742 lines
24 KiB
Markdown
742 lines
24 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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## FRenderCommandFence
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# USWorldSubsystem
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主要管理：
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- TArray<USWContextBase*> SW_Contexts
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- 渲染相关变量：RT_Ready、RenderThreadPoked、RenderThreadResponded处理。
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# ASWorld
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# AShaderWorldActor
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## 大致启动流程
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大致启动流程：
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- BeginPlay()
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1. 设置SWCamera Location。
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2. 清空所有数据。
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3. InitiateWorld()
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1. 更新相关变量：GenerateCollision_last、VerticalRangeMeters_last、WorldHasBounds_OnRebuild。**Segmented_Initialized** 、**bExportPhysicalMaterialID_cached**
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2. 设置高度生成用材质变量 Generator;bool bHadGeneratorAtRebuildTime = IsValid(Generator);
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3. LOD_Num与WorldDimensionMeters计算。
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4. 重新生成若干数组：
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1. LODs_DimensionsMeters
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2. ClipMapToUpdateAndMove
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3. ClipMapToUpdate
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4. NeedSegmentedUpdate
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5. AdaptiveTopology
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5. 相关线程安全变量：
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1. Shareable_ID_FarLOD
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2. UpdateHOverTime
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6. ComputeOptimalVirtualCacheSize()
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7. for (int32 i = (WorldHasBounds_OnRebuild ? -1 : 0); i < LOD_Num; i++)
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8. Toggle Async creation of Clipmap Meshes
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9. Async TaskGraph ClipMapMeshCreation
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- Tick()
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- 初始化
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1. 取得USWorldSubsystem指针，并且进行初始化。
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- ReadbacksManagement()
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- CollisionManagement()
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- SpawnablesManagement()
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- TerrainAndSpawnablesManagement()
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### ReadbacksManagement()
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- ThreadSafe
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- bool
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- **bProcessingHeightRetrieval**
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- **bProcessingHeightRetrievalRT**
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- FSWShareableSamplePoints
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- PointsPendingReadBacks
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- FSWColorRead
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- ReadBackHeightData
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- FRenderCommandFence
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- HeightReadBackFence
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```c++
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void AShaderWorldActor::ReadbacksManagement()
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{
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if (!bProcessingHeightRetrieval.IsValid())
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bProcessingHeightRetrieval = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
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if (!bProcessingHeightRetrievalRT.IsValid())
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bProcessingHeightRetrievalRT = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
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//PointsPendingReadBacks存储从GPU回读的采样坐标位置;在RetrieveHeightAt()调用HeightReadBackFence.BeginFence(true)开启渲染栅栏，不开启这段逻辑不会执行。
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if ((*bProcessingHeightRetrieval.Get()) && (*bProcessingHeightRetrievalRT.Get()) && HeightReadBackFence.IsFenceComplete() && PointsPendingReadBacks.IsValid())
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{
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// ReadBackHeightData uin8 贴图数据
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if (!ReadBackHeightData.IsValid())
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return;
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//For now we do Compute samples on a rendertarget 5x5, therefore 25 positions evaluated per request.
