DistanceFieldAmbientOcclusion.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    DistanceFieldAmbientOcclusion.h
=============================================================================*/
 
#pragma once
 
#include "CoreTypes.h"
#include "ShaderParameterMacros.h"
 
class FDistanceFieldCulledObjectBufferParameters;
class FRDGBuffer;
class FRDGBuilder;
class FRDGTexture;
class FScene;
class FSceneTextureUniformParameters;
class FSceneViewFamily;
class FViewInfo;
struct FSceneTextures;
struct FShaderCompilerEnvironment;
using FRDGBufferRef = FRDGBuffer*;
using FRDGTextureRef = FRDGTexture*;
template <typename TUniformStruct> using TRDGUniformBufferRef = TRDGUniformBuffer<TUniformStruct>*;
 
const int32 GAODownsampleFactor = 2;
 
extern const uint32 UpdateObjectsGroupSize;
 
extern FIntPoint GetBufferSizeForAO(const FViewInfo& View);
 
class FDistanceFieldAOParameters
{
public:
    float GlobalMaxOcclusionDistance;
    float ObjectMaxOcclusionDistance;
    float Contrast;
 
    FDistanceFieldAOParameters(float InOcclusionMaxDistance, float InContrast = 0);
};
 
BEGIN_SHADER_PARAMETER_STRUCT(FTileIntersectionParameters, )
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWStructuredBuffer<FVector4f>, RWTileConeAxisAndCos)
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWStructuredBuffer<FVector4f>, RWTileConeDepthRanges)
 
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWStructuredBuffer<uint>, RWNumCulledTilesArray)
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWStructuredBuffer<uint>, RWCulledTilesStartOffsetArray)
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWBuffer<uint>, RWCulledTileDataArray)
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWBuffer<uint>, RWObjectTilesIndirectArguments)
 
    SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<FVector4f>, TileConeAxisAndCos)
    SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<FVector4f>, TileConeDepthRanges)
 
    SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<uint>, NumCulledTilesArray)
    SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<uint>, CulledTilesStartOffsetArray)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, CulledTileDataArray)
 
    SHADER_PARAMETER(FIntPoint, TileListGroupSize)
END_SHADER_PARAMETER_STRUCT()
 
static const int32 CulledTileDataStride = 2;
static const int32 ConeTraceObjectsThreadGroupSize = 64;
 
void TileIntersectionModifyCompilationEnvironment(EShaderPlatform Platform, FShaderCompilerEnvironment& OutEnvironment);
 
BEGIN_SHADER_PARAMETER_STRUCT(FAOScreenGridParameters, )
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWBuffer<uint>, RWScreenGridConeVisibility)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, ScreenGridConeVisibility)
    SHADER_PARAMETER(FIntPoint, ScreenGridConeVisibilitySize)
END_SHADER_PARAMETER_STRUCT()
 
extern void GetSpacedVectors(uint32 FrameNumber, TArray<FVector, TInlineAllocator<9> >& OutVectors);
 
inline float GetMaxAOViewDistance()
{
    extern float GAOMaxViewDistance;
    // Scene depth stored in fp16 alpha, must fade out before it runs out of range
    // The fade extends past GAOMaxViewDistance a bit
    return FMath::Min(GAOMaxViewDistance, 65000.0f);
}
 
BEGIN_SHADER_PARAMETER_STRUCT(FAOParameters, )
    SHADER_PARAMETER(float, AOObjectMaxDistance)
    SHADER_PARAMETER(float, AOStepScale)
    SHADER_PARAMETER(float, AOStepExponentScale)
    SHADER_PARAMETER(float, AOMaxViewDistance)
    SHADER_PARAMETER(float, AOGlobalMaxOcclusionDistance)
END_SHADER_PARAMETER_STRUCT()
 
BEGIN_SHADER_PARAMETER_STRUCT(FDFAOUpsampleParameters, )
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, BentNormalAOTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, BentNormalAOSampler)
    SHADER_PARAMETER(FVector2f, AOBufferBilinearUVMax)
    SHADER_PARAMETER(float, DistanceFadeScale)
    SHADER_PARAMETER(float, AOMaxViewDistance)
END_SHADER_PARAMETER_STRUCT()
 
namespace DistanceField
{
    FAOParameters SetupAOShaderParameters(const FDistanceFieldAOParameters& AOParameters);
    FDFAOUpsampleParameters SetupAOUpsampleParameters(const FViewInfo& View, FRDGTextureRef DistanceFieldAOBentNormal);
};
 
extern void TrackGPUProgress(FRHICommandListImmediate& RHICmdList, uint32 DebugId);
 
extern bool ShouldRenderDeferredDynamicSkyLight(const FScene* Scene, const FSceneViewFamily& ViewFamily);
extern bool ShouldDoReflectionEnvironment(const FScene* Scene, const FSceneViewFamily& ViewFamily);
 
extern void CullObjectsToView(FRDGBuilder& GraphBuilder, const FScene& Scene, const FViewInfo& View, const FDistanceFieldAOParameters& Parameters, FDistanceFieldCulledObjectBufferParameters& CulledObjectBuffers);
extern void BuildTileObjectLists(FRDGBuilder& GraphBuilder,
    const FScene& Scene,
    const FViewInfo& View,
    const FSceneTextures& SceneTextures,
    FRDGBufferRef ObjectIndirectArguments,
    const FDistanceFieldCulledObjectBufferParameters& CulledObjectBufferParameters,
    FTileIntersectionParameters TileIntersectionParameters,
    FRDGTextureRef DistanceFieldNormal,
    const FDistanceFieldAOParameters& Parameters);
extern FIntPoint GetTileListGroupSizeForView(const FViewInfo& View);