160 lines
6.2 KiB
Markdown
160 lines
6.2 KiB
Markdown
---
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title: Untitled
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date: 2025-06-03 10:19:25
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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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1. ShaderWorldPCGInterop：
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2. ShaderWorld：
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3. ShaderWorldCore：
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# ShaderWorld
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- Class
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- Actor
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- ShaderWorldActor.h:[[#AShaderWorldActor]]
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- SWorld.h:[[#ASWorld]]
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## ASWorld
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## AShaderWorldActor
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## DrawMaterialToRenderTarget
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USWorldSubsystem::DrawMaterialToRenderTarget
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=>
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SWShaderToolBox::DrawMaterial
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=>
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DrawMaterial_CS_RT
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调用路径：
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- AShaderWorldActor::RetrieveHeightAt（好像没有引用）：检索高度
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- AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap
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- AShaderWorldActor::ProcessSegmentedComputation() <- AShaderWorldActor::TerrainAndSpawnablesManagement() <- AShaderWorldActor::Tick()
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- AShaderWorldActor::ComputeHeightMapForClipMap
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- AShaderWorldActor::UpdateClipMap() <- AShaderWorldActor::TerrainAndSpawnablesManagement() <- AShaderWorldActor::Tick()
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- AShaderWorldActor::ComputeDataLayersForClipMap
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- AShaderWorldActor::UpdateClipMap() <- AShaderWorldActor::TerrainAndSpawnablesManagement() <- AShaderWorldActor::Tick()
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- AShaderWorldActor::UpdateCollisionMeshData：更新碰撞模型数据。
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- AShaderWorldActor::CollisionGPU() <- AShaderWorldActor::CollisionManagement() <- AShaderWorldActor::Tick()
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- FSpawnableMesh::UpdateSpawnableData
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- AShaderWorldActor::ProcessSegmentedComputation() <- AShaderWorldActor::TerrainAndSpawnablesManagement() <- AShaderWorldActor::Tick()
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## Cache机制
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AShaderWorldActor::ProcessSegmentedComputation() <- AShaderWorldActor::TerrainAndSpawnablesManagement() <- AShaderWorldActor::Tick()
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# 其他Bug
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## SetTextureParameterValue相关逻辑排查
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- AShaderWorldActor中的SetTextureParameterValue
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- ~~ExportCacheInBounds~~
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- ~~AssignHeightMapToDynamicMaterial~~
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- UpdateStaticDataFor
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- ComputeHeight_Segmented_MapForClipMap：似乎会设置
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- ~~UpdateCollisionMeshData~~
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- [x] [[#InitializeReadBackDependencies]]
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- [x] InitiateMaterials
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### UpdateStaticDataFor
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### ComputeHeight_Segmented_MapForClipMap
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- 作用：
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- 调用顺序：AShaderWorldActor::Tick() -> AShaderWorldActor::TerrainAndSpawnablesManagement() -> AShaderWorldActor::ProcessSegmentedComputation() -> ComputeHeight_Segmented_MapForClipMap
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>// 1) Intersect clipmap with grid quad
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// 2) Gather non computed quads
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// 3) Allocated Compute element to missing Quad
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// 4) Update the indirection data to the new elements
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// 5) Update the Clipmap Heightmap with the grid data
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### UpdateCollisionMeshData
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- 作用：
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1. 判断DynCollisionMat是否有效，无效就使用`Generator`（高度数据生成材质）来创建。
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2. 设置材质参数NoMargin、TexelPerSide、PatchFullSize、MeshScale。
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3. 设置随机种子相关的材质参数。
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4. 设置材质参数PatchLocation。
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5. 生成碰撞数据到`CollisionRT`。
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6. 笔刷功能逻辑：ApplyBrushStackToHeightMap()。
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7. ExportPhysicalMaterialID逻辑。
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8. GPU碰撞数据回读：ShaderWorld::AsyncReadPixelsFromRT()。
