Add manifest support for pass declarations

README.md

@@ -206,10 +206,11 @@ 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.
 
 ## Generated Files
 

SHADER_CONTRACT.md

@@ -97,6 +97,7 @@ 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.
@@ -110,6 +111,52 @@ 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:
+
+```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. Current reserved names include `layerInput` and future pass output names.
+- `output`: optional output name. Use `layerOutput` for the final visible layer result.
+
+Current runtime note: pass manifests are parsed and every declared pass is Slang-validated/compiled, but execution still uses the first pass until multipass render-target routing is enabled. Existing single-pass shaders are unaffected.
+
 ## Slang Entry Point
 
 Your shader file must implement the manifest `entryPoint`.

apps/LoopThroughWithOpenGLCompositing/gl/shader/OpenGLShaderPrograms.cpp

@@ -2,6 +2,7 @@
 
 #include <cstring>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace
@@ -91,7 +92,11 @@ bool OpenGLShaderPrograms::CommitPreparedLayerPrograms(const PreparedShaderBuild
 	for (const PreparedLayerShader& preparedLayer : preparedBuild.layers)
 	{
 		LayerProgram layerProgram;
-		if (!mCompiler.CompilePreparedLayerProgram(preparedLayer.state, preparedLayer.fragmentShaderSource, layerProgram, errorMessageSize, errorMessage))
+		std::vector<std::pair<std::string, std::string>> passSources;
+		passSources.reserve(preparedLayer.passes.size());
+		for (const PreparedLayerShader::Pass& pass : preparedLayer.passes)
+			passSources.push_back(std::make_pair(pass.passId, pass.fragmentShaderSource));
+		if (!mCompiler.CompilePreparedLayerProgram(preparedLayer.state, passSources, layerProgram, errorMessageSize, errorMessage))
 		{
 			for (LayerProgram& program : newPrograms)
 				DestroySingleLayerProgram(program);

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderBuildQueue.cpp

@@ -120,11 +120,15 @@ PreparedShaderBuild ShaderBuildQueue::Build(uint64_t generation, unsigned output
 	{
 		PreparedLayerShader layer;
 		layer.state = state;
-		if (!mRuntimeHost.BuildLayerFragmentShaderSource(state.layerId, layer.fragmentShaderSource, build.message))
+		std::vector<std::pair<std::string, std::string>> passSources;
+		if (!mRuntimeHost.BuildLayerPassFragmentShaderSources(state.layerId, passSources, build.message))
 		{
 			build.succeeded = false;
 			return build;
 		}
+		layer.passes.reserve(passSources.size());
+		for (auto& passSource : passSources)
+			layer.passes.push_back({ std::move(passSource.first), std::move(passSource.second) });
 		build.layers.push_back(std::move(layer));
 	}
 

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderBuildQueue.h

@@ -13,8 +13,14 @@ class RuntimeHost;
 
 struct PreparedLayerShader
 {
+	struct Pass
+	{
+		std::string passId;
+		std::string fragmentShaderSource;
+	};
+
 	RuntimeRenderState state;
-	std::string fragmentShaderSource;
+	std::vector<Pass> passes;
 };
 
 struct PreparedShaderBuild

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderProgramCompiler.cpp

@@ -28,102 +28,118 @@ ShaderProgramCompiler::ShaderProgramCompiler(OpenGLRenderer& renderer, RuntimeHo
 
 bool ShaderProgramCompiler::CompileLayerProgram(const RuntimeRenderState& state, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
 {
-	std::string fragmentShaderSource;
+	std::vector<std::pair<std::string, std::string>> passSources;
 	std::string loadError;
 
-	if (!mRuntimeHost.BuildLayerFragmentShaderSource(state.layerId, fragmentShaderSource, loadError))
+	if (!mRuntimeHost.BuildLayerPassFragmentShaderSources(state.layerId, passSources, loadError))
 	{
 		CopyErrorMessage(loadError, errorMessageSize, errorMessage);
 		return false;
 	}
 
-	return CompilePreparedLayerProgram(state, fragmentShaderSource, layerProgram, errorMessageSize, errorMessage);
+	return CompilePreparedLayerProgram(state, passSources, layerProgram, errorMessageSize, errorMessage);
 }
 
 bool ShaderProgramCompiler::CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::string& fragmentShaderSource, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage)
+{
+	std::vector<std::pair<std::string, std::string>> passSources;
+	passSources.push_back(std::make_pair(std::string("main"), fragmentShaderSource));
+	return CompilePreparedLayerProgram(state, passSources, layerProgram, errorMessageSize, errorMessage);
+}
+
+bool ShaderProgramCompiler::CompilePreparedLayerProgram(const RuntimeRenderState& state, const std::vector<std::pair<std::string, std::string>>& passSources, 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);
 
 	layerProgram.layerId = state.layerId;
 	layerProgram.shaderId = state.shaderId;
+	layerProgram.passes.clear();
 
