In the middle of implementing Catmull-Clark
This commit is contained in:
Stephen M. McQuay
+84
-280
@@ -1,287 +1,91 @@
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from surf.geometry import Vertex, Edge, PolygonMesh
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from collections import defaultdict
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from surf.geometry import PolygonMesh, centroid
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from pprint import pprint as pp # XXX
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def sub_edges(self):
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temp_p = PolygonMesh()
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temp_p.edges = [Edge(), Edge()]
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# temp_p.vertices =
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sub_edges[0].vertices = [self.vertices[0], self.edge_vertex]
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sub_edges[1].vertices = [self.edge_vertex, self.vertices[1]]
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return self.__sub_edges
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def refine(mesh):
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new_vertices = list(mesh.vertices)
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f_vert_offset = len(new_vertices)
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edge_vids_for = defaultdict(list)
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face_vids_for = defaultdict(list)
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new_edges = list(mesh.edges)
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new_faces = []
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# For each face, add a face point
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for cur_face_id, cur_face in enumerate(mesh.faces):
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# Set each face point to be the centroid of all original points for the
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# respective face.
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# here we have already created a list that is a copy of the original
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# verts. we append the new face points to that same list, and simply
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# keep track of offsets into the new vert list ... see e_vert_offset
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# below
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new_face_point = mesh.centroid(cur_face)
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new_vertices.append(new_face_point)
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e_vert_offset = len(new_vertices)
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# For each edge, add an edge point.
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for cur_edge_id, cur_edge in enumerate(mesh.edges):
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# make mapping from edge -> new_face_vert for later
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face_ids_for_edge = mesh.faces_for_edge[cur_edge_id]
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for fid in face_ids_for_edge:
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edge_vids_for[fid].append(cur_edge_id)
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tmp_verts = []
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# Set each edge point to be the average of the two neighbouring, (very
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# recently calculated) face points ...
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tmp_verts.extend([new_vertices[f + f_vert_offset] for f in face_ids_for_edge])
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# ... and its two original endpoints.
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tmp_verts.extend([mesh.vertices[vid] for vid in cur_edge])
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# centroid == average
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new_vertices.append(centroid(tmp_verts))
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# For each face point, add an edge for every edge of the face, connecting
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# the face point to each edge point for the face.
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for trunc_vid in xrange(len(new_vertices[f_vert_offset:e_vert_offset])):
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overall_vid = f_vert_offset + trunc_vid
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for edge_vid in edge_vids_for[trunc_vid]:
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new_edges.append([edge_vid, overall_vid])
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# pp(new_edges)
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# For each original point P
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assert f_vert_offset == len(mesh.vertices)
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for new_vid in xrange(f_vert_offset):
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# take the average F of all n face points for faces touching P ...
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F = centroid([mesh.vertices[vid] for vid in mesh.faces_for_vert[new_vid]])
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print ">>>", F
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# and take the average R of all n edge midpoints for edges touching P
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# wiki is wrong ... it should be the edge points, not midpoints ...
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edges = [mesh.edges[eid] for eid in mesh.edges_for_vert[new_vid]]
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e_verts = []
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for edge in edges:
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e_verts.extend([mesh.vertices[vid] for vid in edge])
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R = centroid(e_verts)
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# where each edge midpoint is the average of its two endpoint vertices.
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# Move each original point to the point (or add it to new_verts)
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v = (F + 2 * R + (len(edges) - 3) * new_vertices[new_vid]) / len(edges)
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return None
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def centroid(face, poly):
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'''
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'''
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# gather all face vertex coords
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face_vertices = face.vertices
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xs = [vertex.x for vertex in face_vertices]
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ys = [vertex.y for vertex in face_vertices]
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zs = [vertex.z for vertex in face_vertices]
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# average each vertex component
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x = sum(xs) / len(xs)
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y = sum(ys) / len(ys)
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z = sum(zs) / len(zs)
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return Vertex(poly, x, y, z)
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if __name__ == '__main__':
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import json
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from surf.geometry import PolygonMesh
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from surf.subd.cc import refine
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def edge_divide(edge, poly):
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'''
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Set each edge vertices to be the average of the two neighboring
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face vertices and its two original end vertices.
