MeshParticleVertexFactory.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    MeshParticleVertexFactory.h: Mesh particle vertex factory definitions.
=============================================================================*/
 
#pragma once
 
#include "CoreMinimal.h"
#include "RHI.h"
#include "UniformBuffer.h"
#include "VertexFactory.h"
#include "Components.h"
#include "SceneManagement.h"
#include "VertexFactory.h"
#include "ParticleVertexFactory.h"
//@todo - parallelrendering - remove once FOneFrameResource no longer needs to be referenced in header
 
class FMaterial;
class FVertexBuffer;
struct FDynamicReadBuffer;
struct FShaderCompilerEnvironment;
 
BEGIN_GLOBAL_SHADER_PARAMETER_STRUCT( FMeshParticleUniformParameters, ENGINE_API)
    SHADER_PARAMETER( FVector4f, SubImageSize )
    SHADER_PARAMETER( uint32, TexCoordWeightA )
    SHADER_PARAMETER( uint32, TexCoordWeightB )
    SHADER_PARAMETER( uint32, PrevTransformAvailable )
    SHADER_PARAMETER( float, DeltaSeconds )
    SHADER_PARAMETER( uint32, bUseLocalSpace )
    SHADER_PARAMETER( FVector3f, LWCTile )
    SHADER_PARAMETER( float, UseVelocityForMotionBlur )
END_GLOBAL_SHADER_PARAMETER_STRUCT()
typedef TUniformBufferRef<FMeshParticleUniformParameters> FMeshParticleUniformBufferRef;
 
class FMeshParticleInstanceVertices;
 
 
class FMeshParticleVertexFactory : public FParticleVertexFactoryBase
{
    DECLARE_VERTEX_FACTORY_TYPE(FMeshParticleVertexFactory);
public:
    FMeshParticleVertexFactory(ERHIFeatureLevel::Type InFeatureLevel)
        : FParticleVertexFactoryBase(InFeatureLevel)
    {
    }
 
    struct FDataType : public FStaticMeshDataType
    {
        FVertexStreamComponent ParticleColorComponent;
 
        FVertexStreamComponent TransformComponent[3];
 
        FVertexStreamComponent VelocityComponent;
 
        FVertexStreamComponent SubUVs;
 
        FVertexStreamComponent SubUVLerpAndRelTime;
 
        bool bInitialized;
 
        FDataType()
        : bInitialized(false)
        {
        }
    };
 
    class FBatchParametersCPU : public FOneFrameResource
    {
    public:
        const struct FMeshParticleInstanceVertex* InstanceBuffer;
        const struct FMeshParticleInstanceVertexDynamicParameter* DynamicParameterBuffer;
        const struct FMeshParticleInstanceVertexPrevTransform* PrevTransformBuffer;
    };
 
    FMeshParticleVertexFactory(EParticleVertexFactoryType InType, ERHIFeatureLevel::Type InFeatureLevel, int32 InDynamicVertexStride, int32 InDynamicParameterVertexStride)
        : FParticleVertexFactoryBase(InType, InFeatureLevel)
        , LODIdx(0xff)
        , DynamicVertexStride(InDynamicVertexStride)
        , DynamicParameterVertexStride(InDynamicParameterVertexStride)
        , InstanceVerticesCPU(nullptr)
    {}
 
    FMeshParticleVertexFactory()
        : FParticleVertexFactoryBase(PVFT_MAX, ERHIFeatureLevel::Num)
        , LODIdx(0xff)
        , DynamicVertexStride(-1)
        , DynamicParameterVertexStride(-1)
        , InstanceVerticesCPU(nullptr)
    {}
 
    static ENGINE_API bool ShouldCompilePermutation(const FVertexFactoryShaderPermutationParameters& Parameters);
 
 
    static ENGINE_API void ModifyCompilationEnvironment(const FVertexFactoryShaderPermutationParameters& Parameters, FShaderCompilerEnvironment& OutEnvironment);
 
    static ENGINE_API void GetPSOPrecacheVertexFetchElements(EVertexInputStreamType VertexInputStreamType, FVertexDeclarationElementList& Elements);
    static ENGINE_API void GetVertexElements(ERHIFeatureLevel::Type FeatureLevel, int32 InDynamicVertexStride, int32 InDynamicParameterVertexStride, FDataType& Data, FVertexDeclarationElementList& Elements);
 
