188 lines
7.0 KiB
Markdown
188 lines
7.0 KiB
Markdown
---
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title: Untitled
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date: 2024-09-25 14:59:32
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excerpt:
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tags:
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rating: ⭐
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---
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# 前言
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可以使用DrawDynamicMeshPass()，实现在插件中使用MeshDraw绘制Pass。
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参考文章：
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- ***UE5，为HairStrands添加自定义深度与模板***:https://zhuanlan.zhihu.com/p/689578355
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# MeshDraw
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推荐学习：
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- CustomDepth
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- RenderBasePassInternal()
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- RenderAnisotropyPass()
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Shader推荐：
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- DepthOnlyVertexShader.usf
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- DepthOnlyPixelShader.usf
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# NaniteMeshDraw
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`Engine\Source\Runtime\Renderer\Private\Nanite\`NaniteMaterials.h & NaniteMaterials.cpp
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PS.使用的Shader必须是`FNaniteGlobalShader`的子类。
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## BasePass
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### DrawBasePass()
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该函数在FDeferredShadingSceneRenderer::RenderBasePassInternal()中调用。
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DrawNaniteMaterialPass() => SubmitNaniteIndirectMaterial()
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## PSO
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- RDG 04 Graphics Pipeline State Initializer https://zhuanlan.zhihu.com/p/582020846
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- FGraphicsPipelineStateInitializer
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- FRHIDepthStencilState* DepthStencilState
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- FRHIBlendState* BlendState
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- FRHIRasterizerState* RasterizerState
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- EPrimitiveType PrimitiveType
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- FBoundShaderStateInput BoundShaderState.VertexDeclarationRHI
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- FBoundShaderStateInput BoundShaderState.VertexShaderRHI
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- FBoundShaderStateInput BoundShaderState.PixelShaderRHI
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- ……
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// 应用
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SetGraphicsPipelineState(RHICmdList, GraphicsPSOInit,0);
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## FMeshPassProcessorRenderState
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- FMeshPassProcessorRenderState
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- FRHIBlendState* BlendState
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- FRHIDepthStencilState* DepthStencilState
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- FExclusiveDepthStencil::Type DepthStencilAccess
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- FRHIUniformBuffer* ViewUniformBuffer
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- FRHIUniformBuffer* InstancedViewUniformBuffer
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- FRHIUniformBuffer* PassUniformBuffer
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- FRHIUniformBuffer* NaniteUniformBuffer
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- uint32 StencilRef = 0;
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### FRHIBlendState
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### FRHIDepthStencilState
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***TStaticDepthStencilState***
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```c++
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DrawRenderState.SetDepthStencilState(TStaticDepthStencilState<false, CF_Equal>::GetRHI());
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template<bool bDepthTest, ECompareFunction CompareFunction, uint32 StencilWriteMask>
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void SetDepthStencilStateForBasePass_Internal(FMeshPassProcessorRenderState& InDrawRenderState)
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{
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InDrawRenderState.SetDepthStencilState(TStaticDepthStencilState<
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bDepthTest, CompareFunction,
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true, CF_Always, SO_Keep, SO_Keep, SO_Replace,
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false, CF_Always, SO_Keep, SO_Keep, SO_Keep,
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0xFF, StencilWriteMask>::GetRHI());
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}
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template<bool bDepthTest, ECompareFunction CompareFunction>
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void SetDepthStencilStateForBasePass_Internal(FMeshPassProcessorRenderState& InDrawRenderState, ERHIFeatureLevel::Type FeatureLevel)
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{
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const static bool bStrataDufferPassEnabled = Strata::IsStrataEnabled() && Strata::IsDBufferPassEnabled(GShaderPlatformForFeatureLevel[FeatureLevel]);
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if (bStrataDufferPassEnabled)
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{
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SetDepthStencilStateForBasePass_Internal<bDepthTest, CompareFunction, GET_STENCIL_BIT_MASK(STRATA_RECEIVE_DBUFFER_NORMAL, 1) | GET_STENCIL_BIT_MASK(STRATA_RECEIVE_DBUFFER_DIFFUSE, 1) | GET_STENCIL_BIT_MASK(STRATA_RECEIVE_DBUFFER_ROUGHNESS, 1) | GET_STENCIL_BIT_MASK(DISTANCE_FIELD_REPRESENTATION, 1) | STENCIL_LIGHTING_CHANNELS_MASK(0x7)>(InDrawRenderState);
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}
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else
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{
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SetDepthStencilStateForBasePass_Internal<bDepthTest, CompareFunction, GET_STENCIL_BIT_MASK(RECEIVE_DECAL, 1) | GET_STENCIL_BIT_MASK(DISTANCE_FIELD_REPRESENTATION, 1) | STENCIL_LIGHTING_CHANNELS_MASK(0x7)>(InDrawRenderState);
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}
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}
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void SetDepthStencilStateForBasePass(
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FMeshPassProcessorRenderState& DrawRenderState,
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ERHIFeatureLevel::Type FeatureLevel,
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bool bDitheredLODTransition,
