Files
UnrealEngine/Engine/Source/Runtime/Renderer/Private/VolumetricFog.cpp
2025-05-18 13:04:45 +08:00

1982 lines
94 KiB
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// Copyright Epic Games, Inc. All Rights Reserved.
/*=============================================================================
VolumetricFog.cpp
=============================================================================*/
#include "VolumetricFog.h"
#include "BasePassRendering.h"
#include "FogRendering.h"
#include "RendererPrivate.h"
#include "ScenePrivate.h"
#include "SceneProxies/SkyLightSceneProxy.h"
#include "SceneUtils.h"
#include "GlobalDistanceField.h"
#include "GlobalDistanceFieldParameters.h"
#include "DistanceFieldAmbientOcclusion.h"
#include "DistanceFieldLightingShared.h"
#include "VolumetricFogShared.h"
#include "VolumeRendering.h"
#include "ScreenRendering.h"
#include "VolumeLighting.h"
#include "PipelineStateCache.h"
#include "ShaderParameterStruct.h"
#include "Math/Halton.h"
#include "VolumetricCloudRendering.h"
#include "Lumen/LumenTranslucencyVolumeLighting.h"
#include "GenerateConservativeDepthBuffer.h"
#include "VirtualShadowMaps/VirtualShadowMapClipmap.h"
#include "ProfilingDebugging/CpuProfilerTrace.h"
#include "DataDrivenShaderPlatformInfo.h"
#include "LightFunctionAtlas.h"
#include "Math/UnrealMathUtility.h"
#include "RayTracing/RayTracing.h"
#include "Nanite/NaniteRayTracing.h"
#include "RHIResourceUtils.h"
#include "PSOPrecacheValidation.h"
using namespace LightFunctionAtlas;
int32 GVolumetricFog = 1;
FAutoConsoleVariableRef CVarVolumetricFog(
TEXT("r.VolumetricFog"),
GVolumetricFog,
TEXT("Whether to allow the volumetric fog feature."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogInjectShadowedLightsSeparately = 1;
FAutoConsoleVariableRef CVarVolumetricFogInjectShadowedLightsSeparately(
TEXT("r.VolumetricFog.InjectShadowedLightsSeparately"),
GVolumetricFogInjectShadowedLightsSeparately,
TEXT("Whether to allow the volumetric fog feature."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
float GVolumetricFogDepthDistributionScale = 32.0f;
FAutoConsoleVariableRef CVarVolumetricFogDepthDistributionScale(
TEXT("r.VolumetricFog.DepthDistributionScale"),
GVolumetricFogDepthDistributionScale,
TEXT("Scales the slice depth distribution."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogGridPixelSize = 16;
FAutoConsoleVariableRef CVarVolumetricFogGridPixelSize(
TEXT("r.VolumetricFog.GridPixelSize"),
GVolumetricFogGridPixelSize,
TEXT("XY Size of a cell in the voxel grid, in pixels."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogGridSizeZ = 64;
FAutoConsoleVariableRef CVarVolumetricFogGridSizeZ(
TEXT("r.VolumetricFog.GridSizeZ"),
GVolumetricFogGridSizeZ,
TEXT("How many Volumetric Fog cells to use in z."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogTemporalReprojection = 1;
FAutoConsoleVariableRef CVarVolumetricFogTemporalReprojection(
TEXT("r.VolumetricFog.TemporalReprojection"),
GVolumetricFogTemporalReprojection,
TEXT("Whether to use temporal reprojection on volumetric fog."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogJitter = 1;
FAutoConsoleVariableRef CVarVolumetricFogJitter(
TEXT("r.VolumetricFog.Jitter"),
GVolumetricFogJitter,
TEXT("Whether to apply jitter to each frame's volumetric fog computation, achieving temporal super sampling."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
float GVolumetricFogHistoryWeight = .9f;
FAutoConsoleVariableRef CVarVolumetricFogHistoryWeight(
TEXT("r.VolumetricFog.HistoryWeight"),
GVolumetricFogHistoryWeight,
TEXT("How much the history value should be weighted each frame. This is a tradeoff between visible jittering and responsiveness."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogHistoryMissSupersampleCount = 4;
FAutoConsoleVariableRef CVarVolumetricFogHistoryMissSupersampleCount(
TEXT("r.VolumetricFog.HistoryMissSupersampleCount"),
GVolumetricFogHistoryMissSupersampleCount,
TEXT("Number of lighting samples to compute for voxels whose history value is not available.\n")
TEXT("This reduces noise when panning or on camera cuts, but introduces a variable cost to volumetric fog computation. Valid range [1, 16]."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
float GInverseSquaredLightDistanceBiasScale = 1.0f;
FAutoConsoleVariableRef CVarInverseSquaredLightDistanceBiasScale(
TEXT("r.VolumetricFog.InverseSquaredLightDistanceBiasScale"),
GInverseSquaredLightDistanceBiasScale,
TEXT("Scales the amount added to the inverse squared falloff denominator. This effectively removes the spike from inverse squared falloff that causes extreme aliasing."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogEmissive = 1;
FAutoConsoleVariableRef CVarVolumetricFogEmissive(
TEXT("r.VolumetricFog.Emissive"),
GVolumetricFogEmissive,
TEXT("Whether to allow the volumetric fog emissive component."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int32 GVolumetricFogRectLightTexture = 0;
FAutoConsoleVariableRef CVarVolumetricRectLightTexture(
TEXT("r.VolumetricFog.RectLightTexture"),
GVolumetricFogRectLightTexture,
TEXT("Whether to allow the volumetric fog to use rect light source texture."),
ECVF_RenderThreadSafe
);
int32 GVolumetricFogConservativeDepth = 1;
FAutoConsoleVariableRef CVarVolumetricFogConservativeDepth(
TEXT("r.VolumetricFog.ConservativeDepth"),
GVolumetricFogConservativeDepth,
TEXT("[Experimental] Whether to allow the volumetric to use conservative depth to accelerate computations."),
ECVF_Scalability | ECVF_RenderThreadSafe
);
int GVolumetricFogInjectRaytracedLights = 0;
FAutoConsoleVariableRef CVarVolumetricInjectRaytracedLights(
TEXT("r.VolumetricFog.InjectRaytracedLights"),
GVolumetricFogInjectRaytracedLights,
TEXT("Whether lights with ray traced shadows are injected into volumetric fog"),
ECVF_Scalability | ECVF_RenderThreadSafe
);
float GLightScatteringSampleJitterMultiplier = 0;
FAutoConsoleVariableRef CVarLightScatteringSampleJitterMultiplier(
TEXT("r.VolumetricFog.LightScatteringSampleJitterMultiplier"),
GLightScatteringSampleJitterMultiplier,
TEXT("Multiplier for random offset value used to jitter each world sample position when generating the 3D fog volume. Enable/disable with r.VolumetricFog.Jitter"),
ECVF_RenderThreadSafe | ECVF_Scalability
);
static TAutoConsoleVariable<float> CVarVolumetricFogLightSoftFading(
TEXT("r.VolumetricFog.LightSoftFading"),
0,
TEXT("Enabled when >0, controls the soft fading of spot and rect light edges in order to make them appear smoother, resulting in less flickering. A value of 1 is a good starting point and it means that fading will be applied over the size of 1 froxel on the screen."),
ECVF_RenderThreadSafe | ECVF_Scalability);
static const TCHAR* VolumetricFogGlobalPSOCollectorName = TEXT("VolumetricFogGlobalPSOCollector");
int32 GetVolumetricFogGridPixelSize()
{
return FMath::Max(1, GVolumetricFogGridPixelSize);
}
static int32 GetVolumetricFogGridSizeZ()
{
return FMath::Max(1, GVolumetricFogGridSizeZ);
}
static FIntPoint GetVolumetricFogTextureResourceRes(const FViewInfo& View)
{
// Allocate texture using scene render targets size so we do not reallocate every frame when dynamic resolution is used in order to avoid resources allocation hitches.
FIntPoint BufferSize = View.GetSceneTexturesConfig().Extent;
// Make sure the buffer size has some minimum resolution to make sure everything is always valid.
BufferSize.X = FMath::Max(1, BufferSize.X);
BufferSize.Y = FMath::Max(1, BufferSize.Y);
return BufferSize;
}
IMPLEMENT_GLOBAL_SHADER_PARAMETER_STRUCT(FVolumetricFogGlobalData, "VolumetricFog");
DECLARE_GPU_STAT(VolumetricFog);
FVolumetricFogGlobalData::FVolumetricFogGlobalData()
{}
FVector3f VolumetricFogTemporalRandom(uint32 FrameNumber)
{
// Center of the voxel
FVector3f RandomOffsetValue(.5f, .5f, .5f);
if (GVolumetricFogJitter && GVolumetricFogTemporalReprojection)
{
RandomOffsetValue = FVector3f(Halton(FrameNumber & 1023, 2), Halton(FrameNumber & 1023, 3), Halton(FrameNumber & 1023, 5));
}
return RandomOffsetValue;
}
float GetVolumetricFogLightSoftFading()
{
return FMath::Max(0.0f, CVarVolumetricFogLightSoftFading.GetValueOnAnyThread());
}
void SetupVolumetricFogIntegrationParameters(
FVolumetricFogIntegrationParameters& Out,
FViewInfo& View,
const FVolumetricFogIntegrationParameterData& IntegrationData)
{
Out.VolumetricFog = View.VolumetricFogResources.VolumetricFogGlobalData;
FMatrix44f UnjitteredInvTranslatedViewProjectionMatrix = FMatrix44f(View.ViewMatrices.ComputeInvProjectionNoAAMatrix() * View.ViewMatrices.GetTranslatedViewMatrix().GetTransposed());
Out.UnjitteredClipToTranslatedWorld = UnjitteredInvTranslatedViewProjectionMatrix;
FMatrix TranslatedWorldToWorld = FTranslationMatrix(-View.ViewMatrices.GetPreViewTranslation());
FMatrix44f UnjitteredTranslatedViewProjectionMatrix = FMatrix44f(TranslatedWorldToWorld * View.PrevViewInfo.ViewMatrices.GetViewMatrix() * View.PrevViewInfo.ViewMatrices.ComputeProjectionNoAAMatrix());
Out.UnjitteredPrevTranslatedWorldToClip = UnjitteredTranslatedViewProjectionMatrix;
int32 OffsetCount = IntegrationData.FrameJitterOffsetValues.Num();
for (int32 i = 0; i < OffsetCount; ++i)
{
Out.FrameJitterOffsets[i] = IntegrationData.FrameJitterOffsetValues.GetData()[i];
}
extern float GVolumetricFogHistoryWeight;
Out.HistoryWeight = IntegrationData.bTemporalHistoryIsValid ? GVolumetricFogHistoryWeight : 0.0f;
extern int32 GVolumetricFogHistoryMissSupersampleCount;
Out.HistoryMissSuperSampleCount = FMath::Clamp(GVolumetricFogHistoryMissSupersampleCount, 1, 16);
}
static const uint32 VolumetricFogGridInjectionGroupSize = 4;
namespace
{
class FPermutationUseEmissive : SHADER_PERMUTATION_BOOL("USE_EMISSIVE");
class FPermutationLocalFogVolume : SHADER_PERMUTATION_BOOL("USE_LOCAL_FOG_VOLUMES");
}
class FVolumetricFogMaterialSetupCS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FVolumetricFogMaterialSetupCS);
SHADER_USE_PARAMETER_STRUCT(FVolumetricFogMaterialSetupCS, FGlobalShader);
using FPermutationDomain = TShaderPermutationDomain<FPermutationUseEmissive, FPermutationLocalFogVolume>;
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER(FLinearColor, GlobalAlbedo)
SHADER_PARAMETER(FLinearColor, GlobalEmissive)
SHADER_PARAMETER(float, GlobalExtinctionScale)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FFogUniformParameters, Fog)
SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, View)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
SHADER_PARAMETER_STRUCT(FLocalFogVolumeUniformParameters, LFV)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture3D<float4>, RWVBufferA)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture3D<float4>, RWVBufferB)
END_SHADER_PARAMETER_STRUCT()
public:
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZE"), VolumetricFogGridInjectionGroupSize);
}
};
IMPLEMENT_GLOBAL_SHADER(FVolumetricFogMaterialSetupCS, "/Engine/Private/VolumetricFog.usf", "MaterialSetupCS", SF_Compute);
/** Vertex shader used to write to a range of slices of a 3d volume texture. */
class FWriteToBoundingSphereVS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FWriteToBoundingSphereVS);
SHADER_USE_PARAMETER_STRUCT(FWriteToBoundingSphereVS, FGlobalShader);
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
SHADER_PARAMETER(FMatrix44f, ViewToVolumeClip)
SHADER_PARAMETER(FVector2f, ClipRatio)
SHADER_PARAMETER(FVector4f, ViewSpaceBoundingSphere)
SHADER_PARAMETER(int32, MinZ)
END_SHADER_PARAMETER_STRUCT()
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.CompilerFlags.Add(CFLAG_VertexToGeometryShader);
}
};
IMPLEMENT_GLOBAL_SHADER(FWriteToBoundingSphereVS, "/Engine/Private/VolumetricFog.usf", "WriteToBoundingSphereVS", SF_Vertex);
BEGIN_SHADER_PARAMETER_STRUCT(FInjectShadowedLocalLightCommonParameters, )
SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, ViewUniformBuffer)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FDeferredLightUniformStruct, DeferredLight)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FLightFunctionAtlasGlobalParameters, LightFunctionAtlas)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, WhiteDummyTexture)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
SHADER_PARAMETER(float, PhaseG)
SHADER_PARAMETER(float, InverseSquaredLightDistanceBiasScale)
SHADER_PARAMETER(uint32, LightFunctionAtlasLightIndex)
END_SHADER_PARAMETER_STRUCT()
static bool SetupInjectShadowedLocalLightCommonParameters(
FRDGBuilder& GraphBuilder,
FViewInfo& View,
const FVolumetricFogIntegrationParameterData& IntegrationData,
const FExponentialHeightFogSceneInfo& FogInfo,
const FLightSceneInfo* LightSceneInfo,
FInjectShadowedLocalLightCommonParameters& OutCommonParameters)
{
// We also bind the default light function texture because when we are out of atlas tile, we fallback to use a white light function so we need the RHI to be created
OutCommonParameters.WhiteDummyTexture = GSystemTextures.GetWhiteDummy(GraphBuilder);
SetupVolumetricFogIntegrationParameters(OutCommonParameters.VolumetricFogParameters, View, IntegrationData);
OutCommonParameters.ViewUniformBuffer = View.ViewUniformBuffer;
OutCommonParameters.PhaseG = FogInfo.VolumetricFogScatteringDistribution;
OutCommonParameters.InverseSquaredLightDistanceBiasScale = GInverseSquaredLightDistanceBiasScale;
FDeferredLightUniformStruct* DeferredLightStruct = GraphBuilder.AllocParameters<FDeferredLightUniformStruct>();
*DeferredLightStruct = GetDeferredLightParameters(View, *LightSceneInfo);
OutCommonParameters.DeferredLight = GraphBuilder.CreateUniformBuffer(DeferredLightStruct);
return true;
}
/** Shader that adds direct lighting contribution from the given light to the current volume lighting cascade. */
class FInjectShadowedLocalLightPS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FInjectShadowedLocalLightPS);
SHADER_USE_PARAMETER_STRUCT(FInjectShadowedLocalLightPS, FGlobalShader);
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_INCLUDE(FInjectShadowedLocalLightCommonParameters, Common)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumeShadowingShaderParameters, VolumeShadowingShaderParameters)
SHADER_PARAMETER_STRUCT_INCLUDE(FVirtualShadowMapSamplingParameters, VirtualShadowMapSamplingParameters)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, ConservativeDepthTexture)
SHADER_PARAMETER(uint32, UseConservativeDepthTexture)
SHADER_PARAMETER(int32, VirtualShadowMapId)
RENDER_TARGET_BINDING_SLOTS()
END_SHADER_PARAMETER_STRUCT()
class FDynamicallyShadowed : SHADER_PERMUTATION_BOOL("DYNAMICALLY_SHADOWED");
class FTemporalReprojection : SHADER_PERMUTATION_BOOL("USE_TEMPORAL_REPROJECTION");
class FSampleLightFunctionAtlas : SHADER_PERMUTATION_BOOL("USE_LIGHT_FUNCTION_ATLAS");
class FEnableShadows : SHADER_PERMUTATION_BOOL("ENABLE_SHADOW_COMPUTATION");
class FVirtualShadowMap : SHADER_PERMUTATION_BOOL("VIRTUAL_SHADOW_MAP");
class FRectLightTexture : SHADER_PERMUTATION_BOOL("USE_RECT_LIGHT_TEXTURE");
class FLightSoftFading : SHADER_PERMUTATION_BOOL("USE_LIGHT_SOFT_FADING");
using FPermutationDomain = TShaderPermutationDomain<
FDynamicallyShadowed,
FTemporalReprojection,
FSampleLightFunctionAtlas,
FEnableShadows,
FVirtualShadowMap,
FRectLightTexture,
FLightSoftFading>;
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
FVirtualShadowMapArray::SetShaderDefines(OutEnvironment);
}
static EShaderPermutationPrecacheRequest ShouldPrecachePermutation(const FGlobalShaderPermutationParameters& Parameters)
{
FPermutationDomain PermutationVector(Parameters.PermutationId);
if (PermutationVector.Get<FLightSoftFading>() && GetVolumetricFogLightSoftFading() <= 0.0f)
{
return EShaderPermutationPrecacheRequest::NotUsed;
}
return FGlobalShader::ShouldPrecachePermutation(Parameters);
}
};
IMPLEMENT_GLOBAL_SHADER(FInjectShadowedLocalLightPS, "/Engine/Private/VolumetricFog.usf", "InjectShadowedLocalLightPS", SF_Pixel);
#if RHI_RAYTRACING
class FInjectShadowedLocalLightRGS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FInjectShadowedLocalLightRGS);
SHADER_USE_ROOT_PARAMETER_STRUCT(FInjectShadowedLocalLightRGS, FGlobalShader);
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_INCLUDE(FInjectShadowedLocalLightCommonParameters, Common)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FSceneUniformParameters, Scene)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FNaniteRayTracingUniformParameters, NaniteRayTracing)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture3D, OutVolumeTexture)
SHADER_PARAMETER_RDG_BUFFER_SRV(RaytracingAccelerationStructure, TLAS)
SHADER_PARAMETER(int32, FirstSlice)
END_SHADER_PARAMETER_STRUCT()
class FTemporalReprojection : SHADER_PERMUTATION_BOOL("USE_TEMPORAL_REPROJECTION");
class FSampleLightFunctionAtlas : SHADER_PERMUTATION_BOOL("USE_LIGHT_FUNCTION_ATLAS");
class FRectLightTexture : SHADER_PERMUTATION_BOOL("USE_RECT_LIGHT_TEXTURE");
class FLightSoftFading : SHADER_PERMUTATION_BOOL("USE_LIGHT_SOFT_FADING");
using FPermutationDomain = TShaderPermutationDomain<
FTemporalReprojection,
FSampleLightFunctionAtlas,
FRectLightTexture,
FLightSoftFading>;
static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& Parameters)
{
return ShouldCompileRayTracingShadersForProject(Parameters.Platform);
}
static ERayTracingPayloadType GetRayTracingPayloadType(const int32 PermutationId)
{
return ERayTracingPayloadType::RayTracingMaterial;
}
static const FShaderBindingLayout* GetShaderBindingLayout(const FShaderPermutationParameters& Parameters)
{
return RayTracing::GetShaderBindingLayout(Parameters.Platform);
}
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.SetDefine(TEXT("USE_RAYTRACED_SHADOWS"), TEXT("1"));
// Only ray traced shadowed lights use this RGS
OutEnvironment.SetDefine(TEXT("ENABLE_SHADOW_COMPUTATION"), TEXT("1"));
}
};
IMPLEMENT_GLOBAL_SHADER(FInjectShadowedLocalLightRGS, "/Engine/Private/VolumetricFog.usf", "InjectShadowedLocalLightRGS", SF_RayGen);
class FRayTraceDirectionalLightVolumeShadowMapRGS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FRayTraceDirectionalLightVolumeShadowMapRGS);
SHADER_USE_ROOT_PARAMETER_STRUCT(FRayTraceDirectionalLightVolumeShadowMapRGS, FGlobalShader);
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, View)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FSceneUniformParameters, Scene)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FNaniteRayTracingUniformParameters, NaniteRayTracing)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FForwardLightUniformParameters, ForwardLightStruct)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture3D, OutShadowVolumeTexture)
SHADER_PARAMETER_RDG_BUFFER_SRV(RaytracingAccelerationStructure, TLAS)
SHADER_PARAMETER(float, LightScatteringSampleJitterMultiplier)
END_SHADER_PARAMETER_STRUCT()
static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& Parameters)
{
return ShouldCompileRayTracingShadersForProject(Parameters.Platform);
}
static ERayTracingPayloadType GetRayTracingPayloadType(const int32 PermutationId)
{
return ERayTracingPayloadType::RayTracingMaterial;
}
static const FShaderBindingLayout* GetShaderBindingLayout(const FShaderPermutationParameters& Parameters)
{
return RayTracing::GetShaderBindingLayout(Parameters.Platform);
}
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.SetDefine(TEXT("USE_RAYTRACED_SHADOWS"), TEXT("1"));
}
};
IMPLEMENT_GLOBAL_SHADER(FRayTraceDirectionalLightVolumeShadowMapRGS, "/Engine/Private/VolumetricFog.usf", "InjectShadowedDirectionalLightRGS", SF_RayGen);
bool LightHasRayTracedShadows(const FLightSceneInfo* LightSceneInfo, const FSceneViewFamily& ViewFamily);
static void RenderRaytracedDirectionalShadowVolume(
FRDGBuilder& GraphBuilder,
FViewInfo& View,
const FScene& Scene,
const FVolumetricFogIntegrationParameterData& IntegrationData,
FRDGTextureRef& OutRaytracedShadowsVolume)
{
const bool bUseRaytracedShadows = IsRayTracingEnabled(Scene.GetShaderPlatform())
&& View.IsRayTracingAllowedForView()
&& GRHISupportsRayTracing
&& GRHISupportsRayTracingShaders
&& GVolumetricFogInjectRaytracedLights;
if (!bUseRaytracedShadows)
{
return;
}
// Following how RenderLightFunctionForVolumetricFog is selecting the main directional light, even though we could support all of them.
const FLightSceneProxy* SelectedForwardDirectionalLightProxy = View.ForwardLightingResources.SelectedForwardDirectionalLightProxy;
const FLightSceneInfo* DirectionalLightSceneInfo = nullptr;
for (const FLightSceneInfo* LightSceneInfo : Scene.DirectionalLights)
{
if (LightSceneInfo->ShouldRenderLightViewIndependent()
&& LightSceneInfo->ShouldRenderLight(View, true)
&& LightHasRayTracedShadows(LightSceneInfo, *View.Family)
&& LightSceneInfo->Proxy == SelectedForwardDirectionalLightProxy)
{
DirectionalLightSceneInfo = LightSceneInfo;
break;
}
}
if (DirectionalLightSceneInfo)
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::RaytraceDirLightShadow");
int32 VolumetricFogGridPixelSize;
const FIntVector VolumetricFogResourceGridSize = GetVolumetricFogResourceGridSize(View, VolumetricFogGridPixelSize);
FRDGTextureDesc RaytracedShadowsVolumeDesc(FRDGTextureDesc::Create3D(
VolumetricFogResourceGridSize,
PF_R16F,
FClearValueBinding::Black,
TexCreate_ShaderResource | TexCreate_UAV | TexCreate_ReduceMemoryWithTilingMode | TexCreate_3DTiling));
OutRaytracedShadowsVolume = GraphBuilder.CreateTexture(RaytracedShadowsVolumeDesc, TEXT("VolumetricFog.RaytracedShadowVolume"));
FRayTraceDirectionalLightVolumeShadowMapRGS::FParameters* PassParameters = GraphBuilder.AllocParameters<FRayTraceDirectionalLightVolumeShadowMapRGS::FParameters>();
PassParameters->OutShadowVolumeTexture = GraphBuilder.CreateUAV(OutRaytracedShadowsVolume);
PassParameters->TLAS = View.GetRayTracingSceneLayerViewChecked(ERayTracingSceneLayer::Base);
PassParameters->View = View.ViewUniformBuffer;
PassParameters->Scene = GetSceneUniformBufferRef(GraphBuilder, View);
PassParameters->NaniteRayTracing = Nanite::GRayTracingManager.GetUniformBuffer();
PassParameters->ForwardLightStruct = View.ForwardLightingResources.ForwardLightUniformBuffer;
PassParameters->LightScatteringSampleJitterMultiplier = GVolumetricFogJitter ? GLightScatteringSampleJitterMultiplier : 0;
SetupVolumetricFogIntegrationParameters(PassParameters->VolumetricFogParameters, View, IntegrationData);
TShaderRef<FRayTraceDirectionalLightVolumeShadowMapRGS> RayGenerationShader = View.ShaderMap->GetShader<FRayTraceDirectionalLightVolumeShadowMapRGS>();
ClearUnusedGraphResources(RayGenerationShader, PassParameters);
const uint32 DispatchSize = VolumetricFogResourceGridSize.X * VolumetricFogResourceGridSize.Y * VolumetricFogResourceGridSize.Z;
GraphBuilder.AddPass(
RDG_EVENT_NAME("RayTracedShadowedDirectionalLight"),
PassParameters,
ERDGPassFlags::Compute,
[&View, RayGenerationShader, PassParameters, DispatchSize](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
FRHIBatchedShaderParameters& GlobalResources = RHICmdList.GetScratchShaderParameters();
SetShaderParameters(GlobalResources, RayGenerationShader, *PassParameters);
FRHIUniformBuffer* SceneUniformBuffer = PassParameters->Scene->GetRHI();
FRHIUniformBuffer* NaniteRayTracingUniformBuffer = PassParameters->NaniteRayTracing->GetRHI();
TOptional<FScopedUniformBufferStaticBindings> StaticUniformBufferScope = RayTracing::BindStaticUniformBufferBindings(View, SceneUniformBuffer, NaniteRayTracingUniformBuffer, RHICmdList);
RHICmdList.RayTraceDispatch(View.MaterialRayTracingData.PipelineState, RayGenerationShader.GetRayTracingShader(), View.MaterialRayTracingData.ShaderBindingTable, GlobalResources, DispatchSize, 1);
}
);
}
}
void FDeferredShadingSceneRenderer::PrepareRayTracingVolumetricFogShadows(const FViewInfo& View, const FScene& Scene, TArray<FRHIRayTracingShader*>& OutRayGenShaders)
{
const bool bEnabled = View.bHasRayTracingShadows && View.IsRayTracingAllowedForView() && ::ShouldRenderVolumetricFog(&Scene, *View.Family) && GVolumetricFogInjectRaytracedLights;
if (!bEnabled)
{
return;
}