    ENGINE_API void SetData(FRHICommandListBase& RHICmdList, const FDataType& InData);
 
    UE_DEPRECATED(5.4, "SetData requires a command list.")
    ENGINE_API void SetData(const FDataType& InData);
 
    inline void SetUniformBuffer( const FMeshParticleUniformBufferRef& InMeshParticleUniformBuffer )
    {
        MeshParticleUniformBuffer = InMeshParticleUniformBuffer;
    }
 
    inline FRHIUniformBuffer* GetUniformBuffer()
    {
        return MeshParticleUniformBuffer;
    }
    
    void SetStrides(int32 InDynamicVertexStride, int32 InDynamicParameterVertexStride)
    {
        ensure(!IsInitialized());
        DynamicVertexStride = InDynamicVertexStride;
        DynamicParameterVertexStride = InDynamicParameterVertexStride;
    }
    
    ENGINE_API void SetInstanceBuffer(const FVertexBuffer* InstanceBuffer, uint32 StreamOffset, uint32 Stride);
 
    ENGINE_API void SetDynamicParameterBuffer(const FVertexBuffer* InDynamicParameterBuffer, uint32 StreamOffset, uint32 Stride);
 
    ENGINE_API uint8* LockPreviousTransformBuffer(FRHICommandListBase& RHICmdList, uint32 ParticleCount);
    ENGINE_API void UnlockPreviousTransformBuffer(FRHICommandListBase& RHICmdList);
    ENGINE_API FRHIShaderResourceView* GetPreviousTransformBufferSRV() const;
 
    ENGINE_API void Copy(const FMeshParticleVertexFactory& Other);
 
    // FRenderResource interface.
    ENGINE_API virtual void InitRHI(FRHICommandListBase& RHICmdList) override;
 
    FMeshParticleInstanceVertices*& GetInstanceVerticesCPU()
    {
        return InstanceVerticesCPU;
    }
 
    void SetLODIdx(uint8 InLODIdx)
    {
        LODIdx = InLODIdx;
    }
 
    uint8 GetLODIdx() const
    {
        return LODIdx;
    }
protected:
    static ENGINE_API void GetVertexElements(ERHIFeatureLevel::Type FeatureLevel, int32 InDynamicVertexStride, int32 InDynamicParameterVertexStride, FDataType& Data, FVertexDeclarationElementList& Elements, FVertexStreamList& InOutStreams);
 
protected:
    FDataType Data;
    
    uint8 LODIdx;
 
    int32 DynamicVertexStride;
    int32 DynamicParameterVertexStride;
    
    FRHIUniformBuffer* MeshParticleUniformBuffer;
 
    FDynamicReadBuffer PrevTransformBuffer;
 
    FMeshParticleInstanceVertices* InstanceVerticesCPU;
};
 
 
inline FMeshParticleVertexFactory* ConstructMeshParticleVertexFactory(ERHIFeatureLevel::Type InFeatureLevel)
{
    return new FMeshParticleVertexFactory(InFeatureLevel);
}
 
inline FMeshParticleVertexFactory* ConstructMeshParticleVertexFactory(EParticleVertexFactoryType InType, ERHIFeatureLevel::Type InFeatureLevel, int32 InDynamicVertexStride, int32 InDynamicParameterVertexStride)
{
    return new FMeshParticleVertexFactory(InType, InFeatureLevel, InDynamicVertexStride, InDynamicParameterVertexStride);
}