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//每次请求可以读取25个点。
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const int NumOfVertex = 25;
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PositionsOfReadBacks.Empty();
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PositionsOfReadBacks.AddUninitialized(25);
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uint8* ReadData8 = (uint8*)ReadBackHeightData->ReadData.GetData();
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uint16 MaterialIndice = 0;
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for (int32 k = 0; k < NumOfVertex; k++)
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{
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FVector3f& PositionSample = PositionsOfReadBacks[k];
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if (RendererAPI == EGeoRenderingAPI::OpenGL)
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{
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int X = k % 5;
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int Y = k / 5;
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int index = X + Y * 5;
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Y = (5 - 1) - Y;
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index = X + Y * 5;
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PositionSample = FVector3f(PointsPendingReadBacks->PositionsXY[2 * k], PointsPendingReadBacks->PositionsXY[2 * k + 1], GetHeightFromGPURead(&ReadData8[index * 4], MaterialIndice) / HeightScale);
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}
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else
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PositionSample = FVector3f(PointsPendingReadBacks->PositionsXY[2 * k], PointsPendingReadBacks->PositionsXY[2 * k + 1], GetHeightFromGPURead(&ReadData8[k * 4], MaterialIndice) / HeightScale);
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}
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if(HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks))
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{
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//SW_LOG("HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks) PositionsOfReadBacks[0] %s",*PositionsOfReadBacks[0].ToString())
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}
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else
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{
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//SW_LOG("Fail HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks)")
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}
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bProcessingHeightRetrieval->AtomicSet(false);
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bProcessingHeightRetrievalRT->AtomicSet(false);
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}
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//For now MinMax is here
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//处理FClipMapMeshElement的最大最小队列？
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if (UseSegmented())
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{
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if(WorldHasBounds_OnRebuild)
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{
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FClipMapMeshElement& MeshEl = FarLOD_BoundedWorld;
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if (MeshEl.MinMaxQueue.Num() > 0)
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{
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MeshEl.ProcessMinMaxQueue(SWorldSubsystem);
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}
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}
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for (FClipMapMeshElement& MeshEl : Meshes)
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{
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if (MeshEl.MinMaxQueue.Num() > 0)
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{
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MeshEl.ProcessMinMaxQueue(SWorldSubsystem);
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}
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}
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}
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}
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```
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### CollisionManagement()
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- ThreadSafe
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- bool
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- bProcessingGroundCollision
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- bPreprocessingCollisionUpdate
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- EditRebuild：传递Bool值给 rebuild。
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- FSWCollisionManagementShareableData
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- CollisionShareable
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- FRenderCommandFence
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- 1
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- bool
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- RedbuildCollisionContext
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- Array
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- CollisionWorkQueue：类型为FCollisionProcessingWork。
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- CollisionReadToProcess
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```c++
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void AShaderWorldActor::CollisionManagement(float& DeltaT)
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{
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SCOPED_NAMED_EVENT_TEXT("AShaderWorldActor::CollisionManagement", FColor::Magenta);
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SW_FCT_CYCLE()
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/*
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* Can we execute compute shader?
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* Do we need to rebuild collision?
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* Did ShaderWorld toggled collision generation On/Off?
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* Are we pending a full rebuild of the Shader World?
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*/
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if (!SetupCollisions())
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return;
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/*
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* Using collision updates, update Collision meshes
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*/
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if (!CollisionFinalizeWork())
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return;
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if (CollisionProcess.IsFenceComplete())
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{
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/*
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* Convert Compute shader results to actionable collision updates
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*/
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if (!CollisionPreprocessGPU())
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{
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CollisionProcess.BeginFence(true);
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return;
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}
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}
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/*
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* Process GPU work queue by launching GPU tasks to evaluate the collision of new tiles
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*/
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CollisionGPU();
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// Timer
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{
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CollisionUpdateTimeAcu += DeltaT;
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if (CollisionUpdateTimeAcu <= 1.f / 10.f || CollisionWorkQueue.Num() > 0 || !CollisionProcess.IsFenceComplete())
