gluPerspective specifies a viewing frustum into the world coordinate system. In general, the aspect ratio in gluPerspective should match the aspect ratio of the associated viewport. For example, $ "aspect" ~=~ 2.0 $ means the viewer's angle of view is twice as wide in x as it is in y. If the viewport is twice as wide as it is tall, it displays the image without distortion.The matrix generated by gluPerspective is multiplied by the current matrix, just as if glMultMatrix were called with the generated matrix. To load the perspective matrix onto the current matrix stack instead, precede the call to gluPerspective with a call to glLoadIdentity.
Given
f defined as follows:
f ~=~ cotangent"("{"fovy" over 2}")" The generated matrix is
left ( ~~ down 130 { matrix { ccol { {f over "aspect"} above 0 above 0 above 0 } ccol { 0 above f above 0 above 0 } ccol { 0 above 0 above {{"zFar" + "zNear"} over {"zNear" - "zFar"}} above -1 } ccol { 0 above 0 above {{2 * "zFar" * "zNear"} over {"zNear" - "zFar"}} above 0} }} ~~~ right )