   Recommend a C math library
  Hello, I'm looking for a 3D math library (or a physics lib which includes math) with the following characteristics:- Free for commercial use, non-GPL licence.- Supports at least matrix and vector math.- Provides a C API (I'm not using C++).- Simple and readable interface with documentation.So far I've found Kazmath, but I'd like to explore other alternatives as well.   
  XnaMath.h from the latest DirectX SDK is quite ok. Its supports all sorts of 3d vector and matrix math, its for free and it has a C interface.   