RSoft is a software rendering library oriented around math.
If you're looking for a user friendly software rendering library, Silk.h is a good alternative.
This demos can run on the web
A basic example showing the types of shapes that can be rendered and transformations that can be done. Run in your browser
A basic example showing how textures are rendered and transformations that can be done. Run in your browser
A simple raycasting demo with textured walls. Run in your browser
A simple psuedo 3D rendering example. Run in your browser