+  - `TriggerFired`
+- runtime events
+  - `ShaderReloadRequested`
+  - `PackagesRescanned`
+  - `PersistStateRequested`
+- render events
+  - `OverlayApplied`
+  - `OverlaySettled`
+  - `SnapshotPublished`
+- backend events
+  - `InputSignalChanged`
+  - `OutputLateFrameDetected`
+  - `OutputDroppedFrameDetected`
+- health events
+  - `SubsystemWarningRaised`
+  - `SubsystemRecovered`
+
+Why this phase comes second:
+
+- it provides a migration path away from direct cross-calls
+- it makes ownership explicit before data structures are split apart
+- it lets you move one subsystem at a time without losing coordination
+
+Suggested outcome:
+
+- the app stops relying on “shared object plus mutex plus polling” as the default coordination pattern
+
+### Phase 3. Split `RuntimeHost` into persistent state, render snapshot state, and service-facing coordination
+
+After the event model exists, break apart `RuntimeHost`.
+
+Recommended split:
+
+- `RuntimeStore`
+  - owns config and saved layer data
+  - handles serialization/deserialization
+  - does not sit on the live render path
+- `RuntimeCoordinator`
+  - resolves control actions
+  - validates mutations
+  - publishes new snapshots
+  - bridges events between services and render
+- `RuntimeSnapshotProvider`
+  - publishes immutable render snapshots
+  - avoids large shared mutable structures on the render path
+
+Why this phase comes before render-thread isolation:
+
+- render isolation is easier when the render thread consumes clean snapshots instead of a large mutable host object
+- otherwise the GL refactor still drags along too much shared state complexity
+
+Primary design rule:
+
+- render should read snapshots
+- persistence should write stored state
+- services should request mutations through the coordinator
+
+### Phase 4. Make the render thread the sole GL owner
+
+With state and coordination cleaner, move to a dedicated render-thread model.
+
+Target behavior:
+
+- one thread owns the GL context
+- input callbacks never perform GL work directly
+- output callbacks never perform GL work directly
+- preview presentation, texture upload, render passes, readback, and output pack work are all issued by the render thread
+
+Other threads should only:
+
+- enqueue new video frames
+- enqueue control updates
+- enqueue backend events
+- consume produced output buffers
+
+Why this phase comes here:
+
+- it is much safer once state access and control coordination are no longer centered on `RuntimeHost`
+- it avoids coupling the render-thread refactor to storage and service refactors at the same time
+
+Expected benefits:
+
+- less cross-thread GL contention
+- easier timing reasoning
+- much lower risk of callback-driven stalls
+- a clearer foundation for future GPU pipeline work
+
+### Phase 5. Refactor live state layering into an explicit composition model
+
+Once rendering and snapshots are isolated, formalize how final parameter values are derived.
+
+Recommended layers:
+
+- base persisted state
+- operator-committed live state
+- transient automation overlay
+
+Render should derive final values from a clear composition rule such as:
+
+- `final = base + committed + transient`
+
+Why this phase follows render isolation:
+
+- once render owns snapshot consumption, it becomes much easier to cleanly evaluate layered state without touching persistence or control services
+- it turns the current OSC overlay behavior into a first-class model instead of an implementation detail
+
+Expected benefits:
+
+- fewer one-off sync rules
+- clearer behavior for OSC, UI changes, and automation
+- easier future expansion to presets, cues, or timed transitions
+
+### Phase 6. Move persistence onto a background snapshot writer
+
+After the state model is explicit, persistence should become a background concern rather than a synchronous side effect of mutations.
+
+Target behavior:
+
+- mutations update authoritative in-memory stored state
+- persistence requests are queued
+- disk writes are debounced and coalesced
+- writes are atomic and versioned where practical
+
+Why this phase comes after state splitting:
+
+- otherwise persistence logic will need to be rewritten twice
+- it should operate on the new `RuntimeStore` model, not on the current mixed-responsibility object
+
+Expected benefits:
+
+- less timing interference
+- better corruption resistance
+- cleaner restart/recovery semantics
+
+### Phase 7. Make DeckLink/backend lifecycle explicit with a state machine
+
+Once the render and state layers are cleaner, refactor the video backend into an explicit lifecycle model.
+
+Suggested states:
+
+- uninitialized
+- devices-discovered
+- configured
+- prerolling
+- running
+- degraded
+- stopping
+- stopped
+- failed
+
+Why this phase belongs here:
+
+- the backend should integrate with the new event model
+- degraded/recovery behavior will be easier once rendering and state coordination are already more deterministic
+
+Expected benefits:
+
+- safer startup/shutdown ordering
+- clearer recovery behavior
+- easier handling of missing input, dropped frames, or reconfiguration
+- a clearer place to own playout headroom policy, output queue sizing, and late-frame recovery behavior
+
+### Phase 8. Add structured health, telemetry, and operational reporting
+
+This phase should happen after the main ownership changes so the telemetry can reflect the final architecture instead of a transient one.
+
+Recommended coverage:
+
+- render queue depth
+- GL lock wait time, if any shared lock remains
+- input callback latency
+- input upload skip count
+- output scheduling lag
+- output queue depth and spare-buffer depth
+- readback timing
+- readback fence wait timing
+- synchronous readback fallback count
+- preview present timing and skipped-preview count
+- snapshot publish frequency
+- persistence queue depth
+- event queue depth
+- backend state transitions
+- warning/error counters per subsystem
+
+Also replace modal-only error handling with:
+
+- structured in-app health state
+- severity-based logging
+- rolling log files
+- operator-visible degraded-state messages
+
+Why this phase comes last:
+
+- it should instrument the architecture you intend to keep
+- otherwise instrumentation work gets invalidated by the refactor
+
+## Recommended Execution Order
+
+If this is approached as a serious architecture program rather than opportunistic cleanup, the recommended order is:
+
+1. Define subsystem boundaries and target architecture.
+2. Introduce the internal event model.
+3. Split `RuntimeHost`.
+4. Make the render thread the sole GL owner.
+5. Formalize live state layering and composition.
+6. Move persistence to a background snapshot writer.
+7. Refactor DeckLink/backend lifecycle into an explicit state machine.
+8. Add structured telemetry, health reporting, and operational diagnostics.
+
+## Why This Order Makes Sense
+
+This order tries to avoid doing foundational work twice.
+
+- The event model comes before major subsystem extraction so coordination patterns stabilize early.
+- `RuntimeHost` is split before render isolation so the render thread does not inherit the current monolithic state model.
+- Live state layering is formalized only after render ownership is clearer.
+- Persistence is moved later so it can target the final state model rather than the current one.
+- Telemetry is intentionally late so it instruments the architecture that survives the refactor.
+
+## Short Version
+
+The app is in a much better place than it was before the OSC timing work, but the main remaining architectural risk is still shared ownership. Too many responsibilities converge on `RuntimeHost` and the shared GL path. The most sensible path forward is:
+
+1. define boundaries
+2. establish an event model
+3. split state ownership
+4. isolate rendering
+5. formalize layered live state
+6. background persistence
+7. explicit backend lifecycle
+8. health and telemetry
+
+That sequence gives each later phase a cleaner foundation than the current app has today.

