More http post end points filled

CMakeLists.txt

@@ -333,6 +333,8 @@ set(RENDER_CADENCE_APP_SOURCES
 	"${RENDER_CADENCE_APP_DIR}/render/RuntimeShaderParams.h"
 	"${RENDER_CADENCE_APP_DIR}/render/SimpleMotionRenderer.cpp"
 	"${RENDER_CADENCE_APP_DIR}/render/SimpleMotionRenderer.h"
+	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeLayerModel.cpp"
+	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeLayerModel.h"
 	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeShaderBridge.cpp"
 	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeShaderBridge.h"
 	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeSlangShaderCompiler.cpp"
@@ -821,6 +823,27 @@ endif()
 
 add_test(NAME RenderCadenceCompositorRuntimeShaderParamsTests COMMAND RenderCadenceCompositorRuntimeShaderParamsTests)
 
+add_executable(RenderCadenceCompositorRuntimeLayerModelTests
+	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeLayerModel.cpp"
+	"${RENDER_CADENCE_APP_DIR}/runtime/SupportedShaderCatalog.cpp"
+	"${APP_DIR}/shader/ShaderPackageRegistry.cpp"
+	"${APP_DIR}/runtime/support/RuntimeJson.cpp"
+	"${CMAKE_CURRENT_SOURCE_DIR}/tests/RenderCadenceCompositorRuntimeLayerModelTests.cpp"
+)
+
+target_include_directories(RenderCadenceCompositorRuntimeLayerModelTests PRIVATE
+	"${APP_DIR}"
+	"${APP_DIR}/runtime/support"
+	"${APP_DIR}/shader"
+	"${RENDER_CADENCE_APP_DIR}/runtime"
+)
+
+if(MSVC)
+	target_compile_options(RenderCadenceCompositorRuntimeLayerModelTests PRIVATE /W3)
+endif()
+
+add_test(NAME RenderCadenceCompositorRuntimeLayerModelTests COMMAND RenderCadenceCompositorRuntimeLayerModelTests)
+
 add_executable(RenderCadenceCompositorSupportedShaderCatalogTests
 	"${APP_DIR}/shader/ShaderPackageRegistry.cpp"
 	"${APP_DIR}/runtime/support/RuntimeJson.cpp"
@@ -873,9 +896,12 @@ add_test(NAME RenderCadenceCompositorJsonWriterTests COMMAND RenderCadenceCompos
 
 add_executable(RenderCadenceCompositorRuntimeStateJsonTests
 	"${APP_DIR}/runtime/support/RuntimeJson.cpp"
+	"${APP_DIR}/shader/ShaderPackageRegistry.cpp"
 	"${RENDER_CADENCE_APP_DIR}/app/AppConfig.cpp"
 	"${RENDER_CADENCE_APP_DIR}/app/AppConfigProvider.cpp"
 	"${RENDER_CADENCE_APP_DIR}/json/JsonWriter.cpp"
+	"${RENDER_CADENCE_APP_DIR}/runtime/RuntimeLayerModel.cpp"
+	"${RENDER_CADENCE_APP_DIR}/runtime/SupportedShaderCatalog.cpp"
 	"${CMAKE_CURRENT_SOURCE_DIR}/tests/RenderCadenceCompositorRuntimeStateJsonTests.cpp"
 )
 

apps/RenderCadenceCompositor/README.md

@@ -41,6 +41,7 @@ Included now:
 - latest-N system-memory frame exchange
 - rendered-frame warmup
 - background Slang compile of `shaders/happy-accident`
+- app-owned display/render layer model for shader build readiness
 - app-owned submission of a completed shader artifact
 - render-thread-only GL commit once the artifact is ready
 - manifest-driven stateless single-pass shader packages
@@ -149,7 +150,8 @@ Current endpoints:
 - `GET /api/state`: returns OpenAPI-shaped display data with cadence telemetry, supported shaders, output status, and a read-only current runtime layer
 - `GET /docs/openapi.yaml` and `GET /openapi.yaml`: serves the OpenAPI document
 - `GET /docs`: serves Swagger UI
-- OpenAPI POST routes are present but return `{ "ok": false, "error": "Endpoint is not implemented in RenderCadenceCompositor yet." }`
+- `POST /api/layers/add` and `POST /api/layers/remove` mutate the app-owned display layer model only
+- other OpenAPI POST routes are present but return `{ "ok": false, "error": "Endpoint is not implemented in RenderCadenceCompositor yet." }`
 
 The HTTP server runs on its own thread. It serves static UI/docs files, samples/copies telemetry through callbacks, and does not call render work or DeckLink scheduling.
 
@@ -208,7 +210,7 @@ Current runtime shader support is deliberately limited to stateless single-pass
 
 The `/api/state` shader list uses the same support rules as runtime shader compilation and reports only packages this app can run today. Unsupported manifest feature sets such as multipass, temporal, feedback, texture-backed, font-backed, or text-parameter shaders are hidden from the control UI for now.
 
-The current runtime shader is also exposed as a read-only display layer with manifest parameter defaults. POST control endpoints still intentionally return "not implemented" responses until the control/state ownership model is ported.
+Runtime shaders are exposed through `RuntimeLayerModel` as display layers with manifest parameter defaults. The model also records whether each layer has a render-ready artifact. Stage 1 add/remove POST controls mutate this app-owned model and may start background shader builds, but multi-layer render-scene handoff is not ported yet.
 
 Successful handoff signs:
 
@@ -258,6 +260,7 @@ This app keeps the same core behavior but splits it into modules that can grow:
 - `frames/`: system-memory handoff
 - `platform/`: COM/Win32/hidden GL context support
 - `render/`: cadence, simple rendering, PBO readback
+- `runtime/`: app-owned shader layer readiness model, runtime Slang build bridge, and completed artifact handoff
 - `control/`: local HTTP API edge and runtime-state JSON presentation
 - `json/`: compact JSON serialization helpers
 - `video/`: DeckLink output wrapper and scheduling thread

apps/RenderCadenceCompositor/app/RenderCadenceApp.h

@@ -3,15 +3,19 @@
 #include "AppConfig.h"
 #include "AppConfigProvider.h"
 #include "../logging/Logger.h"
+#include "../runtime/RuntimeLayerModel.h"
 #include "../runtime/RuntimeShaderBridge.h"
 #include "../runtime/SupportedShaderCatalog.h"
 #include "../control/RuntimeStateJson.h"
 #include "../telemetry/TelemetryHealthMonitor.h"
 #include "../video/DeckLinkOutput.h"
 #include "../video/DeckLinkOutputThread.h"
+#include "RuntimeJson.h"
 
