[flohofwoe]

The 3D scene is described by formulas instead of data. It's a bit similar to how SDF demos describe a 3D scene by combing shape formulas into a single formula for the whole scene (SDF = signed distance fields).

E.g. see:

https://iquilezles.org/articles/distfunctions/

[kragen]

while i know you didn't say this was using an sdf, i want to point out that it doesn't seem to be using an sdf, just in case anyone is wondering; it seems to be a conventional whitted-style raytracer that computes sphere–ray intersections in closed form by solving the quadratic