-	PassProgram passProgram;
-	passProgram.passId = "main";
-	passProgram.shaderTextureBase = mTextureBindings.ResolveShaderTextureBase(state, mRuntimeHost.GetMaxTemporalHistoryFrames());
-	passProgram.textureBindings.swap(textureBindings);
-	passProgram.textBindings.swap(textBindings);
+	for (const auto& passSource : passSources)
+	{
+		GLint compileResult = GL_FALSE;
+		GLint linkResult = GL_FALSE;
+		const char* fragmentSource = passSource.second.c_str();
 
-	const GLuint globalParamsIndex = glGetUniformBlockIndex(newProgram.get(), "GlobalParams");
-	if (globalParamsIndex != GL_INVALID_INDEX)
-		glUniformBlockBinding(newProgram.get(), globalParamsIndex, kGlobalParamsBindingPoint);
+		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;
+		}
 
-	const unsigned historyCap = mRuntimeHost.GetMaxTemporalHistoryFrames();
-	glUseProgram(newProgram.get());
-	mTextureBindings.AssignLayerSamplerUniforms(newProgram.get(), state, passProgram, historyCap);
-	glUseProgram(0);
+		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;
+		}
 
-	passProgram.program = newProgram.release();
-	passProgram.vertexShader = newVertexShader.release();
-	passProgram.fragmentShader = newFragmentShader.release();
-	layerProgram.passes.push_back(std::move(passProgram));
+		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.first;
+		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;
 }
 

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderProgramCompiler.h

@@ -5,6 +5,8 @@
 #include "ShaderTextureBindings.h"
 
 #include <string>
+#include <utility>
+#include <vector>
 
 class ShaderProgramCompiler
 {
@@ -16,6 +18,7 @@ public:
 
 	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<std::pair<std::string, std::string>>& passSources, LayerProgram& layerProgram, int errorMessageSize, char* errorMessage);
 	bool CompileDecodeShader(int errorMessageSize, char* errorMessage);
 	bool CompileOutputPackShader(int errorMessageSize, char* errorMessage);
 

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.cpp

@@ -1301,6 +1301,20 @@ bool RuntimeHost::TryAdvanceFrame()
 }
 
 bool RuntimeHost::BuildLayerFragmentShaderSource(const std::string& layerId, std::string& fragmentShaderSource, std::string& error)
+{
+	std::vector<std::pair<std::string, std::string>> passSources;
+	if (!BuildLayerPassFragmentShaderSources(layerId, passSources, error))
+		return false;
+	if (passSources.empty())
+	{
+		error = "Shader layer produced no compiled passes: " + layerId;
+		return false;
+	}
+	fragmentShaderSource = passSources.front().second;
+	return true;
+}
+
+bool RuntimeHost::BuildLayerPassFragmentShaderSources(const std::string& layerId, std::vector<std::pair<std::string, std::string>>& passSources, std::string& error)
 {
 	try
 	{
@@ -1324,16 +1338,25 @@ bool RuntimeHost::BuildLayerFragmentShaderSource(const std::string& layerId, std
 		}
 
 		ShaderCompiler compiler(mRepoRoot, mWrapperPath, mGeneratedGlslPath, mPatchedGlslPath, mConfig.maxTemporalHistoryFrames);
-		return compiler.BuildLayerFragmentShaderSource(shaderPackage, fragmentShaderSource, error);
+		passSources.clear();
+		passSources.reserve(shaderPackage.passes.size());
+		for (const ShaderPassDefinition& pass : shaderPackage.passes)
+		{
+			std::string fragmentShaderSource;
+			if (!compiler.BuildPassFragmentShaderSource(shaderPackage, pass, fragmentShaderSource, error))
+				return false;
+			passSources.push_back(std::make_pair(pass.id, std::move(fragmentShaderSource)));
+		}
+		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;
 	}
 }
@@ -1673,35 +1696,8 @@ bool RuntimeHost::ScanShaderPackages(std::string& error)
 
 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);
+	ShaderPackageRegistry registry(mConfig.maxTemporalHistoryFrames);
+	return registry.ParseManifest(manifestPath, shaderPackage, error);
 }
 
 bool RuntimeHost::NormalizeAndValidateValue(const ShaderParameterDefinition& definition, const JsonValue& value, ShaderParameterValue& normalizedValue, std::string& error) const

apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.h

@@ -9,6 +9,7 @@
 #include <map>
 #include <mutex>
 #include <string>
+#include <utility>
 #include <vector>
 
 class RuntimeHost
@@ -51,6 +52,7 @@ public:
 	bool TryAdvanceFrame();
 
 	bool BuildLayerFragmentShaderSource(const std::string& layerId, std::string& fragmentShaderSource, std::string& error);
+	bool BuildLayerPassFragmentShaderSources(const std::string& layerId, std::vector<std::pair<std::string, std::string>>& passSources, std::string& error);
 	std::vector<RuntimeRenderState> GetLayerRenderStates(unsigned outputWidth, unsigned outputHeight) const;
 	bool TryGetLayerRenderStates(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const;
 	void RefreshDynamicRenderStateFields(std::vector<RuntimeRenderState>& states) const;