 #include <chrono>
 #include <filesystem>
+#include <map>
+#include <memory>
 #include <mutex>
 #include <string>
 #include <thread>
@@ -71,6 +75,7 @@ public:
 	bool Start(std::string& error)
 	{
 		LoadSupportedShaderCatalog();
+		InitializeRuntimeLayerModel();
 
 		Log("app", "Starting render thread.");
 		if (!detail::StartRenderThread(mRenderThread, error, 0))
@@ -174,6 +179,12 @@ private:
 		callbacks.getStateJson = [this]() {
 			return BuildStateJson();
 		};
+		callbacks.addLayer = [this](const std::string& body) {
+			return HandleAddLayer(body);
+		};
+		callbacks.removeLayer = [this](const std::string& body) {
+			return HandleRemoveLayer(body);
+		};
 
 		std::string error;
 		if (!mHttpServer.Start(
@@ -191,17 +202,15 @@ private:
 	std::string BuildStateJson()
 	{
 		CadenceTelemetrySnapshot telemetry = mHttpTelemetry.Sample(mFrameExchange, mOutput, mOutputThread, mRenderThread);
-		RuntimeDisplayState runtimeState = CopyRuntimeDisplayState(telemetry);
+		RuntimeLayerModelSnapshot layerSnapshot = CopyRuntimeLayerSnapshot(telemetry);
 		return RuntimeStateToJson(RuntimeStateJsonInput{
 			mConfig,
 			telemetry,
 			mHttpServer.Port(),
 			mVideoOutputEnabled,
 			mVideoOutputStatus,
-			mShaderCatalog.Shaders(),
-			runtimeState.compileSucceeded,
-			runtimeState.compileMessage,
-			runtimeState.activeShaderPackage
+			mShaderCatalog,
+			layerSnapshot
 		});
 	}
 
@@ -226,17 +235,9 @@ private:
 		}
 
 		Log("runtime-shader", "Starting background Slang build for shader '" + mConfig.runtimeShaderId + "'.");
-		SetRuntimeDisplayState(true, "Runtime Slang build started for shader '" + mConfig.runtimeShaderId + "'.", mConfig.runtimeShaderId);
-		mShaderBridge.Start(
-			mConfig.runtimeShaderId,
-			[this](const RuntimeShaderArtifact& artifact) {
-				SetRuntimeDisplayState(true, artifact.message.empty() ? "Runtime shader artifact is ready." : artifact.message, artifact.shaderId);
-				mRenderThread.SubmitRuntimeShaderArtifact(artifact);
-			},
-			[this](const std::string& message) {
-				SetRuntimeDisplayState(false, message);
-				LogError("runtime-shader", "Runtime Slang build failed: " + message);
-			});
+		const std::string layerId = FirstRuntimeLayerId();
+		if (!layerId.empty())
+			StartLayerShaderBuild(layerId, mConfig.runtimeShaderId, true);
 	}
 
 	void LoadSupportedShaderCatalog()
@@ -252,41 +253,185 @@ private:
 		Log("runtime-shader", "Supported shader catalog loaded with " + std::to_string(mShaderCatalog.Shaders().size()) + " shader(s).");
 	}
 
+	void InitializeRuntimeLayerModel()
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		std::string error;
+		if (!mRuntimeLayerModel.InitializeSingleLayer(mShaderCatalog, mConfig.runtimeShaderId, error))
+		{
+			LogWarning("runtime-shader", error + " Runtime shader build disabled.");
+			mConfig.runtimeShaderId.clear();
+			mRuntimeLayerModel.Clear();
+		}
+	}
+
 	void StopRuntimeShaderBuild()
 	{
-		mShaderBridge.Stop();
+		StopAllRuntimeShaderBuilds();
 	}
 
-	struct RuntimeDisplayState
+	void MarkRuntimeBuildStarted(const std::string& message)
 	{
-		bool compileSucceeded = true;
-		std::string compileMessage;
-		const ShaderPackage* activeShaderPackage = nullptr;
-	};
-
-	void SetRuntimeDisplayState(bool compileSucceeded, const std::string& compileMessage, const std::string& activeShaderId = std::string())
-	{
-		std::lock_guard<std::mutex> lock(mRuntimeDisplayMutex);
-		mRuntimeCompileSucceeded = compileSucceeded;
-		mRuntimeCompileMessage = compileMessage;
-		if (!activeShaderId.empty())
-			mActiveShaderId = activeShaderId;
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		std::string error;
+		const std::string layerId = mRuntimeLayerModel.FirstLayerId();
+		if (!layerId.empty())
+			mRuntimeLayerModel.MarkBuildStarted(layerId, message, error);
 	}
 
