无法从后台缓冲区（DirectX9）捕获数据 [英] Unable to capture data from Back Buffer (DirectX9)

问题描述

我想找到最快的方法来截图。到目前为止，我发现可以使用GDI或DirectX。使用GDI我能够捕获屏幕在35ms，而使用DirectX前缓冲区需要73ms平均。我想要更快的方法比这。为此，在DirectX中捕获Back Buffer似乎是一个好的方法。我使用下面的代码来做同样的：

I am trying to find the fastest method to take the screenshot. So far I've figured out that either GDI, or DirectX can be used. Using GDI I am able to capture the screen in 35ms, while using DirectX Front buffer it takes 73ms average. I want even faster method than this. For this purpose capturing Back Buffer in DirectX seems to be a good method. I am using the following code to do the same:

    D3DDISPLAYMODE  ddm;
    D3DPRESENT_PARAMETERS   d3dpp;

    if((g_pD3D=Direct3DCreate9(D3D_SDK_VERSION))==NULL)
    {
        ErrorMessage("Unable to Create Direct3D ");
        return E_FAIL;
    }

    if(FAILED(g_pD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,&ddm)))
    {
        ErrorMessage("Unable to Get Adapter Display Mode");
        return E_FAIL;
    }

    ZeroMemory(&d3dpp,sizeof(D3DPRESENT_PARAMETERS));

    d3dpp.Windowed=WINDOW_MODE;
    d3dpp.Flags=D3DPRESENTFLAG_LOCKABLE_BACKBUFFER;
    d3dpp.BackBufferFormat=ddm.Format;
    d3dpp.BackBufferHeight=nDisplayHeight=gScreenRect.bottom =ddm.Height;
    d3dpp.BackBufferWidth=nDisplayWidth=gScreenRect.right =ddm.Width;
    d3dpp.MultiSampleType=D3DMULTISAMPLE_NONE;
//  d3dpp.SwapEffect=D3DSWAPEFFECT_DISCARD;
    d3dpp.SwapEffect=D3DSWAPEFFECT_COPY;
    d3dpp.hDeviceWindow=hWnd;
    d3dpp.PresentationInterval=D3DPRESENT_INTERVAL_DEFAULT;
    d3dpp.FullScreen_RefreshRateInHz=D3DPRESENT_RATE_DEFAULT;

    if(FAILED(g_pD3D->CreateDevice(D3DADAPTER_DEFAULT,D3DDEVTYPE_HAL,hWnd,D3DCREATE_SOFTWARE_VERTEXPROCESSING ,&d3dpp,&g_pd3dDevice)))
    {
        ErrorMessage("Unable to Create Device");
        return E_FAIL;
    }

    if(FAILED(g_pd3dDevice->CreateOffscreenPlainSurface(ddm.Width, ddm.Height, D3DFMT_A8R8G8B8, D3DPOOL_SCRATCH, &g_pSurface, NULL)))
    {
        ErrorMessage("Unable to Create Surface");
        return E_FAIL;
    }

g_pd3dDevice->GetBackBuffer(0,0,D3DBACKBUFFER_TYPE_MONO,&g_pSurface);
D3DXSaveSurfaceToFile("d:\\v\\temp.bmp",D3DXIFF_BMP,g_pSurface,NULL,NULL);

问题是，输出文件测量为5MB，但在输出中只显示黑色。而在同一个代码，如果我使用GetFrontBufferData我可以成功捕获屏幕。我做错了什么？请帮助我。

The problem is, that the output file measures 5MB, but shows nothing but black color in the output. While in the same code if I use GetFrontBufferData I can successfully capture the screen. Am I doing anything wrong? Please help me..

推荐答案

以下是截图：

IDirect3DSurface9 *offscreenSurface = 0;
d3dDevice->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &offscreenSurface);
D3DXSaveSurfaceToFile( filename, D3DXIFF_BMP, offscreenSurface, 0, 0 )

在之前运行 现在。

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