docs/OSC_CONTROL.md

@@ -8,11 +8,15 @@ Set the UDP port in `config/runtime-host.json`:
 
 ```json
 {
-  "oscPort": 9000
+  "oscBindAddress": "127.0.0.1",
+  "oscPort": 9000,
+  "oscSmoothing": 0.18
 }
 ```
 
 Set `oscPort` to `0` to disable the OSC listener.
+Set `oscBindAddress` to `127.0.0.1` to keep OSC local to the host, or `0.0.0.0` to listen on all IPv4 interfaces.
+Set `oscSmoothing` to a value from `0.0` to `1.0` to add a subtle per-frame easing amount for numeric OSC controls. `0.0` disables smoothing, and larger values respond more quickly.
 
 ## Address Pattern
 
@@ -47,6 +51,8 @@ Matching is exact first. If that fails, names are compared in a simplified form
 
 If multiple layers use the same shader package ID or display name, the first matching layer in the stack is controlled. Use the internal layer ID shown in the UI when you need to target one duplicate layer precisely.
 
+In the control UI, each parameter row has a small **OSC** button. Clicking it copies that parameter's exact OSC address to the clipboard, which is the safest way to target controls with long names or duplicate shader layers.
+
 ## Values
 
 The listener accepts these OSC argument types:
@@ -59,17 +65,21 @@ The listener accepts these OSC argument types:
 
 Single-argument messages become scalar JSON values. Multi-argument messages become JSON arrays, which lets OSC drive `vec2` and `color` parameters.
 
+OSC updates are coalesced by target route and applied once per render tick, so rapid controller motion does not force one runtime mutation, disk write, and UI push per incoming UDP packet. Numeric OSC controls can also be slightly smoothed with `oscSmoothing`.
+
 Examples:
 
 ```text
 /VideoShaderToys/fisheye-reproject/panDegrees 45.0
 /VideoShaderToys/fisheye-reproject/fisheyeModel "equisolid"
 /VideoShaderToys/video-transform/pan 0.25 -0.5
-/VideoShaderToys/composition-guides/lineColor 1.0 0.8 0.1 1.0
+/VideoShaderToys/safe-area-guides/lineColor 1.0 0.8 0.1 1.0
 ```
 
 Values are validated with the same shader parameter rules used by the REST API. Invalid values or unknown addresses are ignored and reported to the native debug output.
 
+OSC-driven parameter changes are not autosaved to `runtime/runtime_state.json`. Stack edits made through the UI and preset operations still persist as before. Smoothing only applies to numeric controls such as floats, `vec2`, and `color`; booleans, enums, text, and triggers stay immediate.
+
 For `trigger` parameters, the OSC value is treated as a pulse. A simple integer or boolean message is enough:
 
 ```text
@@ -112,10 +122,21 @@ send('127.0.0.1:9000', '/VideoShaderToys/fisheye-reproject/tiltDegrees', {type:
 
 ## Network
 
-The listener binds to localhost only:
+By default the listener binds to localhost only:
 