-	RuntimeDisplayState CopyRuntimeDisplayState(const CadenceTelemetrySnapshot& telemetry) const
+	void MarkRuntimeBuildReady(const RuntimeShaderArtifact& artifact)
 	{
-		std::lock_guard<std::mutex> lock(mRuntimeDisplayMutex);
-		RuntimeDisplayState state;
-		state.compileSucceeded = mRuntimeCompileSucceeded && telemetry.shaderBuildFailures == 0;
-		state.compileMessage = mRuntimeCompileMessage;
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		std::string error;
+		if (!mRuntimeLayerModel.MarkBuildReady(artifact, error))
+			LogWarning("runtime-shader", error);
+	}
+
+	void MarkRuntimeBuildFailed(const std::string& message)
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		if (!mRuntimeLayerModel.MarkBuildFailedForShader(mConfig.runtimeShaderId, message))
+			LogWarning("runtime-shader", "Runtime shader failed without a matching display layer: " + message);
+	}
+
+	void MarkRuntimeBuildFailedForLayer(const std::string& layerId, const std::string& message)
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		std::string error;
+		if (!mRuntimeLayerModel.MarkBuildFailed(layerId, message, error))
+			LogWarning("runtime-shader", error);
+	}
+
+	std::string FirstRuntimeLayerId() const
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		return mRuntimeLayerModel.FirstLayerId();
+	}
+
+	void StartLayerShaderBuild(const std::string& layerId, const std::string& shaderId, bool submitToRender)
+	{
+		{
+			std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+			std::string error;
+			mRuntimeLayerModel.MarkBuildStarted(layerId, "Runtime Slang build started for shader '" + shaderId + "'.", error);
+		}
+
+		auto bridge = std::make_unique<RuntimeShaderBridge>();
+		RuntimeShaderBridge* bridgePtr = bridge.get();
+		{
+			std::lock_guard<std::mutex> lock(mShaderBuildMutex);
+			auto existingIt = mShaderBuilds.find(layerId);
+			if (existingIt != mShaderBuilds.end())
+				existingIt->second->Stop();
+			mShaderBuilds[layerId] = std::move(bridge);
+		}
+
+		bridgePtr->Start(
+			layerId,
+			shaderId,
+			[this, submitToRender](const RuntimeShaderArtifact& artifact) {
+				MarkRuntimeBuildReady(artifact);
+				if (submitToRender)
+					mRenderThread.SubmitRuntimeShaderArtifact(artifact);
+			},
+			[this, layerId](const std::string& message) {
+				MarkRuntimeBuildFailedForLayer(layerId, message);
+				LogError("runtime-shader", "Runtime Slang build failed: " + message);
+			});
+	}
+
+	void StopLayerShaderBuild(const std::string& layerId)
+	{
+		std::unique_ptr<RuntimeShaderBridge> bridge;
+		{
+			std::lock_guard<std::mutex> lock(mShaderBuildMutex);
+			auto bridgeIt = mShaderBuilds.find(layerId);
+			if (bridgeIt == mShaderBuilds.end())
+				return;
+			bridge = std::move(bridgeIt->second);
+			mShaderBuilds.erase(bridgeIt);
+		}
+		bridge->Stop();
+	}
+
+	void StopAllRuntimeShaderBuilds()
+	{
+		std::map<std::string, std::unique_ptr<RuntimeShaderBridge>> builds;
+		{
+			std::lock_guard<std::mutex> lock(mShaderBuildMutex);
+			builds.swap(mShaderBuilds);
+		}
+		for (auto& entry : builds)
+			entry.second->Stop();
+	}
+
+	ControlActionResult HandleAddLayer(const std::string& body)
+	{
+		std::string shaderId;
+		std::string error;
+		if (!ExtractStringField(body, "shaderId", shaderId, error))
+			return { false, error };
+
+		std::string layerId;
+		{
+			std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+			if (!mRuntimeLayerModel.AddLayer(mShaderCatalog, shaderId, layerId, error))
+				return { false, error };
+		}
+
+		StartLayerShaderBuild(layerId, shaderId, false);
+		return { true, std::string() };
+	}
+
+	ControlActionResult HandleRemoveLayer(const std::string& body)
+	{
+		std::string layerId;
+		std::string error;
+		if (!ExtractStringField(body, "layerId", layerId, error))
+			return { false, error };
+
+		{
+			std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+			if (!mRuntimeLayerModel.RemoveLayer(layerId, error))
+				return { false, error };
+		}
+
+		StopLayerShaderBuild(layerId);
+		return { true, std::string() };
+	}
+
+	static bool ExtractStringField(const std::string& body, const char* fieldName, std::string& value, std::string& error)
+	{
+		JsonValue root;
+		std::string parseError;
+		if (!ParseJson(body.empty() ? "{}" : body, root, parseError) || !root.isObject())
+		{
+			error = parseError.empty() ? "Request body must be a JSON object." : parseError;
+			return false;
+		}
+
+		const JsonValue* field = root.find(fieldName);
+		if (!field || !field->isString() || field->asString().empty())
+		{
+			error = std::string("Request field '") + fieldName + "' must be a non-empty string.";
+			return false;
+		}
+
+		value = field->asString();
+		error.clear();
+		return true;
+	}
+
+	RuntimeLayerModelSnapshot CopyRuntimeLayerSnapshot(const CadenceTelemetrySnapshot& telemetry) const
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		RuntimeLayerModelSnapshot snapshot = mRuntimeLayerModel.Snapshot();
 		if (telemetry.shaderBuildFailures > 0)
-			state.compileMessage = "Runtime shader GL commit failed; see logs for details.";
-		if (state.compileMessage.empty())
-			state.compileMessage = mConfig.runtimeShaderId.empty()
-				? "Runtime shader build disabled."
-				: "Runtime shader build has not completed yet.";
-		state.activeShaderPackage = mShaderCatalog.FindPackage(mActiveShaderId);
-		return state;
+		{
+			snapshot.compileSucceeded = false;
+			snapshot.compileMessage = "Runtime shader GL commit failed; see logs for details.";
+		}
+		return snapshot;
 	}
 
 	RenderThread& mRenderThread;
@@ -297,12 +442,11 @@ private:
 	TelemetryHealthMonitor mTelemetryHealth;
 	CadenceTelemetry mHttpTelemetry;
 	HttpControlServer mHttpServer;
-	RuntimeShaderBridge mShaderBridge;
 	SupportedShaderCatalog mShaderCatalog;
-	mutable std::mutex mRuntimeDisplayMutex;
-	bool mRuntimeCompileSucceeded = true;
-	std::string mRuntimeCompileMessage;
-	std::string mActiveShaderId;
+	mutable std::mutex mRuntimeLayerMutex;
+	RuntimeLayerModel mRuntimeLayerModel;
+	std::mutex mShaderBuildMutex;
+	std::map<std::string, std::unique_ptr<RuntimeShaderBridge>> mShaderBuilds;
 	bool mStarted = false;
 	bool mVideoOutputEnabled = false;
 	std::string mVideoOutputStatus = "DeckLink output not started.";

apps/RenderCadenceCompositor/control/HttpControlServer.cpp

@@ -266,6 +266,18 @@ HttpControlServer::HttpResponse HttpControlServer::ServePost(const HttpRequest&
 	if (!IsKnownPostEndpoint(request.path))
 		return TextResponse("404 Not Found", "Not Found");
 
+	if (request.path == "/api/layers/add" && mCallbacks.addLayer)
+	{
+		const ControlActionResult result = mCallbacks.addLayer(request.body);
+		return JsonResponse(result.ok ? "200 OK" : "400 Bad Request", ActionResponse(result.ok, result.error));
+	}
+
+	if (request.path == "/api/layers/remove" && mCallbacks.removeLayer)
+	{
+		const ControlActionResult result = mCallbacks.removeLayer(request.body);
+		return JsonResponse(result.ok ? "200 OK" : "400 Bad Request", ActionResponse(result.ok, result.error));
+	}
+
 	return {
 		"400 Bad Request",
 		"application/json",

apps/RenderCadenceCompositor/control/HttpControlServer.h

@@ -19,9 +19,17 @@ struct HttpControlServerConfig
 	std::chrono::milliseconds idleSleep = std::chrono::milliseconds(10);
 };
 
+struct ControlActionResult
+{
+	bool ok = false;
+	std::string error;
+};
+
 struct HttpControlServerCallbacks
 {
 	std::function<std::string()> getStateJson;
+	std::function<ControlActionResult(const std::string&)> addLayer;
+	std::function<ControlActionResult(const std::string&)> removeLayer;
 };
 
 class UniqueSocket

apps/RenderCadenceCompositor/control/RuntimeStateJson.h

@@ -3,6 +3,7 @@
 #include "../app/AppConfig.h"
 #include "../app/AppConfigProvider.h"
 #include "../json/JsonWriter.h"
+#include "../runtime/RuntimeLayerModel.h"
 #include "../runtime/SupportedShaderCatalog.h"
 #include "../telemetry/CadenceTelemetryJson.h"
 