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'''
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edge_ids = poly.edge_ids_with_parent(edge.id)
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if edge_ids:
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return edge_ids
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else:
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# otherwise split it
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xs = []
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ys = []
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zs = []
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for face in edge.faces:
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centroid_v = centroid(face, None)
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xs.append(centroid_v.x)
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ys.append(centroid_v.y)
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zs.append(centroid_v.z)
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for vertex in edge.vertices:
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xs.append(vertex.x)
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ys.append(vertex.y)
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zs.append(vertex.z)
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x = sum(xs) / len(xs)
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y = sum(ys) / len(ys)
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z = sum(zs) / len(zs)
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e0 = Edge(poly)
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e1 = Edge(poly)
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edge_vertex = Vertex(poly, x, y, z)
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edge_vertex.edge_ids = [e0.id, e1.id]
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e0.vertex_ids = [edge.vertices[0].id, edge_vertex.id]
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e1.vertex_ids = [edge_vertex.id, edge.vertices[1].id]
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e0.edge_ids = edge.winged_edges_at_vertex(0)
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e0.edge_ids.append(e1.id)
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e1.edge_ids = edge.winged_edges_at_vertex(1)
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e1.edge_ids.append(e0.id)
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e0.parent_id = edge.id
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e1.parent_id = edge.id
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# add all these to the new polygon
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poly.edge_ids.append(e0.id)
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poly.edge_ids.append(e1.id)
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poly.vertices.append(edge_vertex.id)
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return e0.id, e1.id, edge_vertex.id
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def sub_faces(self):
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setup_sub_divisions()
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return sub_faces()
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def interior_edges(self):
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setup_sub_divisions()
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return self.__interior_edges
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def setup_sub_divisions(polygon, face):
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'''
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v0 ev0 v1
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*------e0-----*
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| | |
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ev3 e|11----f5----e|1 ev1
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*------e2-----*
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v3 ev2 v2
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'''
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# create empty sub_faces that will be filled with edge references
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# below
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# these need to at least exist so the interior edges have
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# something to reference
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# sub_faces = [Face(polygon) for edge in face.edge_ids]
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# set up empty edge objects to be filled below
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# interior_edges = [Edge(polygon) for edge in face.edge_ids]
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# # each interior edge connects the exterior edge vertex (mid-point)
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# # to the faceVertex (centroid)
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# for edge_id in range(len(face.edges)):
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# prevIndex = (edge_id - 1) % len(face.edges)
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# nextIndex = (edge_id + 1) % len(face.edges)
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# # end vertices are face centroid and currEdge edge_vertex
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# interior_edges[edge_id].vertices = [
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# face.edges[edge_id],
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# edge_vertex, self.centroid
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# ]
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# # wing edges are the current edge's sub_edges (ordered same as
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# # vertex order) and the prev and next interior edges
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# self.__interior_edges[index].edges = [
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# self.edges[index].sub_edges[0],
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# self.edges[index].sub_edges[1],
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# self.__interior_edges[prevIndex],
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# self.__interior_edges[nextIndex]
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# ]
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# # edge faces are the new sub_faces (current and next faces), the
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# # current will be define below
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# # and the next will be defined on the next iteration (or
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# # already defined on the last iteration)
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# self.__interior_edges[index].faces = [
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# self.__sub_faces[index],
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# self.__sub_faces[nextIndex]
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# ]
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# # now reference the current edge back into the faces,
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# # and the edge.sub_edges, and the edge.edge_vertex
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# # current subFace (same index as current interior edge)
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# # set its edges to reference the same edges used to setup the
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# # interior edge
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# # order will be pretty important on these steps...