for (int32 TemporalReprojection = 0; TemporalReprojection < 2; ++TemporalReprojection)
{
for (int32 UseLightFunction = 0; UseLightFunction < 2; ++UseLightFunction)
{
for (int32 UseRectLightTexture = 0; UseRectLightTexture < 2; ++UseRectLightTexture)
{
FInjectShadowedLocalLightRGS::FPermutationDomain PermutationVector;
PermutationVector.Set<FInjectShadowedLocalLightRGS::FTemporalReprojection>((bool)TemporalReprojection);
PermutationVector.Set<FInjectShadowedLocalLightRGS::FSampleLightFunctionAtlas>((bool)UseLightFunction);
PermutationVector.Set<FInjectShadowedLocalLightRGS::FRectLightTexture>((bool)UseRectLightTexture);
TShaderMapRef<FInjectShadowedLocalLightRGS> RayGenerationShader(View.ShaderMap, PermutationVector);
OutRayGenShaders.Add(RayGenerationShader.GetRayTracingShader());
}
}
}
{
TShaderMapRef<FRayTraceDirectionalLightVolumeShadowMapRGS> RayGenerationShader(View.ShaderMap);
OutRayGenShaders.Add(RayGenerationShader.GetRayTracingShader());
}
}
#endif // RHI_RAYTRACING
const FProjectedShadowInfo* GetShadowForInjectionIntoVolumetricFog(const FVisibleLightInfo& VisibleLightInfo)
{
for (int32 ShadowIndex = 0; ShadowIndex < VisibleLightInfo.ShadowsToProject.Num(); ShadowIndex++)
{
FProjectedShadowInfo* ProjectedShadowInfo = VisibleLightInfo.ShadowsToProject[ShadowIndex];
if (ProjectedShadowInfo->bAllocated
&& ProjectedShadowInfo->bWholeSceneShadow
&& !ProjectedShadowInfo->bRayTracedDistanceField)
{
return ProjectedShadowInfo;
}
}
return nullptr;
}
bool LightHasRayTracedShadows(const FLightSceneInfo* LightSceneInfo, const FSceneViewFamily& ViewFamily)
{
return GetLightOcclusionType(*LightSceneInfo->Proxy, ViewFamily) == FLightOcclusionType::Raytraced && GVolumetricFogInjectRaytracedLights;
}
bool LightNeedsSeparateInjectionIntoVolumetricFogForOpaqueShadow(const FViewInfo& View, const FLightSceneInfo* LightSceneInfo, const FVisibleLightInfo& VisibleLightInfo, const FScene& InScene)
{
#if RHI_RAYTRACING
bool bTestRayTracedShadows = View.bHasRayTracingShadows && View.IsRayTracingAllowedForView();
#else
bool bTestRayTracedShadows = false;
#endif
const FLightSceneProxy* LightProxy = LightSceneInfo->Proxy;
if (GVolumetricFogInjectShadowedLightsSeparately
&& (LightProxy->GetLightType() == LightType_Point || LightProxy->GetLightType() == LightType_Spot || LightProxy->GetLightType() == LightType_Rect)
&& !LightProxy->HasStaticLighting()
&& LightProxy->CastsDynamicShadow()
&& LightProxy->CastsVolumetricShadow())
{
const FStaticShadowDepthMap* StaticShadowDepthMap = LightProxy->GetStaticShadowDepthMap();
const bool bStaticallyShadowed = LightSceneInfo->IsPrecomputedLightingValid() && StaticShadowDepthMap && StaticShadowDepthMap->Data && StaticShadowDepthMap->TextureRHI;
const bool bHasVirtualShadowMap = VisibleLightInfo.GetVirtualShadowMapId( &View ) != INDEX_NONE;
const bool bHasRayTracedShadows = (bTestRayTracedShadows) ? LightHasRayTracedShadows(LightSceneInfo, *View.Family) : false;
return GetShadowForInjectionIntoVolumetricFog(VisibleLightInfo) != NULL || bStaticallyShadowed || bHasVirtualShadowMap || bHasRayTracedShadows;
}
return false;
}
FIntPoint CalculateVolumetricFogBoundsForLight(const FSphere& LightBounds, const FViewInfo& View, FIntVector VolumetricFogGridSize, FVector GridZParams)
{
FIntPoint VolumeZBounds;
FVector ViewSpaceLightBoundsOrigin = View.ViewMatrices.GetViewMatrix().TransformPosition(LightBounds.Center);
int32 FurthestSliceIndexUnclamped = ComputeZSliceFromDepth(ViewSpaceLightBoundsOrigin.Z + LightBounds.W, GridZParams);
int32 ClosestSliceIndexUnclamped = ComputeZSliceFromDepth(ViewSpaceLightBoundsOrigin.Z - LightBounds.W, GridZParams);
VolumeZBounds.X = FMath::Clamp(ClosestSliceIndexUnclamped, 0, VolumetricFogGridSize.Z - 1);
VolumeZBounds.Y = FMath::Clamp(FurthestSliceIndexUnclamped, 0, VolumetricFogGridSize.Z - 1);
return VolumeZBounds;
}
static bool OverrideDirectionalLightInScatteringUsingHeightFog(const FViewInfo& View, const FExponentialHeightFogSceneInfo& FogInfo)
{
return FogInfo.bOverrideLightColorsWithFogInscatteringColors && View.bUseDirectionalInscattering && !View.FogInscatteringColorCubemap;
}
static bool OverrideSkyLightInScatteringUsingHeightFog(const FViewInfo& View, const FExponentialHeightFogSceneInfo& FogInfo)
{
return FogInfo.bOverrideLightColorsWithFogInscatteringColors;
}
/** */
class FCircleRasterizeVertexBuffer : public FVertexBuffer
{
public:
virtual void InitRHI(FRHICommandListBase& RHICmdList) override
{
const FRHIBufferCreateDesc CreateDesc =
FRHIBufferCreateDesc::CreateVertex<FScreenVertex>(TEXT("FCircleRasterizeVertexBuffer"), NumVertices)
.AddUsage(EBufferUsageFlags::Static)
.SetInitialState(ERHIAccess::VertexOrIndexBuffer)
.SetInitActionInitializer();
TRHIBufferInitializer<FScreenVertex> DestVertex = RHICmdList.CreateBufferInitializer(CreateDesc);
const int32 NumSegments = NumVertices - 1;
const float RadiansPerRingSegment = PI / (float)NumSegments;
// Boost the effective radius so that the edges of the circle approximation lie on the circle, instead of the vertices
const float RadiusScale = 1.0f / FMath::Cos(RadiansPerRingSegment);
for (int32 VertexIndex = 0; VertexIndex < NumVertices; VertexIndex++)
{
float Angle = VertexIndex / (float)(NumVertices - 1) * 2 * PI;
// WriteToBoundingSphereVS only uses UV
DestVertex[VertexIndex].Position = FVector2f::ZeroVector;
DestVertex[VertexIndex].UV = FVector2f(RadiusScale * FMath::Cos(Angle) * .5f + .5f, RadiusScale * FMath::Sin(Angle) * .5f + .5f);
}
VertexBufferRHI = DestVertex.Finalize();
}
static int32 NumVertices;
};
int32 FCircleRasterizeVertexBuffer::NumVertices = 8;
TGlobalResource<FCircleRasterizeVertexBuffer> GCircleRasterizeVertexBuffer;
/** */
class FCircleRasterizeIndexBuffer : public FIndexBuffer
{
public:
virtual void InitRHI(FRHICommandListBase& RHICmdList) override
{
const int32 NumTriangles = FCircleRasterizeVertexBuffer::NumVertices - 2;
TArray<uint16> Indices;
Indices.Empty(NumTriangles * 3);
for (int32 TriangleIndex = 0; TriangleIndex < NumTriangles; TriangleIndex++)
{
int32 LeadingVertexIndex = TriangleIndex + 2;
Indices.Add(0);
Indices.Add(LeadingVertexIndex - 1);
Indices.Add(LeadingVertexIndex);
}
// Create index buffer. Fill buffer with initial data upon creation
IndexBufferRHI = UE::RHIResourceUtils::CreateIndexBufferFromArray(RHICmdList, TEXT("FCircleRasterizeIndexBuffer"), EBufferUsageFlags::Static, MakeConstArrayView(Indices));
}
};
TGlobalResource<FCircleRasterizeIndexBuffer> GCircleRasterizeIndexBuffer;
void SetupInjectShadowedLocalLightPSO(
FRHIVertexShader* VertexShader,
FRHIGeometryShader* GeometryShader,
FRHIPixelShader* PixelShader,
FGraphicsPipelineStateInitializer& GraphicsPSOInit)
{
GraphicsPSOInit.RasterizerState = TStaticRasterizerState<FM_Solid, CM_None>::GetRHI();
GraphicsPSOInit.DepthStencilState = TStaticDepthStencilState<false, CF_Always>::GetRHI();
// Accumulate the contribution of multiple lights
GraphicsPSOInit.BlendState = TStaticBlendState<CW_RGBA, BO_Add, BF_One, BF_One, BO_Add, BF_Zero, BF_One>::GetRHI();
GraphicsPSOInit.BoundShaderState.VertexDeclarationRHI = GScreenVertexDeclaration.VertexDeclarationRHI;
GraphicsPSOInit.BoundShaderState.VertexShaderRHI = VertexShader;
GraphicsPSOInit.BoundShaderState.SetGeometryShader(GeometryShader);
GraphicsPSOInit.BoundShaderState.PixelShaderRHI = PixelShader;
GraphicsPSOInit.PrimitiveType = PT_TriangleList;
}
void FSceneRenderer::RenderLocalLightsForVolumetricFog(
FRDGBuilder& GraphBuilder,
FViewInfo& View, int32 ViewIndex,
bool bUseTemporalReprojection,
const FVolumetricFogIntegrationParameterData& IntegrationData,
const FExponentialHeightFogSceneInfo& FogInfo,
FIntVector VolumetricFogViewGridSize,
FVector GridZParams,
const FRDGTextureDesc& VolumeDesc,
FRDGTextureRef ConservativeDepthTexture,
TConstArrayView<const FLightSceneInfo*> LightsToInject,
TConstArrayView<const FLightSceneInfo*> RayTracedLightsToInject,
FRDGTexture*& OutLocalShadowedLightScattering)
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::LocalLights");
// Setup the light function atlas
const bool bUseLightFunctionAtlas = LightFunctionAtlas::IsEnabled(View, ELightFunctionAtlasSystem::VolumetricFog);
TRDGUniformBufferRef<FLightFunctionAtlasGlobalParameters> LightFunctionAtlasGlobalParameters = LightFunctionAtlas::BindGlobalParameters(GraphBuilder, View);
// Now voxelise all the light we have just gathered.
bool bClearExecuted = false;
if (LightsToInject.Num() > 0)
{
for (int32 LightIndex = 0; LightIndex < LightsToInject.Num(); LightIndex++)
{
const FLightSceneInfo* LightSceneInfo = LightsToInject[LightIndex];
const FVisibleLightInfo& VisibleLightInfo = VisibleLightInfos[LightSceneInfo->Id];
const FSphere LightBounds = LightSceneInfo->Proxy->GetBoundingSphere();
const FIntPoint VolumeZBounds = CalculateVolumetricFogBoundsForLight(LightBounds, View, VolumetricFogViewGridSize, GridZParams);
if (VolumeZBounds.X < VolumeZBounds.Y)
{
bool bIsShadowed = LightNeedsSeparateInjectionIntoVolumetricFogForOpaqueShadow(View, LightSceneInfo, VisibleLightInfo, *Scene);
bool bUsesRectLightTexture = GVolumetricFogRectLightTexture && LightSceneInfo->Proxy->HasSourceTexture();
int32 VirtualShadowMapId = VisibleLightInfo.GetVirtualShadowMapId(&View);
const bool bUseVSM = bIsShadowed && VirtualShadowMapArray.IsAllocated() && VirtualShadowMapId != INDEX_NONE;
FInjectShadowedLocalLightPS::FParameters* PassParameters = GraphBuilder.AllocParameters<FInjectShadowedLocalLightPS::FParameters>();
// Light function parameters
bool bValid = SetupInjectShadowedLocalLightCommonParameters(
GraphBuilder,
View,
IntegrationData,
FogInfo,
LightSceneInfo,
PassParameters->Common
);
PassParameters->Common.LightFunctionAtlas = LightFunctionAtlasGlobalParameters;
if (!bValid)
{
continue;
}
const bool bHasTextureBeenCreated = bClearExecuted == true;
OutLocalShadowedLightScattering = bHasTextureBeenCreated ? OutLocalShadowedLightScattering : GraphBuilder.CreateTexture(VolumeDesc, TEXT("VolumetricFog.LocalShadowedLightScattering"));
PassParameters->RenderTargets[0] = FRenderTargetBinding(OutLocalShadowedLightScattering, bClearExecuted ? ERenderTargetLoadAction::ELoad : ERenderTargetLoadAction::EClear);
bClearExecuted = true;
PassParameters->VirtualShadowMapSamplingParameters = VirtualShadowMapArray.GetSamplingParameters(GraphBuilder, ViewIndex);
PassParameters->ConservativeDepthTexture = ConservativeDepthTexture;
PassParameters->UseConservativeDepthTexture = GVolumetricFogConservativeDepth > 0 ? 1 : 0;
PassParameters->VirtualShadowMapId = VirtualShadowMapId;
const FProjectedShadowInfo* ProjectedShadowInfo = GetShadowForInjectionIntoVolumetricFog(VisibleLightInfo);
const bool bDynamicallyShadowed = ProjectedShadowInfo != NULL;
GetVolumeShadowingShaderParameters(GraphBuilder, View, LightSceneInfo, ProjectedShadowInfo, PassParameters->VolumeShadowingShaderParameters);
FInjectShadowedLocalLightPS::FPermutationDomain PermutationVector;
PermutationVector.Set< FInjectShadowedLocalLightPS::FDynamicallyShadowed >(bDynamicallyShadowed);
PermutationVector.Set< FInjectShadowedLocalLightPS::FTemporalReprojection >(bUseTemporalReprojection);
PermutationVector.Set< FInjectShadowedLocalLightPS::FSampleLightFunctionAtlas >(bUseLightFunctionAtlas);
PermutationVector.Set< FInjectShadowedLocalLightPS::FEnableShadows >(bIsShadowed);
PermutationVector.Set< FInjectShadowedLocalLightPS::FVirtualShadowMap >(bUseVSM);
PermutationVector.Set< FInjectShadowedLocalLightPS::FRectLightTexture >(bUsesRectLightTexture);
PermutationVector.Set< FInjectShadowedLocalLightPS::FLightSoftFading >(GetVolumetricFogLightSoftFading() > 0.0f);
auto VertexShader = View.ShaderMap->GetShader< FWriteToBoundingSphereVS >();
TOptionalShaderMapRef<FWriteToSliceGS> GeometryShader(View.ShaderMap);
auto PixelShader = View.ShaderMap->GetShader< FInjectShadowedLocalLightPS >(PermutationVector);
ClearUnusedGraphResources(PixelShader, PassParameters);
// We execute one pass per light: this is because RDG resources needs to be gathrered before and reference in the PassParameters.