 ```text
 127.0.0.1:<oscPort>
 ```
 
 This keeps the control surface local to the machine running Video Shader Toys.
+
+To accept OSC from other machines on the network, set:
+
+```json
+{
+  "oscBindAddress": "0.0.0.0",
+  "oscPort": 9000
+}
+```
+
+That listens on all IPv4 interfaces, so make sure your firewall and network are configured appropriately.

docs/openapi.yaml

@@ -201,6 +201,7 @@ paths:
     post:
       tags: [Runtime]
       summary: Reload shaders
+      description: Rescans the shader library, re-reads manifests, queues shader compilation, and refreshes shader availability/errors. If a changed shader fails, the previous working stack remains active where possible.
       operationId: reloadShaders
       requestBody:
         required: false
@@ -358,6 +359,8 @@ components:
           $ref: "#/components/schemas/VideoStatus"
         decklink:
           $ref: "#/components/schemas/DeckLinkStatus"
+        videoIO:
+          $ref: "#/components/schemas/VideoIOStatus"
         performance:
           $ref: "#/components/schemas/PerformanceStatus"
         shaders:
@@ -415,6 +418,8 @@ components:
           type: string
     DeckLinkStatus:
       type: object
+      deprecated: true
+      description: Legacy DeckLink-specific status object. Prefer `videoIO` for new clients.
       properties:
         modelName:
           type: string
@@ -430,6 +435,26 @@ components:
           type: boolean
         statusMessage:
           type: string
+    VideoIOStatus:
+      type: object
+      properties:
+        backend:
+          type: string
+          example: decklink
+        modelName:
+          type: string
+        supportsInternalKeying:
+          type: boolean
+        supportsExternalKeying:
+          type: boolean
+        keyerInterfaceAvailable:
+          type: boolean
+        externalKeyingRequested:
+          type: boolean
+        externalKeyingActive:
+          type: boolean
+        statusMessage:
+          type: string
     PerformanceStatus:
       type: object
       properties:
@@ -441,6 +466,18 @@ components:
           type: number
         budgetUsedPercent:
           type: number
+        completionIntervalMs:
+          type: number
+        smoothedCompletionIntervalMs:
+          type: number
+        maxCompletionIntervalMs:
+          type: number
+        lateFrameCount:
+          type: number
+        droppedFrameCount:
+          type: number
+        flushedFrameCount:
+          type: number
     ShaderSummary:
       type: object
       properties:
@@ -452,6 +489,12 @@ components:
           type: string
         category:
           type: string
+        available:
+          type: boolean
+          description: False when the shader package exists but failed manifest or compile validation.
+        error:
+          type: string
+          description: Error text for unavailable shader packages.
         temporal:
           $ref: "#/components/schemas/TemporalState"
     TemporalState:
@@ -490,9 +533,21 @@ components:
           type: string
         label:
           type: string
+        description:
+          type: string
+          description: Short helper text shown under the parameter label in the control UI.
         type:
           type: string
           enum: [float, vec2, color, bool, enum, text, trigger]
+        defaultValue:
+          description: Default parameter value from the shader manifest.
+          oneOf:
+            - type: number
+            - type: boolean
+            - type: string
+            - type: array
+              items:
+                type: number
         min:
           type: array
           items:
@@ -509,6 +564,12 @@ components:
           type: array
           items:
             $ref: "#/components/schemas/ParameterOption"
+        maxLength:
+          type: number
+          description: Maximum length for text parameters.
+        font:
+          type: string
+          description: Font asset id used by text parameters, when declared.
         value:
           description: Current parameter value.
           oneOf:

runtime/README.md

@@ -14,11 +14,12 @@ Packaged documentation:
 
 Generated files:
 
-- `shader_cache/active_shader_wrapper.slang`: generated Slang wrapper for the active shader/layer.
-- `shader_cache/active_shader.raw.frag`: raw GLSL emitted by `slangc`.
-- `shader_cache/active_shader.frag`: patched GLSL consumed by the OpenGL path.
+- `shader_cache/active_shader_wrapper.slang`: generated Slang wrapper for the most recently compiled shader pass.
+- `shader_cache/active_shader.raw.frag`: raw GLSL emitted by `slangc` for the most recently compiled pass.
+- `shader_cache/active_shader.frag`: patched GLSL consumed by the OpenGL path for the most recently compiled pass.
 - `runtime_state.json`: autosaved latest layer stack, layer order, bypass state, shader assignments, and parameter values. The host reloads this file on startup.
 - `stack_presets/*.json`: user-saved layer stack presets.
+- `screenshots/*.png`: screenshots captured from the final output render target through the control UI/API.
 
 Git policy:
 

runtime/templates/shader_wrapper.slang.in

@@ -19,6 +19,7 @@ struct ShaderContext
 	float bypass;
 	int sourceHistoryLength;
 	int temporalHistoryLength;
+	int feedbackAvailable;
 };
 
 cbuffer GlobalParams
@@ -34,16 +35,23 @@ cbuffer GlobalParams
 	float gBypass;
 	int gSourceHistoryLength;
 	int gTemporalHistoryLength;
+	int gFeedbackAvailable;
 {{PARAMETER_UNIFORMS}}};
 
 Sampler2D<float4> gVideoInput;
-{{SOURCE_HISTORY_SAMPLERS}}{{TEMPORAL_HISTORY_SAMPLERS}}{{TEXTURE_SAMPLERS}}
+Sampler2D<float4> gLayerInput;
+{{SOURCE_HISTORY_SAMPLERS}}{{TEMPORAL_HISTORY_SAMPLERS}}{{FEEDBACK_SAMPLER}}{{TEXTURE_SAMPLERS}}
 {{TEXT_SAMPLERS}}
 float4 sampleVideo(float2 tc)
 {
 	return gVideoInput.Sample(tc);
 }
 
+float4 sampleLayerInput(float2 tc)
+{
+	return gLayerInput.Sample(tc);
+}
+
 float4 sampleSourceHistory(int framesAgo, float2 tc)
 {
 	if (gSourceHistoryLength <= 0)
@@ -74,6 +82,8 @@ float4 sampleTemporalHistory(int framesAgo, float2 tc)
 	}
 }
 
+{{FEEDBACK_HELPER}}
+
 {{TEXT_HELPERS}}
 #include "{{USER_SHADER_INCLUDE}}"
 
@@ -94,6 +104,7 @@ float4 fragmentMain(FragmentInput input) : SV_Target
 	context.bypass = gBypass;
 	context.sourceHistoryLength = gSourceHistoryLength;
 	context.temporalHistoryLength = gTemporalHistoryLength;
+	context.feedbackAvailable = gFeedbackAvailable;
 	float4 effectedColor = {{ENTRY_POINT_CALL}};
 	float mixValue = clamp(gBypass > 0.5 ? 0.0 : gMixAmount, 0.0, 1.0);
 	return lerp(context.sourceColor, effectedColor, mixValue);

shaders/SHADER_CONTRACT.md

@@ -55,7 +55,7 @@ float4 shadeVideo(ShaderContext context)
 }
 ```
 
-With `autoReload` enabled in `config/runtime-host.json`, edits to shader source, manifests, and declared texture assets are picked up automatically.
+With `autoReload` enabled in `config/runtime-host.json`, edits to shader source, manifests, and declared texture assets are picked up automatically. You can also use **Reload shaders** in the control UI to manually rescan the shader library.
 
 ## Guidance For Shaders
 
@@ -80,7 +80,7 @@ Important rules:
 - If adapting third-party code, include attribution and source URL in the manifest description when the license allows adaptation.
 - If the source license is unclear or incompatible, do not add the shader package.
 
-Before finishing, compile-check the shader through the runtime wrapper or launch the app and verify the shader appears without an error in the selector.
+Before finishing, compile-check the shader through the runtime wrapper or launch the app and verify the shader appears without an error in the selector. CI also runs shader validation, so every available package in `shaders/` should compile successfully. Intentionally broken examples should stay visibly marked as broken rather than pretending to be production shaders.
 
 ## Manifest Fields
 
@@ -97,9 +97,20 @@ Optional fields:
 - `description`: display/help text for the shader library.
 - `category`: UI grouping label.
 - `entryPoint`: Slang function to call. Defaults to `shadeVideo`.
+- `passes`: advanced render-pass declarations. Omit this for normal single-pass shaders.
 - `textures`: texture assets to load and expose as samplers.
 - `fonts`: packaged font assets for live text parameters.
 - `temporal`: history-buffer requirements.
+- `feedback`: optional previous-frame shader-local feedback surface.
+
+Parameter objects may also include an optional `description` string. The control UI displays it as one-line helper text with the full text available on hover, so use it for short operational guidance rather than long documentation.
+
+Metadata conventions:
+
+- Keep `name` short, human-facing, and in title case.
+- Keep `category` consistent with existing library groups such as `Color`, `Transform`, `Projection`, `Temporal`, `Scopes & Guides`, `Utility`, `Feedback`, and `Calibration`.
+- Keep `description` to one clear sentence in present tense that explains what the shader does for an operator.
+- Avoid placeholder, joke, or overly implementation-heavy descriptions unless the shader is intentionally a diagnostic or broken example.
 
 Shader-visible identifiers must be valid Slang-style identifiers:
 
@@ -110,6 +121,179 @@ Shader-visible identifiers must be valid Slang-style identifiers:
 
 Use letters, numbers, and underscores only, and start with a letter or underscore. For example, `logoTexture` is valid; `logo-texture` is not valid as a shader-visible texture ID.
 