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# self.__sub_faces[index].edges = [
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# self.edges[index].sub_edges[0],
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# self.__interior_edges[index],
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# self.__interior_edges[prevIndex],
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# self.edges[prevIndex].sub_edges[1]
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# ]
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# # just set one of the vertex edges, the other belongs to
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# # another face and will get added when that face is run
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# self.edges[index].edge_vertex.edges.append(
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# self.__interior_edges[index])
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# self.edges[index].sub_edges[0].faces.append(
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# self.__sub_faces[index])
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# self.edges[index].sub_edges[0].faces.append(
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# self.__sub_faces[index])
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pass
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def subdivide_face(poly, face):
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# '''
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# '''
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# # find face centroid
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# fc = face.centroid
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# # find edge vertices
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# for edge in face.edges:
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# x, y, z = edge_mid_vertex(edge)
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pass
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def refine(poly):
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'''
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For each face, add a face vertex
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Set each face vertex to be the centroid of all original vertices for
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the respective face.
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For each edge, add an edge vertex.
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Set each edge vertex to be the average of the two neighbouring face
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vertices and its two original endvertices.
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For each face vertex, add an edge for every edge of the face, connecting
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the face vertex to each edge vertex for the face.
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For each original vertex P, take the average F of all n face vertices for
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faces touching P, and take the average R of all n edge midvertices for
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edges touching P, where each edge midvertex is the average of its two
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endvertex vertices. Move each original vertex to the vertex
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'''
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# create a new storage container for the items
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new_poly = PolygonMesh()
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# for now just test with the first face
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start_face = poly.faces[0]
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# go through the face vertices and add them to the new polygon
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for vertex in start_face.vertices:
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# truly, this needs to be a 'copy' of the vertex, I'll fix that later
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new_poly.vertices.append(vertex)
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# find the face centroid
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# and add the face centroid to the new polygon
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start_centroid = centroid(start_face, new_poly)
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new_poly.vertices.append(start_centroid)
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# for each edge on the face,
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for edge in start_face.edges:
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# divide that edge into two new edges with an edge vertex
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# set their parent object as the original edge
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new_e0_id, new_e1_id, edge_v_id = edge_divide(edge, new_poly)
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# create a new edge connecting the centroid to the edge_vertex
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centroid_to_edge = Edge(new_poly)
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new_poly.edges.append(centroid_to_edge)
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# set the new edge's vertex references
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centroid_to_edge.vertex_ids = [edge_v_id, start_centroid.id]
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# set the new edge's winged_edge references
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# centroid_to_edge.edge_ids = poly.edges ==> get edge by id not yet
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# implemented... edge_v_id.edges
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# set the edge vertex edge references
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edge_v_id.edges.append(centroid_to_edge.id)
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# set the centroid's edge reference
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start_centroid.edge_ids.append(centroid_to_edge.id)
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# now walk through the edges connected to the centroid
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start_centroid.edges[0]
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# need to get an adjacent edge, based on the the shared vertex of the
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# original polygon... centroid to edge_vertex to shared point...
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# start_face.neighbors
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# f = sum(list(
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# set(face_vertices)), Vertex()) / len(list(set(face_vertices)))
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# r = sum(list(
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# set(edge_mid_points)), Vertex())
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# / len(list(set(edge_mid_points)))
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# p = vertex
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# n = len(vertex.edges)
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# v = (f + 2.0 * r + (n - 3.0) * p) / n
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# newVertices.append(v)
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# for vertex, newVertex in zip(poly.vertices, newVertices):
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# vertex.x = newVertex.x
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# vertex.y = newVertex.y
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# vertex.z = newVertex.z
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# # so now what.........
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# # (F + 2R + (n-3) P) / n
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# #
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# # F = average of all face vertices touching P
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# # R = average of all edge vertices touching P
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# # P original point
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# # n = number of edges connecting to P
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# p.faces = faces
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# p.vertices = vertices
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# p.edges = edges
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# # plotting these in excel seems to show the correct values (at first
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# # glace...)
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# # so now what.........
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# # (F + 2R + (n-3) P) / n
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# #
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# # F = average of all face vertices touching P
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# # R = average of all edge vertices touching P
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# # P original point
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# # n = face vertices or edge vertices (should be the same number)
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# return PolygonMesh(vertices, edges, faces)
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cube = json.load(open('blender/samples/cube.json', 'r'))
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p = PolygonMesh(**cube)
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q = refine(p)
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