SlateElementVertexBuffer.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Stats/Stats.h"
#include "Rendering/RenderingCommon.h"
#include "SlateGlobals.h"
#include "RHI.h"
#include "RHICommandList.h"
#include "RHIResourceUtils.h"
#include "RenderResource.h"
#include "Containers/ResourceArray.h"
 
DECLARE_MEMORY_STAT_EXTERN(TEXT("Vertex Buffer Memory (GPU)"), STAT_SlateVertexBufferMemory, STATGROUP_SlateMemory, );
 
template <typename VertexType>
class TSlateElementVertexBuffer : public FVertexBuffer
{
public:
    TSlateElementVertexBuffer()
        : BufferSize(0)
        , MinBufferSize(0)
        , BufferUsageSize(0)
    {}
 
    ~TSlateElementVertexBuffer() {};
 
    void Init( int32 MinNumVertices )
    {
        MinBufferSize = sizeof(VertexType) * FMath::Max( MinNumVertices, 100 );
 
        if ( IsInRenderingThread() )
        {
            InitResource(FRHICommandListImmediate::Get());
        }
        else
        {
            BeginInitResource(this);
        }
    }
 
    void Destroy()
    {
        if ( IsInRenderingThread() )
        {
            ReleaseResource();
        }
        else
        {
            BeginReleaseResource(this);
        }
    }
 
    virtual void InitRHI(FRHICommandListBase& RHICmdList)
    {
        if( !IsValidRef(VertexBufferRHI) )
        {
            check( MinBufferSize > 0 )
    
            SetBufferSize(MinBufferSize);
 
            const FRHIBufferCreateDesc CreateDesc =
                FRHIBufferCreateDesc::CreateVertex(TEXT("SlateElementVertices"), MinBufferSize)
                .AddUsage(EBufferUsageFlags::Dynamic)
                .DetermineInitialState();
 
            VertexBufferRHI = RHICmdList.CreateBuffer(CreateDesc);
 
            // Ensure the vertex buffer could be created
            check(IsValidRef(VertexBufferRHI));
        }
    }
 
    virtual void ReleaseRHI()
    {
        VertexBufferRHI.SafeRelease();
        SetBufferSize(0);
    }
 
    virtual FString GetFriendlyName() const { return TEXT("SlateElementVertices"); }
 
    int32 GetBufferSize() const { return BufferSize; }
 
    int32 GetBufferUsageSize() const { return BufferUsageSize; }
 
    void ResetBufferUsage() { BufferUsageSize = 0; }
 
    void PreFillBuffer(FRHICommandListBase& RHICmdList, int32 RequiredVertexCount, bool bShrinkToMinSize)
    {
        SCOPE_CYCLE_COUNTER(STAT_SlatePreFullBufferTime);
 
        if (RequiredVertexCount > 0 )
        {
#if !SLATE_USE_32BIT_INDICES
            // make sure our index buffer can handle this
            checkf(RequiredVertexCount < 0xFFFF, TEXT("Slate vertex buffer is too large (%d) to work with uint16 indices"), RequiredVertexCount);
#endif
            int32 RequiredBufferSize = RequiredVertexCount*sizeof(VertexType);
 
            // resize if needed
            if (RequiredBufferSize > GetBufferSize() || bShrinkToMinSize)
            {
                ResizeBuffer(RHICmdList, RequiredBufferSize);
            }
 
            BufferUsageSize = RequiredBufferSize;
        }
    }
 
    int32 GetMinBufferSize() const { return MinBufferSize; }
 
private:
    void ResizeBuffer(FRHICommandListBase& RHICmdList, int32 NewSizeBytes)
    {
        QUICK_SCOPE_CYCLE_COUNTER(Slate_RTResizeBuffer);
 
        int32 FinalSize = FMath::Max( NewSizeBytes, MinBufferSize );
 
        if (FinalSize != 0 && FinalSize != BufferSize)
        {
            VertexBufferRHI.SafeRelease();
 
            const FRHIBufferCreateDesc CreateDesc =
                FRHIBufferCreateDesc::CreateVertex(TEXT("SlateElementVertices"), FinalSize)
                .AddUsage(EBufferUsageFlags::Dynamic)
                .DetermineInitialState();
 
            VertexBufferRHI = RHICmdList.CreateBuffer(CreateDesc);
 
            check(IsValidRef(VertexBufferRHI));
 
            SetBufferSize(FinalSize);
        }
    }
 
    void SetBufferSize(int32 NewBufferSize)
    {
        DEC_MEMORY_STAT_BY(STAT_SlateVertexBufferMemory, BufferSize);
        BufferSize = NewBufferSize;
        INC_MEMORY_STAT_BY(STAT_SlateVertexBufferMemory, BufferSize);
    }
 
private:
    int32 BufferSize;
    
    int32 MinBufferSize;
 
    int32 BufferUsageSize;
 
    TSlateElementVertexBuffer( const TSlateElementVertexBuffer& );
    void operator=(const TSlateElementVertexBuffer& );
};
 
 
class FSlateStencilClipVertexBuffer : public FVertexBuffer
{
public:
    FSlateStencilClipVertexBuffer()
    {}
 
    ~FSlateStencilClipVertexBuffer() {};
 
    virtual void InitRHI(FRHICommandListBase& RHICmdList)
    {
        if (!IsValidRef(VertexBufferRHI))
        {
            const uint32 Verts[] = { 0, 1, 2, 3 };
 
            VertexBufferRHI = UE::RHIResourceUtils::CreateVertexBufferFromArray(RHICmdList, TEXT("SlateStencilClipVertexBuffer"), EBufferUsageFlags::Static, MakeConstArrayView(Verts));
 
            // Ensure the vertex buffer could be created
            check(IsValidRef(VertexBufferRHI));
        }
    }
 
    virtual void ReleaseRHI()
    {
        VertexBufferRHI.SafeRelease();
    }
 
    virtual FString GetFriendlyName() const { return TEXT("SlateElementVertices"); }
};
 
extern TGlobalResource<FSlateStencilClipVertexBuffer> GSlateStencilClipVertexBuffer;