+## Render Passes
+
+Most shaders should omit `passes`. The runtime then creates one implicit pass:
+
+```json
+{
+  "id": "main",
+  "source": "shader.slang",
+  "entryPoint": "shadeVideo",
+  "output": "layerOutput"
+}
+```
+
+Advanced shaders may declare explicit passes. All passes may live in one `.slang` file by using different `entryPoint` values, or they may be split across multiple source files:
+
+```json
+{
+  "passes": [
+    {
+      "id": "blurX",
+      "source": "blur-x.slang",
+      "entryPoint": "blurHorizontal",
+      "inputs": ["layerInput"],
+      "output": "blurredX"
+    },
+    {
+      "id": "final",
+      "source": "final.slang",
+      "entryPoint": "finish",
+      "inputs": ["blurredX"],
+      "output": "layerOutput"
+    }
+  ]
+}
+```
+
+Pass fields:
+
+- `id`: required pass identifier. It must be a valid shader identifier and unique inside the package.
+- `source`: required Slang source path relative to the package directory.
+- `entryPoint`: optional Slang function for this pass. Defaults to the package-level `entryPoint`.
+- `inputs`: optional list of named inputs. The first input is used as the pass input texture.
+- `output`: optional output name. Use `layerOutput` for the final visible layer result.
+
+Pass input names:
+
+- `layerInput`: the input to this layer, before any of its passes run.
+- `previousPass`: the previous pass output in this layer. If there is no previous pass, this falls back to `layerInput`.
+- Any earlier pass `id` or `output` name from the same layer.
+
+If `inputs` is omitted, the first pass samples `layerInput` and later passes sample `previousPass`.
+
+Single-file multipass example:
+
+```json
+{
+  "passes": [
+    {
+      "id": "mask",
+      "source": "shader.slang",
+      "entryPoint": "makeMask",
+      "output": "maskBuffer"
+    },
+    {
+      "id": "final",
+      "source": "shader.slang",
+      "entryPoint": "finish",
+      "inputs": ["maskBuffer"],
+      "output": "layerOutput"
+    }
+  ]
+}
+```
+
+Pass output names:
+
+- `layerOutput`: the final visible output of this layer.
+- Any other name creates an intermediate 16-bit float render target that later passes may sample.
+
+If the final declared pass does not explicitly output `layerOutput`, the runtime still treats that final pass as the visible layer output. Existing single-pass shaders are unaffected.
+
+## Feedback Surface
+
+Shaders may opt in to a persistent previous-frame feedback surface:
+
+```json
+{
+  "feedback": {
+    "enabled": true,
+    "writePass": "final"
+  }
+}
+```
+
+Fields:
+
+- `enabled`: when `true`, the runtime allocates one persistent `RGBA16F` feedback surface for this shader at the current render resolution.
+- `writePass`: optional pass `id` whose output should become next frame's feedback surface. If omitted, the runtime uses the final declared pass, or the implicit `main` pass for single-pass shaders.
+
+Behavior:
+
+- all passes may sample the same previous-frame feedback surface
+- one designated pass writes the next feedback surface
+- feedback is previous-frame state, not same-frame pass chaining
+
+Guardrails:
+
+- Feedback is best suited to image-like state such as trails, masks, luminance fields, decay maps, and shader-local analysis buffers.
+- Feedback is not a precise long-term data store. The surface uses `RGBA16F`, so repeated accumulation, exact counters, and tightly packed metadata can drift or clamp over time.
+- The feedback surface is currently filtered like an image, not configured as strict texel-addressed storage. If you reserve texels as data slots, sample them carefully and do not assume exact CPU-style array semantics.
+- Each feedback-enabled layer allocates two full-resolution feedback textures for ping-pong state. This increases VRAM use and adds one extra full-frame feedback copy per rendered frame.
+- In multipass shaders, feedback remains previous-frame state even when a pass also consumes same-frame pass outputs. Do not treat feedback as another same-frame intermediate buffer.
+
+Single-pass example:
+
+```json
+{
+  "id": "feedback-glow",
+  "name": "Feedback Glow",
+  "feedback": {
+    "enabled": true
+  },
+  "parameters": []
+}
+```
+
+Multipass example:
+
+```json
+{
+  "passes": [
+    {
+      "id": "analysis",
+      "source": "shader.slang",
+      "entryPoint": "analyzeFrame",
+      "output": "analysisBuffer"
+    },
+    {
+      "id": "final",
+      "source": "shader.slang",
+      "entryPoint": "finishFrame",
+      "inputs": ["analysisBuffer"],
+      "output": "layerOutput"
+    }
+  ],
+  "feedback": {
+    "enabled": true,
+    "writePass": "final"
+  }
+}
+```
+
+The wrapper exposes:
+
+```slang
+float4 sampleFeedback(float2 uv);
+```
+
+On the first frame, or after a reset, `sampleFeedback` returns transparent black.
+
+Feedback resets when:
+
+- a layer bypass state changes
+- a layer changes shader
+- the layer itself is removed
+- a shader is reloaded or recompiled
+- render dimensions change
+- the app restarts
+
+Ordinary stack add/remove/reorder operations on other layers are intended to preserve feedback state for unchanged feedback-enabled layers.
+
+So feedback should be treated as live runtime state, not durable saved state.
+
 ## Slang Entry Point
 
 Your shader file must implement the manifest `entryPoint`.
@@ -155,6 +339,7 @@ struct ShaderContext
     float bypass;
     int sourceHistoryLength;
     int temporalHistoryLength;
+    int feedbackAvailable;
 };
 ```
 
@@ -163,7 +348,7 @@ Fields:
 - `uv`: normalized texture coordinates, usually `0..1`.
 - `sourceColor`: decoded RGBA source video at `uv`.
 - `inputResolution`: decoded input video resolution in pixels.
-- `outputResolution`: shader render resolution in pixels. The current pipeline renders the shader stack at input resolution, then scales the final frame to the configured DeckLink output mode.
+- `outputResolution`: shader render resolution in pixels. The current pipeline renders the shader stack at input resolution, then scales the final frame to the configured video I/O output mode.
 - `time`: elapsed runtime time in seconds.
 - `utcTimeSeconds`: current UTC time of day from the host PC clock, expressed as seconds since UTC midnight.
 - `utcOffsetSeconds`: host PC local UTC offset in seconds. Add this to `utcTimeSeconds` and wrap to `0..86400` to get local time of day.
@@ -173,12 +358,13 @@ Fields:
 - `bypass`: `1.0` when the layer is bypassed, otherwise `0.0`.
 - `sourceHistoryLength`: number of usable source-history frames currently available.
 - `temporalHistoryLength`: number of usable temporal frames currently available for this layer.
+- `feedbackAvailable`: `1` when previous-frame feedback exists for this layer, otherwise `0`.
 
 Color/precision notes:
 
 - `context.sourceColor`, `sampleVideo()`, and temporal history samples are display-referred Rec.709-like RGB, not linear-light RGB.
-- The host prefers 10-bit DeckLink YUV capture and output when the card/mode supports it, with automatic 8-bit fallback.
-- Internal decoded, layer, composite, output, and temporal render targets are 16-bit floating point, so gradients and LUT work have more headroom than the packed DeckLink byte formats.
+- The current DeckLink backend prefers 10-bit YUV capture and output when the card/mode supports it, with automatic 8-bit fallback. If external keying is enabled, output prefers 10-bit YUVA (`Ay10`) when supported so shader alpha can drive the key signal, then falls back to 8-bit BGRA.
+- Internal decoded, layer, composite, output, and temporal render targets are 16-bit floating point, so gradients and LUT work have more headroom than packed byte video I/O formats.
 - Do not add extra Rec.709 or linear conversions unless the shader intentionally documents that behavior.
 
 ## Helper Functions
@@ -186,17 +372,23 @@ Color/precision notes:
 The wrapper provides:
 
