Do you plan, by chance, to release the source code ?
Sure thing, I'll release the source code when it'll be more complete and some cleaning up is in order.
how is OpenGL handy for such kind of thing ?
Classical, cheatless ray tracing, where ray's are traced for every pixel, is very slow and hardly doable in realtime. I cheat a lot here :twisted: . I exploit the fact that the color of an object doesn't change much in nearby pixels, trace fewer rays, if they didn?¢_Tt hit the same object then trace more ray's, otherwise I interpolate between them, and by using OpenGL I get almost free quad interpolation done by hardware, not to mention bilinear filtering and other cool stuff, and also a possibility to do polygonal rendering on top of it. Of course because of this some limitations are introduced and there are sampling artifact (like poor specular highlights on spheres from a far, and missing very small objects), but it's a sacrifice I'm willing to make.