LumenReflections.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "BlueNoise.h"
#include "ShaderParameterMacros.h"
 
class FLumenCardTracingInputs;
class FLumenCardTracingParameters;
class FLumenMeshSDFGridParameters;
class FRDGBuilder;
class FScene;
class FSceneTextureParameters;
class FSceneView;
class FSceneViewFamily;
class FViewFamilyInfo;
class FViewInfo;
struct FLumenSceneFrameTemporaries;
struct FSceneTextures;
enum class EDiffuseIndirectMethod;
enum class EReflectionsMethod;
enum class ERDGPassFlags : uint16;
 
namespace LumenRadianceCache
{ 
    class FRadianceCacheInterpolationParameters; 
}
 
namespace LumenReflections
{
    BEGIN_SHADER_PARAMETER_STRUCT(FCompositeParameters, )
        SHADER_PARAMETER(float, MaxRoughnessToTrace)
        SHADER_PARAMETER(float, MaxRoughnessToTraceForFoliage)
        SHADER_PARAMETER(float, InvRoughnessFadeLength)
        SHADER_PARAMETER(float, ReflectionSmoothBias)
    END_SHADER_PARAMETER_STRUCT()
 
    void SetupCompositeParameters(const FViewInfo& View, EReflectionsMethod ReflectionsMethod, LumenReflections::FCompositeParameters& OutParameters);
    bool UseAsyncCompute(const FViewFamilyInfo& ViewFamily, EDiffuseIndirectMethod DiffuseIndirectMethod, EReflectionsMethod ReflectionsMethod);
}
 
BEGIN_SHADER_PARAMETER_STRUCT(FLumenReflectionsVisualizeTracesParameters, )
    SHADER_PARAMETER_RDG_BUFFER_UAV(RWBuffer<float4>, RWVisualizeTracesData)
    SHADER_PARAMETER(uint32, VisualizeTraceCoherency)
END_SHADER_PARAMETER_STRUCT()
 
BEGIN_SHADER_PARAMETER_STRUCT(FLumenReflectionTracingParameters, )
    SHADER_PARAMETER_STRUCT_INCLUDE(FLumenReflectionsVisualizeTracesParameters, VisualizeTracesParameters)
    SHADER_PARAMETER(FIntPoint, ReflectionDownsampleFactorXY)
    SHADER_PARAMETER(FIntPoint, ReflectionTracingViewMin)
    SHADER_PARAMETER(FIntPoint, ReflectionTracingViewSize)
    SHADER_PARAMETER(FIntPoint, ReflectionTracingBufferSize)
    SHADER_PARAMETER(FVector2f, ReflectionTracingBufferInvSize)
    SHADER_PARAMETER(float, MaxRayIntensity)
    SHADER_PARAMETER(uint32, ReflectionPass)
    SHADER_PARAMETER(uint32, UseJitter)
    SHADER_PARAMETER(uint32, UseHighResSurface)
    SHADER_PARAMETER(uint32, MaxReflectionBounces)
    SHADER_PARAMETER(uint32, MaxRefractionBounces)
    SHADER_PARAMETER(uint32, ReflectionsStateFrameIndex)
    SHADER_PARAMETER(uint32, ReflectionsStateFrameIndexMod8)
    SHADER_PARAMETER(uint32, ReflectionsRayDirectionFrameIndex)
 
    SHADER_PARAMETER(float, NearFieldMaxTraceDistance)
    SHADER_PARAMETER(float, NearFieldMaxTraceDistanceDitherScale)
    SHADER_PARAMETER(float, NearFieldSceneRadius)
    SHADER_PARAMETER(float, FarFieldMaxTraceDistance)
 
    SHADER_PARAMETER_STRUCT_INCLUDE(LumenReflections::FCompositeParameters, ReflectionsCompositeParameters)
    SHADER_PARAMETER_TEXTURE(Texture2D, PreIntegratedGF)
    SHADER_PARAMETER_SAMPLER(SamplerState, PreIntegratedGFSampler)
 
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float4>, RayBuffer)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D<uint>, RayTraceDistance)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, DownsampledDepth)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, DownsampledClosureIndex)
 
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, TraceHit)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, TraceRadiance)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, TraceMaterialId)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, TraceBookmark)
 
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2DArray<float3>, RWTraceRadiance)
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2DArray<float3>, RWTraceBackgroundVisibility)
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2DArray<float>, RWTraceHit)
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2DArray<uint>, RWTraceMaterialId)
    SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2DArray<uint2>, RWTraceBookmark)
 
    SHADER_PARAMETER_STRUCT_REF(FBlueNoise, BlueNoise)
END_SHADER_PARAMETER_STRUCT()
 