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return;
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CollisionUpdateTimeAcu = 0.f;
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}
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/*
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* Gather relevant collision tiles
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* If an old tile is not relevant anymore, release it.
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* If a new location needs to be computed: allocate a tile and add its relevant computation work to the GPU work queue
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*/
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CollisionCPU();
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}
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```
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#### SetupCollisions()
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```c++
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bool AShaderWorldActor::SetupCollisions()
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{
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SW_FCT_CYCLE()
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if (!bHadGeneratorAtRebuildTime)
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return false;
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if (!Shareable_ID.IsValid() || Meshes.Num() <= 0)
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return false;
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//初始化线程安全变量
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if (!bProcessingGroundCollision.IsValid())
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bProcessingGroundCollision = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
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if (!bPreprocessingCollisionUpdate.IsValid())
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bPreprocessingCollisionUpdate = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
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if (EditRebuild)
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{
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EditRebuild.AtomicSet(false);
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rebuild = true;
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}
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if (rebuild)
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RedbuildCollisionContext = true;
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//重建相关变量初始化
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if (RedbuildCollisionContext)
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{
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if (!(*bProcessingGroundCollision.Get()) && !(*bPreprocessingCollisionUpdate.Get())
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&& CollisionProcess.IsFenceComplete()
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&& (CollisionMesh.Num() <= 0)
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&& (UsedCollisionMesh.Num() <= 0))
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{
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CollisionShareable = nullptr;
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CollisionWorkQueue.Empty();
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CollisionReadToProcess.Empty();
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RedbuildCollisionContext = false;
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}
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}
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if (RedbuildCollisionContext)
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return false;
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if (!GenerateCollision)
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return false;
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if (!CollisionShareable.IsValid())
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CollisionShareable = MakeShared<FSWCollisionManagementShareableData, ESPMode::ThreadSafe>(CollisionResolution, CollisionVerticesPerPatch);
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if ((*bProcessingGroundCollision.Get()) || (*bPreprocessingCollisionUpdate.Get()) || !CameraSet || (Meshes.Num() == 0))
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return false;
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//Let the data layer be computed before generating collisions and trying to extract material IDs
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if (bExportPhysicalMaterialID && (WorldCycle < 2))
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return false;
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if (CollisionVisibleChanged)
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{
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if (GetWorld())
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{
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for (auto& ColM : CollisionMesh)
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{
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if (auto& Mesh = ColM.Value.Mesh)
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{
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Mesh->SetMeshSectionVisible(0, CollisionVisible);
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}
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}
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}
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CollisionVisibleChanged.AtomicSet(false);
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}
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return true;
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}
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```
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### SpawnablesManagement()
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### TerrainAndSpawnablesManagement()
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## PreEditChange() / PostEditChangeProperty()
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**PreEditChange()** 主要针对以下两个变量的设置：
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- PreventReRegistration：防止重新注册。
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- RuntimePropertyEditing：实时属性修改。
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**PostEditChangeProperty()**
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里面比较关键的逻辑有：
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- EditRebuildVegetation.AtomicSet(true);
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- 在Setup()中清空Bioms数组。
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- EditRebuild.AtomicSet(true);
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- 在SetupCollisions()设置rebuild = true。
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如果RuntimePropertyEditing为true，在最后会将RuntimePropertyEditing设置为false。PreventReRegistration也会设置为false。
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## Rebuild变量
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主要出现在：
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- Setup():调用RebuildCleanup()清空所有数据。
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- SetupCollision(): RedbuildCollisionContext = true。
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- ProcessSpawnablePending():如果处于重建状态就直接返回。
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- InitiateClipMapMeshes():如果处于重建状态就直接返回。
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- FinalizeAsyncWork():如果处于重建状态就直接返回。
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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
|
||
- 作用：初始化几个GPU数据回读用的RT。
|
||
- 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。
|
||
### InitiateMaterials
|
||
作用：初始化`TArray<FClipMapMeshElement> Meshes;`的Material、`Producers`
|
||
调用顺序：BeginPlay() -> InitiateWorld() -> InitiateMaterials()
|
||
|
||
经过断点调试，会设置WorldSettings里的Material（地形Material）的HeightMap与NormalMap。
|
||
|
||
|
||
#
|
||
SWorldSubsystem->DrawMaterialToRenderTarget
|
||
|
||
|
||
# Rebuild逻辑
|
||
## 重要函数
|
||
- AShaderWorldActor::BeginPlay()
|
||
- AShaderWorldActor::Setup()（<- TerrainAndSpawnablesManagement(float& DeltaT) <- Tick()）
|
||
|
||
## Rebuild逻辑顺序
|
||
1. AShaderWorldActor::BeginPlay()
|
||
1.
