vault backup: 2025-06-25 23:32:48

2025-06-25 23:32:48 +08:00
parent 33539f99f0
commit a92bd7ebd9
2 changed files with 204 additions and 3 deletions
--- a/03-UnrealEngine/Rendering/RenderFeature/ShaderWorldPlugin/ShaderWorld.md
+++ b/03-UnrealEngine/Rendering/RenderFeature/ShaderWorldPlugin/ShaderWorld.md
@@ -57,10 +57,107 @@ rating: ⭐
 	- TerrainAndSpawnablesManagement()

 ### ReadbacksManagement()
-相关线程安全变量： 
- - **bProcessingHeightRetrieval**
- - **bProcessingHeightRetrievalRT**
+- ThreadSafe
+	 - bool
+		 - **bProcessingHeightRetrieval**
+		 - **bProcessingHeightRetrievalRT**
+	 - FSWShareableSamplePoints
+		 - PointsPendingReadBacks
+	 - FSWColorRead
+		 - ReadBackHeightData
+ - FRenderCommandFence
+	 - HeightReadBackFence

+```c++
+void AShaderWorldActor::ReadbacksManagement()
+{
+	if (!bProcessingHeightRetrieval.IsValid())
+		bProcessingHeightRetrieval = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
+	if (!bProcessingHeightRetrievalRT.IsValid())
+		bProcessingHeightRetrievalRT = MakeShared<FThreadSafeBool, ESPMode::ThreadSafe>();
+	
+	//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。
+	if ((*bProcessingHeightRetrieval.Get()) && (*bProcessingHeightRetrievalRT.Get()) && HeightReadBackFence.IsFenceComplete() && PointsPendingReadBacks.IsValid())
+	{
+		// ReadBackHeightData uin8 贴图数据
+		if (!ReadBackHeightData.IsValid())
+			return;
+		
+		//For now we do Compute samples on a rendertarget 5x5, therefore 25 positions evaluated per request.
+		//每次请求可以读取25个点。
+		const int NumOfVertex = 25;
+
+		PositionsOfReadBacks.Empty();
+		PositionsOfReadBacks.AddUninitialized(25);
+
+		uint8* ReadData8 = (uint8*)ReadBackHeightData->ReadData.GetData();
+			uint16 MaterialIndice = 0;
+		for (int32 k = 0; k < NumOfVertex; k++)
+		{
+			FVector3f& PositionSample = PositionsOfReadBacks[k];
+
+			if (RendererAPI == EGeoRenderingAPI::OpenGL)
+			{
+				int X = k % 5;
+				int Y = k / 5;
+
+				int index = X + Y * 5;
+
+				Y = (5 - 1) - Y;
+
+				index = X + Y * 5;
+
+				PositionSample = FVector3f(PointsPendingReadBacks->PositionsXY[2 * k], PointsPendingReadBacks->PositionsXY[2 * k + 1], GetHeightFromGPURead(&ReadData8[index * 4], MaterialIndice) / HeightScale);
+			}
+			else
+				PositionSample = FVector3f(PointsPendingReadBacks->PositionsXY[2 * k], PointsPendingReadBacks->PositionsXY[2 * k + 1], GetHeightFromGPURead(&ReadData8[k * 4], MaterialIndice) / HeightScale);
+
+		}
+
+		if(HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks))
+		{
+			//SW_LOG("HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks) PositionsOfReadBacks[0] %s",*PositionsOfReadBacks[0].ToString())
+		}
+		else
+		{
+			//SW_LOG("Fail HeightRetrieveDelegate.ExecuteIfBound(PositionsOfReadBacks)")
+		}
+
+		bProcessingHeightRetrieval->AtomicSet(false);
+		bProcessingHeightRetrievalRT->AtomicSet(false);
+	}
+
+	//For now MinMax is here
+	//处理FClipMapMeshElement的最大最小队列？
+	if (UseSegmented())
+	{
+		if(WorldHasBounds_OnRebuild)
+		{
+			FClipMapMeshElement& MeshEl = FarLOD_BoundedWorld;
+
+			if (MeshEl.MinMaxQueue.Num() > 0)
+			{
+				MeshEl.ProcessMinMaxQueue(SWorldSubsystem);
+			}
+		}
+		
+		for (FClipMapMeshElement& MeshEl : Meshes)
+		{
+
+			if (MeshEl.MinMaxQueue.Num() > 0)
+			{
+				MeshEl.ProcessMinMaxQueue(SWorldSubsystem);
+			}
+		}
+	}
+}
+```
+
+### CollisionManagement()
+
+### SpawnablesManagement()
+
+### TerrainAndSpawnablesManagement()

 ## PreEditChange() / PostEditChangeProperty()
 **PreEditChange()** 主要针对以下两个变量的设置：