@@ -19,10 +20,8 @@ struct RuntimeStateJsonInput
 	unsigned short serverPort = 0;
 	bool videoOutputEnabled = false;
 	std::string videoOutputStatus;
-	const std::vector<SupportedShaderSummary>& shaders;
-	bool runtimeCompileSucceeded = true;
-	std::string runtimeCompileMessage;
-	const ShaderPackage* activeShaderPackage = nullptr;
+	const SupportedShaderCatalog& shaderCatalog;
+	const RuntimeLayerModelSnapshot& runtimeLayers;
 };
 
 inline void WriteVideoIoStatusJson(JsonWriter& writer, const RuntimeStateJsonInput& input)
@@ -112,6 +111,17 @@ inline void WriteFeedbackJson(JsonWriter& writer, const FeedbackSettings& feedba
 	writer.EndObject();
 }
 
+inline const char* RuntimeLayerBuildStateName(RuntimeLayerBuildState state)
+{
+	switch (state)
+	{
+	case RuntimeLayerBuildState::Pending: return "pending";
+	case RuntimeLayerBuildState::Ready: return "ready";
+	case RuntimeLayerBuildState::Failed: return "failed";
+	}
+	return "unknown";
+}
+
 inline void WriteParameterDefinitionJson(JsonWriter& writer, const ShaderParameterDefinition& parameter)
 {
 	writer.BeginObject();
@@ -164,22 +174,34 @@ inline void WriteParameterDefinitionJson(JsonWriter& writer, const ShaderParamet
 inline void WriteLayersJson(JsonWriter& writer, const RuntimeStateJsonInput& input)
 {
 	writer.BeginArray();
-	if (input.activeShaderPackage)
+	for (const RuntimeLayerReadModel& layer : input.runtimeLayers.displayLayers)
 	{
-		const ShaderPackage& shaderPackage = *input.activeShaderPackage;
+		const ShaderPackage* shaderPackage = input.shaderCatalog.FindPackage(layer.shaderId);
 		writer.BeginObject();
-		writer.KeyString("id", "runtime-layer-1");
-		writer.KeyString("shaderId", shaderPackage.id);
-		writer.KeyString("shaderName", shaderPackage.displayName.empty() ? shaderPackage.id : shaderPackage.displayName);
-		writer.KeyBool("bypass", false);
+		writer.KeyString("id", layer.id);
+		writer.KeyString("shaderId", layer.shaderId);
+		writer.KeyString("shaderName", layer.shaderName);
+		writer.KeyBool("bypass", layer.bypass);
+		writer.KeyString("buildState", RuntimeLayerBuildStateName(layer.buildState));
+		writer.KeyBool("renderReady", layer.renderReady);
+		writer.KeyString("message", layer.message);
 		writer.Key("temporal");
-		WriteTemporalJson(writer, shaderPackage.temporal);
+		if (shaderPackage)
+			WriteTemporalJson(writer, shaderPackage->temporal);
+		else
+			WriteTemporalJson(writer, TemporalSettings());
 		writer.Key("feedback");
-		WriteFeedbackJson(writer, shaderPackage.feedback);
+		if (shaderPackage)
+			WriteFeedbackJson(writer, shaderPackage->feedback);
+		else
+			WriteFeedbackJson(writer, FeedbackSettings());
 		writer.Key("parameters");
 		writer.BeginArray();
-		for (const ShaderParameterDefinition& parameter : shaderPackage.parameters)
+		if (shaderPackage)
+		{
+			for (const ShaderParameterDefinition& parameter : shaderPackage->parameters)
 				WriteParameterDefinitionJson(writer, parameter);
+		}
 		writer.EndArray();
 		writer.EndObject();
 	}
@@ -209,9 +231,9 @@ inline std::string RuntimeStateToJson(const RuntimeStateJsonInput& input)
 
 	writer.Key("runtime");
 	writer.BeginObject();
-	writer.KeyUInt("layerCount", input.activeShaderPackage ? 1 : 0);
-	writer.KeyBool("compileSucceeded", input.runtimeCompileSucceeded);
-	writer.KeyString("compileMessage", input.runtimeCompileMessage);
+	writer.KeyUInt("layerCount", static_cast<uint64_t>(input.runtimeLayers.displayLayers.size()));
+	writer.KeyBool("compileSucceeded", input.runtimeLayers.compileSucceeded);
+	writer.KeyString("compileMessage", input.runtimeLayers.compileMessage);
 	writer.EndObject();
 
 	writer.Key("video");
@@ -250,7 +272,7 @@ inline std::string RuntimeStateToJson(const RuntimeStateJsonInput& input)
 	writer.KeyNull("runtimeEvents");
 	writer.Key("shaders");
 	writer.BeginArray();
-	for (const SupportedShaderSummary& shader : input.shaders)
+	for (const SupportedShaderSummary& shader : input.shaderCatalog.Shaders())
 	{
 		writer.BeginObject();
 		writer.KeyString("id", shader.id);

