Hey there. I am trying to figure out how I would use screen coords. (ex. 0, 0, 100, 100) when creating a quad instead of (0.0f, 0.0f, 1.0f, 1.0f). I hope you get what I'm trying to say. The first one uses pixels, and the second, it uses units in OpenGL. I don't need to do it through my entire app. Just when I draw a certain quad. How do I do this? Thanks in advance, Matt U.

You want to set an orthographic projection matrix that corresponds to your screen size. You can do this by using the function gluOrtho2D function like gluOrtho2D( 0, 0, screen_width, screen_height ), then use glVertex2i for specifying coordinates.