def triangulate_cdt(self):
vertices = list()
#print "preparing constrained delaunay triangulation"
for coord_pair in self.src_polygon.exterior.coords:
vertices.append(coord_pair)
border = [p2t.Point(x, y) for x, y in vertices[1:]]
#print "initializing cdt"
cdt = p2t.CDT(border)
#print "adding holes"
for interior_ring in self.src_polygon.interiors:
hole = list()
for coord_pair in interior_ring.coords:
hole.append(coord_pair)
else:
cdt.add_hole([p2t.Point(x, y) for x, y in hole[1:]])
#print "performing cdt"
triangles = cdt.triangulate()
#print "done"
self.triangles = list()
for t in triangles:
triangle = Polygon([(t.a.x, t.a.y), (t.b.x, t.b.y),
(t.c.x, t.c.y)])
self.triangles.append(triangle)
else:
self.triangles = sorted(self.triangles,
key=attrgetter('area'),
reverse=True)
def get_tris_repr(self):
if self.__triangulation is None:
cdt = p2t.CDT(
[Point2(*i) for i in self.__geometry.exterior.coords[:-1]])
for interior in self.__geometry.interiors:
cdt.add_hole([Point2(*i) for i in interior.coords[:-1]])
self.__triangulation = cdt.triangulate()
return self.__triangulation
def triangulate(self):
""""
Returns triangles that form the same shape as the polygon
:return list of Triangle
"""
p2t_points = [p2t.Point(p[0], p[1]) for p in self.points]
cdt = p2t.CDT(p2t_points)
p2t_triangles = cdt.triangulate()
triangles = [Triangle([t.a.x, t.a.y], [t.b.x, t.b.y], [t.c.x, t.c.y]) for t in p2t_triangles]
return triangles
def triangulate(poly):
"""
Takes a polygon and returns a shape representing it with triangular pieces
For now just returns the delaunay triangulation for testing (until I get
a real triangulation library)
"""
cdt = p2t.CDT(poly)
triangles = cdt.triangulate()
pieces = []
for t in triangles:
pieces.append(
Piece([
Point(t.a.x, t.a.y),
Point(t.b.x, t.b.y),
Point(t.c.x, t.c.y)
]))
return Shape(pieces)
def triangulate(cls, polygon):
"""
Triangulate the given polygon
"""
epoints, ipoints = cls.epoints_ipoints(polygon)
plane = Plane(epoints)
epoints = cls.preprocess(map(plane.to2D, epoints))
if not epoints:
return []
cdt = p2t.CDT(epoints)
for hole in ipoints:
hole = cls.preprocess(map(plane.to2D, hole))
if hole:
cdt.add_hole(hole)
triangles2d = cdt.triangulate()
return [list(map(plane.to3D, [t.a, t.b, t.c])) for t in triangles2d]
def cd_triangulate_single_polygon(self, polygon):
u"""
Perform a Constrained Delaunay Triangulation on a single polygon. The
given polygon needs to be continuous (no multi-polygon) but may contain
holes.
"""
# creating a complete list of the polygon's vertices
vertices = list()
for coord_pair in polygon.exterior.coords:
vertices.append(coord_pair)
# creating the necessary data structure for the triangulation (list of
# vertex points) excluding the duplicated start and end vertex
border = [p2t.Point(x, y) for x, y in vertices[1:]]
# initializing triangulation
cdt = p2t.CDT(border)
# adding holes to triangulation configuration
for interior_ring in polygon.interiors:
hole = list()
for coord_pair in interior_ring.coords:
hole.append(coord_pair)
else:
cdt.add_hole([p2t.Point(x, y) for x, y in hole[1:]])
# performing triangulation and returning result
return cdt.triangulate()
def triangulatePolygon( verts, holes = None ): polyline = [] x, y = None, None for i in range( 0, len( verts ), 2 ): xx, yy = verts[i], verts[i+1] if xx == x and yy == y: continue polyline.append( p2t.Point( xx, yy ) ) x = xx y = yy cdt = p2t.CDT( polyline ) if holes: for hole in holes: cdt.add_hole( hole ) triangles = cdt.triangulate() result = [] for t in triangles: result.append( t.a.x ) result.append( t.a.y ) result.append( t.b.x ) result.append( t.b.y ) result.append( t.c.x ) result.append( t.c.y ) return result