Advanced-Graphics is a project mainly written in C++ and C, it's free.
Source code for Advanced Graphics Spring 2011 at the Colorado School of Mines
ShadowVolume - Display realistic shadows using the shadow volume algorithm. The program first calculates a polygon to represent the projection of the shadow of the model and then uses the stencil buffer to mask out the areas in shadow.
VectorField - Visualize 2D field lines using shaders. The field lines are followed backwards and forwards from each pixel and samples are taken from a randomly generated texture to produce a smearing along the field line.