我正在尝试编写一个Windows C ++程序，该程序将尝试从当前显示在屏幕上的任何内容中选择一种感兴趣的颜色。
我尝试过以下GDI，Direct3D9和Direct3D11 DXGI的示例，它们似乎只能用于捕获Windows桌面和/或我自己的应用程序自己的输出。当我启动全屏Direct3D游戏时，我似乎最终得到了一些空白像素数据。
必须有可能实现这一点，否则OBS Studio，FRAPS等不会像它们那样透明地工作。
我知道我可以尝试对OBS Studio进行逆向工程，但是有没有人有一个更简洁的C ++解决方案来捕获任意Windows应用程序的视频输出作为某种像素缓冲区？
编辑：我还应该提到，常规桌面窗口的捕获似乎工作。这是给我带来麻烦的全屏游戏。
编辑：评论者要求我的GDI代码。这是我的GDI和D3D9代码。如您所见，我根据我发现的相互矛盾的示例尝试了一些变体：
std::wstring GetScreenColor(COLORREF& colorRef)
{
std::wstring retVal;
//const int desktopWidth(GetDeviceCaps(desktopHdc, HORZRES));
//const int desktopHeight(GetDeviceCaps(desktopHdc, VERTRES));
// const int desktopWidth(GetSystemMetrics(SM_CXVIRTUALSCREEN));
// const int desktopHeight(GetSystemMetrics(SM_CYVIRTUALSCREEN));
const int desktopWidth(GetSystemMetrics(SM_CXSCREEN));
const int desktopHeight(GetSystemMetrics(SM_CYSCREEN));
HWND desktopHwnd(GetDesktopWindow());
// HDC desktopHdc(GetDC(NULL));
HDC desktopHdc(GetDC(desktopHwnd));
HDC myHdc(CreateCompatibleDC(desktopHdc));
const HBITMAP desktopBitmap(CreateCompatibleBitmap(desktopHdc, desktopWidth, desktopHeight));
SelectObject(myHdc, desktopBitmap);
// BitBlt(myHdc, 0, 0, desktopWidth, desktopHeight, desktopHdc, 0, 0, SRCCOPY);
BitBlt(myHdc, 0, 0, desktopWidth, desktopHeight, desktopHdc, 0, 0, SRCCOPY | CAPTUREBLT);
//SelectObject(myHdc, hOld);
ReleaseDC(NULL, desktopHdc);
BITMAPINFO bitmapInfo = { 0 };
bitmapInfo.bmiHeader.biSize = sizeof(bitmapInfo.bmiHeader);
bitmapInfo.bmiHeader.biWidth = desktopWidth;
bitmapInfo.bmiHeader.biHeight = -desktopHeight;
bitmapInfo.bmiHeader.biPlanes = 1;
bitmapInfo.bmiHeader.biBitCount = 24;
bitmapInfo.bmiHeader.biCompression = BI_RGB;
bitmapInfo.bmiHeader.biSizeImage = 0;
// TODO: use a persistent buffer?
const unsigned long numPixels(desktopHeight * desktopWidth);
ColorBGRS* rawPixels(new ColorBGRS[numPixels]);
if (!GetDIBits(myHdc, desktopBitmap, 0, desktopHeight, rawPixels, &bitmapInfo, DIB_RGB_COLORS))
{
delete[] rawPixels;
ReleaseDC(desktopHwnd, desktopHdc);
DeleteDC(myHdc);
DeleteObject(desktopBitmap);
return L"GetDIBits() failed";
}
unsigned long redSum(0);
unsigned long greenSum(0);
unsigned long blueSum(0);
for (unsigned long index(0); index < numPixels; ++index)
{
blueSum += rawPixels[index].blue;
greenSum += rawPixels[index].green;
redSum += rawPixels[index].red;
}
const unsigned long redAverage(redSum / numPixels);
const unsigned long blueAverage(blueSum / numPixels);
const unsigned long greenAverage(greenSum / numPixels);
colorRef = RGB(redAverage, greenAverage, blueAverage);
delete[] rawPixels;
ReleaseDC(desktopHwnd, desktopHdc);
DeleteDC(myHdc);
DeleteObject(desktopBitmap);
return std::wstring();
}
std::wstring GetScreenColor2(COLORREF& colorRef)
{
IDirect3D9* d3d9(Direct3DCreate9(D3D_SDK_VERSION));
if (!d3d9)
{
d3d9->Release();
return L"Direct3DCreate9() failed";
}
D3DDISPLAYMODE d3dDisplayMode;
if (FAILED(d3d9->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &d3dDisplayMode)))
{
return L"GetAdapterDisplayMode() failed";
}
D3DPRESENT_PARAMETERS d3dPresentParams;
ZeroMemory(&d3dPresentParams, sizeof(D3DPRESENT_PARAMETERS));
d3dPresentParams.Windowed = TRUE;
d3dPresentParams.Flags = D3DPRESENTFLAG_LOCKABLE_BACKBUFFER;
d3dPresentParams.BackBufferFormat = d3dDisplayMode.Format;
d3dPresentParams.BackBufferCount = 1;
d3dPresentParams.BackBufferHeight = d3dDisplayMode.Height;
d3dPresentParams.BackBufferWidth = d3dDisplayMode.Width;
d3dPresentParams.MultiSampleType = D3DMULTISAMPLE_NONE;
d3dPresentParams.SwapEffect = D3DSWAPEFFECT_DISCARD;
//d3dPresentParams.SwapEffect = D3DSWAPEFFECT_COPY;
d3dPresentParams.hDeviceWindow = NULL; //hWnd;
d3dPresentParams.PresentationInterval = D3DPRESENT_INTERVAL_DEFAULT;
d3dPresentParams.FullScreen_RefreshRateInHz = D3DPRESENT_RATE_DEFAULT;
