Device-Independent Bitmaps

Windows, and therefore DirectX, uses the device-independent bitmap (DIB) as its native graphics file format. Essentially, a DIB is a file that contains information describing an image's dimensions, the number of colors it uses, values describing those colors, and data that describes each pixel. Additionally, a DIB contains some lesser-used parameters, like information about file compression, significant colors (if all are not used), and physical dimensions of the image (in case it will end up in print). DIB files usually have the .bmp file extension, although they might occasionally have a .dib extension.

Because the DIB is so pervasive in Windows programming, the Platform SDK already contains many functions that you can use with DirectX. For example, the following application-defined function, taken from the Ddutil.cpp file that comes with the DirectX APIs in the Platform SDK, combines Win32® and DirectX functions to load a DIB onto a DirectX surface.

extern "C" IDirectDrawSurface * DDLoadBitmap(IDirectDraw *pdd, 
    LPCSTR szBitmap, int dx, int dy) 
{ 
    HBITMAP             hbm; 
    BITMAP              bm; 
    DDSURFACEDESC       ddsd; 
    IDirectDrawSurface *pdds; 
 
    // 
    //  This is the Win32 part. 
    //  Try to load the bitmap as a resource.
    //  If that fails, try it as a file. 
   // 
    hbm = (HBITMAP)LoadImage(
            GetModuleHandle(NULL), szBitmap, 
            IMAGE_BITMAP, dx, dy, LR_CREATEDIBSECTION); 
 
    if (hbm == NULL) 
        hbm = (HBITMAP)LoadImage(
                NULL, szBitmap, IMAGE_BITMAP, dx, dy,
                LR_LOADFROMFILE|LR_CREATEDIBSECTION); 
 
    if (hbm == NULL) 
        return NULL; 
 
    // 
    // Get the size of the bitmap. 
    // 
    GetObject(hbm, sizeof(bm), &bm); 
 
    // 
    // Now, return to DirectX function calls. 
    // Create a DirectDrawSurface for this bitmap. 
    // 
    ZeroMemory(&ddsd, sizeof(ddsd)); 
    ddsd.dwSize = sizeof(ddsd); 
    ddsd.dwFlags = DDSD_CAPS | DDSD_HEIGHT |DDSD_WIDTH; 
    ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN; 
    ddsd.dwWidth = bm.bmWidth; 
    ddsd.dwHeight = bm.bmHeight; 
 
    if (pdd->CreateSurface(&ddsd, &pdds, NULL) != DD_OK) 
        return NULL; 
 
    DDCopyBitmap(pdds, hbm, 0, 0, 0, 0); 
 
    DeleteObject(hbm); 
 
    return pdds; 
} 
 

For more detailed information about DIB files, see the Platform SDK.