 ```slang
+float4 sampleLayerInput(float2 uv);
 float4 sampleVideo(float2 uv);
 float4 sampleSourceHistory(int framesAgo, float2 uv);
 float4 sampleTemporalHistory(int framesAgo, float2 uv);
+float4 sampleFeedback(float2 uv);
 ```
 
-`sampleVideo` samples the live decoded source video.
+`sampleLayerInput` samples the input arriving at this shader layer before any of the layer's own passes run. If this layer follows another shader, it sees that previous shader's output. If this is the first shader layer, it sees the decoded source image.
+
+`sampleVideo` samples the current pass input texture. In single-pass shaders this is usually the layer input. In multipass shaders it may instead be a named pass output or `previousPass`, depending on the manifest routing for that pass.
 
 `sampleSourceHistory` samples previous decoded source frames. `framesAgo` is clamped into the available range. If no history is available, it falls back to `sampleVideo`.
 
 `sampleTemporalHistory` samples previous pre-layer input frames for temporal shaders that request `preLayerInput` history. `framesAgo` is clamped into the available range. If no temporal history is available, it falls back to `sampleVideo`.
 
+`sampleFeedback` samples the shader-local previous-frame feedback surface. If feedback has not been written yet, it returns transparent black.
+
 Example:
 
 ```slang
@@ -207,6 +399,57 @@ float4 shadeVideo(ShaderContext context)
 }
 ```
 
+Layer-input example:
+
+```slang
+float4 finishPass(ShaderContext context)
+{
+    float3 baseColor = sampleLayerInput(context.uv).rgb;
+    float3 passResult = context.sourceColor.rgb;
+    return float4(baseColor + passResult * 0.25, 1.0);
+}
+```
+
+Feedback example:
+
+```slang
+float4 shadeVideo(ShaderContext context)
+{
+    float4 previous = sampleFeedback(context.uv);
+    float4 current = context.sourceColor;
+    return lerp(current, previous, 0.2);
+}
+```
+
+Multipass feedback example:
+
+```slang
+float4 analyzeFrame(ShaderContext context)
+{
+    float4 previous = sampleFeedback(context.uv);
+    float luma = dot(context.sourceColor.rgb, float3(0.2126, 0.7152, 0.0722));
+    return float4(lerp(previous.rgb, float3(luma), 0.1), 1.0);
+}
+
+float4 finishFrame(ShaderContext context)
+{
+    float4 analysis = context.sourceColor;
+    return float4(analysis.rgb, 1.0);
+}
+```
+
+In that multipass case:
+
+- `analyzeFrame` reads last frame's feedback
+- `finishFrame` receives the same-frame pass output through normal multipass routing
+- the `writePass` decides which pass output becomes next frame's feedback
+
+That means:
+
+- use `context.sourceColor` or `sampleVideo()` when you want this pass's routed input
+- use `sampleLayerInput()` when you want the pre-pass layer input
+- use `sampleFeedback()` when you want previous-frame persistent shader-local state
+
 ## Parameters
 
 Manifest parameters are exposed to Slang as global values with the same `id`.
@@ -547,6 +790,8 @@ When a shader compiles, the runtime writes generated files under `runtime/shader
 
 These files are ignored by git and are useful for debugging compiler output. If a shader fails to compile, inspect the wrapper first; it shows the exact generated Slang code including your included shader.
 
+For multipass shaders, these files reflect the most recently compiled pass. If a package has several passes, the reported compile error and pass name are usually more useful than assuming the cache contains the first pass.
+
 ## Common Pitfalls
 
 - Do not use hyphens in parameter IDs, texture IDs, or entry point names.

shaders/anamorphic-desqueeze/shader.json

@@ -11,11 +11,24 @@
       "type": "enum",
       "default": "x1_33",
       "options": [
-        { "value": "x1_3", "label": "1.3x" },
-        { "value": "x1_33", "label": "1.33x" },
-        { "value": "x1_5", "label": "1.5x" },
-        { "value": "x2_0", "label": "2x" }
-      ]
+        {
+          "value": "x1_3",
+          "label": "1.3x"
+        },
+        {
+          "value": "x1_33",
+          "label": "1.33x"
+        },
+        {
+          "value": "x1_5",
+          "label": "1.5x"
+        },
+        {
+          "value": "x2_0",
+          "label": "2x"
+        }
+      ],
+      "description": "Horizontal stretch factor matching the anamorphic lens or adapter."
     },
     {
       "id": "framing",
@@ -23,24 +36,50 @@
       "type": "enum",
       "default": "fit",
       "options": [
-        { "value": "fit", "label": "Fit" },
-        { "value": "fill", "label": "Fill" }
-      ]
+        {
+          "value": "fit",
+          "label": "Fit"
+        },
+        {
+          "value": "fill",
+          "label": "Fill"
+        }
+      ],
+      "description": "Fit preserves the whole image; Fill crops to remove borders."
     },
     {
       "id": "pan",
       "label": "Pan",
       "type": "vec2",
-      "default": [0.0, 0.0],
-      "min": [-1.0, -1.0],
-      "max": [1.0, 1.0],
-      "step": [0.001, 0.001]
+      "default": [
+        0,
+        0
+      ],
+      "min": [
+        -1,
+        -1
+      ],
+      "max": [
+        1,
+        1
+      ],
+      "step": [
+        0.001,
+        0.001
+      ],
+      "description": "Reframes the desqueezed image after fit/fill scaling."
     },
     {
       "id": "outsideColor",
       "label": "Outside Color",
       "type": "color",
-      "default": [0.0, 0.0, 0.0, 1.0]
+      "default": [
+        0,
+        0,
+        0,
+        1
+      ],
+      "description": "Color used where the remapped image samples outside the source frame."
     }
   ]
 }

shaders/balatro-swirl/shader.json

@@ -9,37 +9,41 @@
       "id": "spinRotation",
       "label": "Spin Rotation",
       "type": "float",
-      "default": -2.0,
-      "min": -8.0,
-      "max": 8.0,
-      "step": 0.05
+      "default": -2,
+      "min": -8,
+      "max": 8,
+      "step": 0.05,
+      "description": "Base rotation applied to the swirl field."
     },
     {
       "id": "spinSpeed",
       "label": "Spin Speed",
       "type": "float",
-      "default": 7.0,
-      "min": 0.0,
-      "max": 20.0,
-      "step": 0.1
+      "default": 7,
+      "min": 0,
+      "max": 20,
+      "step": 0.1,
