mieko / rbpoly2tri

Ruby Bindings to poly2tri: Constrained Delaunay Triangulation

Synopsis

These are Ruby 1.9.2+ bindings to poly2tri. It produces very nice triangulated meshes out of pretty arbitrary polygons.

This release contains an a (slightly-modified) version of Revision 31c314fae1 of the poly2tri C++ branch. Both poly2tri and rbpoly2tri are available under BSD/MIT-style permissive licenses. See poly2tri/LICENSE and LICENSE for details.

poly2tri Homepage

To install via RubyGems:

gem install rbpoly2tri

To install from repo:

gem build rbpoly2tri.gemspec
gem install rbpoly2tri-<version>.gem

Simple Usage:

require 'rbpoly2tri'

# The initial input must be simple (non-intersecting, no holes), and
# repeated vertices are not allowed.  Holes may be added later.

inp = [[100.0, 0.0], [0.0, 0.0], [0.0, 47.85714326530613],
       [-4.999999, 50.0], [0.0, 50.0], [0.0, 100.0], [100.0, 100.0],
       [100.0, 50.0], [200.0, 50.0], [100.0, 5.0]]

# CDT.  You know, Constrained Delaunay Triangulation.
tess = Poly2Tri::CDT.new(inp)

# if you're in the mood to add a hole to this polygon, now's the time:
tess.add_hole [[10, 10], [10,30], [30, 30], [30,10]]

tess.triangulate!
triangles = tess.triangles # => A huge amount of vertices, man.

See Also:

• If you're into this type of thing, you might want to check out rbclipper, my bindings to Clipper, a polygon clipping library.