CGAL users discussion list

[Agnel C J Kurian <>]

I am using Constrained_triangulation_2 to triangulate a polygon with holes in
it. I am adding the external boundary and the boundary of the holes as
constraints.

How do I then exclude the faces/edges which fall within the holes?

A solution was suggested here:
http://stackoverflow.com/questions/406301/406647#406647 (However, I have not
been able to act on it till now.)

"You can then tag the triangles of the triangulation by any traversal
algorithm: start with a triangle incident to the infinite vertex and tag it as
being outside, and each time you cross a constraint, switch to the opposite 
tag
(inside if you were previously tagging the triangles as outsider, outside if
you were tagging triangles as insider before)."

How do I check when I cross a constraint? How do I tag a triangle?