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||
|
||
|
||
# Debug
|
||
1. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次
|
||
2. UpdateCollisionMeshData
|
||
3. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次
|
||
4. [[#RetrieveHeightAt]]
|
||
5. UpdateCollisionMeshData 3次
|
||
6. AShaderWorldActor::ComputeHeight_Segmented_MapForClipMap 十多次
|
||
|
||
# RetrieveHeightAt
|
||
可能存在bug待排查的：
|
||
- ShaderWorldSubsystem->LoadSampleLocationsInRT()
|
||
- ShaderWorldSubsystem->DrawMaterialToRenderTarget()
|
||
|
||
## 相关变量
|
||
- FThreadSafeBool
|
||
- bProcessingHeightRetrieval
|
||
- bProcessingHeightRetrievalRT
|
||
- MID
|
||
- GeneratorDynamicForReadBack
|
||
- UShaderWorldRT2D（`UTextureRenderTarget2D`）
|
||
- ReadRequestLocation：RTF_RG32f，初始化于`InitializeReadBackDependencies() <- InitiateWorld()`
|
||
- ReadRequestLocationHeightmap：RTF_RGBA8，初始化于`InitializeReadBackDependencies() <- InitiateWorld()`
|
||
|
||
|
||
|
||
## 代码
|
||
```c++
|
||
bool AShaderWorldActor::RetrieveHeightAt(const TArray<FVector>& Origin, const FSWHeightRetrievalDelegate& Callback)
|
||
{
|
||
if (!GeneratorDynamicForReadBack || !SWorldSubsystem)
|
||
return false;
|
||
|
||
if (!bProcessingHeightRetrieval.IsValid())
|
||
{
|
||
bProcessingHeightRetrieval = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
|
||
bProcessingHeightRetrieval->AtomicSet(false);
|
||
}
|
||
if (!bProcessingHeightRetrievalRT.IsValid())
|
||
{
|
||
bProcessingHeightRetrievalRT = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
|
||
bProcessingHeightRetrievalRT->AtomicSet(false);
|
||
}
|
||
|
||
|
||
if (!(*bProcessingHeightRetrieval.Get()) && ReadRequestLocation && ReadRequestLocationHeightmap && GeneratorDynamicForReadBack)
|
||
{
|
||
bProcessingHeightRetrieval->AtomicSet(true);
|
||
bProcessingHeightRetrievalRT->AtomicSet(false);
|
||
HeightRetrieveDelegate = Callback;
|
||
|
||
//初始化采样点数组结构体FSWShareableSamplePoints
|
||
PointsPendingReadBacks = MakeShared<FSWShareableSamplePoints, ESPMode::ThreadSafe>();
|
||
TSharedPtr<FSWShareableSamplePoints>& Samples = PointsPendingReadBacks;
|
||
|
||
FBox BoundingBoxRead(Origin);
|
||
|
||
Samples->PositionsXY.SetNum(25 * 2);
|
||
for (int i = 0; i < 25; i++)
|
||
{
|
||
if (i < Origin.Num())
|
||
{
|
||
Samples->PositionsXY[i * 2] = Origin[i].X;
|
||
Samples->PositionsXY[i * 2 + 1] = Origin[i].Y;
|
||
}
|
||
else
|
||
{
|
||
Samples->PositionsXY[i * 2] = 0.f;
|
||
Samples->PositionsXY[i * 2 + 1] = 0.f;
|
||
}
|
||
}
|
||
|
||
if (USWorldSubsystem* ShaderWorldSubsystem = SWorldSubsystem)
|
||
{
|
||
//从渲染线程
|
||
ShaderWorldSubsystem->LoadSampleLocationsInRT(ReadRequestLocation, Samples);
|
||
|
||
#if SW_COMPUTE_GENERATION
|
||
ShaderWorldSubsystem->DrawMaterialToRenderTarget(
|
||
{ false,
|
||
false,
|
||
GetWorld()->Scene,
|
||
(float)GetWorld()->TimeSeconds,
|
||
false,
|
||
true,
|
||
ReadRequestLocationHeightmap->SizeX,
|
||
10,
|
||
FVector(0.f),
|
||
true,
|
||
ReadRequestLocation,
|
||
GeneratorDynamicForReadBack,
|
||
ReadRequestLocationHeightmap
|
||
});
|
||
#else
|
||
UKismetRenderingLibrary::DrawMaterialToRenderTarget(this, ReadRequestLocationHeightmap, GeneratorDynamicForReadBack);
|
||
#endif
|
||
|
||
int32 Size_RT_Readback = ReadRequestLocationHeightmap.Get()->SizeX;
|
||
|
||