// Not many lights cast shadow so that is acceptable (LightRendering is doing the same things).
// If light shadow maps woud be in a common resources (atlas, texture array, bindless) we could have a single pass for all the lights.
// NOTE: light functions are already in an atlas so they are not a problem.
GraphBuilder.AddPass(
RDG_EVENT_NAME("ShadowedLights"),
PassParameters,
ERDGPassFlags::Raster,
[PassParameters, &View, this, VertexShader, GeometryShader, PixelShader, VolumeZBounds, LightBounds, VolumetricFogViewGridSize](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
FGraphicsPipelineStateInitializer GraphicsPSOInit;
RHICmdList.ApplyCachedRenderTargets(GraphicsPSOInit);
SetupInjectShadowedLocalLightPSO(VertexShader.GetVertexShader(), GeometryShader.GetGeometryShader(), PixelShader.GetPixelShader(), GraphicsPSOInit);
#if PSO_PRECACHING_VALIDATE
if (PSOCollectorStats::IsFullPrecachingValidationEnabled())
{
static const int32 GlobalPSOCollectorIndex = FGlobalPSOCollectorManager::GetIndex(VolumetricFogGlobalPSOCollectorName);
PSOCollectorStats::CheckGlobalGraphicsPipelineStateInCache(GraphicsPSOInit, GlobalPSOCollectorIndex);
}
#endif // PSO_PRECACHING_VALIDATE
SetGraphicsPipelineState(RHICmdList, GraphicsPSOInit, 0);
SetShaderParameters(RHICmdList, PixelShader, PixelShader.GetPixelShader(), *PassParameters);
FWriteToBoundingSphereVS::FParameters VSPassParameters;
VSPassParameters.MinZ = VolumeZBounds.X;
VSPassParameters.ViewSpaceBoundingSphere = FVector4f(FVector4f(View.ViewMatrices.GetViewMatrix().TransformPosition(LightBounds.Center)), LightBounds.W); // LWC_TODO: precision loss
VSPassParameters.ViewToVolumeClip = FMatrix44f(View.ViewMatrices.ComputeProjectionNoAAMatrix()); // LWC_TODO: Precision loss?
VSPassParameters.ClipRatio = GetVolumetricFogFroxelToScreenSVPosRatio(View);
VSPassParameters.VolumetricFogParameters = PassParameters->Common.VolumetricFogParameters;
SetShaderParameters(RHICmdList, VertexShader, VertexShader.GetVertexShader(), VSPassParameters);
if (GeometryShader.IsValid())
{
SetShaderParametersLegacyGS(RHICmdList, GeometryShader, VolumeZBounds.X);
}
// Set the sub region of the texture according to the current dynamic resolution scale.
RHICmdList.SetViewport(0.0f, 0.0f, 0.0f, VolumetricFogViewGridSize.X, VolumetricFogViewGridSize.Y, 1.0f);
RHICmdList.SetStreamSource(0, GCircleRasterizeVertexBuffer.VertexBufferRHI, 0);
const int32 NumInstances = VolumeZBounds.Y - VolumeZBounds.X;
const int32 NumTriangles = FCircleRasterizeVertexBuffer::NumVertices - 2;
RHICmdList.DrawIndexedPrimitive(GCircleRasterizeIndexBuffer.IndexBufferRHI, 0, 0, FCircleRasterizeVertexBuffer::NumVertices, 0, NumTriangles, NumInstances);
});
}
}
}
#if RHI_RAYTRACING
if (RayTracedLightsToInject.Num() > 0)
{
if (!bClearExecuted)
{
OutLocalShadowedLightScattering = GraphBuilder.CreateTexture(VolumeDesc, TEXT("VolumetricFog.LocalShadowedLightScattering"));
AddClearUAVPass(GraphBuilder, GraphBuilder.CreateUAV(OutLocalShadowedLightScattering), 0.0f);
bClearExecuted = true;
}
for (int32 LightIndex = 0; LightIndex < RayTracedLightsToInject.Num(); LightIndex++)
{
const FLightSceneInfo* LightSceneInfo = RayTracedLightsToInject[LightIndex];
const FSphere LightBounds = LightSceneInfo->Proxy->GetBoundingSphere();
const FIntPoint VolumeZBounds = CalculateVolumetricFogBoundsForLight(LightBounds, View, VolumetricFogViewGridSize, GridZParams);
if (VolumeZBounds.X < VolumeZBounds.Y)
{
bool bUsesRectLightTexture = GVolumetricFogRectLightTexture && LightSceneInfo->Proxy->HasSourceTexture();
FInjectShadowedLocalLightRGS::FParameters* PassParameters = GraphBuilder.AllocParameters<FInjectShadowedLocalLightRGS::FParameters>();
PassParameters->OutVolumeTexture = GraphBuilder.CreateUAV(OutLocalShadowedLightScattering);
PassParameters->TLAS = View.GetRayTracingSceneLayerViewChecked(ERayTracingSceneLayer::Base);
PassParameters->FirstSlice = VolumeZBounds.X;
PassParameters->Scene = GetSceneUniformBufferRef(GraphBuilder);
PassParameters->NaniteRayTracing = Nanite::GRayTracingManager.GetUniformBuffer();
bool bValid = SetupInjectShadowedLocalLightCommonParameters(
GraphBuilder,
View,
IntegrationData,
FogInfo,
LightSceneInfo,
PassParameters->Common
);
PassParameters->Common.LightFunctionAtlas = LightFunctionAtlasGlobalParameters;
if (!bValid)
{
continue;
}
FInjectShadowedLocalLightRGS::FPermutationDomain PermutationVector;
PermutationVector.Set< FInjectShadowedLocalLightRGS::FTemporalReprojection >(bUseTemporalReprojection);
PermutationVector.Set< FInjectShadowedLocalLightRGS::FSampleLightFunctionAtlas >(bUseLightFunctionAtlas);
PermutationVector.Set< FInjectShadowedLocalLightRGS::FRectLightTexture >(bUsesRectLightTexture);
PermutationVector.Set< FInjectShadowedLocalLightRGS::FLightSoftFading >(GetVolumetricFogLightSoftFading() > 0.0f);
TShaderMapRef<FInjectShadowedLocalLightRGS> RayGenerationShader(GetGlobalShaderMap(FeatureLevel), PermutationVector);
ClearUnusedGraphResources(RayGenerationShader, PassParameters);
// TODO: better bounds
const int32 NumSlices = VolumeZBounds.Y - VolumeZBounds.X;
const uint32 DispatchSize = VolumeDesc.Extent.X * VolumeDesc.Extent.Y * NumSlices;
GraphBuilder.AddPass(
RDG_EVENT_NAME("RayTracedShadowedLights"),
PassParameters,
ERDGPassFlags::Compute,
[this, &View, RayGenerationShader, PassParameters, DispatchSize](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
FRHIBatchedShaderParameters& GlobalResources = RHICmdList.GetScratchShaderParameters();
SetShaderParameters(GlobalResources, RayGenerationShader, *PassParameters);
FRHIUniformBuffer* SceneUniformBuffer = PassParameters->Scene->GetRHI();
FRHIUniformBuffer* NaniteRayTracingUniformBuffer = PassParameters->NaniteRayTracing->GetRHI();
TOptional<FScopedUniformBufferStaticBindings> StaticUniformBufferScope = RayTracing::BindStaticUniformBufferBindings(View, SceneUniformBuffer, NaniteRayTracingUniformBuffer, RHICmdList);
RHICmdList.RayTraceDispatch(View.MaterialRayTracingData.PipelineState, RayGenerationShader.GetRayTracingShader(), View.MaterialRayTracingData.ShaderBindingTable, GlobalResources, DispatchSize, 1);
}
);
}
}
}
#endif
}
IMPLEMENT_GLOBAL_SHADER_PARAMETER_STRUCT(FLumenTranslucencyLightingUniforms, "LumenGIVolumeStruct");
class FVolumetricFogLightScatteringCS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FVolumetricFogLightScatteringCS);
SHADER_USE_PARAMETER_STRUCT(FVolumetricFogLightScatteringCS, FGlobalShader);
class FTemporalReprojection : SHADER_PERMUTATION_BOOL("USE_TEMPORAL_REPROJECTION");
class FDistanceFieldSkyOcclusion : SHADER_PERMUTATION_BOOL("DISTANCE_FIELD_SKY_OCCLUSION");
class FSuperSampleCount : SHADER_PERMUTATION_SPARSE_INT("HISTORY_MISS_SUPER_SAMPLE_COUNT", 1, 4, 8, 16);
class FLumenGI : SHADER_PERMUTATION_BOOL("LUMEN_GI");
class FVirtualShadowMap : SHADER_PERMUTATION_BOOL("VIRTUAL_SHADOW_MAP");
class FRaytracedShadowsVolume : SHADER_PERMUTATION_BOOL("USE_RAYTRACED_SHADOWS_VOLUME");
class FSampleLightFunctionAtlas : SHADER_PERMUTATION_BOOL("USE_LIGHT_FUNCTION_ATLAS");
class FMegaLights : SHADER_PERMUTATION_BOOL("USE_MEGA_LIGHTS");
class FLightSoftFading : SHADER_PERMUTATION_BOOL("USE_LIGHT_SOFT_FADING");
using FPermutationDomain = TShaderPermutationDomain<
FSuperSampleCount,
FTemporalReprojection,
FDistanceFieldSkyOcclusion,
FLumenGI,
FVirtualShadowMap,
FRaytracedShadowsVolume,
FSampleLightFunctionAtlas,
FMegaLights,
FLightSoftFading>;
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, View)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FForwardLightUniformParameters, ForwardLightStruct)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FFogUniformParameters, Fog)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FLightFunctionAtlasGlobalParameters, LightFunctionAtlas)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
SHADER_PARAMETER_RDG_TEXTURE(Texture3D, MegaLightsVolume)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, VBufferA)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, VBufferB)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, LocalShadowedLightScattering)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, DirectionalLightLightFunctionTexture)
SHADER_PARAMETER_SAMPLER(SamplerState, DirectionalLightLightFunctionSampler)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, CloudShadowmapTexture)
SHADER_PARAMETER_SAMPLER(SamplerState, CloudShadowmapSampler)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, ConservativeDepthTexture)
SHADER_PARAMETER_RDG_TEXTURE(Texture2D, PrevConservativeDepthTexture)
SHADER_PARAMETER_RDG_TEXTURE(Texture3D, LightScatteringHistory)
SHADER_PARAMETER_RDG_TEXTURE_SRV(Texture3D, RaytracedShadowsVolume)
SHADER_PARAMETER_SAMPLER(SamplerState, LightScatteringHistorySampler)
SHADER_PARAMETER_RDG_UNIFORM_BUFFER(FLumenTranslucencyLightingUniforms, LumenGIVolumeStruct)
SHADER_PARAMETER_STRUCT_INCLUDE(FVirtualShadowMapSamplingParameters, VirtualShadowMapSamplingParameters)
SHADER_PARAMETER_STRUCT_INCLUDE(FAOParameters, AOParameters)
SHADER_PARAMETER_STRUCT_INCLUDE(FGlobalDistanceFieldParameters2, GlobalDistanceFieldParameters)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture2D, RWLightScattering)
SHADER_PARAMETER(uint32, SampleSkyLightDiffuseEnvMap)
SHADER_PARAMETER(FMatrix44f, DirectionalLightFunctionTranslatedWorldToShadow)
SHADER_PARAMETER(FMatrix44f, CloudShadowmapTranslatedWorldToLightClipMatrix)
SHADER_PARAMETER(FVector3f, MobileDirectionalLightColor)
SHADER_PARAMETER(FVector3f, MobileDirectionalLightDirection)
SHADER_PARAMETER(FVector2f, PrevConservativeDepthTextureSize)
SHADER_PARAMETER(FVector2f, UseHeightFogColors)
SHADER_PARAMETER(FVector2f, LightScatteringHistoryPreExposureAndInv)
SHADER_PARAMETER(float, StaticLightingScatteringIntensity)
SHADER_PARAMETER(float, SkyLightUseStaticShadowing)
SHADER_PARAMETER(float, PhaseG)
SHADER_PARAMETER(float, InverseSquaredLightDistanceBiasScale)
SHADER_PARAMETER(float, LightScatteringSampleJitterMultiplier)
SHADER_PARAMETER(float, CloudShadowmapFarDepthKm)
SHADER_PARAMETER(float, CloudShadowmapStrength)
SHADER_PARAMETER(float, UseDirectionalLightShadowing)
SHADER_PARAMETER(uint32, UseConservativeDepthTexture)
SHADER_PARAMETER(uint32, UseEmissive)
SHADER_PARAMETER(uint32, MobileHasDirectionalLight)
SHADER_PARAMETER(uint32, DirectionalApplyLightFunctionFromAtlas)
SHADER_PARAMETER(uint32, DirectionalLightFunctionAtlasLightIndex)
END_SHADER_PARAMETER_STRUCT()
static FIntVector GetGroupSize()
{
return FIntVector(4, 4, 4);
}
static int32 GetSuperSampleCount(int32 InSampleCount)
{
if (InSampleCount <= 1)
{
return 1;
}
else if (InSampleCount <= 4)
{
return 4;
}
else if (InSampleCount <= 8)
{
return 8;
}
return 16;
}
static FPermutationDomain RemapPermutation(FPermutationDomain PermutationVector, EShaderPlatform ShaderPlatform)
{
if (IsMobilePlatform(ShaderPlatform))
{
PermutationVector.Set<FDistanceFieldSkyOcclusion>(false);
PermutationVector.Set<FTemporalReprojection>(false);
PermutationVector.Set<FSampleLightFunctionAtlas>(false);
PermutationVector.Set<FMegaLights>(false);
}
if (!FDataDrivenShaderPlatformInfo::GetSupportsLumenGI(ShaderPlatform))
{
PermutationVector.Set<FLumenGI>(false);
}
if (!ShouldCompileRayTracingShadersForProject(ShaderPlatform))
{
PermutationVector.Set<FRaytracedShadowsVolume>(false);
}
if (!MegaLights::ShouldCompileShaders(ShaderPlatform))
{
PermutationVector.Set<FMegaLights>(false);
}
if (PermutationVector.Get<FLumenGI>())
{
PermutationVector.Set<FDistanceFieldSkyOcclusion>(false);
}
return PermutationVector;
}
static bool ShouldCompilePermutation(const FGlobalShaderPermutationParameters& Parameters)
{
FPermutationDomain PermutationVector(Parameters.PermutationId);
if (RemapPermutation(PermutationVector, Parameters.Platform) != PermutationVector)
{
return false;
}
return true;
}
static EShaderPermutationPrecacheRequest ShouldPrecachePermutation(const FShaderPermutationParameters& Parameters)
{
const bool bSupportsLumenGI = FDataDrivenShaderPlatformInfo::GetSupportsLumenGI(Parameters.Platform);
FPermutationDomain PermutationVector = RemapPermutation(FPermutationDomain(Parameters.PermutationId), Parameters.Platform);
if (PermutationVector.Get<FLumenGI>() && !bSupportsLumenGI)
{
return EShaderPermutationPrecacheRequest::NotUsed;
}
// We cannot skip the precaching of FDistanceFieldSkyOcclusion because the runtime logic to enable it is complex and not only based on project support & cvar values.
