OpenGLBinaryProgramUtils.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    OpenGLBinaryProgramUtils.h
=============================================================================*/
 
#pragma once
#include "OpenGLDrvPrivate.h"
 
class FOpenGLProgramBinary
{
public:
    FOpenGLProgramBinary() {};
    FOpenGLProgramBinary(TArray<uint8>&& ProgramMemory) : OwnedData(MoveTemp(ProgramMemory)), DataView(OwnedData) 
    {
        INC_MEMORY_STAT_BY(STAT_OpenGLShaderLRUProgramMemory, DataView.Num());
        check(IsOwned());
        check(IsValid());
    }
 
    // No ownership, just a view to a region within the mmapped PSO cache.
    FOpenGLProgramBinary(TArrayView<const uint8> ProgramMemory) : DataView(ProgramMemory) 
    {
        INC_MEMORY_STAT_BY(STAT_OpenGLShaderLRUProgramMemoryMapped, DataView.Num());
        check(!IsOwned());
        check(IsValid());
    }
 
    FOpenGLProgramBinary& operator= (FOpenGLProgramBinary&& rhs) = default;
 
    FOpenGLProgramBinary(FOpenGLProgramBinary&& Src) = default;
 
    ~FOpenGLProgramBinary()
    {
        if(IsOwned())
        {
            DEC_MEMORY_STAT_BY(STAT_OpenGLShaderLRUProgramMemory, DataView.Num());
        }
        else
        {
            // This should only change when shutting down the PSO cache, i.e. DataView.IsEmpty() during normal use.
            DEC_MEMORY_STAT_BY(STAT_OpenGLShaderLRUProgramMemoryMapped, DataView.Num());
        }
    }
 
    bool IsValid() const { return DataView.Num() > 0; }
    bool IsOwned() const { return OwnedData.Num() > 0; }
    const TArrayView<const uint8> GetDataView() const { return DataView; }
private:
    // The data when programs are owned.
    TArray<uint8> OwnedData;
    // a view to the raw program binary, either points to OwnedData or an array view within the mmapped prebuilt PSO cache.
    TArrayView<const uint8> DataView;
};
 
namespace UE
{
    namespace OpenGL
    {
        // Program Binary helpers.
 
        bool IsStoringCompressedBinaryPrograms();
 
        struct FCompressedProgramBinaryHeader
        {
            static const uint32 NotCompressed = 0xFFFFFFFF;
            uint32 UncompressedSize;
        };
 
        FOpenGLProgramBinary GetProgramBinaryFromGLProgram(GLuint Program);
        bool GetUncompressedProgramBinaryFromGLProgram(GLuint Program, TArray<uint8>& ProgramBinaryOUT);
        bool GetCompressedProgramBinaryFromGLProgram(GLuint Program, TArray<uint8>& ProgramBinaryOUT);
        void CompressProgramBinary(const TArrayView<const uint8>& UncompressedProgramBinary, TArray<uint8>& ProgramBinaryOUT);
        bool UncompressCompressedBinaryProgram(const TArrayView<const uint8>& CompressedProgramBinary, TArray<uint8>& UncompressedProgramBinaryOUT);
    }
}