ShaderParameterMetadataBuilder.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
#include "CoreMinimal.h"
#include "HAL/Platform.h"
#include "RHI.h"
#include "RHIDefinitions.h"
#include "ShaderParameterMacros.h"
#include "ShaderParameterMetadata.h"
#include "Templates/AlignmentTemplates.h"
 
class FShaderParametersMetadataBuilder
{
public:
    FShaderParametersMetadataBuilder() {}
 
    explicit FShaderParametersMetadataBuilder(const FShaderParametersMetadata* RootParametersMetadata)
    {
        if (RootParametersMetadata)
        {
            Members = RootParametersMetadata->GetMembers();
            NextMemberOffset = RootParametersMetadata->GetSize();
        }
    }
 
    template<typename T>
    void AddParam(
        const TCHAR* Name,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        )
    {
        using TParamTypeInfo = TShaderParameterTypeInfo<T>;
 
        NextMemberOffset = Align(NextMemberOffset, TParamTypeInfo::Alignment);
 
        Members.Emplace(
            Name,
            TEXT(""),
            __LINE__,
            NextMemberOffset,
            TParamTypeInfo::BaseType,
            Precision,
            TParamTypeInfo::NumRows,
            TParamTypeInfo::NumColumns,
            TParamTypeInfo::NumElements,
            TParamTypeInfo::GetStructMetadata()
            );
 
        NextMemberOffset += sizeof(typename TParamTypeInfo::TAlignedType);
    }
 
    template<typename T>
    void AddParamArray(
        const TCHAR* Name,
        int32 NumElements,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        )
    {
        using TParamTypeInfo = TShaderParameterTypeInfo<T>;
 
        NextMemberOffset = Align(NextMemberOffset, SHADER_PARAMETER_ARRAY_ELEMENT_ALIGNMENT);
 
        Members.Emplace(
            Name,
            TEXT(""),
            __LINE__,
            NextMemberOffset,
            TParamTypeInfo::BaseType,
            Precision,
            TParamTypeInfo::NumRows,
            TParamTypeInfo::NumColumns,
            NumElements,
            TParamTypeInfo::GetStructMetadata()
            );
 
        NextMemberOffset += sizeof(typename TParamTypeInfo::TAlignedType) * NumElements;
    }
 
    template<typename T>
    void AddReferencedStruct(
        const TCHAR* Name,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        )
    {
        AddReferencedStruct(Name, TShaderParameterStructTypeInfo<T>::GetStructMetadata(), Precision);
    }
 
    RENDERCORE_API void AddReferencedStruct(
        const TCHAR* Name,
        const FShaderParametersMetadata* StructMetadata,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    template<typename T>
    void AddIncludedStruct(
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    )
    {
        AddIncludedStruct(TShaderParameterStructTypeInfo<T>::GetStructMetadata(), Precision);
    }
 
    RENDERCORE_API void AddIncludedStruct(
        const FShaderParametersMetadata* StructMetadata,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    );
 
    template<typename T>
    uint32 AddNestedStruct(
        const TCHAR* Name,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        )
    {
        using TParamTypeInfo = TShaderParameterStructTypeInfo<T>;
 
        NextMemberOffset = Align(NextMemberOffset, TParamTypeInfo::Alignment);
        const uint32 ThisMemberOffset = NextMemberOffset;
 
        Members.Emplace(
            Name,
            TEXT(""),
            __LINE__,
            NextMemberOffset,
            UBMT_NESTED_STRUCT,
            Precision,
            TParamTypeInfo::NumRows,
            TParamTypeInfo::NumColumns,
            TParamTypeInfo::NumElements,
            TParamTypeInfo::GetStructMetadata()
        );
 
        NextMemberOffset += sizeof(typename TParamTypeInfo::TAlignedType);
        return ThisMemberOffset;
    }
 
    RENDERCORE_API uint32 AddNestedStruct(
        const TCHAR* Name,
        const FShaderParametersMetadata* StructMetadata,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    RENDERCORE_API void AddBufferSRV(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    RENDERCORE_API void AddBufferUAV(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    RENDERCORE_API void AddRDGBufferSRV(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    RENDERCORE_API void AddRDGBufferUAV(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
        );
 
    RENDERCORE_API void AddTexture(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    );
 
    RENDERCORE_API void AddRDGTexture(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    );
 
    RENDERCORE_API void AddSampler(
        const TCHAR* Name,
        const TCHAR* ShaderType,
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    );
 
    RENDERCORE_API void AddRenderTargetBindingSlots(
        const TCHAR* Name = TEXT("RenderTargets"),
        const TCHAR* ShaderType = TEXT(""),
        EShaderPrecisionModifier::Type Precision = EShaderPrecisionModifier::Float
    );
 
    void AlignNextMemberToStruct()
    {
        NextMemberOffset = Align(NextMemberOffset, SHADER_PARAMETER_STRUCT_ALIGNMENT);
    }
 
    uint32 GetNextMemberOffset() const { return NextMemberOffset; }
 
    RENDERCORE_API FShaderParametersMetadata* Build(
        FShaderParametersMetadata::EUseCase UseCase,
        const TCHAR* ShaderParameterName
        );
 
    RENDERCORE_API FShaderParametersMetadata* Build(
        FShaderParametersMetadata::EUseCase InUseCase,
        EUniformBufferBindingFlags InBindingFlags,
        const TCHAR* InLayoutName,
        const TCHAR* InStructTypeName,
        const TCHAR* InShaderVariableName,
        const TCHAR* InStaticSlotName,
        const ANSICHAR* InFileName,
        const int32 InFileLine,
        bool bForceCompleteInitialization = false,
        FRHIUniformBufferLayoutInitializer* OutLayoutInitializer = nullptr,
        FShaderParametersMetadata::EUsageFlags InUsageFlags = FShaderParametersMetadata::EUsageFlags::None
        );
 
private:
    TArray<FShaderParametersMetadata::FMember> Members;
    uint32 NextMemberOffset = 0;
};