[otaviogood]

The geometry in my raytracer can either be ray-traced primitives, like spheres or boxes, or it can be "signed distance functions" (SDFs), which let you define all kinda of crazy shapes. Inigo Quilez does a good job of explaining SDFs here: https://www.iquilezles.org/www/articles/distfunctions/distfu... The refraction math in my code is around line 799 or 809 depending on what you're looking for. There are a few errors in the refraction code in this version. :/ But caustics are handled well by my renderer.