apps/RenderCadenceCompositor/runtime/RuntimeLayerModel.cpp

@@ -0,0 +1,224 @@
+#include "RuntimeLayerModel.h"
+
+#include <utility>
+
+namespace RenderCadenceCompositor
+{
+bool RuntimeLayerModel::InitializeSingleLayer(const SupportedShaderCatalog& shaderCatalog, const std::string& shaderId, std::string& error)
+{
+	Clear();
+	if (shaderId.empty())
+	{
+		error.clear();
+		return true;
+	}
+
+	const ShaderPackage* shaderPackage = shaderCatalog.FindPackage(shaderId);
+	if (!shaderPackage)
+	{
+		error = "Shader '" + shaderId + "' is not in the supported shader catalog.";
+		return false;
+	}
+
+	Layer layer;
+	layer.id = AllocateLayerId();
+	layer.shaderId = shaderPackage->id;
+	layer.shaderName = shaderPackage->displayName.empty() ? shaderPackage->id : shaderPackage->displayName;
+	layer.buildState = RuntimeLayerBuildState::Pending;
+	layer.message = "Runtime Slang build is waiting to start.";
+	mLayers.push_back(std::move(layer));
+	error.clear();
+	return true;
+}
+
+bool RuntimeLayerModel::AddLayer(const SupportedShaderCatalog& shaderCatalog, const std::string& shaderId, std::string& layerId, std::string& error)
+{
+	const ShaderPackage* shaderPackage = shaderCatalog.FindPackage(shaderId);
+	if (!shaderPackage)
+	{
+		error = "Shader '" + shaderId + "' is not in the supported shader catalog.";
+		return false;
+	}
+
+	Layer layer;
+	layer.id = AllocateLayerId();
+	layer.shaderId = shaderPackage->id;
+	layer.shaderName = shaderPackage->displayName.empty() ? shaderPackage->id : shaderPackage->displayName;
+	layer.buildState = RuntimeLayerBuildState::Pending;
+	layer.message = "Runtime Slang build is waiting to start.";
+	layerId = layer.id;
+	mLayers.push_back(std::move(layer));
+	error.clear();
+	return true;
+}
+
+bool RuntimeLayerModel::RemoveLayer(const std::string& layerId, std::string& error)
+{
+	for (auto layerIt = mLayers.begin(); layerIt != mLayers.end(); ++layerIt)
+	{
+		if (layerIt->id != layerId)
+			continue;
+
+		mLayers.erase(layerIt);
+		error.clear();
+		return true;
+	}
+
+	error = "Unknown runtime layer id: " + layerId;
+	return false;
+}
+
+void RuntimeLayerModel::Clear()
+{
+	mLayers.clear();
+}
+
+bool RuntimeLayerModel::MarkBuildStarted(const std::string& layerId, const std::string& message, std::string& error)
+{
+	Layer* layer = FindLayer(layerId);
+	if (!layer)
+	{
+		error = "Unknown runtime layer id: " + layerId;
+		return false;
+	}
+
+	layer->buildState = RuntimeLayerBuildState::Pending;
+	layer->message = message;
+	layer->renderReady = false;
+	layer->artifact = RuntimeShaderArtifact();
+	error.clear();
+	return true;
+}
+
+bool RuntimeLayerModel::MarkBuildReady(const RuntimeShaderArtifact& artifact, std::string& error)
+{
+	Layer* layer = artifact.layerId.empty() ? FindFirstLayerForShader(artifact.shaderId) : FindLayer(artifact.layerId);
+	if (!layer)
+	{
+		error = artifact.layerId.empty()
+			? "No runtime layer is waiting for shader artifact: " + artifact.shaderId
+			: "No runtime layer is waiting for shader artifact on layer: " + artifact.layerId;
+		return false;
+	}
+
+	layer->shaderName = artifact.displayName.empty() ? artifact.shaderId : artifact.displayName;
+	layer->buildState = RuntimeLayerBuildState::Ready;
+	layer->message = artifact.message;
+	layer->renderReady = true;
+	layer->artifact = artifact;
+	error.clear();
+	return true;
+}
+
+bool RuntimeLayerModel::MarkBuildFailedForShader(const std::string& shaderId, const std::string& message)
+{
+	Layer* layer = FindFirstLayerForShader(shaderId);
+	if (!layer)
+		return false;
+
+	std::string error;
+	return MarkBuildFailed(layer->id, message, error);
+}
+
+bool RuntimeLayerModel::MarkBuildFailed(const std::string& layerId, const std::string& message, std::string& error)
+{
+	Layer* layer = FindLayer(layerId);
+	if (!layer)
+	{
+		error = "Unknown runtime layer id: " + layerId;
+		return false;
+	}
+
+	layer->buildState = RuntimeLayerBuildState::Failed;
+	layer->message = message;
+	layer->renderReady = false;
+	layer->artifact = RuntimeShaderArtifact();
+	error.clear();
+	return true;
+}
+
+bool RuntimeLayerModel::MarkRenderCommitFailed(const std::string& layerId, const std::string& message, std::string& error)
+{
+	return MarkBuildFailed(layerId, message, error);
+}
+
+RuntimeLayerModelSnapshot RuntimeLayerModel::Snapshot() const
+{
+	RuntimeLayerModelSnapshot snapshot;
+	snapshot.compileSucceeded = true;
+
+	for (const Layer& layer : mLayers)
+	{
+		snapshot.displayLayers.push_back(ToReadModel(layer));
+		if (!layer.message.empty() && snapshot.compileMessage.empty())
+			snapshot.compileMessage = layer.message;
+		if (layer.buildState == RuntimeLayerBuildState::Failed)
+			snapshot.compileSucceeded = false;
+		if (layer.renderReady)
+		{
+			RuntimeRenderLayerModel renderLayer;
+			renderLayer.id = layer.id;
+			renderLayer.shaderId = layer.shaderId;
+			renderLayer.artifact = layer.artifact;
+			snapshot.renderLayers.push_back(std::move(renderLayer));
+		}
+	}
+
+	if (snapshot.compileMessage.empty())
+		snapshot.compileMessage = mLayers.empty() ? "Runtime shader build disabled." : "Runtime shader build has not completed yet.";
+	return snapshot;
+}
+
+std::string RuntimeLayerModel::FirstLayerId() const
+{
+	return mLayers.empty() ? std::string() : mLayers.front().id;
+}
+
+RuntimeLayerModel::Layer* RuntimeLayerModel::FindLayer(const std::string& layerId)
+{
+	for (Layer& layer : mLayers)
+	{
+		if (layer.id == layerId)
+			return &layer;
+	}
+	return nullptr;
+}
+
+const RuntimeLayerModel::Layer* RuntimeLayerModel::FindLayer(const std::string& layerId) const
+{
+	for (const Layer& layer : mLayers)
+	{
+		if (layer.id == layerId)
+			return &layer;
+	}
+	return nullptr;
+}
+
+RuntimeLayerModel::Layer* RuntimeLayerModel::FindFirstLayerForShader(const std::string& shaderId)
+{
+	for (Layer& layer : mLayers)
+	{
+		if (layer.shaderId == shaderId)
+			return &layer;
+	}
+	return nullptr;
+}
+
+std::string RuntimeLayerModel::AllocateLayerId()
+{
+	return "runtime-layer-" + std::to_string(mNextLayerNumber++);
+}
+
+RuntimeLayerReadModel RuntimeLayerModel::ToReadModel(const Layer& layer)
+{
+	RuntimeLayerReadModel readModel;
+	readModel.id = layer.id;
+	readModel.shaderId = layer.shaderId;
+	readModel.shaderName = layer.shaderName;
+	readModel.bypass = layer.bypass;
+	readModel.buildState = layer.buildState;
+	readModel.message = layer.message;
+	readModel.renderReady = layer.renderReady;
+	return readModel;
+}
+}

