I wrote together with a friend a lib that allows the creation of CPU based realtime raytracing applications. Realtime is atm. not 2 MegaPixel fullscreen with 16 sampels perpixel, but hopefully it will be some day.
We just finished our work on 0.2 version, which is the first version that offers others to use our lib, as it includes not only demos, but also the headers and libs needed for development, documentation and some tutorials.
SFML is used to implement the ScreenBuffer, that is a device that talks with the OS and puts Pixels onto the screen.
In 0.1 we used also Threads but decided to move to boost.
As for 0.2 the libs are not fast and we got a lot of features that are currently unused we decided to work on a 0.3 version which will look the same, that means programmers wont need to change their code.
This 0.3 version will bring you needed speed and implementations and hopefully far more tutorials.
Have fun with this:
http://www.determinationmusic.de/package.7zEDIT: Any feedback is very welcome!