Schemeray
Download
You can download this from the github project.
Description
Raytracers are really fun things. With a minimal amount of effort, you can make something which generates incredibly gorgeous images. It also quickly demonstrates the performance of the working platform.
I had to write one myself, and in Gambit Scheme of course. It supports only the basics: spheres, planes, triangles, point lights, reflections, and .obj file loading. Gambit performed very well, although I've lost the benchmarking results.
I am no longer working on this project, but I plan to take it back up again. It's very helpful to implement graphical algorithms in my raytracer when I'm trying to understand them, instead of jumping into a more difficult real-time rasterizer.
The github project also contains a port to PreScheme, a statically-typed dialet of Scheme (just a subset) which compiles completely out to C.