Efficient and reliable triangulation of polygons

Abstract

The author discusses a triangulation algorithm that is based on repeatedly clipping ears of a polygon. The main focus of the work was on designing an algorithm that is (1) completely reliable, (2) easy to implement, and (3) fast in practice. The algorithm was implemented in ANSI C, based on floating-point arithmetic. Due to a series of heuristics that get applied as a back-up for the standard ear-clipping process if the code detects deficiencies in the input polygon, the triangulation code can handle any type of polygonal input data, be it simple or not. Based on his implementation he reports on different strategies (geometric hashing, bounding volume trees) for speeding up the ear-clipping process in practice. The code has been tuned accordingly, and CPU-time statistics document that it tends to be faster than other popular triangulation codes. The code forms the core of a package for triangulating the faces of 3D polyhedra, and it has been successfully incorporated into two industrial graphics packages.