Funny story! I'm an undergrad Computer Science student who received this postcard raytracer from my Pixar recruiter back in November when they visited my school (CMU). To try and woo my recruiter, I changed the "PIXAR" text to say "HIRE ME" and sent it back to them. I also called fork() twice before the render loop to use 4 cores (plus a spooky mmap call to share the memory).

Here's the gist of my modified code (clang-formatted with comments): https://gist.github.com/Flafla2/d2f44c9e5e5a0ff13e6071fb782d...

And here's what it renders: https://i.imgur.com/Yhqt0Le.png

I didn't end up moving forward with my offer at Pixar, but I had a ton of fun with this! Super awesome idea, Pixar sure knows how to get computer graphics programmers thinking.

If anyone is interested in diving deeper into distance field ray marching and using it in a production game engine, check out my article on the topic here: http://flafla2.github.io/2016/10/01/raymarching.html