Take screenshot of DirectX full-screen application

Question

This boggles me. DirectX bypasses everything and talks directly to the device driver, thus GDI and other usual methods won\'t work - unless Aero is disabled (or unavailable

Answer 1

Following J99's answer, I made the code work for both windowed and fullscreen modes. It is also done in D3D9.

  IDirect3DSurface9* surface;
  D3DDISPLAYMODE mode;
  pDev->GetDisplayMode(0, &mode); // pDev is my *IDirect3DDevice
  // we can capture only the entire screen,
  // so width and height must match current display mode
  pDev->CreateOffscreenPlainSurface(mode.Width, mode.Height, D3DFMT_A8R8G8B8, D3DPOOL_SCRATCH, &surface, NULL);
  if(pDev->GetFrontBufferData(0, surface)==D3D_OK)
  {
    if(bWindowed) // a global config variable
    {
      // get client area in desktop coordinates
      // this might need to be changed to support multiple screens
      RECT r;
      GetClientRect(hWnd, &r); // hWnd is our window handle
      POINT p = {0, 0};
      ClientToScreen(hWnd, &p);
      SetRect(&r, p.x, p.y, p.x+r.right, p.y+r.bottom);
      D3DXSaveSurfaceToFile(szFilename, D3DXIFF_JPG, surface, NULL, &r);
    }
    else
      D3DXSaveSurfaceToFile(szFilename, D3DXIFF_JPG, surface, NULL, NULL);
  }
  surface->Release();

It looks like format and pool parameters of CreateOffscreenPlainSurface must be exactly the same.