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const FMaterial& MaterialResource,
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bool bEnableReceiveDecalOutput,
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bool bForceEnableStencilDitherState)
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{
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const bool bMaskedInEarlyPass = (MaterialResource.IsMasked() || bDitheredLODTransition) && MaskedInEarlyPass(GShaderPlatformForFeatureLevel[FeatureLevel]);
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if (bEnableReceiveDecalOutput)
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{
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if (bMaskedInEarlyPass)
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{
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SetDepthStencilStateForBasePass_Internal<false, CF_Equal>(DrawRenderState, FeatureLevel);
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}
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else if (DrawRenderState.GetDepthStencilAccess() & FExclusiveDepthStencil::DepthWrite)
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{
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SetDepthStencilStateForBasePass_Internal<true, CF_GreaterEqual>(DrawRenderState, FeatureLevel);
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}
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else
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{
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SetDepthStencilStateForBasePass_Internal<false, CF_GreaterEqual>(DrawRenderState, FeatureLevel);
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}
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}
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else if (bMaskedInEarlyPass)
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{
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DrawRenderState.SetDepthStencilState(TStaticDepthStencilState<false, CF_Equal>::GetRHI());
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}
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if (bForceEnableStencilDitherState)
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{
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SetDepthStencilStateForBasePass_Internal<false, CF_Equal>(DrawRenderState, FeatureLevel);
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}
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}
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```
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### CustomStencil
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#### InitCustomDepthStencilContext()
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根据当前平台是否支持使用ComputeShader直接输出结果（bComputeExport）、以及是否写入Stencil缓存，以此来创建不同的资源。最终输出FCustomDepthContext。
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```c++
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struct FCustomDepthContext
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{
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FRDGTextureRef InputDepth = nullptr;
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FRDGTextureSRVRef InputStencilSRV = nullptr;
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FRDGTextureRef DepthTarget = nullptr;
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FRDGTextureRef StencilTarget = nullptr;
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bool bComputeExport = true;
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};
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```
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#### EmitCustomDepthStencilTargets()
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根据bComputeExport，分别使用RDG的ComputeShader与PixelShader输出DepthStencil。
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- CS使用FComputeShaderUtils::AddPass()
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- PS使用NaniteExportGBuffer.usf的**EmitCustomDepthStencilPS()**，FPixelShaderUtils::AddFullscreenPass()
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以**FEmitCustomDepthStencilPS**(NaniteExportGBuffer.usf)为例，额外输入的Nanite相关变量：
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- FSceneUniformParameters Scene
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- StructuredBuffer`<`FPackedView`>` InViews
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- ByteAddressBuffer VisibleClustersSWHW？
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- FIntVector4, PageConstants
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- Texture2D`<`UlongType`>`, VisBuffer64
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- ByteAddressBuffer MaterialSlotTable
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#### FinalizeCustomDepthStencil()
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替换输出的Depth&Stencil。
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# FViewInfo
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FViewInfo& ViewInfo
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- WriteView.bSceneHasSkyMaterial |= bSceneHasSkyMaterial;
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- WriteView.bHasSingleLayerWaterMaterial |= bHasSingleLayerWaterMaterial;
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- WriteView.bHasCustomDepthPrimitives |= bHasCustomDepthPrimitives;
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- WriteView.bHasDistortionPrimitives |= bHasDistortionPrimitives;
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- WriteView.bUsesCustomDepth |= bUsesCustomDepth;
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- WriteView.bUsesCustomStencil |= bUsesCustomStencil;
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- FRelevancePacket::Finalize()
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相关性：
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- 相关性定义
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- FStaticMeshBatchRelevance
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- FMaterialRelevance
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- View相关计算
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- FViewInfo::Init()
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- FRelevancePacket
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- FRelevancePacket::Finalize()
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# 相关宏定义
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- SCOPE_CYCLE_COUNTER(STAT_BasePassDrawTime);：
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- DECLARE_CYCLE_STAT_EXTERN(TEXT("Base pass drawing"),STAT_BasePassDrawTime,STATGROUP_SceneRendering, RENDERCORE_API);
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- DEFINE_STAT(STAT_BasePassDrawTime);
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- DEFINE_GPU_STAT(NaniteBasePass);
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- DECLARE_GPU_STAT_NAMED_EXTERN(NaniteBasePass, TEXT("Nanite BasePass"));
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- GET_STATID(STAT_CLP_BasePass)
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- FRDGParallelCommandListSet ParallelCommandListSet(InPass, RHICmdList, GET_STATID(STAT_CLP_BasePass), View, FParallelCommandListBindings(PassParameters));
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- DECLARE_CYCLE_STAT(TEXT("BasePass"), STAT_CLP_BasePass, STATGROUP_ParallelCommandListMarkers); |