+      "description": "How quickly the swirl pattern rotates."
     },
     {
       "id": "spinAmount",
       "label": "Spin Amount",
       "type": "float",
       "default": 0.25,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Amount of radial twisting in the swirl."
     },
     {
       "id": "spinEase",
       "label": "Spin Ease",
       "type": "float",
-      "default": 1.0,
-      "min": 0.0,
-      "max": 3.0,
-      "step": 0.01
+      "default": 1,
+      "min": 0,
+      "max": 3,
+      "step": 0.01,
+      "description": "Changes how strongly the twist falls off from the center."
     },
     {
       "id": "contrast",
@@ -47,59 +51,94 @@
       "type": "float",
       "default": 3.5,
       "min": 0.5,
-      "max": 8.0,
-      "step": 0.05
+      "max": 8,
+      "step": 0.05,
+      "description": "Adjusts separation between dark and bright areas."
     },
     {
       "id": "lighting",
       "label": "Lighting",
       "type": "float",
       "default": 0.4,
-      "min": 0.0,
+      "min": 0,
       "max": 1.5,
-      "step": 0.01
+      "step": 0.01,
+      "description": "Strength of the highlight/shadow modulation."
     },
     {
       "id": "offset",
       "label": "Offset",
       "type": "vec2",
-      "default": [0.0, 0.0],
-      "min": [-1.0, -1.0],
-      "max": [1.0, 1.0],
-      "step": [0.001, 0.001]
+      "default": [
+        0,
+        0
+      ],
+      "min": [
+        -1,
+        -1
+      ],
+      "max": [
+        1,
+        1
+      ],
+      "step": [
+        0.001,
+        0.001
+      ],
+      "description": "Moves the generated field in normalized coordinates."
     },
     {
       "id": "colour1",
       "label": "Colour 1",
       "type": "color",
-      "default": [0.871, 0.267, 0.231, 1.0]
+      "default": [
+        0.871,
+        0.267,
+        0.231,
+        1
+      ],
+      "description": "Primary warm swirl color."
     },
     {
       "id": "colour2",
       "label": "Colour 2",
       "type": "color",
-      "default": [0.0, 0.42, 0.706, 1.0]
+      "default": [
+        0,
+        0.42,
+        0.706,
+        1
+      ],
+      "description": "Secondary cool swirl color."
     },
     {
       "id": "colour3",
       "label": "Colour 3",
       "type": "color",
-      "default": [0.086, 0.137, 0.145, 1.0]
+      "default": [
+        0.086,
+        0.137,
+        0.145,
+        1
+      ],
+      "description": "Dark base color in the swirl."
     },
     {
       "id": "isRotate",
       "label": "Rotate Field",
       "type": "bool",
-      "default": false
+      "default": false,
+      "description": "Rotates the whole generated field over time."
     },
     {
       "id": "sourceMix",
       "label": "Source Mix",
       "type": "float",
-      "default": 0.0,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "default": 0,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Blends the generated effect with the incoming video."
     }
   ]
 }

shaders/balatro-swirl/shader.slang

@@ -6,6 +6,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	float2 uv = (screenCoords - 0.5 * screenSize) / safeScreenLength - offset - seedOffset;
 	float uvLength = length(uv);
 
+	// First warp: convert to polar space and twist the angle more near the
+	// center, creating the large spiral motion.
 	float speed = spinRotation * spinEase * 0.2;
 	if (isRotate)
 		speed = time * speed;
@@ -19,6 +21,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	speed = (time + seed * 17.0) * spinSpeed;
 	float2 uv2 = float2(uv.x + uv.y, uv.x + uv.y);
 
+	// Second warp: a short iterative feedback loop turns the spiral into
+	// painterly bands while preserving a fixed compile-time loop bound.
 	for (int i = 0; i < 5; ++i)
 	{
 		uv2 += float2(sin(max(uv.x, uv.y)), sin(max(uv.x, uv.y))) + uv;
@@ -32,6 +36,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	float c1p = max(0.0, 1.0 - contrastMod * abs(1.0 - paintRes));
 	float c2p = max(0.0, 1.0 - contrastMod * abs(paintRes));
 	float c3p = 1.0 - min(1.0, c1p + c2p);
+	// Three soft band weights drive the palette; lighting rides on the brightest
+	// bands so the swirl keeps dimensional highlights.
 	float light = (lighting - 0.2) * max(c1p * 5.0 - 4.0, 0.0) + lighting * max(c2p * 5.0 - 4.0, 0.0);
 
 	float safeContrast = max(contrast, 0.001);

shaders/broken-shader-example/shader.json

@@ -9,7 +9,8 @@
       "id": "badToggle",
       "label": "Bad Toggle",
       "type": "boolean",
-      "default": true
+      "default": true,
+      "description": "Intentionally unsupported parameter type used to test shader error handling."
     }
   ]
 }

shaders/composition-guides/shader.json

@@ -9,55 +9,67 @@
       "id": "showThirds",
       "label": "Rule of Thirds",
       "type": "bool",
-      "default": true
+      "default": true,
+      "description": "Shows vertical and horizontal thirds lines."
     },
     {
       "id": "showCrosshair",
       "label": "Center Crosshair",
       "type": "bool",
-      "default": true
+      "default": true,
+      "description": "Shows a center crosshair for lens/framing alignment."
     },
     {
       "id": "lineColor",
       "label": "Line Color",
       "type": "color",
-      "default": [1.0, 1.0, 1.0, 1.0]
+      "default": [
+        1,
+        1,
+        1,
+        1
+      ],
+      "description": "Color used for guide lines and marks."
     },
     {
       "id": "lineOpacity",
       "label": "Line Opacity",
       "type": "float",
       "default": 0.65,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Overall visibility of the guide lines."
     },
     {
       "id": "lineThicknessPixels",
       "label": "Line Thickness",
       "type": "float",
-      "default": 2.0,
+      "default": 2,
       "min": 0.5,
-      "max": 12.0,
-      "step": 0.1
+      "max": 12,
+      "step": 0.1,
+      "description": "Guide line width in output pixels."
     },
     {
       "id": "crosshairSizePixels",
       "label": "Crosshair Size",
       "type": "float",
-      "default": 54.0,
-      "min": 8.0,
-      "max": 240.0,
-      "step": 1.0
+      "default": 54,
+      "min": 8,
+      "max": 240,
+      "step": 1,
+      "description": "Length of each crosshair arm in output pixels."
