Isomorphic Triangulation of Simple Polygons  Diana Garroway  

Limitations:
This
applet works for most polygons, but does occasionally fail by producing
a triangulation that has edges that cross at nonvertex intersections. This is due to a bug in the algorithm to embed
the spiderweb connectivity into the polygons. This
algorithm was developed by Diana Garroway is outlined below. The algorithm sometimes has trouble with
skinny polygons, and polygons with large vertex weights.
Note: The triangulation is correct in most cases, but
please try another polygon if you see this problem.
Embeding Algorithm (just for interest!):
For i =
MaxWeight down to MinWeight do
For each polygon vertex j
if j
has weight i
create new vertex epsilon distance inside
polygon from j
Weight of j = Weight of j1
For each polygon vertex j
if j
has not been projected and j has Weight >= i and j is an ear of the
inner polygon of weight i
project j's newest epsilon
vertex to fall on edge (j1, j+1)
if j
has already been projected, project j's newest epsilon vertex
> This algorithm can fail on skinny polygons because
epsilon is fixed and it is possible that epsilon distance from the
vertex is outside of the polygon.
>
This algorithm can also fail if a polygon vertex never becomes an ear of
the inner polygon. This rarely happens, but is possible for
polygons with large vertex sets.
> If you have a better algorithm, please email
dianag@cim.mcgill.ca !