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1. ShaderWorld::GSWReadbackManager.AddPendingReadBack()，将回读Task增加`TArray<FReadBackTask> PendingReads;`。
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2. 之后会在USWorldSubsystem::Tick()中调用ShaderWorld::GSWReadbackManager.TickReadBack()，不断检查是否可回读，并进行最终回读。
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- 调用顺序：Tick() -> CollisionManagement() -> CollisionGPU() -> UpdateCollisionMeshData()
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```c++
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namespace ShaderWorld
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{
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FORCEINLINE void AsyncReadPixelsFromRT(UShaderWorldRT2D* InRT, TSharedPtr<FSWColorRead, ESPMode::ThreadSafe> Destination, TSharedPtr < FThreadSafeBool, ESPMode::ThreadSafe> Completion)
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{
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ENQUEUE_RENDER_COMMAND(ReadGeoClipMapRTCmd)(
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[InRT, HeightData = Destination, Completion = Completion](FRHICommandListImmediate& RHICmdList)
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{
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check(IsInRenderingThread());
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if (HeightData.IsValid() && InRT->GetResource())
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{
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FRDGBuilder GraphBuilder(RHICmdList);
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TSharedPtr<FRHIGPUTextureReadback> ReadBackStaging = MakeShared<FRHIGPUTextureReadback>(TEXT("SWGPUTextureReadback"));
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FRDGTextureRef RDGSourceTexture = RegisterExternalTexture(GraphBuilder, InRT->GetResource()->TextureRHI, TEXT("SWSourceTextureToReadbackTexture"));
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AddEnqueueCopyPass(GraphBuilder, ReadBackStaging.Get(), RDGSourceTexture);
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GraphBuilder.Execute();
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ShaderWorld::GSWReadbackManager.AddPendingReadBack(RHICmdList, GPixelFormats[RDGSourceTexture->Desc.Format].BlockBytes, RDGSourceTexture->Desc.Extent.X, RDGSourceTexture->Desc.Extent.Y, ReadBackStaging, const_cast<TSharedPtr<FSWColorRead, ESPMode::ThreadSafe>&>(HeightData), const_cast<TSharedPtr < FThreadSafeBool, ESPMode::ThreadSafe>&>(Completion));
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}
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});
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}
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```
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### InitializeReadBackDependencies
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- 作用：初始化几个GPU数据回读用的RT。
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- 调用顺序：BeginPlay() -> InitiateWorld() -> InitializeReadBackDependencies()
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1. 初始化3个RT：ReadRequestLocation、ReadRequestLocationHeightmap、GeneratorDynamicForReadBack。
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2. 会设置`TObjectPtr < UMaterialInstanceDynamic> GeneratorDynamicForReadBack`各种变量
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```c++
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GeneratorDynamicForReadBack->SetScalarParameterValue("HeightReadBack", 1.f);
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GeneratorDynamicForReadBack->SetTextureParameterValue("SpecificLocationsRT", ReadRequestLocation);
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GeneratorDynamicForReadBack->SetScalarParameterValue("NoMargin", 0.f);
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GeneratorDynamicForReadBack->SetScalarParameterValue("N", N);
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GeneratorDynamicForReadBack->SetScalarParameterValue("NormalMapSelect", 0.f);
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GeneratorDynamicForReadBack->SetScalarParameterValue("HeightMapToggle", 1.f);
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```
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3. 设置随机种子相关Shader Parameter。
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### InitiateMaterials
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作用：初始化`TArray<FClipMapMeshElement> Meshes;`的Material、`Producers`
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调用顺序：BeginPlay() -> InitiateWorld() -> InitiateMaterials()
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经过断点调试，会设置WorldSettings里的Material（地形Material）的HeightMap与NormalMap。
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#
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SWorldSubsystem->DrawMaterialToRenderTarget
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# Rebuild逻辑
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## 重要函数
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- AShaderWorldActor::BeginPlay()
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- AShaderWorldActor::Setup()（<- TerrainAndSpawnablesManagement(float& DeltaT) <- Tick()）
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## Rebuild逻辑顺序
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1. AShaderWorldActor::BeginPlay()
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1.
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# Debug
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1. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次
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2. UpdateCollisionMeshData
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3. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次
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4. RetrieveHeightAt
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5. UpdateCollisionMeshData 3次
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6. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次 |