UE4通過插件添加GlobalShader

#include "SimpleColor.h" #include "Runtime/RenderCore/Public/PixelShaderUtils.h" #include "Containers/DynamicRHIResourceArray.h" // 基础的静态顶点缓冲 class FSimpleScreenVertexBuffer : public FVertexBuffer { public: // 为渲染资源初始化RHI void InitRHI() { // FFilterVertex 表示顶点数据是用来过滤纹理的， VERTEXBUFFER_ALIGNMENT 是内存分配时的对齐方式 TResourceArray<FFilterVertex, VERTEXBUFFER_ALIGNMENT> Vertices; Vertices.SetNumUninitialized(6); Vertices[0].Position = FVector4(-1, 1, 0, 1); Vertices[0].UV = FVector2D(0, 0); Vertices[1].Position = FVector4(1, 1, 0, 1); Vertices[1].UV = FVector2D(1, 0); Vertices[2].Position = FVector4(-1, -1, 0, 1); Vertices[2].UV = FVector2D(0, 1); Vertices[3].Position = FVector4(1, -1, 0, 1); Vertices[3].UV = FVector2D(1, 1); // 创建顶点缓冲区， 用上方创建的初始数据填充该缓冲 FRHIResourceCreateInfo CreateInfo(&Vertices); VertexBufferRHI = RHICreateVertexBuffer(Vertices.GetResourceDataSize(), BUF_Static, CreateInfo); } }; // 声明一个顶点缓冲 TGlobalResource<FSimpleScreenVertexBuffer> GSimpleScreenVertexBuffer; // 基础的顶点着色器 class FSimpleColorVS : public FGlobalShader { public: DECLARE_GLOBAL_SHADER(FSimpleColorVS); static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& Parameters) { return true; } static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment) { FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment); } FSimpleColorVS() {} FSimpleColorVS(const ShaderMetaType::CompiledShaderInitializerType& Initializer) : FGlobalShader(Initializer) {} }; // 像素着色器，参数作为cpp和HLSL的桥梁 class FSimpleColorPS : public FGlobalShader { public: DECLARE_GLOBAL_SHADER(FSimpleColorPS); SHADER_USE_PARAMETER_STRUCT(FSimpleColorPS, FGlobalShader); // 和游戏线程的参数一一对应 BEGIN_SHADER_PARAMETER_STRUCT(FParameters, ) SHADER_PARAMETER(FVector4, InputColor) END_SHADER_PARAMETER_STRUCT() static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& Parameters) { return IsFeatureLevelSupported(Parameters.Platform, ERHIFeatureLevel::SM5); } static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment) { FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment); } }; // 告诉引擎创建着色器以及着色器的入口位置 // 着色器类型 着色器路径 着色器函数名 类型 IMPLEMENT_GLOBAL_SHADER(FSimpleColorVS, "/CustomShaders/PixelShader.usf", "MainVertexShader", SF_Vertex); IMPLEMENT_GLOBAL_SHADER(FSimpleColorPS, "/CustomShaders/PixelShader.usf", "MainPixelShader", SF_Pixel); void FSimpleColor::DrawToRenderTarget_RenderThread(FRHICommandListImmediate& RHICmdList, const FShaderUsageParameters& DrawParameters, FTextureRHIRef UserRenderTarget) { QUICK_SCOPE_CYCLE_COUNTER(STAT_CustomGlobalShaderPlugin_PixelShader); // 为UE4前端收集CPU分析数据 SCOPED_DRAW_EVENT(RHICmdList, CustomGlobalShaderPlugin_Pixel); // 为分析GPU活动添加的元数据，可以用RenderDoc这种工具查看 FRHIRenderPassInfo RenderPassInfo(DrawParameters.RenderTarget->GetRenderTargetResource()->GetRenderTargetTexture(), ERenderTargetActions::Clear_Store); RHICmdList.BeginRenderPass(RenderPassInfo, TEXT("CustomGlobalShaderPlugin_OutputToRenderTarget")); auto ShaderMap = GetGlobalShaderMap(GMaxRHIFeatureLevel); TShaderMapRef<FSimpleColorVS> VertexShader(ShaderMap); TShaderMapRef<FSimpleColorPS> PixelShader(ShaderMap); // 设置图形管线状态 FGraphicsPipelineStateInitializer GraphicsPSOInit; RHICmdList.ApplyCachedRenderTargets(GraphicsPSOInit); GraphicsPSOInit.BlendState = TStaticBlendState<>::GetRHI(); GraphicsPSOInit.RasterizerState = TStaticRasterizerState<>::GetRHI(); GraphicsPSOInit.DepthStencilState = TStaticDepthStencilState<false, CF_Always>::GetRHI(); GraphicsPSOInit.BoundShaderState.VertexDeclarationRHI = GFilterVertexDeclaration.VertexDeclarationRHI; GraphicsPSOInit.BoundShaderState.VertexShaderRHI = GETSAFERHISHADER_VERTEX(*VertexShader); GraphicsPSOInit.BoundShaderState.PixelShaderRHI = GETSAFERHISHADER_PIXEL(*PixelShader); GraphicsPSOInit.PrimitiveType = PT_TriangleStrip; SetGraphicsPipelineState(RHICmdList, GraphicsPSOInit); // 设置像素着色器颜色，将游戏线程的参数传进来 FSimpleColorPS::FParameters PassParameters; PassParameters.InputColor = FVector4(DrawParameters.InputColor.R, DrawParameters.InputColor.G, DrawParameters.InputColor.B, DrawParameters.InputColor.A) / 255.0f; // 提交参数到RHI命令列表 SetShaderParameters(RHICmdList, *PixelShader, PixelShader->GetPixelShader(), PassParameters); // 绘制 RHICmdList.SetStreamSource(0, GSimpleScreenVertexBuffer.VertexBufferRHI, 0); RHICmdList.DrawPrimitive(0, 2, 1); // 完成渲染目标 RHICmdList.CopyToResolveTarget(DrawParameters.RenderTarget->GetRenderTargetResource()->GetRenderTargetTexture(), DrawParameters.RenderTarget->GetRenderTargetResource()->TextureRHI, FResolveParams()); RHICmdList.EndRenderPass(); }