geompack, a C code which carries out certain geometric computations, including the Delaunay triangulation and Voronoi diagram of a set of points in the plane, by Barry Joe.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
geompack is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version.
geometry, a C library which carries out geometric calculations in 2, 3 and N dimensional space.
Original FORTRAN77 version by Barry Joe; This version by John Burkardt.