Rotating teh Screen

Hello. I have been making DS homebrew for a while, and i though i give opengl a shot. I have made a 3D room no problems, but I want to make a game where the ds is held on its side,so how do I go from A to B:…

Don’t know the details about the DS, but I’d say rotating the screen should be as simple as doing a glRotate as one of the very first view transformations.
Probably start with a gluPerspective or glOrtho, then the glRotate and then the normal view transformations.
(Remember that the order of the transformations is applied in reverse order to the geometry)