Unable to draw over a Dialog
Posted on 2009-05-07
I am currently drawing an image using OpenGL into a CWnd. The Window is hidden and the image is drawn to the front buffer and then saved as a .bmp.
The problem is that there is another dialog on the screen at the same time and it is obstructing the hidden window I am drawing onto. This results in the saved bitmap having part of the obstructed dialog drawn on it. I have attempted to draw to the back buffer but all this does is leave the area that the dialog was obstructing being drawn in left black.
I have tried setting the tried using calls like SetFocus(), BringWindowToTop(), SetWindowPos(), etc with the idea of bring my window to the top of the pile but none of those ideas have worked. I suspect the reason is because the obstructing dialog is run independent from my Window, it's in C# my one is in C++.
I should also say that I have been able solve this problem on an 32 ibt XP machine but not on 64 bit XP. The same code also acts differently on Vista machines. I suspected it might have something to do with graphics cards as NVidea and ATi.