// It involves checking lumen support and the presence of GetLumenTranslucencyGIVolume().Texture0 which might not be present if no translucent are present.
if (PermutationVector.Get<FTemporalReprojection>() && (GVolumetricFogTemporalReprojection == 0))
{
return EShaderPermutationPrecacheRequest::NotUsed;
}
const int32 SuperSampleCount = FVolumetricFogLightScatteringCS::GetSuperSampleCount(GVolumetricFogHistoryMissSupersampleCount);
if (PermutationVector.Get<FSuperSampleCount>() != SuperSampleCount)
{
return EShaderPermutationPrecacheRequest::NotUsed;
}
return EShaderPermutationPrecacheRequest::Precached;
}
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZE_X"), GetGroupSize().X);
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZE_Y"), GetGroupSize().Y);
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZE_Z"), GetGroupSize().Z);
FForwardLightingParameters::ModifyCompilationEnvironment(Parameters.Platform, OutEnvironment);
FVirtualShadowMapArray::SetShaderDefines(OutEnvironment);
}
};
IMPLEMENT_GLOBAL_SHADER(FVolumetricFogLightScatteringCS, "/Engine/Private/VolumetricFog.usf", "LightScatteringCS", SF_Compute);
uint32 VolumetricFogIntegrationGroupSize = 8;
class FVolumetricFogFinalIntegrationCS : public FGlobalShader
{
DECLARE_GLOBAL_SHADER(FVolumetricFogFinalIntegrationCS);
SHADER_USE_PARAMETER_STRUCT(FVolumetricFogFinalIntegrationCS, FGlobalShader);
BEGIN_SHADER_PARAMETER_STRUCT(FParameters, )
SHADER_PARAMETER_STRUCT_REF(FViewUniformShaderParameters, ViewUniformBuffer)
SHADER_PARAMETER_RDG_TEXTURE(Texture3D<float4>, LightScattering)
SHADER_PARAMETER_RDG_TEXTURE_UAV(RWTexture3D<float4>, RWIntegratedLightScattering)
SHADER_PARAMETER(float, VolumetricFogNearFadeInDistanceInv)
SHADER_PARAMETER_STRUCT_INCLUDE(FVolumetricFogIntegrationParameters, VolumetricFogParameters)
END_SHADER_PARAMETER_STRUCT()
static void ModifyCompilationEnvironment(const FGlobalShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment)
{
FGlobalShader::ModifyCompilationEnvironment(Parameters, OutEnvironment);
OutEnvironment.SetDefine(TEXT("THREADGROUP_SIZE"), VolumetricFogIntegrationGroupSize);
}
};
IMPLEMENT_GLOBAL_SHADER(FVolumetricFogFinalIntegrationCS, "/Engine/Private/VolumetricFog.usf", "FinalIntegrationCS", SF_Compute);
bool DoesPlatformSupportVolumetricFogVoxelization(const FStaticShaderPlatform Platform)
{
// Substrate requires HLSL2021 which must be cross-compiled for D3D11 and Vulkan to be consumed by FXC compiler.
// This cross-compilation toolchain does not support geometry shaders.
const bool bCanRHICompileGeometryShaders =!Substrate::IsSubstrateEnabled() || GetMaxSupportedFeatureLevel(Platform) > ERHIFeatureLevel::SM5;
return !IsMobilePlatform(Platform) && bCanRHICompileGeometryShaders;
}
bool ShouldRenderVolumetricFog(const FScene* Scene, const FSceneViewFamily& ViewFamily)
{
return ShouldRenderFog(ViewFamily)
&& Scene
&& GVolumetricFog
&& ViewFamily.EngineShowFlags.VolumetricFog
&& Scene->ExponentialFogs.Num() > 0
&& Scene->ExponentialFogs[0].bEnableVolumetricFog
&& Scene->ExponentialFogs[0].VolumetricFogDistance > 0;
}
FVector GetVolumetricFogGridZParams(float VolumetricFogStartDistance, float NearPlane, float FarPlane, int32 GridSizeZ)
{
// Don't spend lots of resolution right in front of the near plane
NearPlane = FMath::Max(NearPlane, double(VolumetricFogStartDistance));
return CalculateGridZParams(NearPlane, FarPlane, GVolumetricFogDepthDistributionScale, GridSizeZ);
}
static FIntVector GetVolumetricFogGridSize(const FIntPoint& TargetResolution, int32& OutVolumetricFogGridPixelSize)
{
extern int32 GLightGridSizeZ;
FIntPoint VolumetricFogGridSizeXY;
int32 VolumetricFogGridPixelSize = GetVolumetricFogGridPixelSize();
VolumetricFogGridSizeXY = FIntPoint::DivideAndRoundUp(TargetResolution, VolumetricFogGridPixelSize);
if(VolumetricFogGridSizeXY.X > GMaxVolumeTextureDimensions || VolumetricFogGridSizeXY.Y > GMaxVolumeTextureDimensions) //clamp to max volume texture dimensions. only happens for extreme resolutions (~8x2k)
{
float PixelSizeX = (float)TargetResolution.X / GMaxVolumeTextureDimensions;
float PixelSizeY = (float)TargetResolution.Y / GMaxVolumeTextureDimensions;
VolumetricFogGridPixelSize = FMath::Max(FMath::CeilToInt(PixelSizeX), FMath::CeilToInt(PixelSizeY));
VolumetricFogGridSizeXY = FIntPoint::DivideAndRoundUp(TargetResolution, VolumetricFogGridPixelSize);
}
OutVolumetricFogGridPixelSize = VolumetricFogGridPixelSize;
return FIntVector(VolumetricFogGridSizeXY.X, VolumetricFogGridSizeXY.Y, GetVolumetricFogGridSizeZ());
}
FIntVector GetVolumetricFogResourceGridSize(const FViewInfo& View, int32& OutVolumetricFogGridPixelSize)
{
return GetVolumetricFogGridSize(GetVolumetricFogTextureResourceRes(View), OutVolumetricFogGridPixelSize);
}
FIntVector GetVolumetricFogViewGridSize(const FViewInfo& View, int32& OutVolumetricFogGridPixelSize)
{
return GetVolumetricFogGridSize(View.ViewRect.Size(), OutVolumetricFogGridPixelSize);
}
FVector2f GetVolumetricFogUVMaxForSampling(const FVector2f& ViewRectSize, FIntVector VolumetricFogResourceGridSize, int32 VolumetricFogResourceGridPixelSize)
{
float ViewRectSizeXSafe = FMath::DivideAndRoundUp<int32>(int32(ViewRectSize.X), VolumetricFogResourceGridPixelSize) * VolumetricFogResourceGridPixelSize - (VolumetricFogResourceGridPixelSize / 2 + 1);
float ViewRectSizeYSafe = FMath::DivideAndRoundUp<int32>(int32(ViewRectSize.Y), VolumetricFogResourceGridPixelSize) * VolumetricFogResourceGridPixelSize - (VolumetricFogResourceGridPixelSize / 2 + 1);
return FVector2f(ViewRectSizeXSafe, ViewRectSizeYSafe) / (FVector2f(VolumetricFogResourceGridSize.X, VolumetricFogResourceGridSize.Y) * VolumetricFogResourceGridPixelSize);
}
FVector2f GetVolumetricFogPrevUVMaxForTemporalBlend(const FVector2f& ViewRectSize, FIntVector VolumetricFogResourceGridSize, int32 VolumetricFogResourceGridPixelSize)
{
float ViewRectSizeXSafe = FMath::DivideAndRoundUp<int32>(int32(ViewRectSize.X), VolumetricFogResourceGridPixelSize) * VolumetricFogResourceGridPixelSize;
float ViewRectSizeYSafe = FMath::DivideAndRoundUp<int32>(int32(ViewRectSize.Y), VolumetricFogResourceGridPixelSize) * VolumetricFogResourceGridPixelSize;
return FVector2f(ViewRectSizeXSafe, ViewRectSizeYSafe) / (FVector2f(VolumetricFogResourceGridSize.X, VolumetricFogResourceGridSize.Y) * VolumetricFogResourceGridPixelSize);
}
FVector2f GetVolumetricFogFroxelToScreenSVPosRatio(const FViewInfo& View)
{
const FIntPoint ViewRectSize = View.ViewRect.Size();
// Calculate how much the Fog froxel volume "overhangs" the actual view frustum to the right and bottom.
// This needs to be applied on SVPos because froxel pixel size (see r.VolumetricFog.GridPixelSize) does not align perfectly with view rect.
