def triangulate(loops: List[List[Vec]]) -> List[List[Vec]]:
tessalator = glu.gluNewTess()
vertices = []
def new_vertex(pos):
vertices.append(pos[:2])
glu.gluTessProperty(tessalator, glu.GLU_TESS_WINDING_RULE, glu.GLU_TESS_WINDING_ODD)
glu.gluTessCallback(tessalator, glu.GLU_TESS_EDGE_FLAG_DATA, lambda *args: None)
glu.gluTessCallback(tessalator, glu.GLU_TESS_BEGIN, lambda *args: None)
glu.gluTessCallback(tessalator, glu.GLU_TESS_VERTEX, new_vertex)
glu.gluTessCallback(tessalator, glu.GLU_TESS_COMBINE, lambda *args: args[0])
glu.gluTessCallback(tessalator, glu.GLU_TESS_END, lambda: None)
glu.gluTessBeginPolygon(tessalator, 0)
for loop in loops:
glu.gluTessBeginContour(tessalator)
for point in loop:
point = point[0],point[1], 0
glu.gluTessVertex(tessalator, point, point)
glu.gluTessEndContour(tessalator)
glu.gluTessEndPolygon(tessalator)
glu.gluDeleteTess(tessalator)
return [vertices[i:i+3] for i in range(0,len(vertices),3)]
def triangulate(self, polygon):
"""
Triangulates polygon
:param polygon: shapely.geometry.polygon
Polygon to tessellate
:return: list, list
Array of triangle vertex indices [t0i0, t0i1, t0i2, t1i0, t1i1, ... ]
Array of polygon points [(x0, y0), (x1, y1), ... ]
"""
# Create tessellation object
tess = GLU.gluNewTess()
# Setup callbacks
GLU.gluTessCallback(tess, GLU.GLU_TESS_BEGIN, self._on_begin_primitive)
GLU.gluTessCallback(tess, GLU.GLU_TESS_VERTEX, self._on_new_vertex)
GLU.gluTessCallback(tess, GLU.GLU_TESS_EDGE_FLAG, self._on_edge_flag)
GLU.gluTessCallback(tess, GLU.GLU_TESS_COMBINE, self._on_combine)
GLU.gluTessCallback(tess, GLU.GLU_TESS_ERROR, self._on_error)
GLU.gluTessCallback(tess, GLU.GLU_TESS_END, self._on_end_primitive)
# Reset data
del self.tris[:]
del self.pts[:]
self.vertex_index = 0
# Define polygon
GLU.gluTessBeginPolygon(tess, None)
def define_contour(contour):
vertices = list(contour.coords) # Get vertices coordinates
if vertices[0] == vertices[-1]: # Open ring
vertices = vertices[:-1]
self.pts += vertices
GLU.gluTessBeginContour(tess) # Start contour
# Set vertices
for vertex in vertices:
point = (vertex[0], vertex[1], 0)
GLU.gluTessVertex(tess, point, self.vertex_index)
self.vertex_index += 1
GLU.gluTessEndContour(tess) # End contour
# Polygon exterior
define_contour(polygon.exterior)
# Interiors
for interior in polygon.interiors:
define_contour(interior)
# Start tessellation
GLU.gluTessEndPolygon(tess)
# Free resources
GLU.gluDeleteTess(tess)
return self.tris, self.pts
def __del__( self ):
if hasattr( self,'__tess' ):
# checking this might be speared, but shit happens ?
GLU.gluDeleteTess( self.__tess )
