- no question about his being productive, but I’m guessing Epic did their own version of ue3 for ios. Carmack probably stuck to working on getting idtech on there http://www.youtube.com/watch?v=keu4GiTGQ6M

To start: love your book and blog!

You wrote “it seems like the eye is quite good at picking up slight irregularities in tessellated spheres when they are rotating”, and I’d have to agree. Immediately this idea came to mind: how about using a sphere with tesselation based on its parametric equation (modified to prevent too many triangles at the poles) with a good level of tesselation around its ‘equatorial’ circumference. Then use a billboard-technique so that we always see this equator on edge, and show the rotation of the balls by rotating the texture-coordinates instead of the geometry?

For rendering reflections the same trick could be applied, although the computation of the correct texture transform would get a bit hairy I think.

That said: I love the technique employed by Voofoo, especially how it gives them the ability to create exceptional anti-aliasing. I wonder how they handle occlusion by non-ball objects, since those objects are not being raytraced.. Perhaps this is all done in a deffered renderer: render all the normal geometry first and then do a ‘manual’ depth comparison inside the ball-shader?

By the way, we sort of ‘met by proxy’ 16 years ago when you mentioned GUM in Ray Tracing News v7n4, which was a program I wrote as a front-end for POV and Polyray: http://tog.acm.org/resources/RTNews/html/rtnv7n4.html#art14 (with CSG visualisation in wireframe, yay!

In any event, thanks for taking the time to pull all this good stuff together and publishing it here!

Lex