Efficiently updating constrained delaunay triangulations
(1995) Finding the constrained Delaunay triangulation and constrained Voronoi diagram of a simple polygon in linear-time.
Section 35.9 describes a class which implements a constrained or constrained Delaunay triangulation with an additional data structure to describe how the constraints are refined by the edges of the triangulations.
Section 35.10 describes a hierarchical data structure for fast point location queries.
Qhull implements the Quickhull algorithm for computing the convex hull.
It handles roundoff errors from floating point arithmetic.
I have already tested couple of implementations but they all worked only for small amount of points (up to 20,000).