FVector Barycentre = BoundingBoxRead.GetCenter();
|
||
FVector Extent = BoundingBoxRead.GetExtent();
|
||
float gridspacing = Extent.X * 2.0 / (Size_RT_Readback - 1);
|
||
|
||
if (IsValid(BrushManager))
|
||
BrushManager->ApplyBrushStackToHeightMap(this, 0, ReadRequestLocationHeightmap.Get(), Barycentre, gridspacing, Size_RT_Readback, true, true, ReadRequestLocation.Get());
|
||
|
||
|
||
ReadBackHeightData = MakeShared<FSWColorRead, ESPMode::ThreadSafe>();
|
||
ReadBackHeightData->ReadData.SetNum(25);
|
||
|
||
ENQUEUE_RENDER_COMMAND(ReadGeoClipMapRTCmd)(
|
||
[InRT = ReadRequestLocationHeightmap, HeightData = ReadBackHeightData, Completion = bProcessingHeightRetrievalRT](FRHICommandListImmediate& RHICmdList)
|
||
{
|
||
check(IsInRenderingThread());
|
||
|
||
if (HeightData.IsValid() && InRT->GetResource())
|
||
{
|
||
FRDGBuilder GraphBuilder(RHICmdList);
|
||
|
||
TSharedPtr<FRHIGPUTextureReadback> ReadBackStaging = MakeShared<FRHIGPUTextureReadback>(TEXT("SWGPUTextureReadback"));
|
||
|
||
FRDGTextureRef RDGSourceTexture = RegisterExternalTexture(GraphBuilder, InRT->GetResource()->TextureRHI, TEXT("SWSourceTextureToReadbackTexture"));
|
||
|
||
AddEnqueueCopyPass(GraphBuilder, ReadBackStaging.Get(), RDGSourceTexture);
|
||
|
||
GraphBuilder.Execute();
|
||
|
||
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));
|
||
|
||
}
|
||
|
||
});
|
||
|
||
HeightReadBackFence.BeginFence(true);
|
||
}
|
||
|
||
return true;
|
||
}
|
||
|
||
return false;
|
||
}
|
||
```
|
||
|
||
|
||
### RequestReadBackLoad
|
||
```c++
|
||
bool USWorldSubsystem::LoadSampleLocationsInRT(UShaderWorldRT2D* LocationsRequestedRT,
|
||
TSharedPtr<FSWShareableSamplePoints>& Samples)
|
||
{
|
||
if (!RenderThreadResponded)
|
||
return false;
|
||
|
||
const SWSampleRequestComputeData ReadBackData(LocationsRequestedRT, Samples);
|
||
SWToolBox->RequestReadBackLoad(ReadBackData);
|
||
return true;
|
||
}
|
||
```
|
||
# SWShaderToolBox
|
||
## RequestReadBackLoad
|
||
```c++
|
||
void SWShaderToolBox::RequestReadBackLoad(const SWSampleRequestComputeData& Data) const
|
||
{
|
||
if (Data.CPU)
|
||
return CPUTools.RequestReadBackLoad(Data);
|
||
|
||
ENQUEUE_RENDER_COMMAND(ShaderTools_copy_rt)
|
||
([this, Data](FRHICommandListImmediate& RHICmdList)
|
||
{
|
||
if (Data.SamplesXY && Data.SamplesXY->GetResource())
|
||
RequestReadBackLoad_RT(RHICmdList,Data);
|
||
}
|
||
);
|
||
|
||
}
|
||
|
||
void SWShaderToolBox::RequestReadBackLoad_RT(FRHICommandListImmediate& RHICmdList, const SWSampleRequestComputeData& Data) const
|
||
{
|
||
if (!(Data.SamplesXY && Data.SamplesXY->GetResource()))
|
||
return;
|
||
|
||
FRDGBuilder GraphBuilder(RHICmdList);
|
||
|
||
{
|
||
RDG_EVENT_SCOPE(GraphBuilder, "ShaderWorld PositionReadBack");
|
||
RDG_GPU_STAT_SCOPE(GraphBuilder, ShaderWorldReadBack);
|
||
|
||
FIntVector GroupCount;
|
||
GroupCount.X = FMath::DivideAndRoundUp((float)Data.SamplesXY->GetResource()->GetSizeX(), (float)SW_LoadReadBackLocations_GroupSizeX);
|
||
GroupCount.Y = FMath::DivideAndRoundUp((float)Data.SamplesXY->GetResource()->GetSizeY(), (float)SW_LoadReadBackLocations_GroupSizeY);
|
||
GroupCount.Z = 1;
|
||
|
||
const FUnorderedAccessViewRHIRef RT_UAV = GraphBuilder.RHICmdList.CreateUnorderedAccessView(Data.SamplesXY->GetResource()->TextureRHI);
|
||
|
||