int32 VolumetricFogGridPixelSize;
const FIntVector VolumetricFogGridSize = GetVolumetricFogViewGridSize(View, VolumetricFogGridPixelSize);
const FVector2f FogPhysicalSize = FVector2f(VolumetricFogGridSize.X, VolumetricFogGridSize.Y) * VolumetricFogGridPixelSize;
const FVector2f ClipRatio = FogPhysicalSize / FVector2f(ViewRectSize);
return ClipRatio;
}
FRDGTextureDesc GetVolumetricFogRDGTextureDesc(const FIntVector& VolumetricFogResourceGridSize)
{
return FRDGTextureDesc::Create3D(
VolumetricFogResourceGridSize,
PF_FloatRGBA,
FClearValueBinding::Black,
TexCreate_ShaderResource | TexCreate_RenderTargetable | TexCreate_UAV | TexCreate_ReduceMemoryWithTilingMode | TexCreate_3DTiling);
}
void SetupVolumetricFogGlobalData(const FViewInfo& View, FVolumetricFogGlobalData& Parameters)
{
const FScene* Scene = (FScene*)View.Family->Scene;
const FExponentialHeightFogSceneInfo& FogInfo = Scene->ExponentialFogs[0];
int32 VolumetricFogGridPixelSize;
const FIntVector VolumetricFogViewGridSize = GetVolumetricFogViewGridSize(View, VolumetricFogGridPixelSize);
const FIntVector VolumetricFogResourceGridSize = GetVolumetricFogResourceGridSize(View, VolumetricFogGridPixelSize);
Parameters.ViewGridSizeInt = VolumetricFogViewGridSize;
Parameters.ViewGridSize = FVector3f(VolumetricFogViewGridSize);
Parameters.ResourceGridSizeInt = VolumetricFogResourceGridSize;
Parameters.ResourceGridSize = FVector3f(VolumetricFogResourceGridSize);
FVector ZParams = GetVolumetricFogGridZParams(FogInfo.VolumetricFogStartDistance, View.NearClippingDistance, FogInfo.VolumetricFogDistance, VolumetricFogResourceGridSize.Z);
Parameters.GridZParams = (FVector3f)ZParams;
Parameters.SVPosToVolumeUV = FVector2f::UnitVector / (FVector2f(VolumetricFogResourceGridSize.X, VolumetricFogResourceGridSize.Y) * VolumetricFogGridPixelSize);
Parameters.FogGridToPixelXY = FIntPoint(VolumetricFogGridPixelSize, VolumetricFogGridPixelSize);
Parameters.MaxDistance = FogInfo.VolumetricFogDistance;
Parameters.HeightFogInscatteringColor = View.ExponentialFogColor;
Parameters.HeightFogDirectionalLightInscatteringColor = FVector3f::ZeroVector;
if (OverrideDirectionalLightInScatteringUsingHeightFog(View, FogInfo))
{
Parameters.HeightFogDirectionalLightInscatteringColor = FVector3f(View.DirectionalInscatteringColor);
}
Parameters.LightSoftFading = GetVolumetricFogLightSoftFading();
}
void FViewInfo::SetupVolumetricFogUniformBufferParameters(FViewUniformShaderParameters& ViewUniformShaderParameters) const
{
const FScene* Scene = (const FScene*)Family->Scene;
if (ShouldRenderVolumetricFog(Scene, *Family))
{
const FExponentialHeightFogSceneInfo& FogInfo = Scene->ExponentialFogs[0];
int32 VolumetricFogResourceGridPixelSize;
int32 VolumetricFogViewGridPixelSize;
const FIntVector VolumetricFogResourceGridSize = GetVolumetricFogResourceGridSize(*this, VolumetricFogResourceGridPixelSize);
const FIntVector VolumetricFogViewGridSize = GetVolumetricFogViewGridSize(*this, VolumetricFogViewGridPixelSize);
ViewUniformShaderParameters.VolumetricFogInvGridSize = FVector3f(1.0f / VolumetricFogResourceGridSize.X, 1.0f / VolumetricFogResourceGridSize.Y, 1.0f / VolumetricFogResourceGridSize.Z);
const FVector ZParams = GetVolumetricFogGridZParams(FogInfo.VolumetricFogStartDistance, NearClippingDistance, FogInfo.VolumetricFogDistance, VolumetricFogResourceGridSize.Z);
ViewUniformShaderParameters.VolumetricFogGridZParams = (FVector3f)ZParams;
ViewUniformShaderParameters.VolumetricFogSVPosToVolumeUV = FVector2f::UnitVector / (FVector2f(VolumetricFogResourceGridSize.X, VolumetricFogResourceGridSize.Y) * VolumetricFogResourceGridPixelSize);
ViewUniformShaderParameters.VolumetricFogMaxDistance = FogInfo.VolumetricFogDistance;
}
else
{
ViewUniformShaderParameters.VolumetricFogInvGridSize = FVector3f::ZeroVector;
ViewUniformShaderParameters.VolumetricFogGridZParams = FVector3f::ZeroVector;
ViewUniformShaderParameters.VolumetricFogSVPosToVolumeUV = FVector2f::ZeroVector;
ViewUniformShaderParameters.VolumetricFogViewGridUVToPrevViewRectUV = FVector2f::ZeroVector;
ViewUniformShaderParameters.VolumetricFogMaxDistance = 0;
}
}
bool FSceneRenderer::ShouldRenderVolumetricFog() const
{
return ::ShouldRenderVolumetricFog(Scene, ViewFamily);
}
void FSceneRenderer::SetupVolumetricFog()
{
if (ShouldRenderVolumetricFog())
{
const FExponentialHeightFogSceneInfo& FogInfo = Scene->ExponentialFogs[0];
for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
{
FViewInfo& View = Views[ViewIndex];
FVolumetricFogGlobalData GlobalData;
SetupVolumetricFogGlobalData(View, GlobalData);
View.VolumetricFogResources.VolumetricFogGlobalData = TUniformBufferRef<FVolumetricFogGlobalData>::CreateUniformBufferImmediate(GlobalData, UniformBuffer_SingleFrame);
}
}
else
{
for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
{
FViewInfo& View = Views[ViewIndex];
if (View.ViewState)
{
View.ViewState->LightScatteringHistory = NULL;
View.ViewState->LightScatteringHistoryPreExposure = 1.0f;
View.ViewState->PrevLightScatteringViewGridUVToViewRectVolumeUV = FVector2f::One();
View.ViewState->VolumetricFogPrevViewGridRectUVToResourceUV = FVector2f::One();
View.ViewState->VolumetricFogPrevUVMax = FVector2f::One();
View.ViewState->VolumetricFogPrevUVMaxForTemporalBlend = FVector2f::One();
int32 VolumetricFogResourceGridPixelSize;
View.ViewState->VolumetricFogPrevResourceGridSize = GetVolumetricFogResourceGridSize(View, VolumetricFogResourceGridPixelSize);
}
}
}
}
void FSceneRenderer::ComputeVolumetricFog(FRDGBuilder& GraphBuilder,
const FSceneTextures& SceneTextures)
{
if (!ShouldRenderVolumetricFog())
{
return;
}
const FExponentialHeightFogSceneInfo& FogInfo = Scene->ExponentialFogs[0];
TRACE_CPUPROFILER_EVENT_SCOPE(FSceneRenderer::ComputeVolumetricFog);
QUICK_SCOPE_CYCLE_COUNTER(STAT_VolumetricFog);
RDG_CSV_STAT_EXCLUSIVE_SCOPE(GraphBuilder, VolumetricFog);
RDG_EVENT_SCOPE_STAT(GraphBuilder, VolumetricFog, "ComputeVolumetricFog");
RDG_GPU_STAT_SCOPE(GraphBuilder, VolumetricFog);
// Gather lights that need to be rendered with shadow from opaque or light functions.
struct FLightsToInject
{
TArray<const FLightSceneInfo*, SceneRenderingAllocator> Lights;
TArray<const FLightSceneInfo*, SceneRenderingAllocator> RayTracedLights;
FLightSceneInfo* DirectionalLightFunction = nullptr;
bool bUseDirectionalLightShadowing = false;
};
TArray<FLightsToInject, TInlineAllocator<2>> LightsToInjectPerView;
LightsToInjectPerView.SetNum(Views.Num());
for (auto LightIt = Scene->Lights.CreateConstIterator(); LightIt; ++LightIt)
{
const FLightSceneInfoCompact& LightSceneInfoCompact = *LightIt;
// Nothing to do for black lights.
if (LightSceneInfoCompact.Color.IsAlmostBlack())
{
continue;
}
FLightSceneInfo* LightSceneInfo = LightSceneInfoCompact.LightSceneInfo;
for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
{
FViewInfo& View = Views[ViewIndex];
FLightsToInject& LightsToInject = LightsToInjectPerView[ViewIndex];
if (!LightSceneInfo->ShouldRenderLight(View))
{
continue;
}
const FLightSceneProxy* LightSceneProxy = LightSceneInfo->Proxy;
if (LightSceneProxy->GetVolumetricScatteringIntensity() > SMALL_NUMBER)
{
bool bIsShadowed = LightNeedsSeparateInjectionIntoVolumetricFogForOpaqueShadow(View, LightSceneInfo, VisibleLightInfos[LightSceneInfo->Id], *Scene);
bool bUsesRectLightTexture = GVolumetricFogRectLightTexture && LightSceneProxy->HasSourceTexture();
if (bIsShadowed || bUsesRectLightTexture)
{
const FSphere LightBounds = LightSceneProxy->GetBoundingSphere();
if ((View.ViewMatrices.GetViewOrigin() - LightBounds.Center).SizeSquared() < (FogInfo.VolumetricFogDistance + LightBounds.W) * (FogInfo.VolumetricFogDistance + LightBounds.W))
{
#if RHI_RAYTRACING
const bool bRayTracedLight = (View.bHasRayTracingShadows && View.IsRayTracingAllowedForView()) ? LightHasRayTracedShadows(LightSceneInfo, ViewFamily) : false;
if (bRayTracedLight)
{
LightsToInject.RayTracedLights.Add(LightSceneInfo);
}
else
#endif
{
LightsToInject.Lights.Add(LightSceneInfo);
}
}
}
}
// The only directional light we can accept in the volumetric fog because we use the forward lighting data in the Scattering compute shader.
const FLightSceneProxy* SelectedForwardDirectionalLightProxy = View.ForwardLightingResources.SelectedForwardDirectionalLightProxy;
if (LightSceneProxy == SelectedForwardDirectionalLightProxy && LightSceneProxy->GetLightType() == LightType_Directional)
{
LightsToInject.bUseDirectionalLightShadowing = LightSceneProxy->CastsVolumetricShadow();
if (CheckForLightFunction(LightSceneInfo) && ViewFamily.EngineShowFlags.LightFunctions)
{
LightsToInject.DirectionalLightFunction = LightSceneInfo;
}
}
}
}
for (int32 ViewIndex = 0; ViewIndex < Views.Num(); ViewIndex++)
{
FViewInfo& View = Views[ViewIndex];
const FLightsToInject& LightsToInject = LightsToInjectPerView[ViewIndex];
RDG_GPU_MASK_SCOPE(GraphBuilder, View.GPUMask);
// Allocate texture using scene render targets size so we do not reallocate every frame when dynamic resolution is used in order to avoid resources allocation hitches.
const FIntPoint BufferSize = View.GetSceneTexturesConfig().Extent;
int32 VolumetricFogGridPixelSize;
const FIntVector VolumetricFogResourceGridSize = GetVolumetricFogResourceGridSize(View, VolumetricFogGridPixelSize);
const FIntVector VolumetricFogViewGridSize = GetVolumetricFogViewGridSize(View, VolumetricFogGridPixelSize);
const FVector GridZParams = GetVolumetricFogGridZParams(FogInfo.VolumetricFogStartDistance, View.NearClippingDistance, FogInfo.VolumetricFogDistance, VolumetricFogViewGridSize.Z);
FVolumetricFogIntegrationParameterData IntegrationData;
IntegrationData.FrameJitterOffsetValues.Empty(16);
IntegrationData.FrameJitterOffsetValues.AddZeroed(16);
IntegrationData.FrameJitterOffsetValues[0] = VolumetricFogTemporalRandom(View.Family->FrameNumber);
for (int32 FrameOffsetIndex = 1; FrameOffsetIndex < GVolumetricFogHistoryMissSupersampleCount; FrameOffsetIndex++)
{
IntegrationData.FrameJitterOffsetValues[FrameOffsetIndex] = VolumetricFogTemporalRandom(View.Family->FrameNumber - FrameOffsetIndex);
}
const bool bIsMobilePlatform = IsMobilePlatform(View.GetShaderPlatform());
// Mobile has limited capacities with SRV binding so do not enable atlas sampling on there.
const bool bUseLightFunctionAtlasEnabledAndSupported = LightFunctionAtlas::IsEnabled(*Scene, ELightFunctionAtlasSystem::VolumetricFog) && !bIsMobilePlatform;
const bool bUseTemporalReprojection =
GVolumetricFogTemporalReprojection
&& View.ViewState
&& !bIsMobilePlatform;
IntegrationData.bTemporalHistoryIsValid =
bUseTemporalReprojection
&& !View.bCameraCut
&& !View.bPrevTransformsReset
&& ViewFamily.bRealtimeUpdate
&& View.ViewState->LightScatteringHistory;
FMatrix44f DirectionalLightFunctionTranslatedWorldToShadow = FMatrix44f::Identity;
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog");
FRDGTextureRef ConservativeDepthTexture;
// To use a depth target format, and depth tests, we will have to render depth from a PS depth output. Keeping it simple for now with all the tests happening in shader.
if (GVolumetricFogConservativeDepth > 0)
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::ConservativeDepth");
FIntPoint ConservativeDepthTextureSize = FIntPoint(VolumetricFogViewGridSize.X, VolumetricFogViewGridSize.Y);
ConservativeDepthTexture = GraphBuilder.CreateTexture(FRDGTextureDesc::Create2D(ConservativeDepthTextureSize, PF_R16F,
FClearValueBinding::Black, TexCreate_RenderTargetable | TexCreate_ShaderResource | TexCreate_UAV), TEXT("VolumetricFog.ConservativeDepthTexture"));
AddGenerateConservativeDepthBufferPass(View, GraphBuilder, ConservativeDepthTexture, GetVolumetricFogGridPixelSize());
}
else
{
ConservativeDepthTexture = GraphBuilder.RegisterExternalTexture(GSystemTextures.BlackDummy);
}
FRDGTexture* LightFunctionTexture = GraphBuilder.RegisterExternalTexture(GSystemTextures.WhiteDummy);
FRDGTexture* BlackDummyTexture = GraphBuilder.RegisterExternalTexture(GSystemTextures.BlackDummy);
FRDGTexture* VolumetricBlackDummyTexture = GraphBuilder.RegisterExternalTexture(GSystemTextures.VolumetricBlackDummy);
const bool bUseEmissive = GVolumetricFogEmissive > 0;
// The potential light function for the main directional light is kept separate to be applied during the main VolumetricFogLightScattering pass (as an optimisation).
