alt Hacker NewsShow HN: A physically-based GPU ray tracer written in Julia
We ported pbrt-v4 to Julia and built it into a Makie backend. Any Makie plot can now be rendered with physically-based path tracing.
Julia compiles user-defined physics directly into GPU kernels, so anyone can extend the ray tracer with new materials and media - a black hole with gravitational lensing is ~200 lines of Julia.
Runs on AMD, NVIDIA, and CPU via KernelAbstractions.jl, with Metal coming soon.
Demo scenes: github.com/SimonDanisch/RayDemo
Comments
It's says:
>the reference implementation from Physically Based Rendering (Pharr, Jakob, Humphreys)
I'd like to know a little about the process you went through for the port. That book * sounds like an excellent resource to start from but what was it like using it and the code?
Is the material description part of the language the same as in PBRT?
I'm asking because I had a lot of trouble trying to describe interfaces between materials, only to find out that what I wanted to do was not possible in PBRT without modifying the code. Apparently, in PBRT a material can only have one other material touching it. So, for example rendering a glass filled with water and ice is not possible without hacks. From a user's point of view this is a bit of a let-down, of course.
That's an impressive accomplishment and a fantastic tool to explore.
I don't hear nearly as much about Julia as I used to. A few years ago the view was that it was about to replace Python as the language of choice for data science. Seems like that didn't happen?
honestly the AMD-first bit surprised me - usually ROCm support is an afterthought or just broken outright.
curious about BVH traversal specifically. dynamic dispatch patterns across GPU backends can get weird fast. did KernelAbstractions hold up there or were there vendor-specific fallbacks needed for the heavier acceleration structure work?
On iOS Safari the videos are fullscreening themselves as I scroll. I've seen this on other blogs before but I don't know what causes it. Super annoying
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As an aside, it is really interesting to see a computational package that, while supporting multiple GPU vendors, was first vetted on AMD, not NVidia. It is encouraging to see ROCM finally shaking off its reputation for poor support.