PositionVertexBuffer.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Math/Vector.h"
#include "RenderResource.h"
#include "RHIFwd.h"
 
class FPositionVertexData;
struct FStaticMeshBuildVertex;
struct FConstMeshBuildVertexView;
 
struct FPositionVertex
{
    FVector3f   Position;
 
    friend FArchive& operator<<(FArchive& Ar, FPositionVertex& V)
    {
        Ar << V.Position;
        return Ar;
    }
};
 
class FPositionVertexBuffer : public FVertexBuffer
{
public:
 
    ENGINE_API FPositionVertexBuffer();
 
    ENGINE_API ~FPositionVertexBuffer();
 
    ENGINE_API void CleanUp();
 
    void ENGINE_API Init(uint32 NumVertices, bool bInNeedsCPUAccess = true);
 
    ENGINE_API void Init(const TArray<FStaticMeshBuildVertex>& InVertices, bool bInNeedsCPUAccess = true);
    ENGINE_API void Init(const FConstMeshBuildVertexView& InVertices, bool bInNeedsCPUAccess = true);
    
    ENGINE_API void Init(const FPositionVertexBuffer& InVertexBuffer, bool bInNeedsCPUAccess = true);
 
    ENGINE_API void Init(const TArray<FVector3f>& InPositions, bool bInNeedsCPUAccess = true);
 
    ENGINE_API bool AppendVertices( const FStaticMeshBuildVertex* Vertices, const uint32 NumVerticesToAppend );
 
    ENGINE_API void Serialize(FArchive& Ar, bool bInNeedsCPUAccess);
 
    void SerializeMetaData(FArchive& Ar);
 
    ENGINE_API void SetMetaData(uint32 InStride, uint32 InNumVertices);
 
    void ClearMetaData();
 
    ENGINE_API void operator=(const FPositionVertexBuffer &Other);
 
    // Vertex data accessors.
    inline FVector3f& VertexPosition(uint32 VertexIndex)
    {
        checkSlow(VertexIndex < GetNumVertices());
        return ((FPositionVertex*)(Data + VertexIndex * Stride))->Position;
    }
    inline const FVector3f& VertexPosition(uint32 VertexIndex) const
    {
        checkSlow(VertexIndex < GetNumVertices());
        return ((FPositionVertex*)(Data + VertexIndex * Stride))->Position;
    }
    // Other accessors.
    inline uint32 GetStride() const
    {
        return Stride;
    }
    inline uint32 GetNumVertices() const
    {
        return NumVertices;
    }
    ENGINE_API bool GetAllowCPUAccess() const;
    
    inline SIZE_T GetAllocatedSize() const { return (Data != nullptr) ? Stride * NumVertices : 0; }
 
    FBufferRHIRef CreateRHIBuffer(FRHICommandListBase& RHICmdList);
 
    void InitRHIForStreaming(FRHIBuffer* IntermediateBuffer, FRHIResourceReplaceBatcher& Batcher);
    void ReleaseRHIForStreaming(FRHIResourceReplaceBatcher& Batcher);
 
    // FRenderResource interface.
    ENGINE_API virtual void InitRHI(FRHICommandListBase& RHICmdList) override;
    ENGINE_API virtual void ReleaseRHI() override;
    virtual FString GetFriendlyName() const override { return TEXT("PositionOnly Static-mesh vertices"); }
 
    ENGINE_API void BindPositionVertexBuffer(const class FVertexFactory* VertexFactory, struct FStaticMeshDataType& Data) const;
 
    void* GetVertexData() { return Data; }
    const void* GetVertexData() const { return Data; }
 
    FRHIShaderResourceView* GetSRV() const { return PositionComponentSRV; }
 
private:
 
    FShaderResourceViewRHIRef PositionComponentSRV;
 
    FPositionVertexData* VertexData;
 
    uint8* Data;
 
    uint32 Stride;
 
    uint32 NumVertices;
 
    bool bNeedsCPUAccess = true;
 
    void AllocateData(bool bInNeedsCPUAccess = true);
};