Vfxgal is a geometric algorithms library for the VFX industry. It contains a very fast and robust voronoi fracturer, as well as several other geometric algorithms (plane-clip, hull-clip etc). Vfxgal comes with Houdini11 bindings but has been written in such a way that minimal work is needed to bind to other frameworks.
Project Page: https://github.com/nerdvegas/vfxgal
Language: C++, python
Platform: Linux, OSX
License: GNU LGPL