const FRDGBufferRef LocationRequest = CreateUploadBuffer(
|
||
GraphBuilder,
|
||
TEXT("SWLoadSampleLocations"),
|
||
sizeof(float),
|
||
Data.SamplesSource->PositionsXY.Num(),
|
||
Data.SamplesSource->PositionsXY.GetData(),
|
||
Data.SamplesSource->PositionsXY.Num() * Data.SamplesSource->PositionsXY.GetTypeSize()
|
||
);
|
||
|
||
const FRDGBufferSRVRef LocationRequestSRV = GraphBuilder.CreateSRV(FRDGBufferSRVDesc(LocationRequest, PF_R32_FLOAT));;
|
||
|
||
FLoadReadBackLocations_CS::FPermutationDomain PermutationVector;
|
||
TShaderMapRef<FLoadReadBackLocations_CS> ComputeShader(GetGlobalShaderMap(GMaxRHIFeatureLevel), PermutationVector);
|
||
|
||
FLoadReadBackLocations_CS::FParameters* PassParameters = GraphBuilder.AllocParameters<FLoadReadBackLocations_CS::FParameters>();
|
||
PassParameters->SampleDim = Data.SamplesXY->GetResource()->GetSizeX();
|
||
PassParameters->DestLocationsTex = RT_UAV;
|
||
PassParameters->SourceLocationBuffer = LocationRequestSRV;
|
||
|
||
|
||
GraphBuilder.AddPass(
|
||
RDG_EVENT_NAME("ShaderWorld LoadReadBacklocations_CS"),
|
||
PassParameters,
|
||
ERDGPassFlags::Compute |
|
||
ERDGPassFlags::NeverCull,
|
||
[PassParameters, ComputeShader, GroupCount](FRHICommandList& RHICmdList)
|
||
{
|
||
FComputeShaderUtils::Dispatch(RHICmdList, ComputeShader, *PassParameters, GroupCount);
|
||
});
|
||
|
||
}
|
||
|
||
GraphBuilder.Execute();
|
||
}
|
||
```
|
||
|
||
FLoadReadBackLocations_CS
|
||
```c++
|
||
uint SampleDim;
|
||
RWTexture2D<float2> DestLocationsTex;
|
||
Buffer<float> SourceLocationBuffer;
|
||
|
||
[numthreads(THREADGROUP_SIZEX, THREADGROUP_SIZEY, THREADGROUP_SIZEZ)]
|
||
void SampleLocationLoaderCS(uint3 ThreadId : SV_DispatchThreadID)
|
||
{
|
||
if (any(ThreadId.xy >= SampleDim.xx))
|
||
return;
|
||
|
||
uint IndexPixel = (ThreadId.x + ThreadId.y * SampleDim) * 2;
|
||
|
||
DestLocationsTex[ThreadId.xy] = float2(SourceLocationBuffer[IndexPixel],SourceLocationBuffer[IndexPixel + 1]);
|
||
}
|
||
```
|
||
|
||
|
||
# FSWDrawMaterial_SL_CS
|
||
IMPLEMENT_MATERIAL_SHADER_TYPE(template<>, FSWDrawMaterial_SL_CS, TEXT("/ShaderWorld/ShaderWorldUtilities.usf"), TEXT("DrawMaterialCS"), SF_Compute);
|
||
|
||
FMeshMaterialShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
|
||
OutEnvironment.SetDefine(TEXT("SW_DRAW_WITH_HEIGHTNORMAL"), 0);
|
||
OutEnvironment.SetDefine(TEXT("SW_DRAWMATERIAL"), 1);
|
||
OutEnvironment.SetDefine(TEXT("SW_SPECIFIC_LOCATION_DRAW"), 1);
|
||
|
||
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZEX"), bIsMobileRenderer ? SW_MobileLowSharedMemory_GroupSizeX : FComputeShaderUtils::kGolden2DGroupSize);
|
||
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZEY"), bIsMobileRenderer ? SW_MobileLowSharedMemory_GroupSizeY : FComputeShaderUtils::kGolden2DGroupSize);
|
||
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZEZ"), 1);
|
||
|
||
#
|
||
- M_Blank_HeightLayer
|
||
- MFC_WorldPositionNormal_Layer
|
||
- M_Blank_HeightLayer（未连接）
|
||
- MFC_Position_ForCache
|
||
- 其他
|
||
- MF_CacheRead_Reference_Tessellation
|
||
- MFC_CacheRead：没有其他引用
|
||
- MFC_CacheRead_Tessellationt
|
||
- MFC_CacheReadNoVertexManipulation
|
||
- MFC_ExternalCacheRead
|
||
|
||
|
||
|
||
# 植被生成逻辑
|
||
Tick() => TerrainAndSpawnablesManagement() => UpdateSpawnables() => UpdateSpawnable()
|