Adds the voronoi module and demo

This commit is contained in:
Johann Dreo 2014-05-13 15:27:25 +02:00
commit ca985518b0
3 changed files with 144 additions and 18 deletions

View file

@ -159,23 +159,26 @@ else:
hull_edges = list(utils.tour(hull))
LOGN( "\t\tHull of",len(hull_edges),"edges" )
LOGN( "\tRemove triangles that have at least one edge in common with the convex hull" )
def adjoin_hull(triangle):
"""Return True if the given triangle has at least one edge that is in the set hull_edges."""
for (p,q) in utils.tour(list(triangle)):
if (p,q) in hull_edges or (q,p) in hull_edges:
return True
return False
LOGN( "\tRemove triangles that are not sub-parts of the Penrose tiling" )
# def adjoin_hull(triangle):
# """Return True if the given triangle has at least one edge that is in the set hull_edges."""
# for (p,q) in utils.tour(list(triangle)):
# if (p,q) in hull_edges or (q,p) in hull_edges:
# return True
# return False
def acute_triangle(triangle):
"""Return True if the center of the circumcircle of the given triangle lies inside the triangle.
That is if the triangle is acute."""
return triangulation.in_triangle( triangulation.circumcircle(triangle)[0], triangle )
# FIXME at depth 3, some triangles have an edge in the convex hull...
# Filter out edges that are in hull_edges
tri_nohull = list(filter_if_not( adjoin_hull, triangles ))
# tri_nohull = list(filter_if_not( adjoin_hull, triangles ))
# Filter out triangles that are obtuse
triangulated = list(filter_if_not( acute_triangle, tri_nohull ))
# triangulated = list(filter_if_not( acute_triangle, tri_nohull ))
triangulated = list(filter_if_not( acute_triangle, triangles ))
LOGN( "\t\tRemoved", len(triangles)-len(triangulated), "triangles" )
triangulation_edges = triangulation.edges_of( triangulated )
@ -189,15 +192,18 @@ else:
########################################################################
if args.voronoi:
voronoi_centers = utils.load_points(args.voronoi)
# voronoi_centers = utils.load_points(args.voronoi)
pass
else:
LOGN( "Compute the nodes of the Voronoï diagram" )
voronoi_centers = voronoi.centers(triangulated)
# LOGN( "Compute the nodes of the Voronoï diagram" )
voronoi_graph = voronoi.dual( triangulated )
voronoi_edges = voronoi.edges_of( voronoi_graph )
voronoi_centers = voronoi_graph.keys()
with open("d%i_voronoi_centers.points" % depth, "w") as fd:
for p in voronoi_centers:
fd.write( "%f %f\n" % (p[0],p[1]) )
# with open("d%i_voronoi_centers.points" % depth, "w") as fd:
# for p in voronoi_centers:
# fd.write( "%f %f\n" % (p[0],p[1]) )
########################################################################
@ -238,8 +244,9 @@ uberplot.scatter_segments( ax, penrose_segments, edgecolor=tcol, alpha=0.9, line
# triangulation
uberplot.plot_segments( ax, triangulation_edges, edgecolor="green", alpha=0.2, linewidth=1 )
# Voronoï centers
uberplot.scatter_points( ax, voronoi_centers, edgecolor="none", facecolor="green", linewidth=0 )
# Voronoï
uberplot.scatter_points( ax, voronoi_centers, edgecolor="magenta", facecolor="white", s=200, alpha=0.5 )
uberplot.plot_segments( ax, voronoi_edges, edgecolor="magenta", alpha=0.2, linewidth=1 )
ax.set_aspect('equal')

View file

@ -39,7 +39,8 @@ def scatter_segments( ax, segments, **kwargs ):
def scatter_points( ax, points, **kwargs ):
x = [i[0] for i in points]
y = [i[1] for i in points]
ax.scatter( x,y, s=20, marker='o', **kwargs)
# ax.scatter( x,y, s=20, marker='o', **kwargs)
ax.scatter( x,y, marker='o', **kwargs)
if __name__=="__main__":

118
voronoi.py Normal file
View file

@ -0,0 +1,118 @@
#/usr/bin/env python
from utils import tour,LOG,LOGN,x,y
import triangulation
def nodes( triangles ):
"""Compute the locations of the centers of all the circumscribed circles of the given triangles"""
for triangle in triangles:
(cx,cy),r = triangulation.circumcircle(triangle)
yield (cx,cy)
def edge_in( edge, edges ):
"""Return True if the given edge (or its symetric) is in the given polygon."""
n,m = edge
assert( len(n) == 2 )
assert( len(m) == 2 )
return (n,m) in edges or (m,n) in edges
def neighbours( triangle, polygons ):
"""Returns the set of triangles in candidates that have an edge in common with the given triangle."""
for polygon in polygons:
if polygon == triangle:
continue
# Convert list of points to list of edges, because we want to find EDGE neighbours.
edges_poly = list(tour(list(polygon )))
assert( len(list(edges_poly)) > 0 )
edges_tri = list(tour(list(triangle)))
assert( len(list(edges_tri)) > 0 )
# If at least one of the edge that are in availables polygons are also in the given triangle.
# Beware the symetric edges.
# if any( edge_in( edge, edges_tri ) for edge in edges_poly ):
# yield polygon
for edge in edges_poly:
if edge_in( edge, edges_tri ):
yield polygon
break
def dual( triangles ):
graph = {}
def add_edge( current, neighbor ):
if current in graph:
if neighbor not in graph[current]:
graph[current].append( neighbor )
else:
graph[current] = [ neighbor ]
for triangle in triangles:
assert( len(triangle) == 3 )
current_node = triangulation.circumcircle(triangle)[0]
assert( len(current_node) == 2 )
for neighbor_triangle in neighbours( triangle, triangles ):
neighbor_node = triangulation.circumcircle(neighbor_triangle)[0]
assert( len(neighbor_node) == 2 )
add_edge( current_node, neighbor_node )
add_edge( neighbor_node, current_node )
return graph
def edges_of( graph ):
# edges = set()
edges = []
for k in graph:
for n in graph[k]:
if k != n and (k,n) not in edges and (n,k) not in edges:
# edges.add( (k,n) )
edges.append( (k,n) )
return edges
if __name__ == "__main__":
import sys
import random
import utils
import uberplot
import triangulation
import matplotlib.pyplot as plot
if len(sys.argv) > 1:
scale = 100
nb = int(sys.argv[1])
points = [ (scale*random.random(),scale*random.random()) for i in range(nb)]
else:
points = [
(0,40),
(100,60),
(40,0),
(50,100),
(90,10),
# (50,50),
]
fig = plot.figure()
triangles = triangulation.delaunay_bowyer_watson( points )
delaunay_edges = triangulation.edges_of( triangles )
voronoi_graph = dual( triangles )
voronoi_edges = edges_of( voronoi_graph )
print voronoi_edges
ax = fig.add_subplot(111)
ax.set_aspect('equal')
uberplot.scatter_segments( ax, delaunay_edges, facecolor = "blue" )
uberplot.plot_segments( ax, delaunay_edges, edgecolor = "blue" )
uberplot.scatter_segments( ax, voronoi_edges, facecolor = "red" )
uberplot.plot_segments( ax, voronoi_edges, edgecolor = "red" )
plot.show()