libgeometry

Libgeometry is a computational geometry library built with graphics
and simulators in mind.

It isn't yet finished, but it already provides some nice fundamental
blocks with which to build more complex processors.  It also is an
improvement over the stock libgeometry shipping with plan9(front).

To use it: mk install it and include the geometry.h from your
projects, then link against the generated libgeometry.a$O.

You can find the documentation in doc/, although it doesn't document
the whole API at the moment.  Points (of which are also vectors),
Matrices and Quaternions are mostly complete.  When in doubt, read
the code.