Ray tracing: the next week, in Rust

This is an implementation in Rust of Peter Shirley's "Ray Tracing: The Next Week" book. This is the second of the series:

• Ray tracing in one weekend, in Rust
• Ray tracing: the next week, in Rust
• Ray tracing: the rest of your life, in Rust

Every tagged commit is the code that generates a specific image. In this way it's easy to follow the progress in the book. First git clone this project. Then you can checkout a tag to retrieve the implementation at a specific chapter in the book. For example, with git checkout tags/chapter_06.2 you get the implementation for the second image of chapter 6. With git checkout master you go back to the latest version.

Instead of implementing my own vec3, I preferred using Vector3 from nalgebra crate. For random numbers I used rand. For image loading I used image

Hence dependencies are:

• nalgebra
• rand
• image

What next

You can go on with my Rust implementation for the third book, "Ray tracing: the rest of your life, in Rust".

Improvements

• I easily made the main loop parallel with the rayon crate. Just make sure that Traits are marked Send and Sync and then it's just a matter of using an into_par_iter() iterator.
• I improved BVH implementation¹, e.g. split axis are not chosen randomly but based on widest extension of bounding box along that axis. Objects are sorted along their (doubled) centroid and not their minimum bounding coordinate. Also, I used Box instead of Arc when building the BVH.

1) Ideas taken from @cbiffle's "Rust One-Week-ish Ray Tracer". If you want to see well written idiomatic Rust code have a look at it.