RayTracingInstanceBufferUtil.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "RenderGraphDefinitions.h"
#include "RHIUtilities.h"
#include "CoreMinimal.h"
 
#if RHI_RAYTRACING
 
class FGPUScene;
class FGPUSceneResourceParametersRHI;
struct FRayTracingCullingParameters;
struct FDFVector3;
 
struct UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.") FRayTracingInstanceDescriptor
{
    uint32 GPUSceneInstanceOrTransformIndex;
    uint32 OutputDescriptorIndex;
    uint32 AccelerationStructureIndex;
    uint32 InstanceId;
    uint32 InstanceMaskAndFlags;
    uint32 InstanceContributionToHitGroupIndex;
    union
    {
        uint32 SceneInstanceIndexAndApplyLocalBoundsTransform;
        uint32 bApplyLocalBoundsTransform;
    };
};
 
struct UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.") FRayTracingInstanceGroupEntryRef
{
    uint32 GroupIndex;
    uint32 BaseIndexInGroup;
};
 
PRAGMA_DISABLE_DEPRECATION_WARNINGS
struct UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.") FRayTracingSceneInitializationData
{
    uint32 NumGPUInstanceGroups;
    uint32 NumCPUInstanceGroups;
    uint32 NumGPUInstanceDescriptors;
    uint32 NumCPUInstanceDescriptors;
    uint32 NumNativeGPUSceneInstances;
    uint32 NumNativeCPUInstances;
 
    UE_DEPRECATED(5.6, "No longer used. Use FShaderBindingTable instead.")
    uint32 TotalNumSegments;
 
    // index of each instance geometry in ReferencedGeometries
    TArray<uint32> InstanceGeometryIndices;
    // base offset of each instance entries in the instance upload buffer
    TArray<uint32> BaseUploadBufferOffsets;
    // prefix sum of `Instance.NumTransforms` for all instances in this scene
    TArray<uint32> BaseInstancePrefixSum;
    // reference to corresponding instance group entry
    TArray<FRayTracingInstanceGroupEntryRef> InstanceGroupEntryRefs;
 
    // Unique list of geometries referenced by all instances in this scene.
    // Any referenced geometry is kept alive while the scene is alive.
    TArray<FRHIRayTracingGeometry*> ReferencedGeometries;
 
    FRayTracingSceneInitializationData() = default;
    FRayTracingSceneInitializationData(const FRayTracingSceneInitializationData&) = default;
    FRayTracingSceneInitializationData& operator=(const FRayTracingSceneInitializationData&) = default;
    FRayTracingSceneInitializationData(FRayTracingSceneInitializationData&&) = default;
    FRayTracingSceneInitializationData& operator=(FRayTracingSceneInitializationData&&) = default;
    ~FRayTracingSceneInitializationData() = default;
};
 
UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.")
RENDERER_API FRayTracingSceneInitializationData BuildRayTracingSceneInitializationData(TConstArrayView<FRayTracingGeometryInstance> Instances);
 
UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.")
RENDERER_API void FillRayTracingInstanceUploadBuffer(
    FRayTracingSceneRHIRef RayTracingSceneRHI,
    FVector PreViewTranslation,
    TConstArrayView<FRayTracingGeometryInstance> Instances,
    TConstArrayView<uint32> InstanceGeometryIndices,
    TConstArrayView<uint32> BaseUploadBufferOffsets,
    TConstArrayView<uint32> BaseInstancePrefixSum,
    uint32 NumNativeGPUSceneInstances,
    uint32 NumNativeCPUInstances,
    TArrayView<FRayTracingInstanceDescriptor> OutInstanceUploadData,
    TArrayView<FVector4f> OutTransformData);
 
UE_DEPRECATED(5.6, "Use FRayTracingInstanceBufferBuilder instead.")
RENDERER_API void BuildRayTracingInstanceBuffer(
    FRHICommandList& RHICmdList,
    const FGPUScene* GPUScene,
    const FDFVector3& PreViewTranslation,
    FRHIUnorderedAccessView* InstancesUAV,
    FRHIUnorderedAccessView* HitGroupContributionsUAV,
    FRHIShaderResourceView* InstanceUploadSRV,
    FRHIShaderResourceView* AccelerationStructureAddressesSRV,
    FRHIShaderResourceView* CPUInstanceTransformSRV,
    uint32 NumNativeGPUSceneInstances,
    uint32 NumNativeCPUInstances,
    const FRayTracingCullingParameters* CullingParameters,
    FRHIUnorderedAccessView* OutputStatsUAV,
    FRHIUnorderedAccessView* InstanceExtraDataUAV);
 