apps/RenderCadenceCompositor/runtime/RuntimeLayerModel.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include "RuntimeShaderArtifact.h"
+#include "SupportedShaderCatalog.h"
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace RenderCadenceCompositor
+{
+enum class RuntimeLayerBuildState
+{
+	Pending,
+	Ready,
+	Failed
+};
+
+struct RuntimeLayerReadModel
+{
+	std::string id;
+	std::string shaderId;
+	std::string shaderName;
+	bool bypass = false;
+	RuntimeLayerBuildState buildState = RuntimeLayerBuildState::Pending;
+	std::string message;
+	bool renderReady = false;
+};
+
+struct RuntimeRenderLayerModel
+{
+	std::string id;
+	std::string shaderId;
+	RuntimeShaderArtifact artifact;
+};
+
+struct RuntimeLayerModelSnapshot
+{
+	bool compileSucceeded = true;
+	std::string compileMessage;
+	std::vector<RuntimeLayerReadModel> displayLayers;
+	std::vector<RuntimeRenderLayerModel> renderLayers;
+};
+
+class RuntimeLayerModel
+{
+public:
+	bool InitializeSingleLayer(const SupportedShaderCatalog& shaderCatalog, const std::string& shaderId, std::string& error);
+	void Clear();
+
+	bool AddLayer(const SupportedShaderCatalog& shaderCatalog, const std::string& shaderId, std::string& layerId, std::string& error);
+	bool RemoveLayer(const std::string& layerId, std::string& error);
+	bool MarkBuildStarted(const std::string& layerId, const std::string& message, std::string& error);
+	bool MarkBuildReady(const RuntimeShaderArtifact& artifact, std::string& error);
+	bool MarkBuildFailedForShader(const std::string& shaderId, const std::string& message);
+	bool MarkBuildFailed(const std::string& layerId, const std::string& message, std::string& error);
+	bool MarkRenderCommitFailed(const std::string& layerId, const std::string& message, std::string& error);
+
+	RuntimeLayerModelSnapshot Snapshot() const;
+	std::string FirstLayerId() const;
+
+private:
+	struct Layer
+	{
+		std::string id;
+		std::string shaderId;
+		std::string shaderName;
+		bool bypass = false;
+		RuntimeLayerBuildState buildState = RuntimeLayerBuildState::Pending;
+		std::string message;
+		bool renderReady = false;
+		RuntimeShaderArtifact artifact;
+	};
+
+	Layer* FindLayer(const std::string& layerId);
+	const Layer* FindLayer(const std::string& layerId) const;
+	Layer* FindFirstLayerForShader(const std::string& shaderId);
+	std::string AllocateLayerId();
+	static RuntimeLayerReadModel ToReadModel(const Layer& layer);
+
+	std::vector<Layer> mLayers;
+	uint64_t mNextLayerNumber = 1;
+};
+}

apps/RenderCadenceCompositor/runtime/RuntimeShaderArtifact.h

@@ -7,6 +7,7 @@
 
 struct RuntimeShaderArtifact
 {
+	std::string layerId;
 	std::string shaderId;
 	std::string displayName;
 	std::string fragmentShaderSource;

apps/RenderCadenceCompositor/runtime/RuntimeShaderBridge.cpp

@@ -8,11 +8,17 @@ RuntimeShaderBridge::~RuntimeShaderBridge()
 }
 
 void RuntimeShaderBridge::Start(const std::string& shaderId, ArtifactCallback onArtifactReady, ErrorCallback onError)
+{
+	Start(std::string(), shaderId, std::move(onArtifactReady), std::move(onError));
+}
+
+void RuntimeShaderBridge::Start(const std::string& layerId, const std::string& shaderId, ArtifactCallback onArtifactReady, ErrorCallback onError)
 {
 	Stop();
 	if (shaderId.empty())
 		return;
 
+	mLayerId = layerId;
 	mOnArtifactReady = std::move(onArtifactReady);
 	mOnError = std::move(onError);
 	mStopping.store(false, std::memory_order_release);
@@ -26,6 +32,7 @@ void RuntimeShaderBridge::Stop()
 	if (mThread.joinable())
 		mThread.join();
 	mCompiler.Stop();
+	mLayerId.clear();
 	mOnArtifactReady = ArtifactCallback();
 	mOnError = ErrorCallback();
 }
@@ -39,6 +46,7 @@ void RuntimeShaderBridge::ThreadMain()
 		{
 			if (build.succeeded)
 			{
+				build.artifact.layerId = mLayerId;
 				if (mOnArtifactReady)
 					mOnArtifactReady(build.artifact);
 			}

apps/RenderCadenceCompositor/runtime/RuntimeShaderBridge.h

@@ -20,6 +20,7 @@ public:
 	~RuntimeShaderBridge();
 
 	void Start(const std::string& shaderId, ArtifactCallback onArtifactReady, ErrorCallback onError);
+	void Start(const std::string& layerId, const std::string& shaderId, ArtifactCallback onArtifactReady, ErrorCallback onError);
 	void Stop();
 
 private:
@@ -28,6 +29,7 @@ private:
 	RuntimeSlangShaderCompiler mCompiler;
 	std::thread mThread;
 	std::atomic<bool> mStopping{ false };
+	std::string mLayerId;
 	ArtifactCallback mOnArtifactReady;
 	ErrorCallback mOnError;
 };

docs/RENDER_CADENCE_GOLDEN_RULES.md

@@ -69,6 +69,8 @@ The CPU/build phase may parse manifests, invoke Slang, validate package shape, a
 
 The render thread receives a completed artifact and either commits it at a frame boundary or rejects it. A failed artifact must not disturb the current renderer.
 
+The display/render layer model is app-owned. It may track requested shaders, build state, display metadata, and render-ready artifacts, but it must not perform GL work or drive render cadence directly.
+
 ## 5. No Hidden Blocking In The Cadence Path
 
 The render loop must not do work with unbounded or OS-dependent latency.
@@ -124,6 +126,7 @@ Preferred boundaries:
 - render cadence/thread ownership
 - GL rendering
 - runtime artifact build/bridge
+- app-owned display/render layer model
 - parameter packing
 - system-memory frame exchange
 - DeckLink output scheduling

tests/RenderCadenceCompositorHttpControlServerTests.cpp

@@ -106,6 +106,39 @@ void TestKnownPostEndpointReturnsActionError()
 	Expect(response.body.find("not implemented") != std::string::npos, "unimplemented post reports diagnostic");
 }
 
+void TestLayerPostEndpointsUseCallbacks()
+{
+	using namespace RenderCadenceCompositor;
+
+	HttpControlServer server;
+	HttpControlServerCallbacks callbacks;
+	callbacks.addLayer = [](const std::string& body) {
+		Expect(body.find("solid") != std::string::npos, "add callback receives request body");
+		return ControlActionResult{ true, std::string() };
+	};
+	callbacks.removeLayer = [](const std::string& body) {
+		Expect(body.find("runtime-layer-1") != std::string::npos, "remove callback receives request body");
+		return ControlActionResult{ false, "Unknown layer id." };
+	};
+	server.SetCallbacksForTest(callbacks);
+
+	HttpControlServer::HttpRequest addRequest;
+	addRequest.method = "POST";
+	addRequest.path = "/api/layers/add";
+	addRequest.body = "{\"shaderId\":\"solid\"}";
+	const HttpControlServer::HttpResponse addResponse = server.RouteRequestForTest(addRequest);
+	ExpectEquals(addResponse.status, "200 OK", "add layer callback success returns 200");
+	Expect(addResponse.body.find("\"ok\":true") != std::string::npos, "add layer callback returns action success");
+
+	HttpControlServer::HttpRequest removeRequest;
+	removeRequest.method = "POST";
+	removeRequest.path = "/api/layers/remove";
+	removeRequest.body = "{\"layerId\":\"runtime-layer-1\"}";
+	const HttpControlServer::HttpResponse removeResponse = server.RouteRequestForTest(removeRequest);
+	ExpectEquals(removeResponse.status, "400 Bad Request", "remove layer callback failure returns 400");
+	Expect(removeResponse.body.find("Unknown layer id.") != std::string::npos, "remove layer callback returns diagnostic");
+}
+
 void TestUnknownEndpointReturns404()
 {
 	using namespace RenderCadenceCompositor;
@@ -126,6 +159,7 @@ int main()
 	TestStateEndpointUsesCallback();
 	TestRootServesUiIndex();
 	TestKnownPostEndpointReturnsActionError();
+	TestLayerPostEndpointsUseCallbacks();
 	TestUnknownEndpointReturns404();
 
