LumenSceneGPUDrivenUpdate.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "RenderGraphResources.h"
#include "RHIGPUReadback.h"
 
class FScene;
class FViewInfo;
struct FLumenSceneFrameTemporaries;
 
class FLumenSceneReadback : public FRenderResource
{
public:
    FLumenSceneReadback();
    ~FLumenSceneReadback();
 
    struct FAddOp
    {
        uint32 PrimitiveGroupIndex;
        float DistanceSq;
    };
 
    struct FRemoveOp
    {
        uint32 PrimitiveGroupIndex;
    };
 
    struct FBuffersRHI
    {
        FRHIGPUBufferReadback* AddOps = nullptr;
        FRHIGPUBufferReadback* RemoveOps = nullptr;
    };
 
    struct FBuffersRDG
    {
        FRDGBufferRef AddOps = nullptr;
        FRDGBufferRef RemoveOps = nullptr;
    };
 
    FBuffersRDG GetWriteBuffers(FRDGBuilder& GraphBuilder);
    void SubmitWriteBuffers(FRDGBuilder& GraphBuilder, FBuffersRDG BuffersRDG);
 
    FBuffersRHI GetLatestReadbackBuffers();
 
    int32 GetMaxAddOps() const { return MaxAddOps;  }
    int32 GetMaxRemoveOps() const { return MaxRemoveOps; }
 
    int32 GetAddOpsBufferSizeInBytes() const { return MaxAddOps * sizeof(FAddOp); }
    int32 GetRemoveOpsBufferSizeInBytes() const { return MaxRemoveOps * sizeof(FRemoveOp);  }
 
private:
    const int32 MaxAddOps = 1024;
    const int32 MaxRemoveOps = 1024;
 
    const int32 MaxReadbackBuffers = 4;
    int32 ReadbackBuffersWriteIndex = 0;
    int32 ReadbackBuffersNumPending = 0;
    TArray<FBuffersRHI> ReadbackBuffers;
};
 
namespace LumenScene
{
    float GetCardMaxDistance(const FViewInfo& View);
    float GetCardTexelDensity();
    float GetFarFieldCardTexelDensity();
    float GetFarFieldCardMaxDistance();
    int32 GetCardMinResolution(bool bOrthographicCamera);
 
    void GPUDrivenUpdate(FRDGBuilder& GraphBuilder, const FScene* Scene, TArray<FViewInfo>& Views, const FLumenSceneFrameTemporaries& FrameTemporaries);
};