Why does GetObject return an BITMAP with null bmBits?

Question

Context: I\'m trying to take a screenshot of another window to feed it into OpenCV. I found some code on the web that should be able to convert a BITMAP to something OpenCV can

Answer 1

Just for information. When loading bitmap from file and want to use BITMAP .bmBits (for glTexImage2D, glDrawPixels):

LoadImage(NULL, "path_to.bmp", IMAGE_BITMAP, 0, 0,
                                       LR_LOADFROMFILE);

u must specify flag LR_CREATEDIBSECTION

HBITMAP hBmp = NULL;
BITMAP BMp;
hBmp = (HBITMAP) LoadImage(NULL, "bitmap.bmp", IMAGE_BITMAP, 0, 0,
                                       LR_LOADFROMFILE | LR_CREATEDIBSECTION);
GetObject(hBmp, sizeof(BMp), &BMp);
//BMp.bmBits now points to data