Show HN: A physically based, CPU-only path tracer written in Rust

Hi all, this is a physically based, CPU-only rendering engine written in Rust. It implements a Monte Carlo path tracing algorithm for global illumination. There's a lot of features, including kd-tree mesh acceleration, physical material properties (microfacet BSDF with multiple importance sampling), HDRI environment maps, OBJ/MTL/STL files, depth of field, and particle physics simulation.

It's also parallelized with rayon and available as a library on crates.io. The entire source code, including code for the above examples and more, is very short (\~3K SLOC). We're still looking to extend it with bidirectional path tracing and other features.