This one has me stumped: I'm using a gluPerspective call to create my perspective as following: GLU.gluPerspective(45.0f, 800/600,5,1000); Here's the problem though, I want to be able to change the resolution (from 800x600 to 1024x768) on the fly and recalculate. I'm drawing a background by creating a single quad with a texture mapped on it. How do I determine the exact size of my backplane so I can "draw" the background in a size that'll take up the entire screen (and not bleed over the edges). I'm guessing there's got to be a formula for this somewhere. Can anyone please help?