Add manifest support for pass declarations

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;