AcquireNextFrame 不工作（桌面复制 API 和 D3D11）

Question

我已经整理了这段代码，它截取了桌面的屏幕截图并将其映射为原始像素数据访问，但输出全为零。我不知道我做错了什么。在网上查看了许多 Desktop Duplication Api 示例后，我发现它们与我的没有任何区别。

这是我初始化所有内容的方法，不会引发任何错误。

BOOL init()
{
    CHECKHR(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 0, gFeatureLevels, gNumFeatureLevels, D3D11_SDK_VERSION, &lDevice, &FeatureLevel, &lImmediateContext))
    IDXGIDevice* lDxgiDevice;
    CHECKHR(lDevice->QueryInterface(IID_PPV_ARGS(&lDxgiDevice)))
    IDXGIAdapter* lDxgiAdapter;
    CHECKHR(lDxgiDevice->GetParent(__uuidof(IDXGIAdapter), (void**)&lDxgiAdapter))
    lDxgiDevice->Release();
    IDXGIOutput* lDxgiOutput;
    CHECKHR(lDxgiAdapter->EnumOutputs(0, &lDxgiOutput))
    lDxgiAdapter->Release();
    CHECKHR(lDxgiOutput->GetDesc(&OutputDesc))
    IDXGIOutput1* lDxgiOutput1;
    CHECKHR(lDxgiOutput->QueryInterface(IID_PPV_ARGS(&lDxgiOutput1)))
    lDxgiOutput->Release();
    CHECKHR(lDxgiOutput1->DuplicateOutput(lDevice, &lDeskDupl))
    lDxgiOutput1->Release();
    lDeskDupl->GetDesc(&OutputDuplDesc);
    D3D11_TEXTURE2D_DESC desc;
    desc.Width = OutputDuplDesc.ModeDesc.Width;
    desc.Height = OutputDuplDesc.ModeDesc.Height;
    desc.Format = OutputDuplDesc.ModeDesc.Format;
    desc.ArraySize = 1;
    desc.BindFlags = 0;
    desc.MiscFlags = 0;
    desc.SampleDesc.Count = 1;
    desc.SampleDesc.Quality = 0;
    desc.MipLevels = 1;
    desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ | D3D11_CPU_ACCESS_WRITE;
    desc.Usage = D3D11_USAGE_STAGING;
    CHECKHR(lDevice->CreateTexture2D(&desc, NULL, &lDestImage))
    return TRUE;
}

我正在使用的 CHECKHR 宏已经过我的测试并且可以正常工作，只是为了澄清这不是问题。

这是我用来实际抓取框架的代码：

int main()
{
    init();

    HRESULT hr;
    IDXGIResource* lDesktopResource;
    ID3D11Texture2D* lAcquiredDesktopImage;
    DXGI_OUTDUPL_FRAME_INFO FrameInfo;
    while (true)
    {
        if (SUCCEEDED(lDeskDupl->AcquireNextFrame(INFINITE, &FrameInfo, &lDesktopResource)))
        {
            break;
        }
    }
    hr = lDesktopResource->QueryInterface(IID_PPV_ARGS(&lAcquiredDesktopImage));
    if (FAILED(hr))
    {
        cout << "QueryInterface failed!" << endl;
        system("pause");
    }
    lDesktopResource->Release();
    lImmediateContext->CopyResource(lDestImage, lAcquiredDesktopImage);
    lAcquiredDesktopImage->Release();
    lDeskDupl->ReleaseFrame();
    D3D11_MAPPED_SUBRESOURCE resource;
    UINT subresource = D3D11CalcSubresource(0, 0, 0);
    hr = lImmediateContext->Map(lDestImage, subresource, D3D11_MAP_READ_WRITE, 0, &resource);
    if (FAILED(hr))
    {
        cout << "Map failed!" << endl;
        system("pause");
    }
    BYTE* pb = (BYTE*)(resource.pData);
    for (int i = 0; i < 2000000; i++)
    {
        cout << (int)pb[i] << endl;
    }
    system("pause");
    return 0;
}

所发生的只是 2000000 个零被打印到控制台。有什么我遗漏或看不到的东西吗？

Answer 1

首先，针对您要复制的输出的特定适配器调用D3D11CreateDevice：

BOOL init()
{
    IDXGIFactory* lDxgiFactory;
    CHECKHR(CreateDXGIFactory1(__uuidof(IDXGIFactory), (void**)&lDxgiFactory))
    IDXGIAdapter* lDxgiAdapter;
    CHECKHR(lDxgiFactory->EnumAdapters(0, &lDxgiAdapter))
    lDxgiFactory->Release();
    CHECKHR(D3D11CreateDevice(lDxgiAdapter, D3D_DRIVER_TYPE_UNKNOWN, nullptr, 0, gFeatureLevels, gNumFeatureLevels, D3D11_SDK_VERSION, &lDevice, &FeatureLevel, &lImmediateContext))
    IDXGIDevice* lDxgiDevice;
    CHECKHR(lDevice->QueryInterface(IID_PPV_ARGS(&lDxgiDevice)))
    //IDXGIAdapter* lDxgiAdapter;
    //CHECKHR(lDxgiDevice->GetParent(__uuidof(IDXGIAdapter), (void**)&lDxgiAdapter))
    lDxgiDevice->Release();
    IDXGIOutput* lDxgiOutput;
    CHECKHR(lDxgiAdapter->EnumOutputs(0, &lDxgiOutput))
    lDxgiAdapter->Release();
    CHECKHR(lDxgiOutput->GetDesc(&OutputDesc))
    IDXGIOutput1* lDxgiOutput1;
    CHECKHR(lDxgiOutput->QueryInterface(IID_PPV_ARGS(&lDxgiOutput1)))
    lDxgiOutput->Release();
    CHECKHR(lDxgiOutput1->DuplicateOutput(lDevice, &lDeskDupl))
    // ...

那么，您的代码在AcquireNextFrame 附近不太准确。您需要等待实际帧并在您跳过时在循环中执行ReleaseFrame。

// ...
while (true)
{
    if (SUCCEEDED(lDeskDupl->AcquireNextFrame(INFINITE, &FrameInfo, &lDesktopResource)) && FrameInfo.LastPresentTime.QuadPart)
    {
        break;
    }
    lDeskDupl->ReleaseFrame();
}
// ...