 	if (gFailures != 0)

tests/RenderCadenceCompositorRuntimeLayerModelTests.cpp

@@ -0,0 +1,163 @@
+#include "RuntimeLayerModel.h"
+
+#include <chrono>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <string>
+
+namespace
+{
+int gFailures = 0;
+
+void Expect(bool condition, const std::string& message)
+{
+	if (condition)
+		return;
+
+	++gFailures;
+	std::cerr << "FAIL: " << message << "\n";
+}
+
+std::filesystem::path MakeTestRoot()
+{
+	const auto stamp = std::chrono::steady_clock::now().time_since_epoch().count();
+	const std::filesystem::path root = std::filesystem::temp_directory_path() / ("render-cadence-layer-model-tests-" + std::to_string(stamp));
+	std::filesystem::create_directories(root);
+	return root;
+}
+
+void WriteFile(const std::filesystem::path& path, const std::string& contents)
+{
+	std::filesystem::create_directories(path.parent_path());
+	std::ofstream output(path, std::ios::binary);
+	output << contents;
+}
+
+RenderCadenceCompositor::SupportedShaderCatalog MakeCatalog(std::filesystem::path& root)
+{
+	root = MakeTestRoot();
+	WriteFile(root / "solid" / "shader.slang", "float4 shadeVideo(float2 uv) { return float4(uv, 0.0, 1.0); }\n");
+	WriteFile(root / "solid" / "shader.json", R"({
+		"id": "solid",
+		"name": "Solid",
+		"description": "Solid test shader",
+		"category": "Tests",
+		"entryPoint": "shadeVideo",
+		"parameters": [
+			{ "id": "gain", "label": "Gain", "type": "float", "default": 0.5 }
+		]
+	})");
+
+	RenderCadenceCompositor::SupportedShaderCatalog catalog;
+	std::string error;
+	Expect(catalog.Load(root, 4, error), error.empty() ? "catalog loads test shader" : error);
+	return catalog;
+}
+
+void TestSingleLayerLifecycle()
+{
+	std::filesystem::path root;
+	RenderCadenceCompositor::SupportedShaderCatalog catalog = MakeCatalog(root);
+
+	RenderCadenceCompositor::RuntimeLayerModel model;
+	std::string error;
+	Expect(model.InitializeSingleLayer(catalog, "solid", error), "model initializes a supported startup shader");
+	Expect(model.FirstLayerId() == "runtime-layer-1", "startup layer id is stable");
+
+	Expect(model.MarkBuildStarted(model.FirstLayerId(), "build started", error), "build start updates the layer");
+	RenderCadenceCompositor::RuntimeLayerModelSnapshot snapshot = model.Snapshot();
+	Expect(snapshot.displayLayers.size() == 1, "snapshot exposes the display layer");
+	Expect(snapshot.displayLayers[0].buildState == RenderCadenceCompositor::RuntimeLayerBuildState::Pending, "started layer is pending");
+	Expect(!snapshot.displayLayers[0].renderReady, "started layer is not render-ready yet");
+
+	RuntimeShaderArtifact artifact;
+	artifact.shaderId = "solid";
+	artifact.displayName = "Solid";
+	artifact.fragmentShaderSource = "void main(){}";
+	artifact.message = "build ready";
+	Expect(model.MarkBuildReady(artifact, error), "ready artifact updates the matching layer");
+
+	snapshot = model.Snapshot();
+	Expect(snapshot.compileSucceeded, "ready layer reports compile success");
+	Expect(snapshot.displayLayers[0].buildState == RenderCadenceCompositor::RuntimeLayerBuildState::Ready, "ready layer is marked ready");
+	Expect(snapshot.displayLayers[0].renderReady, "ready layer exposes render readiness");
+	Expect(snapshot.renderLayers.size() == 1, "ready layer produces one render layer artifact");
+	Expect(snapshot.renderLayers[0].artifact.shaderId == "solid", "render layer carries the artifact");
+
+	std::filesystem::remove_all(root);
+}
+
+void TestRejectsUnsupportedStartupShader()
+{
+	std::filesystem::path root;
+	RenderCadenceCompositor::SupportedShaderCatalog catalog = MakeCatalog(root);
+
+	RenderCadenceCompositor::RuntimeLayerModel model;
+	std::string error;
+	Expect(!model.InitializeSingleLayer(catalog, "missing", error), "model rejects unsupported shader ids");
+	Expect(!error.empty(), "unsupported shader rejection explains the problem");
+	Expect(model.Snapshot().displayLayers.empty(), "rejected startup shader leaves no display layer");
+
+	std::filesystem::remove_all(root);
+}
+
+void TestBuildFailureStaysDisplaySide()
+{
+	std::filesystem::path root;
+	RenderCadenceCompositor::SupportedShaderCatalog catalog = MakeCatalog(root);
+
+	RenderCadenceCompositor::RuntimeLayerModel model;
+	std::string error;
+	Expect(model.InitializeSingleLayer(catalog, "solid", error), "model initializes for failure test");
+	Expect(model.MarkBuildFailed(model.FirstLayerId(), "compile failed", error), "build failure updates the layer");
+
+	const RenderCadenceCompositor::RuntimeLayerModelSnapshot snapshot = model.Snapshot();
+	Expect(!snapshot.compileSucceeded, "failed layer reports compile failure");
+	Expect(snapshot.displayLayers[0].buildState == RenderCadenceCompositor::RuntimeLayerBuildState::Failed, "failed layer is marked failed");
+	Expect(!snapshot.displayLayers[0].renderReady, "failed layer is not render-ready");
+	Expect(snapshot.renderLayers.empty(), "failed layer does not produce a render artifact");
+
+	std::filesystem::remove_all(root);
+}
+
+void TestAddAndRemoveLayers()
+{
+	std::filesystem::path root;
+	RenderCadenceCompositor::SupportedShaderCatalog catalog = MakeCatalog(root);
+
+	RenderCadenceCompositor::RuntimeLayerModel model;
+	std::string error;
+	std::string firstLayerId;
+	std::string secondLayerId;
+	Expect(model.AddLayer(catalog, "solid", firstLayerId, error), "first layer can be added");
+	Expect(model.AddLayer(catalog, "solid", secondLayerId, error), "second layer can be added");
+	Expect(firstLayerId != secondLayerId, "added layers receive distinct ids");
+	Expect(model.Snapshot().displayLayers.size() == 2, "added layers appear in display snapshot");
+
+	Expect(model.RemoveLayer(firstLayerId, error), "existing layer can be removed");
+	RenderCadenceCompositor::RuntimeLayerModelSnapshot snapshot = model.Snapshot();
+	Expect(snapshot.displayLayers.size() == 1, "removed layer leaves snapshot");
+	Expect(snapshot.displayLayers[0].id == secondLayerId, "remaining layer identity is preserved");
+	Expect(!model.RemoveLayer(firstLayerId, error), "removed layer cannot be removed twice");
+
+	std::filesystem::remove_all(root);
+}
+}
+
+int main()
+{
+	TestSingleLayerLifecycle();
+	TestRejectsUnsupportedStartupShader();
+	TestBuildFailureStaysDisplaySide();
+	TestAddAndRemoveLayers();
+
+	if (gFailures != 0)
+	{
+		std::cerr << gFailures << " RenderCadenceCompositorRuntimeLayerModel test failure(s).\n";
+		return 1;
+	}
+
+	std::cout << "RenderCadenceCompositorRuntimeLayerModel tests passed.\n";
+	return 0;
+}

