gluPerspective

Here's an alternative to gluPerspective that takes the fovx as a parameter instead of the fovy. All other params stay the same.

Function Perspective( fovx:Float, ratio:Float, near:Float, far:Float )
		Local x:Float=Tan(fovx/2.0)*near
		Local y:Float=x/ratio
		glFrustum -x,x,-y,y,near,far
End Function

Hope it's of some use to you.