apps/LoopThroughWithOpenGLCompositing/shader/ShaderCompiler.cpp

@@ -144,9 +144,19 @@ ShaderCompiler::ShaderCompiler(
 }
 
 bool ShaderCompiler::BuildLayerFragmentShaderSource(const ShaderPackage& shaderPackage, std::string& fragmentShaderSource, std::string& error) const
+{
+	if (shaderPackage.passes.empty())
+	{
+		error = "Shader package has no render passes: " + shaderPackage.id;
+		return false;
+	}
+	return BuildPassFragmentShaderSource(shaderPackage, shaderPackage.passes.front(), fragmentShaderSource, error);
+}
+
+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 +177,7 @@ 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);
@@ -183,8 +193,8 @@ bool ShaderCompiler::BuildWrapperSlangSource(const ShaderPackage& shaderPackage,
 	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;
 }
 

apps/LoopThroughWithOpenGLCompositing/shader/ShaderCompiler.h

@@ -16,9 +16,10 @@ public:
 		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

@@ -250,6 +250,103 @@ 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)
+	{
+		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());
+			}
+		}
+
+		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;
@@ -666,13 +763,15 @@ 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) &&

apps/LoopThroughWithOpenGLCompositing/shader/ShaderTypes.h

@@ -76,6 +76,16 @@ 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 ShaderPackage
 {
 	std::string id;
@@ -86,6 +96,7 @@ 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;

tests/ShaderPackageRegistryTests.cpp

@@ -80,6 +80,34 @@ void TestValidManifest()
 	Expect(package.parameters.size() == 4, "parameters parse");
 	Expect(package.parameters[1].type == ShaderParameterType::Text && package.parameters[1].defaultTextValue == "LIVE", "text parameter parses");
 	Expect(package.parameters[3].type == ShaderParameterType::Trigger, "trigger parameter parses");
+	Expect(package.passes.size() == 1 && package.passes[0].id == "main", "legacy manifests get an implicit main pass");
+
+	std::filesystem::remove_all(root);
+}
+
+void TestExplicitPassManifest()
+{
+	const std::filesystem::path root = MakeTestRoot();
+	WriteShaderPackage(root, "multi", R"({
+		"id": "multi-pass",
+		"name": "Multi Pass",
+		"passes": [
+			{ "id": "blurX", "source": "blur-x.slang", "entryPoint": "blurHorizontal", "inputs": ["layerInput"], "output": "blurredX" },
+			{ "id": "final", "source": "final.slang", "entryPoint": "finish", "inputs": ["blurredX"], "output": "layerOutput" }
+		],
+		"parameters": []
+	})");
+	WriteFile(root / "multi" / "blur-x.slang", "float4 blurHorizontal(float2 uv) { return float4(uv, 0.0, 1.0); }\n");
+	WriteFile(root / "multi" / "final.slang", "float4 finish(float2 uv) { return float4(uv, 1.0, 1.0); }\n");
+
+	ShaderPackageRegistry registry(4);
+	ShaderPackage package;
+	std::string error;
+	Expect(registry.ParseManifest(root / "multi" / "shader.json", package, error), "explicit pass manifest parses");
+	Expect(package.passes.size() == 2, "explicit passes parse");
+	Expect(package.passes[0].id == "blurX" && package.passes[0].entryPoint == "blurHorizontal", "first pass metadata parses");
+	Expect(package.passes[0].inputNames.size() == 1 && package.passes[0].inputNames[0] == "layerInput", "pass inputs parse");
+	Expect(package.passes[1].outputName == "layerOutput", "pass output parses");
 
 	std::filesystem::remove_all(root);
 }
@@ -231,6 +259,7 @@ void TestInvalidPackageDoesNotFailScan()
 int main()
 {
 	TestValidManifest();
+	TestExplicitPassManifest();
 	TestMissingFontAsset();
 	TestInvalidManifest();
 	TestInvalidTemporalSettings();

tests/ShaderSlangValidationTests.cpp

@@ -81,15 +81,19 @@ int main()
 		if (packageIt == packagesById.end())
 			continue;
 
-		std::string fragmentShaderSource;
-		std::string compileError;
-		if (!compiler.BuildLayerFragmentShaderSource(packageIt->second, fragmentShaderSource, compileError))
+		const ShaderPackage& shaderPackage = packageIt->second;
+		for (const ShaderPassDefinition& pass : shaderPackage.passes)
 		{
-			Fail("Shader package '" + packageId + "' failed Slang validation: " + compileError);
-			continue;
+			std::string fragmentShaderSource;
+			std::string compileError;
+			if (!compiler.BuildPassFragmentShaderSource(shaderPackage, pass, fragmentShaderSource, compileError))
+			{
+				Fail("Shader package '" + packageId + "' pass '" + pass.id + "' failed Slang validation: " + compileError);
+				continue;
+			}
+			if (fragmentShaderSource.find("#version 430 core") == std::string::npos)
+				Fail("Shader package '" + packageId + "' pass '" + pass.id + "' generated GLSL without the expected patched GLSL version header.");
 		}
-		if (fragmentShaderSource.find("#version 430 core") == std::string::npos)
-			Fail("Shader package '" + packageId + "' generated GLSL without the expected patched GLSL version header.");
 	}
 
 	std::error_code removeError;