I should note that this is a very old article (from 2006), before D had compile-time function execution. D was still around version 0.166. I suppose that only

I should note that this is a very old article (from 2006), before D had compile-time function execution. D was still around version 0.166. I suppose that only makes this project more impressive, although its techniques are obsolete compared to modern D capabilities. With CTFE, you'd write the raytracing code as you would normally, then simply force evaluation to have it interpreted during compilation.