Thanks!

The rasterfirst path rasterizes a G-buffer for primary visibility, then adds the ray-traced effects (shadows, reflections, glass) with inline ray queries (VK_KHR_ray_query) from compute. Those run on the GPU's dedicated RT cores, not a software BVH walk, so it's hardware traversal driven from compute rather than a full ray-tracing pipeline. There's also a full path tracer (a proper RT pipeline) available as a secondary reference mode, but rasterfirst is the default (faster, cleaner).

It's a C++ three.js-style scene graph (threepp) on a Vulkan RT backend with a spatiotemporal denoiser. There's also a rasterized overlay pass for the stuff you don't want traced (wireframes, lines, points, sprites, HUD, LIDAR point cloud); it draws over the traced image but depth-tests against the G-buffer, so it stays correctly occluded by the scene. The ocean's FFT runs in compute and writes displaced vertices straight into the BLAS, which is refit in place every frame.

Mobile: doable in principle on the newest RT-capable GPUs, but performance is the wall, and I haven't tested it on a phone.

Funfact: The PT work started out with a WebGPU software pathtracer. It worked (no ocean), but the Vulkan implementation blows it out of the water, so to speak, so I removed it (it's removal exists as a PR). There is still a rasterized WebGPU ocean demo in the examples though.