FRDGTexture* DirectionalLightFunctionTexture = GraphBuilder.RegisterExternalTexture(GSystemTextures.WhiteDummy);
// Recover the information about the light use as the forward directional light for cloud shadowing
int AtmosphericDirectionalLightIndex = -1;
FLightSceneProxy* AtmosphereLightProxy = nullptr;
if(View.ForwardLightingResources.SelectedForwardDirectionalLightProxy)
{
FLightSceneProxy* AtmosphereLight0Proxy = Scene->AtmosphereLights[0] ? Scene->AtmosphereLights[0]->Proxy : nullptr;
FLightSceneProxy* AtmosphereLight1Proxy = Scene->AtmosphereLights[1] ? Scene->AtmosphereLights[1]->Proxy : nullptr;
FVolumetricCloudRenderSceneInfo* CloudInfo = Scene->GetVolumetricCloudSceneInfo();
const bool VolumetricCloudShadowMap0Valid = View.VolumetricCloudShadowExtractedRenderTarget[0] != nullptr;
const bool VolumetricCloudShadowMap1Valid = View.VolumetricCloudShadowExtractedRenderTarget[1] != nullptr;
const bool bLight0CloudPerPixelTransmittance = CloudInfo && VolumetricCloudShadowMap0Valid && View.ForwardLightingResources.SelectedForwardDirectionalLightProxy == AtmosphereLight0Proxy && AtmosphereLight0Proxy && AtmosphereLight0Proxy->GetCloudShadowOnSurfaceStrength() > 0.0f;
const bool bLight1CloudPerPixelTransmittance = CloudInfo && VolumetricCloudShadowMap1Valid && View.ForwardLightingResources.SelectedForwardDirectionalLightProxy == AtmosphereLight1Proxy && AtmosphereLight1Proxy && AtmosphereLight1Proxy->GetCloudShadowOnSurfaceStrength() > 0.0f;
if (bLight0CloudPerPixelTransmittance)
{
AtmosphereLightProxy = AtmosphereLight0Proxy;
AtmosphericDirectionalLightIndex = 0;
}
else if (bLight1CloudPerPixelTransmittance)
{
AtmosphereLightProxy = AtmosphereLight1Proxy;
AtmosphericDirectionalLightIndex = 1;
}
}
if (LightsToInject.DirectionalLightFunction)
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::DirLightFunction");
RenderLightFunctionForVolumetricFog(
GraphBuilder,
View,
SceneTextures,
VolumetricFogViewGridSize,
FogInfo.VolumetricFogDistance,
LightsToInject.DirectionalLightFunction,
DirectionalLightFunctionTranslatedWorldToShadow,
DirectionalLightFunctionTexture);
}
View.VolumetricFogResources.IntegratedLightScatteringTexture = nullptr;
TRDGUniformBufferRef<FFogUniformParameters> FogUniformBuffer = CreateFogUniformBuffer(GraphBuilder, View);
FRDGTextureDesc VolumeDesc = GetVolumetricFogRDGTextureDesc(VolumetricFogResourceGridSize);
FRDGTextureDesc VolumeDescFastVRAM = VolumeDesc;
VolumeDescFastVRAM.Flags |= GFastVRamConfig.VolumetricFog;
IntegrationData.VBufferA = GraphBuilder.CreateTexture(VolumeDescFastVRAM, TEXT("VolumetricFog.VBufferA"));
IntegrationData.VBufferA_UAV = GraphBuilder.CreateUAV(FRDGTextureUAVDesc(IntegrationData.VBufferA));
IntegrationData.VBufferB = nullptr;
IntegrationData.VBufferB_UAV = nullptr;
if (bUseEmissive)
{
IntegrationData.VBufferB = GraphBuilder.CreateTexture(VolumeDescFastVRAM, TEXT("VolumetricFog.VBufferB"));
IntegrationData.VBufferB_UAV = GraphBuilder.CreateUAV(FRDGTextureUAVDesc(IntegrationData.VBufferB));
}
FRDGTexture* LocalShadowedLightScattering = GraphBuilder.RegisterExternalTexture(GSystemTextures.VolumetricBlackDummy);
RenderLocalLightsForVolumetricFog(GraphBuilder, View, ViewIndex, bUseTemporalReprojection, IntegrationData, FogInfo,
VolumetricFogViewGridSize, GridZParams, VolumeDescFastVRAM, ConservativeDepthTexture, LightsToInject.Lights, LightsToInject.RayTracedLights, LocalShadowedLightScattering);
FRDGTextureRef RaytracedShadowsVolume = nullptr;
#if RHI_RAYTRACING
RenderRaytracedDirectionalShadowVolume(GraphBuilder, View, *Scene, IntegrationData, RaytracedShadowsVolume);
#endif
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::InitialiseVolume");
FVolumetricFogMaterialSetupCS::FParameters* PassParameters = GraphBuilder.AllocParameters<FVolumetricFogMaterialSetupCS::FParameters>();
PassParameters->GlobalAlbedo = FogInfo.VolumetricFogAlbedo;
PassParameters->GlobalEmissive = FogInfo.VolumetricFogEmissive;
PassParameters->GlobalExtinctionScale = FogInfo.VolumetricFogExtinctionScale;
PassParameters->RWVBufferA = IntegrationData.VBufferA_UAV;
PassParameters->RWVBufferB = IntegrationData.VBufferB_UAV; // FVolumetricFogMaterialSetupCS uses a permutation to not reference that UAV when bUseEmissive is false.
PassParameters->LFV = View.LocalFogVolumeViewData.UniformParametersStruct;
PassParameters->Fog = FogUniformBuffer;
PassParameters->View = View.ViewUniformBuffer;
SetupVolumetricFogIntegrationParameters(PassParameters->VolumetricFogParameters, View, IntegrationData);
FVolumetricFogMaterialSetupCS::FPermutationDomain PermutationVector;
PermutationVector.Set< FPermutationUseEmissive >(bUseEmissive);
PermutationVector.Set< FPermutationLocalFogVolume >(ShouldRenderLocalFogVolumeInVolumetricFog(Scene, ViewFamily, ShouldRenderLocalFogVolume(Scene, ViewFamily)));
auto ComputeShader = View.ShaderMap->GetShader< FVolumetricFogMaterialSetupCS >(PermutationVector);
ClearUnusedGraphResources(ComputeShader, PassParameters);
GraphBuilder.AddPass(
RDG_EVENT_NAME("InitializeVolumeAttributes"),
PassParameters,
ERDGPassFlags::Compute,
[PassParameters, &View, VolumetricFogViewGridSize, IntegrationData, ComputeShader](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
const FIntVector NumGroups = FIntVector::DivideAndRoundUp(VolumetricFogViewGridSize, VolumetricFogGridInjectionGroupSize);
SetComputePipelineState(RHICmdList, ComputeShader.GetComputeShader());
SetShaderParameters(RHICmdList, ComputeShader, ComputeShader.GetComputeShader(), *PassParameters);
DispatchComputeShader(RHICmdList, ComputeShader.GetShader(), NumGroups.X, NumGroups.Y, NumGroups.Z);
UnsetShaderUAVs(RHICmdList, ComputeShader, ComputeShader.GetComputeShader());
});
VoxelizeFogVolumePrimitives(
GraphBuilder,
View,
IntegrationData,
VolumetricFogViewGridSize,
GridZParams,
FogInfo.VolumetricFogDistance,
bUseEmissive);
}
IntegrationData.LightScattering = GraphBuilder.CreateTexture(VolumeDesc, TEXT("VolumetricFog.LightScattering"), ERDGTextureFlags::MultiFrame);
IntegrationData.LightScatteringUAV = GraphBuilder.CreateUAV(FRDGTextureUAVDesc(IntegrationData.LightScattering));
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::LightScattering");
FVolumetricFogLightScatteringCS::FParameters* PassParameters = GraphBuilder.AllocParameters<FVolumetricFogLightScatteringCS::FParameters>();
PassParameters->View = View.ViewUniformBuffer;
PassParameters->ForwardLightStruct = View.ForwardLightingResources.ForwardLightUniformBuffer;
PassParameters->Fog = FogUniformBuffer;
SetupVolumetricFogIntegrationParameters(PassParameters->VolumetricFogParameters, View, IntegrationData);
PassParameters->VBufferA = IntegrationData.VBufferA;
PassParameters->VBufferB = IntegrationData.VBufferB ? IntegrationData.VBufferB : VolumetricBlackDummyTexture;
PassParameters->LocalShadowedLightScattering = LocalShadowedLightScattering;
PassParameters->ConservativeDepthTexture = ConservativeDepthTexture;
PassParameters->UseConservativeDepthTexture = GVolumetricFogConservativeDepth > 0 ? 1 : 0;
PassParameters->UseEmissive = bUseEmissive ? 1 : 0;
if (GVolumetricFogConservativeDepth > 0 && bUseTemporalReprojection && View.ViewState->PrevLightScatteringConservativeDepthTexture.IsValid())
{
PassParameters->PrevConservativeDepthTexture = GraphBuilder.RegisterExternalTexture(View.ViewState->PrevLightScatteringConservativeDepthTexture);
FIntVector TextureSize = View.ViewState->PrevLightScatteringConservativeDepthTexture->GetDesc().GetSize();
PassParameters->PrevConservativeDepthTextureSize = FVector2f(TextureSize.X, TextureSize.Y);
}
else
{
PassParameters->PrevConservativeDepthTexture = BlackDummyTexture;
PassParameters->PrevConservativeDepthTextureSize = FVector2f::UnitVector;
}
PassParameters->DirectionalLightFunctionTranslatedWorldToShadow = DirectionalLightFunctionTranslatedWorldToShadow;
PassParameters->DirectionalLightLightFunctionTexture = DirectionalLightFunctionTexture;
PassParameters->DirectionalLightLightFunctionSampler = TStaticSamplerState<SF_Bilinear, AM_Clamp, AM_Clamp, AM_Clamp>::GetRHI();
auto* LumenUniforms = GraphBuilder.AllocParameters<FLumenTranslucencyLightingUniforms>();
LumenUniforms->Parameters = GetLumenTranslucencyLightingParameters(GraphBuilder, View.GetLumenTranslucencyGIVolume(), View.LumenFrontLayerTranslucency);
PassParameters->LumenGIVolumeStruct = GraphBuilder.CreateUniformBuffer(LumenUniforms);
PassParameters->MegaLightsVolume = View.GetMegaLightsVolume().Texture;
PassParameters->RWLightScattering = IntegrationData.LightScatteringUAV;
PassParameters->VirtualShadowMapSamplingParameters = VirtualShadowMapArray.GetSamplingParameters(GraphBuilder, ViewIndex);
FDistanceFieldAOParameters AOParameterData(Scene->DefaultMaxDistanceFieldOcclusionDistance);
if (Scene->SkyLight
// Skylights with static lighting had their diffuse contribution baked into lightmaps
&& !Scene->SkyLight->bHasStaticLighting
&& View.Family->EngineShowFlags.SkyLighting)
{
AOParameterData = FDistanceFieldAOParameters(Scene->SkyLight->OcclusionMaxDistance, Scene->SkyLight->Contrast);
}
PassParameters->AOParameters = DistanceField::SetupAOShaderParameters(AOParameterData);
PassParameters->GlobalDistanceFieldParameters = SetupGlobalDistanceFieldParameters(View.GlobalDistanceFieldInfo.ParameterData);
FVolumetricCloudRenderSceneInfo* CloudInfo = Scene->GetVolumetricCloudSceneInfo();
FRDGTexture* LightScatteringHistoryRDGTexture = VolumetricBlackDummyTexture;
float LightScatteringHistoryPreExposure = 1.0f;
if (bUseTemporalReprojection && View.ViewState->LightScatteringHistory.IsValid())
{
LightScatteringHistoryRDGTexture = GraphBuilder.RegisterExternalTexture(View.ViewState->LightScatteringHistory);
LightScatteringHistoryPreExposure = View.ViewState->LightScatteringHistoryPreExposure;
}
PassParameters->LightScatteringHistory = LightScatteringHistoryRDGTexture;
PassParameters->LightScatteringHistorySampler = TStaticSamplerState<SF_Bilinear, AM_Clamp, AM_Clamp, AM_Clamp>::GetRHI();
PassParameters->LightScatteringHistoryPreExposureAndInv = FVector2f(LightScatteringHistoryPreExposure, LightScatteringHistoryPreExposure > 0.0f ? 1.0f / LightScatteringHistoryPreExposure : 1.0f);
FSkyLightSceneProxy* SkyLight = Scene->SkyLight;
if (SkyLight
// Skylights with static lighting had their diffuse contribution baked into lightmaps
&& !SkyLight->bHasStaticLighting
&& View.Family->EngineShowFlags.SkyLighting)
{
PassParameters->SkyLightUseStaticShadowing = SkyLight->bWantsStaticShadowing && SkyLight->bCastShadows ? 1.0f : 0.0f;
PassParameters->SampleSkyLightDiffuseEnvMap = 1;
}
else
{
PassParameters->SkyLightUseStaticShadowing = 0.0f;
PassParameters->SampleSkyLightDiffuseEnvMap = 0;
}
// Mobile handles directional differently as of today to handle light masking (does not use and fill up the FForwardLightData).
// Volumetric fog does not work with light mask so we simply pick up the first one available. In the long run we might want something more common.
