I can't believe it's been so long since I did my ray-tracing toy. Anyway, another graphics approach I've always wanted to try is radiosity. So, I've finally been working on it. It's taken a while to implement as I've been trying to be careful around the maths and have somewhat limited spare time, but a couple of days ago I had some minor surgery (yay, hernia op) which has given me a little bit of quiet time, and now it's done. Code's up on github, and another itch scratched. :)
I'm rather pleased at how it's turned out. The way the red and blue wall colours have leached into the surrounding white surfaces, and the soft shadows and darkening in the corners have all worked makes me really rather happy!