BlueRoseNote/03-UnrealEngine/Rendering/RenderingPipeline/Materials&MeshDraw/UE5.5 MeshDraw&SceneProxy探索.md

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title	date	excerpt	tags	rating
Untitled	2024-11-14 12:19:36			⭐

前言

探索思路：

• SceneProxy收集机制的改变。
• GetDynamicMeshElements的调用方式。
• 在SendRenderDynamicData_Concurrent中添加（模仿USkeletalMeshComponent::SendRenderDynamicData_Concurrent()与FDebugSkelMeshSceneProxy）

GetDynamicMeshElements

看得出主要在FDynamicMeshElementContext::GatherDynamicMeshElementsForPrimitive()中调用Primitive->Proxy->GetDynamicMeshElements()。

UE::Tasks::FTask FDynamicMeshElementContext::LaunchAsyncTask(FDynamicPrimitiveIndexQueue* PrimitiveIndexQueue, UE::Tasks::ETaskPriority TaskPriority)
{
	return Pipe.Launch(UE_SOURCE_LOCATION, [this, PrimitiveIndexQueue]
	{
		FOptionalTaskTagScope Scope(ETaskTag::EParallelRenderingThread);
		FDynamicPrimitiveIndex PrimitiveIndex;

		while (PrimitiveIndexQueue->Pop(PrimitiveIndex))
		{
			GatherDynamicMeshElementsForPrimitive(Primitives[PrimitiveIndex.Index], PrimitiveIndex.ViewMask);
		}

#if WITH_EDITOR
		while (PrimitiveIndexQueue->PopEditor(PrimitiveIndex))
		{
			GatherDynamicMeshElementsForEditorPrimitive(Primitives[PrimitiveIndex.Index], PrimitiveIndex.ViewMask);
		}
#endif
	}, TaskPriority);
}

void FDynamicMeshElementContext::GatherDynamicMeshElementsForPrimitive(FPrimitiveSceneInfo* Primitive, uint8 ViewMask)
{
	SCOPED_NAMED_EVENT(DynamicPrimitive, FColor::Magenta);

	TArray<int32, TInlineAllocator<4>> MeshBatchCountBefore;
	MeshBatchCountBefore.SetNumUninitialized(Views.Num());
	for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
	{
		MeshBatchCountBefore[ViewIndex] = MeshCollector.GetMeshBatchCount(ViewIndex);
	}

	MeshCollector.SetPrimitive(Primitive->Proxy, Primitive->DefaultDynamicHitProxyId);

	// If Custom Render Passes aren't in use, there will be only one group, which is the common case.
	if (ViewFamilyGroups.Num() == 1 || Primitive->Proxy->SinglePassGDME())
	{
		Primitive->Proxy->GetDynamicMeshElements(FirstViewFamily.AllViews, FirstViewFamily, ViewMask, MeshCollector);
	}
	else
	{
		for (FViewFamilyGroup& Group : ViewFamilyGroups)
		{
			if (uint8 MaskedViewMask = ViewMask & Group.ViewSubsetMask)
			{
				Primitive->Proxy->GetDynamicMeshElements(FirstViewFamily.AllViews, *Group.Family, MaskedViewMask, MeshCollector);
			}
		}
	}

	for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
	{
		FViewInfo& View = *Views[ViewIndex];

		if (ViewMask & (1 << ViewIndex))
		{
			FDynamicPrimitive& DynamicPrimitive = DynamicPrimitives.Emplace_GetRef();
			DynamicPrimitive.PrimitiveIndex = Primitive->GetIndex();
			DynamicPrimitive.ViewIndex = ViewIndex;
			DynamicPrimitive.StartElementIndex = MeshBatchCountBefore[ViewIndex];
			DynamicPrimitive.EndElementIndex = MeshCollector.GetMeshBatchCount(ViewIndex);
		}
	}
}

SendRenderDynamicData_Concurrent

FDebugSkelMeshSceneProxy::GetDynamicMeshElements

其他？

MeshBuilderSurface.GetMesh(GetLocalToWorld(), MatProxySurface, SDPG_Foreground, false, false, ViewIndex, Collector);