UE4笔记-RHI相关

关于C++上的RHI应用的相关笔记记录:

 

 

Q.UE4读取当前视口屏幕(Camera)的像素数组：

参考

FRenderTarget::ReadPixels

对ENQUEUE_RENDER_COMMAND和ReadSurfaceData的使用

    if(InRect == FIntRect(0, 0, 0, 0))
    {
        InRect = FIntRect(0, 0, GetSizeXY().X, GetSizeXY().Y);
    }

    // Read the render target surface data back.    
    struct FReadSurfaceContext
    {
        FRenderTarget* SrcRenderTarget;
        TArray<FColor>* OutData;
        FIntRect Rect;
        FReadSurfaceDataFlags Flags;
    };

    OutImageData.Reset();
    FReadSurfaceContext Context =
    {
        this,
        &OutImageData,
        InRect,
        InFlags
    };

    ENQUEUE_RENDER_COMMAND(ReadSurfaceCommand)(
        [Context](FRHICommandListImmediate& RHICmdList)
        {
            RHICmdList.ReadSurfaceData(
                Context.SrcRenderTarget->GetRenderTargetTexture(),
                Context.Rect,
                *Context.OutData,
                Context.Flags
                );
        });
    FlushRenderingCommands();

    return OutImageData.Num() > 0;