OK, so this has come up a few times in the past, namely in context of the saturn, and I've seen nothing really positive or in favor of using quads for 3D rendering in discussions on Sega-16 (for 2D games and effects, it's another story).
However, I've seen far more mixed responses in discussions on AtariAge, for example:
From this thread: http://sega-16.com/forum/showthread....462#post190462
Now, I also posted a few quotes from an atariage discussion in the above thread, but to refer back to that same discussion on Atariage:
Originally Posted by kskunk Aug 6, 2009 10:33 PMOriginally Posted by kskunk Aug 10, 2009 12:38 AMOriginally Posted by Atari_Owl Aug 10, 2009 2:05 AMThe NVidia NV1 famously used quads instead of triangles. They put a ton of research into making them work pretty well and developers still cursed it as a toy incapable of Real 3D -- after all, SGI says Real 3D uses triangles! Eventually NVidia relented and offered only triangles. Some people just can't be convinced to think differently.Originally Posted by kskunk Aug 10, 2009 10:29 AM
A post from this much older discussion by veteran jaguar programmer Gorf:
Originally Posted by Gorf Mon Jul 30, 2007 2:37 PM
And this discussion on a current homebrew game using a quad based renderer http://www.atariage.com/forums/topic...ri-owl-project (true 4-point primitives)
Now, one other point, regardless of the math catering to triangles in general and such:
In the context of building 3D models in general, why would quads be any worse than triangles in terms of pure vertices used.
A quad can obviously be built up from 2 triangles, albeit using 6 vertices rather than 4, but conversely can't a quad overlap 2 vertices to create a triangle, using 4 vertices rather than 3?
So in a model with a mix of a lot of quads and triangles it would favor pure quads over triangles in terms of number of vertices. (a model using 4 quads and 4 triangles would take 36 vertices for triangle primitives, but only 32 for quads) Obviously models using more quads would skew things further, and models using primarily triangles would favor triangle primitives (for more complex polygons, quads are generally favored too: a simple pentagon takes 9 points using triangles, 8 for quads; hexagon 12 for trips, 8 for quads; heptagon 15 for trips, 12 for quads; octagon 18 for trips, 12 for quads, etc.