tests/RenderCadenceCompositorRuntimeStateJsonTests.cpp

@@ -1,8 +1,10 @@
 #include "RuntimeStateJson.h"
 
+#include <chrono>
+#include <filesystem>
+#include <fstream>
 #include <iostream>
 #include <string>
-#include <vector>
 
 namespace
 {
@@ -17,29 +19,19 @@ void ExpectContains(const std::string& text, const std::string& fragment, const
 	std::cerr << "FAIL: " << message << "\n";
 }
 
-ShaderPackage MakePackage()
+std::filesystem::path MakeTestRoot()
 {
-	ShaderPackage package;
-	package.id = "solid-color";
-	package.displayName = "Solid Color";
-	package.description = "A single color shader.";
-	package.category = "Generator";
+	const auto stamp = std::chrono::steady_clock::now().time_since_epoch().count();
+	const std::filesystem::path root = std::filesystem::temp_directory_path() / ("render-cadence-state-json-tests-" + std::to_string(stamp));
+	std::filesystem::create_directories(root);
+	return root;
+}
 
-	ShaderPassDefinition pass;
-	pass.id = "main";
-	package.passes.push_back(pass);
-
-	ShaderParameterDefinition color;
-	color.id = "color";
-	color.label = "Color";
-	color.description = "Output color.";
-	color.type = ShaderParameterType::Color;
-	color.defaultNumbers = { 1.0, 0.25, 0.5, 1.0 };
-	color.minNumbers = { 0.0, 0.0, 0.0, 0.0 };
-	color.maxNumbers = { 1.0, 1.0, 1.0, 1.0 };
-	color.stepNumbers = { 0.01, 0.01, 0.01, 0.01 };
-	package.parameters.push_back(color);
-	return package;
+void WriteFile(const std::filesystem::path& path, const std::string& contents)
+{
+	std::filesystem::create_directories(path.parent_path());
+	std::ofstream output(path, std::ios::binary);
+	output << contents;
 }
 }
 
@@ -53,10 +45,41 @@ int main()
 	telemetry.renderFps = 59.94;
 	telemetry.shaderBuildsCommitted = 1;
 
-	std::vector<RenderCadenceCompositor::SupportedShaderSummary> shaders = {
-		{ "solid-color", "Solid Color", "A single color shader.", "Generator" }
-	};
-	const ShaderPackage package = MakePackage();
+	const std::filesystem::path root = MakeTestRoot();
+	WriteFile(root / "solid-color" / "shader.slang", "float4 shadeVideo(float2 uv) { return float4(uv, 0.0, 1.0); }\n");
+	WriteFile(root / "solid-color" / "shader.json", R"({
+		"id": "solid-color",
+		"name": "Solid Color",
+		"description": "A single color shader.",
+		"category": "Generator",
+		"entryPoint": "shadeVideo",
+		"parameters": [
+			{
+				"id": "color",
+				"label": "Color",
+				"description": "Output color.",
+				"type": "color",
+				"default": [1.0, 0.25, 0.5, 1.0],
+				"min": [0.0, 0.0, 0.0, 0.0],
+				"max": [1.0, 1.0, 1.0, 1.0],
+				"step": [0.01, 0.01, 0.01, 0.01]
+			}
+		]
+	})");
+
+	RenderCadenceCompositor::SupportedShaderCatalog shaderCatalog;
+	std::string error;
+	ExpectContains(shaderCatalog.Load(root, 4, error) ? "loaded" : error, "loaded", "test shader catalog should load");
+
+	RenderCadenceCompositor::RuntimeLayerModel layerModel;
+	layerModel.InitializeSingleLayer(shaderCatalog, "solid-color", error);
+	RuntimeShaderArtifact artifact;
+	artifact.shaderId = "solid-color";
+	artifact.displayName = "Solid Color";
+	artifact.fragmentShaderSource = "void main(){}";
+	artifact.message = "Runtime shader committed.";
+	layerModel.MarkBuildReady(artifact, error);
+	const RenderCadenceCompositor::RuntimeLayerModelSnapshot layerSnapshot = layerModel.Snapshot();
 
 	const std::string json = RenderCadenceCompositor::RuntimeStateToJson(RenderCadenceCompositor::RuntimeStateJsonInput{
 		config,
@@ -64,10 +87,8 @@ int main()
 		8080,
 		true,
 		"DeckLink scheduled output running.",
-		shaders,
-		true,
-		"Runtime shader committed.",
-		&package
+		shaderCatalog,
+		layerSnapshot
 	});
 
 	ExpectContains(json, "\"shaders\":[{\"id\":\"solid-color\"", "state JSON should include supported shaders");
@@ -78,6 +99,8 @@ int main()
 	ExpectContains(json, "\"width\":1920", "state JSON should expose output width");
 	ExpectContains(json, "\"height\":1080", "state JSON should expose output height");
 
+	std::filesystem::remove_all(root);
+
 	if (gFailures != 0)
 	{
 		std::cerr << gFailures << " RenderCadenceCompositorRuntimeStateJson test failure(s).\n";