     },
     {
       "id": "crosshairGapPixels",
       "label": "Crosshair Gap",
       "type": "float",
-      "default": 10.0,
-      "min": 0.0,
-      "max": 80.0,
-      "step": 1.0
+      "default": 10,
+      "min": 0,
+      "max": 80,
+      "step": 1,
+      "description": "Empty gap around the exact frame center."
     }
   ]
 }

shaders/crt-bulge/shader.json

@@ -0,0 +1,102 @@
+{
+  "id": "crt-bulge",
+  "name": "CRT Bulge",
+  "description": "Warps the image like convex CRT glass, with optional rounded screen edges and vignette darkening.",
+  "category": "Distortion",
+  "entryPoint": "shadeVideo",
+  "parameters": [
+    {
+      "id": "bulgeAmount",
+      "label": "Bulge",
+      "type": "float",
+      "default": -0.04,
+      "min": -0.5,
+      "max": 0.8,
+      "step": 0.01,
+      "description": "Positive values swell the center outward; negative values pinch it inward."
+    },
+    {
+      "id": "zoom",
+      "label": "Zoom",
+      "type": "float",
+      "default": 1.04,
+      "min": 0.5,
+      "max": 2,
+      "step": 0.01,
+      "description": "Scales the source before distortion, useful for hiding warped edges."
+    },
+    {
+      "id": "edgeRoundness",
+      "label": "Edge Roundness",
+      "type": "float",
+      "default": 0.08,
+      "min": 0,
+      "max": 0.35,
+      "step": 0.01,
+      "description": "Rounds the visible screen corners like older CRT glass."
+    },
+    {
+      "id": "edgeFeather",
+      "label": "Edge Feather",
+      "type": "float",
+      "default": 2,
+      "min": 0,
+      "max": 24,
+      "step": 0.1,
+      "description": "Softens the rounded screen edge in pixels."
+    },
+    {
+      "id": "sourceEdgeFeather",
+      "label": "Source Edge Feather",
+      "type": "float",
+      "default": 1.5,
+      "min": 0,
+      "max": 16,
+      "step": 0.1,
+      "description": "Antialiases warped source edges when the distortion reveals outside-frame pixels."
+    },
+    {
+      "id": "vignetteAmount",
+      "label": "Vignette",
+      "type": "float",
+      "default": 0.18,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Darkens the glass toward the screen edges."
+    },
+    {
+      "id": "edgeMode",
+      "label": "Edge Mode",
+      "type": "enum",
+      "default": "black",
+      "options": [
+        {
+          "value": "black",
+          "label": "Black"
+        },
+        {
+          "value": "clamp",
+          "label": "Clamp"
+        },
+        {
+          "value": "mirror",
+          "label": "Mirror"
+        }
+      ],
+      "description": "Chooses how warped samples outside the source frame are filled."
+    },
+    {
+      "id": "outsideColor",
+      "label": "Outside Color",
+      "type": "color",
+      "default": [
+        0,
+        0,
+        0,
+        1
+      ],
+      "description": "Color used outside the curved screen or source frame."
+    }
+  ]
+}

shaders/crt-bulge/shader.slang

@@ -0,0 +1,71 @@
+float mirroredCoordinate(float coordinate)
+{
+	float wrapped = frac(coordinate * 0.5) * 2.0;
+	return wrapped <= 1.0 ? wrapped : 2.0 - wrapped;
+}
+
+float roundedBoxMask(float2 point, float2 halfSize, float radius, float feather)
+{
+	float2 distanceToEdge = abs(point) - (halfSize - radius);
+	float outsideDistance = length(max(distanceToEdge, float2(0.0, 0.0))) - radius;
+	float insideDistance = min(max(distanceToEdge.x, distanceToEdge.y), 0.0);
+	float signedDistance = outsideDistance + insideDistance;
+	return 1.0 - smoothstep(0.0, max(feather, 0.00001), signedDistance);
+}
+
+float sourceBoundsMask(float2 uv, float2 resolution)
+{
+	float2 pixel = 1.0 / max(resolution, float2(1.0, 1.0));
+	float2 feather = pixel * max(sourceEdgeFeather, 0.0);
+	float left = smoothstep(0.0, max(feather.x, 0.00001), uv.x);
+	float right = 1.0 - smoothstep(1.0 - max(feather.x, 0.00001), 1.0, uv.x);
+	float top = smoothstep(0.0, max(feather.y, 0.00001), uv.y);
+	float bottom = 1.0 - smoothstep(1.0 - max(feather.y, 0.00001), 1.0, uv.y);
+	return saturate(left * right * top * bottom);
+}
+
+float2 applyBulge(float2 uv, float2 resolution)
+{
+	float2 centered = uv * 2.0 - 1.0;
+	float aspect = resolution.x / max(resolution.y, 1.0);
+	float2 aspectCentered = float2(centered.x * aspect, centered.y);
+	float radiusSq = dot(aspectCentered, aspectCentered);
+	float amount = clamp(bulgeAmount, -0.95, 0.95);
+	float scale = 1.0 / max(1.0 + amount * radiusSq, 0.05);
+	return centered * scale / max(zoom, 0.001) * 0.5 + 0.5;
+}
+
+float4 sampleWarped(float2 uv, float2 resolution, out bool insideSource)
+{
+	insideSource = uv.x >= 0.0 && uv.x <= 1.0 && uv.y >= 0.0 && uv.y <= 1.0;
+
+	if (edgeMode == 1)
+		return sampleVideo(clamp(uv, 0.0, 1.0));
+	if (edgeMode == 2)
+		return sampleVideo(float2(mirroredCoordinate(uv.x), mirroredCoordinate(uv.y)));
+
+	float edgeMask = sourceBoundsMask(uv, resolution);
+	float4 color = sampleVideo(clamp(uv, 0.0, 1.0));
+	return lerp(outsideColor, color, edgeMask);
+}
+
+float4 shadeVideo(ShaderContext context)
+{
+	float2 resolution = max(context.outputResolution, float2(1.0, 1.0));
+	float2 sourceUv = applyBulge(context.uv, resolution);
+
+	bool insideSource = false;
+	float4 color = sampleWarped(sourceUv, resolution, insideSource);
+
+	float2 centered = context.uv * 2.0 - 1.0;
+	float feather = max(edgeFeather, 0.0) / min(resolution.x, resolution.y);
+	float screenMask = roundedBoxMask(centered, float2(1.0, 1.0), saturate(edgeRoundness), feather);
+	color = lerp(outsideColor, color, screenMask);
+
+	float2 aspectCentered = float2(centered.x * resolution.x / max(resolution.y, 1.0), centered.y);
+	float edgeDistance = saturate(length(aspectCentered) * 0.72);
+	float vignette = lerp(1.0, 1.0 - saturate(vignetteAmount), smoothstep(0.35, 1.05, edgeDistance));
+	color.rgb *= vignette;
+
+	return saturate(color);
+}

shaders/data-mosh/shader.json

@@ -15,36 +15,52 @@
       "label": "Amount",
       "type": "float",
       "default": 0.45,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Strength of the blocky temporal smear."
     },
     {
       "id": "blockCount",
       "label": "Block Count",
       "type": "vec2",
-      "default": [32.0, 18.0],
