This may seem like a silly question but I want to be certain. If I create a DirectX surface, is it required to be of the same bit depth as the primary/secondary surfaces? i.e. If I have a 32-bit primary surface and I create a 16-bit surface for something or other, will it actually take up only Width*Height*16 or will DirectX force the surface secretly to become 32-bit to be compatible with the primary?
Mainly I want to know because I have a very large bitmap I'd like to store that is only 8-bit mono and I'd rather it didnt take up as much Video Mem as it would if it were put on a 32-bit surface.