IDirect3DDevice9* d3d9Device(0);
if (FAILED(d3d9->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, d3dPresentParams.hDeviceWindow, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dPresentParams, &d3d9Device)))
{
d3d9->Release();
return L"CreateDevice() failed";
}
IDirect3DSurface9* d3d9Surface(0);
// if (FAILED(d3d9Device->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &d3d9Surface))) return L"GetBackBuffer() failed";
if (FAILED(d3d9Device->CreateOffscreenPlainSurface(d3dDisplayMode.Width, d3dDisplayMode.Height, D3DFMT_A8R8G8B8, D3DPOOL_SCRATCH, &d3d9Surface, NULL)))
// if (FAILED(d3d9Device->CreateOffscreenPlainSurface(d3dDisplayMode.Width, d3dDisplayMode.Height, D3DFMT_A8R8G8B8, D3DPOOL_SYSTEMMEM, &d3d9Surface, NULL)))
{
d3d9Device->Release();
d3d9->Release();
return L"CreateOffscreenPlainSurface() failed";
}
if (FAILED(d3d9Device->GetFrontBufferData(0, d3d9Surface)))
{
d3d9Surface->Release();
d3d9Device->Release();
d3d9->Release();
return L"GetFrontBufferData() failed";
}
D3DLOCKED_RECT d3dLockedRect;
if (FAILED(d3d9Surface->LockRect(&d3dLockedRect, 0, D3DLOCK_NO_DIRTY_UPDATE |
D3DLOCK_NOSYSLOCK |
D3DLOCK_READONLY)))
{
d3d9Surface->UnlockRect();
d3d9Surface->Release();
d3d9Device->Release();
d3d9->Release();
return L"LockRect() failed";
}
const unsigned long numPixels(d3dDisplayMode.Height * d3dDisplayMode.Width);
BYTE* rawPixels((BYTE*)(d3dLockedRect.pBits));
colorRef = RGB(*(rawPixels + 2), *(rawPixels + 1), *(rawPixels));
d3d9Surface->UnlockRect();
d3d9Surface->Release();
d3d9Device->Release();
d3d9->Release();
return std::wstring();
}
自Windows 8以来，Desktop Duplication API能够记录游戏等全屏应用程序。我最近为我的一个项目制作了this library，你可以用它作为参考。只有在你的情况下，你需要从纹理中获取原始像素数据，而不是将它们写入视频或图像。
编辑：添加了一个关于丢失访问的重新初始化的小例子。
{
CComPtr<ID3D11Device> pDevice;
CComPtr<IDXGIOutputDuplication> pDeskDupl;
//(...)create devices and duplication interface etc here..
InitializeDesktopDupl(pDevice, &pDeskDupl, &OutputDuplDesc);
while(true) //capture loop gist.
{
IDXGIResource *pDesktopResource = nullptr;
DXGI_OUTDUPL_FRAME_INFO FrameInfo;
RtlZeroMemory(&FrameInfo, sizeof(FrameInfo));
// Get new frame
HRESULT hr = pDeskDupl->AcquireNextFrame(
99,//timeout in ms
&FrameInfo,
&pDesktopResource);
if (hr == DXGI_ERROR_ACCESS_LOST) {
pDeskDupl->ReleaseFrame();
pDeskDupl.Release();
pDesktopResource->Release();
hr = InitializeDesktopDupl(pDevice, &pDeskDupl, &OutputDuplDesc);
if(FAILED(hr)){
//Check if everything is OK before continuing
}
}
}
}
HRESULT InitializeDesktopDupl(ID3D11Device *pDevice, IDXGIOutputDuplication **ppDesktopDupl, DXGI_OUTDUPL_DESC *pOutputDuplDesc)
{
*ppDesktopDupl = NULL;
*pOutputDuplDesc;
// Get DXGI device
CComPtr<IDXGIDevice> pDxgiDevice;
CComPtr<IDXGIOutputDuplication> pDeskDupl = NULL;
DXGI_OUTDUPL_DESC OutputDuplDesc;
HRESULT hr = pDevice->QueryInterface(IID_PPV_ARGS(&pDxgiDevice));
if (FAILED(hr)) { return hr; }
// Get DXGI adapter
CComPtr<IDXGIAdapter> pDxgiAdapter;
hr = pDxgiDevice->GetParent(
__uuidof(IDXGIAdapter),
reinterpret_cast<void**>(&pDxgiAdapter));
pDxgiDevice.Release();
if (FAILED(hr)) { return hr; }
// Get output
CComPtr<IDXGIOutput> pDxgiOutput;
hr = pDxgiAdapter->EnumOutputs(
m_DisplayOutput,
&pDxgiOutput);
if (FAILED(hr)) { return hr; }
pDxgiAdapter.Release();
CComPtr<IDXGIOutput1> pDxgiOutput1;
hr = pDxgiOutput->QueryInterface(IID_PPV_ARGS(&pDxgiOutput1));
if (FAILED(hr)) { return hr; }
pDxgiOutput.Release();
// Create desktop duplication
hr = pDxgiOutput1->DuplicateOutput(
pDevice,
&pDeskDupl);
if (FAILED(hr)) { return hr; }
pDxgiOutput1.Release();
// Create GUI drawing texture
pDeskDupl->GetDesc(&OutputDuplDesc);
pDxgiOutput1.Release();
*ppDesktopDupl = pDeskDupl;
(*ppDesktopDupl)->AddRef();
*pOutputDuplDesc = OutputDuplDesc;
return hr;
}