http://geomalgorithms.com/a12-_hull-3.html

Copyright 2001 softSurfer, 2012 Dan Sunday
This code may be freely used and modified for any purpose
providing that this copyright notice is included with it.
SoftSurfer makes no warranty for this code, and cannot be held
liable for any real or imagined damage resulting from its use.
Users of this code must verify correctness for their application.

file:/src/libbg/chull2.cpp
file:/src/libbg/chull.c
file:/src/libbg/util.c

