Show HN: A physically-based GPU ray tracer written in Julia
simondanisch Thursday, February 19, 2026We 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
Summary
This article provides an in-depth introduction to ray tracing, a rendering technique that simulates the physical behavior of light to create realistic 3D images. It covers the basic principles of ray tracing, including how it calculates the path of light rays, handles reflections and refractions, and can be used to generate complex lighting effects.
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makie.org