c++ - AcquireNextFrame 不工作(桌面复制 API 和 D3D11)

Question

我已经将截取桌面屏幕截图并将其映射为原始像素数据访问的代码放在一起，但输出全为零。我不知道我做错了什么。在网上查看了 Desktop Duplication Api 的许多示例后，我没有发现它们与我的有任何区别。

这是我初始化所有内容的方法，没有出现任何错误。

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有效，只是为了澄清这不是问题所在。

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;
}

所有发生的事情就是将 2000000 个零打印到控制台。有没有我遗漏或看不到的东西？

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 方面不是很准确。您需要等待实际帧并在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();
}
// ...