View Full Version : view frustum dermination

01-07-2002, 12:58 AM
how can i determine view frustum.
i am giving glOrtho3D command.
I want to know equations of planes of view frustum.
will anybody help?

01-07-2002, 01:41 AM
Hello there,

there is an excellent article at
www.markmorley.com (http://www.markmorley.com)

on view frustum clipping which explains
how to do this.


01-07-2002, 02:20 AM
glOrtho doesn't give you a frustum on the projection matrix, it gives you a box.

The plane equations are axis aligned in eye space and displaced by the values you supply in the call, it is really trivial to determine the plane equations, they align with the corresponding axis with the fourth term being the one you generated in the call.

glFrustum will multiply a projective matrix on the stack creating a frustum.

01-07-2002, 06:30 PM
thanks mark!