ScreenSpaceRayTracing.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "RenderGraph.h"
#include "SceneView.h"
#include "ScreenSpaceDenoise.h"
#include "IndirectLightRendering.h"
#include "HZB.h"
 
class FViewInfo;
class FSceneTextureParameters;
 
 
enum class ESSRQuality
{
    VisualizeSSR,
 
    Low,
    Medium,
    High,
    Epic,
 
    MAX
};
 
struct FTiledReflection
{
    FRDGBufferRef DrawIndirectParametersBuffer;
    FRDGBufferRef DispatchIndirectParametersBuffer;
    FRDGBufferRef DispatchClearIndirectParametersBuffer;
    FRDGBufferRef DispatchDownsampledIndirectParametersBuffer;
    FRDGBufferRef DispatchDownsampledClearIndirectParametersBuffer;
    FRDGBufferSRVRef TileListDataBufferSRV;
    FRDGBufferSRVRef ClearTileListDataBufferSRV;
    FRDGBufferSRVRef DownsampledTileListDataBufferSRV;
    FRDGBufferSRVRef DownsampledClearTileListDataBufferSRV;
    uint32 TileSize;
};
 
BEGIN_SHADER_PARAMETER_STRUCT(FCommonScreenSpaceRayParameters, )
    SHADER_PARAMETER_STRUCT_INCLUDE(HybridIndirectLighting::FCommonParameters, CommonDiffuseParameters)
 
    SHADER_PARAMETER(FVector4f, ColorBufferScaleBias)
    SHADER_PARAMETER(FVector2f, ReducedColorUVMax)
    SHADER_PARAMETER(FVector2f, FullResPixelOffset)
 
    SHADER_PARAMETER(float, PixelPositionToFullResPixel)
 
    SHADER_PARAMETER(int32, bRejectUncertainRays)
    SHADER_PARAMETER(int32, bTerminateCertainRay)
 
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, ColorTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, ColorTextureSampler)
 
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, AlphaTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, AlphaTextureSampler)
 
    SHADER_PARAMETER_STRUCT_INCLUDE(FHZBParameters, HZBParameters)
    SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, ViewUniformBuffer)
 
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2D<float4>, DebugOutput)
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2D<float4>, ScreenSpaceRayTracingDebugOutput)
END_SHADER_PARAMETER_STRUCT()
 
namespace ScreenSpaceRayTracing
{
 
BEGIN_SHADER_PARAMETER_STRUCT(FPrevSceneColorMip, )
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, SceneColor)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float>, SceneAlpha)
END_SHADER_PARAMETER_STRUCT()
 
bool ShouldKeepBleedFreeSceneColor(const FViewInfo& View);
 
bool ShouldRenderScreenSpaceReflections(const FViewInfo& View);
bool ShouldRenderScreenSpaceReflectionsWater(const FViewInfo& View);
 
 
void ProcessForNextFrameScreenSpaceRayTracing(
    FRDGBuilder& GraphBuilder,
    const FSceneTextureParameters& SceneTextures,
    const FRDGTextureRef CurrentSceneColor,
    const FViewInfo& View);
 
void GetSSRQualityForView(const FViewInfo& View, ESSRQuality* OutQuality, IScreenSpaceDenoiser::FReflectionsRayTracingConfig* OutRayTracingConfigs);
 
bool IsSSRTemporalPassRequired(const FViewInfo& View);
 
int32 GetSSGIRayCountPerTracingPixel();
 
 
FPrevSceneColorMip ReducePrevSceneColorMip(
    FRDGBuilder& GraphBuilder,
    const FSceneTextureParameters& SceneTextures,
    const FViewInfo& View);
 
 
void RenderScreenSpaceReflections(
    FRDGBuilder& GraphBuilder,
    const FSceneTextureParameters& SceneTextures,
    const FRDGTextureRef CurrentSceneColor,
    const FViewInfo& View,
    ESSRQuality SSRQuality,
    bool bDenoiser,
    IScreenSpaceDenoiser::FReflectionsInputs* DenoiserInputs,
    bool bSingleLayerWater = false,
    FTiledReflection* TiledScreenSpaceReflection = nullptr);
 
bool IsScreenSpaceDiffuseIndirectSupported(const FViewInfo& View);
 
IScreenSpaceDenoiser::FDiffuseIndirectInputs CastStandaloneDiffuseIndirectRays(
    FRDGBuilder& GraphBuilder, 
    const HybridIndirectLighting::FCommonParameters& CommonParameters,
    const FPrevSceneColorMip& PrevSceneColor,
    const FViewInfo& View);
 
void SetupCommonScreenSpaceRayParameters(
    FRDGBuilder& GraphBuilder,
    const FSceneTextureParameters& SceneTextures,
    const ScreenSpaceRayTracing::FPrevSceneColorMip& PrevSceneColor,
    const FViewInfo& View,
    FCommonScreenSpaceRayParameters* OutParameters);
 
FLinearColor ComputeSSRParams(const FViewInfo& View, ESSRQuality SSRQuality, bool bEnableDiscard);
 
} // namespace ScreenSpaceRayTracing