The argument could be made that compile-time processing is highly appropriate for the static inputs of a program, and, at the other extreme, obviously can't be

The argument could be made that compile-time processing is highly appropriate for the static inputs of a program, and, at the other extreme, obviously can't be applied to the dynamic inputs. (Terminology from https://en.wikipedia.org/wiki/Partial_evaluation https://en.wikipedia.org/wiki/Partial_evaluation) Of course, the raytracer source code is the dynamic input of a compiler. The Futamura projection perspective suggests interesting options here for e.g. specializing raytracers in relation to particular scenes.