BEGIN_SHADER_PARAMETER_STRUCT(FLumenReflectionTileParameters, )
    SHADER_PARAMETER_RDG_TEXTURE(Texture2DArray<uint>, LumenTileBitmask)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, ReflectionClearTileData)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, ReflectionResolveTileData)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, ReflectionClearUnusedTracingTileData)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, ReflectionTracingTileData)
    RDG_BUFFER_ACCESS(ClearIndirectArgs, ERHIAccess::IndirectArgs)
    RDG_BUFFER_ACCESS(ResolveIndirectArgs, ERHIAccess::IndirectArgs)
    RDG_BUFFER_ACCESS(ClearUnusedTracingTileIndirectArgs, ERHIAccess::IndirectArgs)
    RDG_BUFFER_ACCESS(TracingIndirectArgs, ERHIAccess::IndirectArgs)
END_SHADER_PARAMETER_STRUCT()
 
BEGIN_SHADER_PARAMETER_STRUCT(FCompactedReflectionTraceParameters, )
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, CompactedTraceTexelAllocator)
    SHADER_PARAMETER_RDG_BUFFER_SRV(Buffer<uint>, CompactedTraceTexelData)
    RDG_BUFFER_ACCESS(IndirectArgs, ERHIAccess::IndirectArgs)
    RDG_BUFFER_ACCESS(RayTraceDispatchIndirectArgs, ERHIAccess::IndirectArgs | ERHIAccess::SRVCompute)
END_SHADER_PARAMETER_STRUCT()
 
namespace LumenReflections
{
    bool UseFarField(const FSceneViewFamily& ViewFamily);
    bool UseHitLighting(const FViewInfo& View, EDiffuseIndirectMethod DiffuseIndirectMethod);
    bool UseTranslucentRayTracing(const FViewInfo& View);
    bool IsHitLightingForceEnabled(const FViewInfo& View, EDiffuseIndirectMethod DiffuseIndirectMethod);
    bool UseSurfaceCacheFeedback();
    bool UseScreenTraces(const FViewInfo& View);
    bool UseDistantScreenTraces(const FViewInfo& View, bool bUseFarField, bool bUseRadianceCache);
    float GetDistantScreenTraceStepOffsetBias();
    bool UseRadianceCache();
    bool UseRadianceCacheSkyVisibility();
    bool UseRadianceCacheStochasticInterpolation();
 
    float GetSampleSceneColorDepthTreshold();
    float GetSampleSceneColorNormalTreshold();
    float GetFarFieldSampleSceneColorDepthTreshold();
    float GetFarFieldSampleSceneColorNormalTreshold();
 
    uint32 GetMaxReflectionBounces(const FViewInfo& View);
    uint32 GetMaxRefractionBounces(const FViewInfo& View);
 
    enum ETraceCompactionMode
    {
        Default,
        FarField,
        HitLighting,
 
        MAX
    };
 
    FCompactedReflectionTraceParameters CompactTraces(
        FRDGBuilder& GraphBuilder,
        const FViewInfo& View,
        const FLumenCardTracingParameters& TracingParameters,
        const FLumenReflectionTracingParameters& ReflectionTracingParameters,
        const FLumenReflectionTileParameters& ReflectionTileParameters,
        bool bCullByDistanceFromCamera,
        float CompactionTracingEndDistanceFromCamera,
        float CompactionMaxTraceDistance,
        ERDGPassFlags ComputePassFlags,
        ETraceCompactionMode TraceCompactionMode = ETraceCompactionMode::Default,
        bool bSortByMaterial = false);
};
 
extern void TraceReflections(
    FRDGBuilder& GraphBuilder,
    const FScene* Scene,
    const FViewInfo& View,
    const FLumenSceneFrameTemporaries& FrameTemporaries,
    bool bTraceMeshObjects,
    const FSceneTextures& SceneTextures,
    const FLumenReflectionTracingParameters& ReflectionTracingParameters, 
    const FLumenReflectionTileParameters& ReflectionTileParameters,
    const FLumenMeshSDFGridParameters& InMeshSDFGridParameters,
    bool bUseRadianceCache,
    EDiffuseIndirectMethod DiffuseIndirectMethod,
    const LumenRadianceCache::FRadianceCacheInterpolationParameters& RadianceCacheParameters,
    const FBoxSphereBounds& FirstPersonWorldSpaceRepresentationViewBounds,
    ERDGPassFlags ComputePassFlags);
 
class FLumenReflectionTracingParameters;
class FLumenReflectionTileParameters;
extern void RenderLumenHardwareRayTracingReflections(
    FRDGBuilder& GraphBuilder,
    const FSceneTextures& SceneTextures,
    const FSceneTextureParameters& SceneTextureParameters,
    const FScene* Scene,
    const FViewInfo& View,
    const FLumenCardTracingParameters& TracingParameters,
    const FLumenReflectionTracingParameters& ReflectionTracingParameters,
    const FLumenReflectionTileParameters& ReflectionTileParameters,
    float MaxTraceDistance,
    bool bUseRadianceCache,
    const LumenRadianceCache::FRadianceCacheInterpolationParameters& RadianceCacheParameters,
    bool bSampleSceneColorAtHit,
    EDiffuseIndirectMethod DiffuseIndirectMethod,
    ERDGPassFlags ComputePassFlags);