-      "min": [2.0, 2.0],
-      "max": [160.0, 120.0],
-      "step": [1.0, 1.0]
+      "default": [
+        32,
+        18
+      ],
+      "min": [
+        2,
+        2
+      ],
+      "max": [
+        160,
+        120
+      ],
+      "step": [
+        1,
+        1
+      ],
+      "description": "Number of glitch blocks across X and Y."
     },
     {
       "id": "tearAmount",
       "label": "Tear",
       "type": "float",
       "default": 0.18,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Horizontal scanline tearing intensity."
     },
     {
       "id": "chromaShift",
       "label": "Chroma Shift",
       "type": "float",
       "default": 1.8,
-      "min": 0.0,
-      "max": 12.0,
-      "step": 0.1
+      "min": 0,
+      "max": 12,
+      "step": 0.1,
+      "description": "Separate color-channel offset in pixels."
     }
   ]
 }

shaders/dvd-bounce/shader.json

@@ -18,7 +18,8 @@
       "default": 0.28,
       "min": 0.12,
       "max": 0.5,
-      "step": 0.01
+      "step": 0.01,
+      "description": "Logo size relative to the frame."
     },
     {
       "id": "bounceSpeed",
@@ -27,34 +28,38 @@
       "default": 0.22,
       "min": 0.02,
       "max": 0.8,
-      "step": 0.01
+      "step": 0.01,
+      "description": "How fast the logo moves between edge hits."
     },
     {
       "id": "edgePadding",
       "label": "Edge Padding",
       "type": "float",
       "default": 0.018,
-      "min": 0.0,
+      "min": 0,
       "max": 0.08,
-      "step": 0.001
+      "step": 0.001,
+      "description": "Inset distance from the frame edges."
     },
     {
       "id": "glowAmount",
       "label": "Glow",
       "type": "float",
       "default": 0.18,
-      "min": 0.0,
+      "min": 0,
       "max": 0.75,
-      "step": 0.01
+      "step": 0.01,
+      "description": "Adds a soft colored glow around the logo."
     },
     {
       "id": "baseAlpha",
       "label": "Alpha",
       "type": "float",
-      "default": 1.0,
+      "default": 1,
       "min": 0.05,
-      "max": 1.0,
-      "step": 0.01
+      "max": 1,
+      "step": 0.01,
+      "description": "Overall opacity of the overlay."
     }
   ]
 }

shaders/ether/shader.json

@@ -9,10 +9,11 @@
       "id": "speed",
       "label": "Speed",
       "type": "float",
-      "default": 1.0,
-      "min": 0.0,
-      "max": 4.0,
-      "step": 0.01
+      "default": 1,
+      "min": 0,
+      "max": 4,
+      "step": 0.01,
+      "description": "Animation speed multiplier; set to 0 to pause motion."
     },
     {
       "id": "depth",
@@ -20,65 +21,95 @@
       "type": "float",
       "default": 2.5,
       "min": 0.2,
-      "max": 8.0,
-      "step": 0.01
+      "max": 8,
+      "step": 0.01,
+      "description": "Raymarch depth through the ether volume."
     },
     {
       "id": "density",
       "label": "Density",
       "type": "float",
       "default": 0.7,
-      "min": 0.0,
-      "max": 2.0,
-      "step": 0.01
+      "min": 0,
+      "max": 2,
+      "step": 0.01,
+      "description": "Density of the volumetric strands."
     },
     {
       "id": "brightness",
       "label": "Brightness",
       "type": "float",
-      "default": 1.0,
-      "min": 0.0,
-      "max": 3.0,
-      "step": 0.01
+      "default": 1,
+      "min": 0,
+      "max": 3,
+      "step": 0.01,
+      "description": "Adjusts the generated effect brightness."
     },
     {
       "id": "contrast",
       "label": "Contrast",
       "type": "float",
-      "default": 1.0,
+      "default": 1,
       "min": 0.25,
-      "max": 3.0,
-      "step": 0.01
+      "max": 3,
+      "step": 0.01,
+      "description": "Adjusts separation between dark and bright areas."
     },
     {
       "id": "offset",
       "label": "Offset",
       "type": "vec2",
-      "default": [0.9, 0.5],
-      "min": [0.0, 0.0],
-      "max": [2.0, 2.0],
-      "step": [0.001, 0.001]
+      "default": [
+        0.9,
+        0.5
+      ],
+      "min": [
+        0,
+        0
+      ],
+      "max": [
+        2,
+        2
+      ],
+      "step": [
+        0.001,
+        0.001
+      ],
+      "description": "Moves the generated field in normalized coordinates."
     },
     {
       "id": "baseColor",
       "label": "Base Color",
       "type": "color",
-      "default": [0.1, 0.3, 0.4, 1.0]
+      "default": [
+        0.1,
+        0.3,
+        0.4,
+        1
+      ],
+      "description": "Low-energy color used in the generated field."
     },
     {
       "id": "energyColor",
       "label": "Energy Color",
       "type": "color",
-      "default": [1.0, 0.5, 0.6, 1.0]
+      "default": [
+        1,
+        0.5,
+        0.6,
+        1
+      ],
+      "description": "High-energy color used in the generated field."
     },
     {
       "id": "sourceMix",
       "label": "Source Mix",
       "type": "float",
-      "default": 0.0,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "default": 0,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Blends the generated effect with the incoming video."
     }
   ]
 }

shaders/false-color/shader.json

@@ -9,34 +9,38 @@
       "id": "blendAmount",
       "label": "Blend",
       "type": "float",
-      "default": 1.0,
-      "min": 0.0,
-      "max": 1.0,
-      "step": 0.01
+      "default": 1,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Mix amount for the processed result."
     },
     {
       "id": "showLuma",
       "label": "Show Luma",
       "type": "bool",
-      "default": false
+      "default": false,
+      "description": "Shows grayscale luminance before applying false-color mapping."
     },
     {
       "id": "lift",
       "label": "Lift",
       "type": "float",
-      "default": 0.0,
+      "default": 0,
       "min": -0.25,
       "max": 0.25,
-      "step": 0.001
+      "step": 0.001,
+      "description": "Offsets luminance before false-color mapping."
     },
     {
       "id": "gain",
       "label": "Gain",
       "type": "float",
-      "default": 1.0,
+      "default": 1,
       "min": 0.25,
-      "max": 2.0,
-      "step": 0.01
+      "max": 2,
+      "step": 0.01,
+      "description": "Scales luminance before false-color mapping."
     }
   ]
 }