## ← Division by Zero - Interactive 3D Graphics

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Showing Revision 2 created 05/24/2016 by Udacity Robot.

1. Here's a perspective projection matrix. Say you multiply a point with a
2. coordinate, 3,7,0,1 by this matrix. I'll save you the effort. You get 3, 7,
3. negative 2.2, 0. W is 0. If you try to divide negative 2 by 2 by 0 without
4. safety glasses on, the world ends. In fact for any point X, Y, 0, 1, we'll get
5. a W of 0. What do all of these points have in common? The points are exactly on
6. one of the faces of the frustum itself. The points are in the anti-frustum, a
7. mirrored frustum behind the camera. The points are on a plane parallel to the
8. near plane that goes through the origin. Or the points are behind the camera.