PRAGMA_ENABLE_DEPRECATION_WARNINGS
 
struct FRayTracingInstanceBufferBuilderInitializer
{
    TConstArrayView<FRayTracingGeometryInstance> Instances;
    TBitArray<> VisibleInstances;
    FVector PreViewTranslation;
    bool bUseLightingChannels = false;
    bool bForceOpaque = false;
    bool bDisableTriangleCull = false;
};
 
class FRayTracingInstanceBufferBuilder
{
public:
 
    RENDERER_API void Init(TConstArrayView<FRayTracingGeometryInstance> InInstances, FVector InPreViewTranslation);
    RENDERER_API void Init(FRayTracingInstanceBufferBuilderInitializer Initializer);
 
    RENDERER_API void FillRayTracingInstanceUploadBuffer(FRHICommandList& RHICmdList);
    RENDERER_API void FillAccelerationStructureAddressesBuffer(FRHICommandList& RHICmdList);
 
    RENDERER_API void BuildRayTracingInstanceBuffer(
        FRHICommandList& RHICmdList,
        const FGPUScene* GPUScene,
        const FRayTracingCullingParameters* CullingParameters,
        FRHIUnorderedAccessView* InstancesUAV,
        FRHIUnorderedAccessView* HitGroupContributionsUAV,
        uint32 MaxNumInstances,
        bool bCompactOutput,
        FRHIUnorderedAccessView* OutputStatsUAV,
        uint32 OutputStatsOffset,
        FRHIUnorderedAccessView* InstanceExtraDataUAV);
 
    RENDERER_API void BuildRayTracingInstanceBuffer(
        FRHICommandList& RHICmdList,
        const FGPUScene* GPUScene,
        const FGPUSceneResourceParametersRHI* GPUSceneParameters,
        const FRayTracingCullingParameters* CullingParameters,
        FRHIUnorderedAccessView* InstancesUAV,
        FRHIUnorderedAccessView* HitGroupContributionsUAV,
        uint32 MaxNumInstances,
        bool bCompactOutput,
        FRHIUnorderedAccessView* OutputStatsUAV,
        uint32 OutputStatsOffset,
        FRHIUnorderedAccessView* InstanceExtraDataUAV);
 
    PRAGMA_DISABLE_DEPRECATION_WARNINGS
 
    uint32 GetMaxNumInstances() const { return Data.NumNativeGPUSceneInstances + Data.NumNativeCPUInstances; }
 
    TConstArrayView<FRHIRayTracingGeometry*> GetReferencedGeometries() const { return Data.ReferencedGeometries; }
    TConstArrayView<uint32> GetInstanceGeometryIndices() const { return Data.InstanceGeometryIndices; }
    TConstArrayView<uint32> GetBaseInstancePrefixSum() const { return Data.BaseInstancePrefixSum; }
 
    PRAGMA_ENABLE_DEPRECATION_WARNINGS
 
private:
 
    TConstArrayView<FRayTracingGeometryInstance> Instances;
    TBitArray<> VisibleInstances;
    FVector PreViewTranslation;
    bool bUseLightingChannels = false;
    bool bForceOpaque = false;
    bool bDisableTriangleCull = false;
 
    PRAGMA_DISABLE_DEPRECATION_WARNINGS
    FRayTracingSceneInitializationData Data;
    PRAGMA_ENABLE_DEPRECATION_WARNINGS
 
    FBufferRHIRef InstanceGroupUploadBuffer;
    FShaderResourceViewRHIRef InstanceGroupUploadSRV;
 
    FBufferRHIRef InstanceUploadBuffer;
    FShaderResourceViewRHIRef InstanceUploadSRV;
 
    FBufferRHIRef TransformUploadBuffer;
    FShaderResourceViewRHIRef TransformUploadSRV;
 
    FByteAddressBuffer AccelerationStructureAddressesBuffer;
};
 
#endif // RHI_RAYTRACING