Crystal Raytracer

A raytracer ported from Ruby to Crystal, optimized to match Rust performance.

Original

Ported from github.com/edin/raytracer (Ruby version).

Performance

Benchmark System:

• CPU: AMD Ryzen 5 5600H with Radeon Graphics
• Cores/Threads: 6 cores / 12 threads
• Workers: 16

Renders a 500x500 image with reflections, shadows, and multiple colored lights:

Note: Actual render times depend heavily on hardware. The important comparison is the relative speedup between implementations (Ruby vs Crystal vs Rust), which should be consistent across different systems.

That you can see using the "benchmark" binary. However, that binary (while equivalent to the others in the original benchmark repo) is buggy (like others in the original benchmark repo) in that outside this very specific scene they are vulnerable to arithmetic overflows and other issues.

The other binaries (including "raytracer") which renders the same scene do proper bounds checking and are slightly slower.

Both "raytracer" and "animated" are also configurable using env vars, which may make them slower or faster.

Build

shards build --release -Dpreview_mt --mcpu=native --mcmodel=kernel

Run

CRYSTAL_WORKERS=16 ./bin/raytracer
CRYSTAL_WORKERS=16 ./bin/benchmark
CRYSTAL_WORKERS=16 ./bin/animated

Output: crystal-raytracer.png

Optimization Journey

See the blog post for the full story of how we got from Ruby to Rust-speed in Crystal.

License

MIT