vrai-tracer

AKA: "true-tracer" (in French)

My attempt at following along with Ray Tracing in One Weekend in Rust.

I plan to use this project as a testbed for implementing and profiling various programming paradigms and techniques in Rust. For example:

• Exploring dynamic dispatch vs. enum-based static dispatch with respect to performance, resource usage, and programming ergonomics.
• Various ways to multithread the raytracer.
• SIMD?

Highlights

Dynamic and Static dispatch... In one codebase?!

Thanks to Rust's powerful Trait system, robust generics, and rich macros, this codebase can switch between Dynamic and Static dispatch by toggling a single feature flag! Enabling the enum_dispatch feature switches the entire project from Trait Object based dynamic dispatch, to enum based static dispatch!

And no, the codebase is not a mess of #[cfg(feature = "enum_dispatch")] declarations 😄. The bulk of the conditionally compiled code lives in src/hittable/mod.rs and src/material/mod.rs, while the rest of the codebase uses types exported from those modules, unaware of the specific dispatch type.

Live preview

I've opted to render directly onto a live framebuffer (courtesy of the great minifb crate). This is neat, since it allows for cool things such as live tweaking of render parameters, scene animation, and visualizing the render progress by sending pixels to the buffer as they're completed. I'll be adding static image output at some point as well.

With non-blocking rendering!

This is surprisingly tricky to get right in Rust, what with the borrow checker not letting me just share a buffer between threads easily.

Check out src/render/nonblocking.rs for how I pulled it off. Spoiler alert: lots of channels!

Usage

cargo run --release [samples] [resolution]

Where resolution is of the form WxH (e.g: 640x480)

I plan to parse CLI parameters properly at some point in the future 😄.

Changing the scene requires modifying the code at the moment. I hope to replace this with a serde based configuration format at some point.

Controls

• Hit Space to start some basic camera movement.
• Hold F to freeze the current scene in place.
• - and = change the FOV.
• W and S move the camera in and away from the direction it's looking.
• < and > change the number of samples.