Advanced: z Precision
One bizarre effect of these transformations is z fighting. The hardware’s floating-point numbers used to do the computation have limited precision. Hence, depth coordinates that are mathematically distinct end up having the same (or even reversed) actual floating-point z values. This in turn causes incorrectly hidden objects in the depth buffer. The effect varies per pixel and can cause disturbing flickering intersections of nearby objects. Precision of z is made even worse with perspective division, which is applied to the depth coordinate along with all the other coordinates: As the transformed depth coordinate moves farther away from the near clipping plane, its location becomes increasingly less precise, as shown in ...
Get OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