PassParameters->MobileDirectionalLightColor = FVector3f::Zero();
PassParameters->MobileDirectionalLightDirection = FVector3f::Zero();
PassParameters->MobileHasDirectionalLight = 0;
for (uint32 ChannelIdx = 0; ChannelIdx < UE_ARRAY_COUNT(Scene->MobileDirectionalLights); ChannelIdx++)
{
FLightSceneInfo* Light = Scene->MobileDirectionalLights[ChannelIdx];
if (Light != nullptr)
{
PassParameters->MobileDirectionalLightColor = FVector3f(Light->Proxy->GetSunIlluminanceAccountingForSkyAtmospherePerPixelTransmittance() * Light->Proxy->GetVolumetricScatteringIntensity());
PassParameters->MobileDirectionalLightDirection = FVector3f(-Light->Proxy->GetDirection());
PassParameters->MobileHasDirectionalLight = 1;
break;
}
}
float StaticLightingScatteringIntensityValue = 0;
if (View.Family->EngineShowFlags.GlobalIllumination && View.Family->EngineShowFlags.VolumetricLightmap)
{
StaticLightingScatteringIntensityValue = FogInfo.VolumetricFogStaticLightingScatteringIntensity;
}
PassParameters->StaticLightingScatteringIntensity = StaticLightingScatteringIntensityValue;
PassParameters->PhaseG = FogInfo.VolumetricFogScatteringDistribution;
PassParameters->InverseSquaredLightDistanceBiasScale = GInverseSquaredLightDistanceBiasScale;
PassParameters->UseDirectionalLightShadowing = LightsToInject.bUseDirectionalLightShadowing ? 1.0f : 0.0f;
PassParameters->LightScatteringSampleJitterMultiplier = GVolumetricFogJitter ? GLightScatteringSampleJitterMultiplier : 0;
PassParameters->UseHeightFogColors = FVector2f(
OverrideDirectionalLightInScatteringUsingHeightFog(View, FogInfo) ? 1.0f : 0.0f,
OverrideSkyLightInScatteringUsingHeightFog(View, FogInfo) ? 1.0f : 0.0f);
FMatrix44f CloudWorldToLightClipShadowMatrix = FMatrix44f::Identity;
float CloudShadowmap_FarDepthKm = 0.0f;
float CloudShadowmap_Strength = 0.0f;
FRDGTexture* CloudShadowmap_RDGTexture = BlackDummyTexture;
if (CloudInfo && AtmosphericDirectionalLightIndex >= 0 && AtmosphereLightProxy && !bIsMobilePlatform)
{
CloudShadowmap_RDGTexture = GraphBuilder.RegisterExternalTexture(View.VolumetricCloudShadowExtractedRenderTarget[AtmosphericDirectionalLightIndex]);
CloudWorldToLightClipShadowMatrix = CloudInfo->GetVolumetricCloudCommonShaderParameters().CloudShadowmapTranslatedWorldToLightClipMatrix[AtmosphericDirectionalLightIndex];
CloudShadowmap_FarDepthKm = CloudInfo->GetVolumetricCloudCommonShaderParameters().CloudShadowmapFarDepthKm[AtmosphericDirectionalLightIndex].X;
CloudShadowmap_Strength = AtmosphereLightProxy->GetCloudShadowOnSurfaceStrength();
}
PassParameters->CloudShadowmapTexture = CloudShadowmap_RDGTexture;
PassParameters->CloudShadowmapSampler = TStaticSamplerState<SF_Bilinear, AM_Clamp, AM_Clamp, AM_Clamp>::GetRHI();
PassParameters->CloudShadowmapFarDepthKm = CloudShadowmap_FarDepthKm;
PassParameters->CloudShadowmapStrength = CloudShadowmap_Strength;
PassParameters->CloudShadowmapTranslatedWorldToLightClipMatrix = CloudWorldToLightClipShadowMatrix;
PassParameters->RaytracedShadowsVolume = RaytracedShadowsVolume ? GraphBuilder.CreateSRV(RaytracedShadowsVolume) : nullptr;
PassParameters->LightFunctionAtlas = LightFunctionAtlas::BindGlobalParameters(GraphBuilder, View);
if (LightsToInject.DirectionalLightFunction && bUseLightFunctionAtlasEnabledAndSupported)
{
PassParameters->DirectionalApplyLightFunctionFromAtlas = LightsToInject.DirectionalLightFunction->Proxy->HasValidLightFunctionAtlasSlot() ? 1 :0;
PassParameters->DirectionalLightFunctionAtlasLightIndex = PassParameters->DirectionalApplyLightFunctionFromAtlas == 1 ? LightsToInject.DirectionalLightFunction->Proxy->GetLightFunctionAtlasLightIndex() : 0;
}
else
{
PassParameters->DirectionalApplyLightFunctionFromAtlas = 0;
PassParameters->DirectionalLightFunctionAtlasLightIndex = 0;
}
const bool bUseLumenGI = View.GetLumenTranslucencyGIVolume().Texture0 != nullptr && FDataDrivenShaderPlatformInfo::GetSupportsLumenGI(View.GetShaderPlatform());
const bool bUseMegaLights = View.GetMegaLightsVolume().Texture != nullptr && MegaLights::IsEnabled(ViewFamily);
const bool bUseGlobalDistanceField = UseGlobalDistanceField() && Scene->DistanceFieldSceneData.NumObjectsInBuffer > 0;
const bool bUseRaytracedShadowsVolume = RaytracedShadowsVolume != nullptr;
const bool bUseDistanceFieldSkyOcclusion =
ViewFamily.EngineShowFlags.AmbientOcclusion
&& !bUseLumenGI
&& Scene->SkyLight
&& Scene->SkyLight->bCastShadows
&& Scene->SkyLight->bCastVolumetricShadow
&& ShouldRenderDistanceFieldAO(Views, ViewFamily.EngineShowFlags)
&& SupportsDistanceFieldAO(View.GetFeatureLevel(), View.GetShaderPlatform())
&& bUseGlobalDistanceField
&& Views.Num() == 1
&& View.IsPerspectiveProjection()
&& !IsMobilePlatform(View.GetShaderPlatform());
const int32 SuperSampleCount = FVolumetricFogLightScatteringCS::GetSuperSampleCount(GVolumetricFogHistoryMissSupersampleCount);
FVolumetricFogLightScatteringCS::FPermutationDomain PermutationVector;
PermutationVector.Set< FVolumetricFogLightScatteringCS::FTemporalReprojection >(bUseTemporalReprojection);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FDistanceFieldSkyOcclusion >(bUseDistanceFieldSkyOcclusion);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FSuperSampleCount >(SuperSampleCount);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FLumenGI >(bUseLumenGI);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FVirtualShadowMap >(VirtualShadowMapArray.IsAllocated() );
PermutationVector.Set< FVolumetricFogLightScatteringCS::FRaytracedShadowsVolume >(bUseRaytracedShadowsVolume);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FSampleLightFunctionAtlas >(bUseLightFunctionAtlasEnabledAndSupported);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FMegaLights>(bUseMegaLights);
PermutationVector.Set< FVolumetricFogLightScatteringCS::FLightSoftFading >(GetVolumetricFogLightSoftFading() > 0.0f);
auto ComputeShader = View.ShaderMap->GetShader< FVolumetricFogLightScatteringCS >(PermutationVector);
ClearUnusedGraphResources(ComputeShader, PassParameters);
GraphBuilder.AddPass(
RDG_EVENT_NAME("LightScattering %dx%dx%d SS:%d %s %s %s",
VolumetricFogViewGridSize.X,
VolumetricFogViewGridSize.Y,
VolumetricFogViewGridSize.Z,
SuperSampleCount,
bUseDistanceFieldSkyOcclusion ? TEXT("DFAO") : TEXT(""),
PassParameters->DirectionalLightLightFunctionTexture ? TEXT("LF") : TEXT(""),
bUseLumenGI ? TEXT("Lumen") : TEXT("")),
PassParameters,
ERDGPassFlags::Compute,
[PassParameters, ComputeShader, &View, this, VolumetricFogViewGridSize](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
const FIntVector NumGroups = FComputeShaderUtils::GetGroupCount(VolumetricFogViewGridSize, FVolumetricFogLightScatteringCS::GetGroupSize());
SetComputePipelineState(RHICmdList, ComputeShader.GetComputeShader());
SetShaderParameters(RHICmdList, ComputeShader, ComputeShader.GetComputeShader(), *PassParameters);
DispatchComputeShader(RHICmdList, ComputeShader.GetShader(), NumGroups.X, NumGroups.Y, NumGroups.Z);
UnsetShaderUAVs(RHICmdList, ComputeShader, ComputeShader.GetComputeShader());
});
}
FRDGTexture* IntegratedLightScattering = GraphBuilder.CreateTexture(VolumeDesc, TEXT("VolumetricFog.IntegratedLightScattering"));
FRDGTextureUAV* IntegratedLightScatteringUAV = GraphBuilder.CreateUAV(FRDGTextureUAVDesc(IntegratedLightScattering));
{
RDG_EVENT_SCOPE(GraphBuilder, "VolumetricFog::FinalIntegration");
FVolumetricFogFinalIntegrationCS::FParameters* PassParameters = GraphBuilder.AllocParameters<FVolumetricFogFinalIntegrationCS::FParameters>();
PassParameters->LightScattering = IntegrationData.LightScattering;
PassParameters->RWIntegratedLightScattering = IntegratedLightScatteringUAV;
PassParameters->VolumetricFogNearFadeInDistanceInv = View.VolumetricFogNearFadeInDistanceInv;
PassParameters->ViewUniformBuffer = View.ViewUniformBuffer;
SetupVolumetricFogIntegrationParameters(PassParameters->VolumetricFogParameters, View, IntegrationData);
GraphBuilder.AddPass(
RDG_EVENT_NAME("FinalIntegration"),
PassParameters,
ERDGPassFlags::Compute,
[PassParameters, &View, VolumetricFogViewGridSize, IntegrationData, this](FRDGAsyncTask, FRHICommandList& RHICmdList)
{
const FIntVector NumGroups = FIntVector::DivideAndRoundUp(VolumetricFogViewGridSize, VolumetricFogIntegrationGroupSize);
auto ComputeShader = View.ShaderMap->GetShader< FVolumetricFogFinalIntegrationCS >();
SetComputePipelineState(RHICmdList, ComputeShader.GetComputeShader());
SetShaderParameters(RHICmdList, ComputeShader, ComputeShader.GetComputeShader(), *PassParameters);
DispatchComputeShader(RHICmdList, ComputeShader.GetShader(), NumGroups.X, NumGroups.Y, 1);
UnsetShaderUAVs(RHICmdList, ComputeShader, ComputeShader.GetComputeShader());
});
}
View.VolumetricFogResources.IntegratedLightScatteringTexture = IntegratedLightScattering;
if (bUseTemporalReprojection)
{
const FVector2f ViewRectSize = FVector2f(View.ViewRect.Size());
GraphBuilder.QueueTextureExtraction(IntegrationData.LightScattering, &View.ViewState->LightScatteringHistory);
View.ViewState->LightScatteringHistoryPreExposure = View.CachedViewUniformShaderParameters->PreExposure;
View.ViewState->PrevLightScatteringViewGridUVToViewRectVolumeUV = ViewRectSize / (FVector2f(VolumetricFogViewGridSize.X, VolumetricFogViewGridSize.Y) * VolumetricFogGridPixelSize);
View.ViewState->VolumetricFogPrevViewGridRectUVToResourceUV = FVector2f(VolumetricFogViewGridSize.X, VolumetricFogViewGridSize.Y) / FVector2f(VolumetricFogResourceGridSize.X, VolumetricFogResourceGridSize.Y);
View.ViewState->VolumetricFogPrevUVMax = GetVolumetricFogUVMaxForSampling(ViewRectSize, VolumetricFogResourceGridSize, VolumetricFogGridPixelSize);
View.ViewState->VolumetricFogPrevUVMaxForTemporalBlend = GetVolumetricFogPrevUVMaxForTemporalBlend(ViewRectSize, VolumetricFogResourceGridSize, VolumetricFogGridPixelSize);
View.ViewState->VolumetricFogPrevResourceGridSize = VolumetricFogResourceGridSize;
}
else if (View.ViewState)
{
View.ViewState->LightScatteringHistory = nullptr;
View.ViewState->LightScatteringHistoryPreExposure = 1.0f;
View.ViewState->PrevLightScatteringViewGridUVToViewRectVolumeUV = FVector2f::One();
View.ViewState->VolumetricFogPrevViewGridRectUVToResourceUV = FVector2f::One();
View.ViewState->VolumetricFogPrevUVMax = FVector2f::One();
View.ViewState->VolumetricFogPrevUVMaxForTemporalBlend = FVector2f::One();
View.ViewState->VolumetricFogPrevResourceGridSize = VolumetricFogResourceGridSize;
}
if (bUseTemporalReprojection && GVolumetricFogConservativeDepth > 0)
{
GraphBuilder.QueueTextureExtraction(ConservativeDepthTexture, &View.ViewState->PrevLightScatteringConservativeDepthTexture);
}
else if (View.ViewState)
{
View.ViewState->PrevLightScatteringConservativeDepthTexture = NULL;
}
}
}
void VolumetricFogGlobalPSOCollector(const FSceneTexturesConfig& SceneTexturesConfig, int32 GlobalPSOCollectorIndex, TArray<FPSOPrecacheData>& PSOInitializers)
{
EShaderPlatform ShaderPlatform = SceneTexturesConfig.ShaderPlatform;
FGlobalShaderMap* GlobalShaderMap = GetGlobalShaderMap(ShaderPlatform);
auto AddPSOInitializer = [&](FRHIPixelShader* PixelShaderRHI)
{
auto VertexShader = GlobalShaderMap->GetShader< FWriteToBoundingSphereVS >();
TOptionalShaderMapRef<FWriteToSliceGS> GeometryShader(GlobalShaderMap);
FGraphicsPipelineStateInitializer GraphicsPSOInit;
SetupInjectShadowedLocalLightPSO(VertexShader.GetVertexShader(), GeometryShader.GetGeometryShader(), PixelShaderRHI, GraphicsPSOInit);
FGraphicsPipelineRenderTargetsInfo RenderTargetsInfo;
RenderTargetsInfo.NumSamples = 1;
FRDGTextureDesc VolumetricFogDesc = GetVolumetricFogRDGTextureDesc(FIntVector());
AddRenderTargetInfo(VolumetricFogDesc.Format, VolumetricFogDesc.Flags, RenderTargetsInfo);
GraphicsPSOInit.StatePrecachePSOHash = RHIComputeStatePrecachePSOHash(GraphicsPSOInit);
ApplyTargetsInfo(GraphicsPSOInit, RenderTargetsInfo);
FPSOPrecacheData PSOPrecacheData;
PSOPrecacheData.bRequired = true;
PSOPrecacheData.Type = FPSOPrecacheData::EType::Graphics;
PSOPrecacheData.GraphicsPSOInitializer = GraphicsPSOInit;
#if PSO_PRECACHING_VALIDATE
PSOPrecacheData.PSOCollectorIndex = GlobalPSOCollectorIndex;
PSOPrecacheData.VertexFactoryType = nullptr;
#endif // PSO_PRECACHING_VALIDATE
PSOInitializers.Add(MoveTemp(PSOPrecacheData));
};
// Precache PSOs are never required
const bool bRequired = false;
EShaderPermutationFlags PermutationFlags = EShaderPermutationFlags::None;
FShaderType* ShaderType = FShaderType::GetShaderTypeByName(FInjectShadowedLocalLightPS::GetStaticType().GetName());
FGlobalShaderType* GlobalShaderType = ShaderType->GetGlobalShaderType();
for (int32 PermutationId = 0; PermutationId < GlobalShaderType->GetPermutationCount(); PermutationId++)
{
if (GlobalShaderType->ShouldCompilePermutation(ShaderPlatform, PermutationId, PermutationFlags) &&
GlobalShaderType->ShouldPrecachePermutation(ShaderPlatform, PermutationId, PermutationFlags) == EShaderPermutationPrecacheRequest::Precached)
{
TShaderRef<FShader> GlobalShader = GlobalShaderMap->GetShader(GlobalShaderType, PermutationId);
FRHIPixelShader* RHIPixelShader = static_cast<FRHIPixelShader*>(GlobalShader.GetRHIShaderBase(SF_Pixel, bRequired));
if (RHIPixelShader)
{
AddPSOInitializer(RHIPixelShader);
}
}
}
}
FRegisterGlobalPSOCollectorFunction RegisterVolumetricFogGlobalPSOCollector(&VolumetricFogGlobalPSOCollector, VolumetricFogGlobalPSOCollectorName);