blender/io_mspgl/mesh.py

   1 import bpy
   2 import math
   3 import mathutils
   4
   5 def make_edge_key(i1, i2):
   6         return (min(i1, i2), max(i1, i2))
   7
   8 class Edge:
   9         def __init__(self, edge):
  10                 if edge.__class__==Edge:
  11                         self._edge = edge._edge
  12                         self.smooth = edge.smooth
  13                 else:
  14                         self._edge = edge
  15                         self.smooth = False
  16                 if edge:
  17                         self.vertices = edge.vertices[:]
  18                         self.key = edge.key
  19                 else:
  20                         self.vertices = []
  21                         self.key = None
  22                 self.faces = []
  23
  24         def __getattr__(self, attr):
  25                 return getattr(self._edge, attr)
  26
  27         def check_smooth(self, limit):
  28                 if len(self.faces)!=2:
  29                         return
  30
  31                 d = self.faces[0].normal.dot(self.faces[1].normal)
  32                 self.smooth = ((d>limit and self.faces[0].use_smooth and self.faces[1].use_smooth) or d>0.99995)
  33
  34         def other_face(self, f):
  35                 if f.index==self.faces[0].index:
  36                         if len(self.faces)>=2:
  37                                 return self.faces[1]
  38                         else:
  39                                 return None
  40                 else:
  41                         return self.faces[0]
  42
  43         def other_vertex(self, v):
  44                 if v.index==self.vertices[0].index:
  45                         return self.vertices[1]
  46                 else:
  47                         return self.vertices[0]
  48
  49
  50 class Vertex:
  51         def __init__(self, vertex):
  52                 if vertex.__class__==Vertex:
  53                         self._vertex = vertex._vertex
  54                         self.uvs = vertex.uvs[:]
  55                         self.tan = vertex.tan
  56                         self.bino = vertex.bino
  57                 else:
  58                         self._vertex = vertex
  59                         self.uvs = []
  60                         self.tan = None
  61                         self.bino = None
  62                 self.index = vertex.index
  63                 self.co = vertex.co
  64                 self.normal = vertex.normal
  65                 self.flag = False
  66                 self.edges = []
  67                 self.faces = []
  68                 self.groups = vertex.groups[:]
  69
  70         def __getattr__(self, attr):
  71                 return getattr(self._vertex, attr)
  72
  73         def __cmp__(self, other):
  74                 if other is None:
  75                         return 1
  76                 return cmp(self.index, other.index)
  77
  78
  79 class VertexGroup:
  80         def __init__(self, group):
  81                 self._group = group
  82                 self.group = group.group
  83                 self.weight = group.weight
  84
  85         def __getattr__(self, attr):
  86                 return getattr(self._group, attr)
  87
  88
  89 class Face:
  90         def __init__(self, face):
  91                 self._face = face
  92                 self.index = face.index
  93                 self.edges = []
  94                 self.vertices = face.vertices[:]
  95                 self.uvs = []
  96                 self.flag = False
  97
  98         def __getattr__(self, attr):
  99                 return getattr(self._face, attr)
 100
 101         def __cmp__(self, other):
 102                 if other is None:
 103                         return 1
 104                 return cmp(self.index, other.index)
 105
 106         def pivot_vertex(self, v):
 107                 n = self.vertices.index(v)
 108                 return [(n+i)%len(self.vertices) for i in range(len(self.vertices))]
 109
 110         def pivot_vertices(self, *vt):
 111                 flags = [(v in vt) for v in self.vertices]
 112                 l = len(self.vertices)
 113                 for i in range(l):
 114                         if flags[i] and not flags[(i+l-1)%l]:
 115                                 return self.vertices[i:]+self.vertices[:i]
 116
 117         def get_edge(self, v1, v2):
 118                 key = make_edge_key(v1.index, v2.index)
 119                 for e in self.edges:
 120                         if e.key==key:
 121                                 return e
 122                 raise KeyError("No edge %s"%(key,))
 123
 124         def other_edge(self, e, v):
 125                 for d in self.edges:
 126                         if d!=e and v in d.vertices:
 127                                 return d
 128
 129         def get_neighbors(self):
 130                 neighbors = [e.other_face(self) for e in self.edges]
 131                 return list(filter(bool, neighbors))
 132
 133
 134 class Line:
 135         def __init__(self, e):
 136                 self.edge = e
 137                 self.vertices = e.vertices[:]
 138                 self.flag = False
 139
 140
 141 class UvLayer:
 142         def __init__(self, arg):
 143                 if type(arg)==str:
 144                         self._layer = None
 145                         self.name = arg
 146                 else:
 147                         self._layer = arg
 148                         self.name = arg.name
 149                         self.uvs = [d.uv for d in self.data]
 150
 151                 self.unit = None
 152                 self.hidden = False
 153
 154                 dot = self.name.find('.')
 155                 if dot>=0:
 156                         ext = self.name[dot:]
 157                         if ext.startswith(".unit") and ext[5:].isdigit():
 158                                 self.unit = int(ext[5:])
 159                         elif ext==".hidden":
 160                                 self.hidden = True
 161
 162         def __getattr__(self, attr):
 163                 return getattr(self._layer, attr)
 164
 165
 166 class Mesh:
 167         def __init__(self, mesh):
 168                 self._mesh = mesh
 169
 170                 self.winding_test = mesh.winding_test
 171                 self.tbn_vecs = mesh.tbn_vecs
 172                 self.vertex_groups = mesh.vertex_groups
 173
 174                 # Clone basic data
 175                 self.vertices = [Vertex(v) for v in self.vertices]
 176                 for v in self.vertices:
 177                         v.groups = [VertexGroup(g) for g in v.groups]
 178
 179                 self.faces = [Face(f) for f in self.polygons]
 180                 self.edges = [Edge(e) for e in self.edges]
 181                 self.loops = self.loops[:]
 182                 self.materials = self.materials[:]
 183
 184                 # Clone only the desired UV layers
 185                 if self.use_uv=='NONE' or not self.uv_layers:
 186                         self.uv_layers = []
 187                 else:
 188                         self.uv_layers = [UvLayer(u) for u in self.uv_layers]
 189                         self.uv_layers = sorted([u for u in self.uv_layers if not u.hidden], key=(lambda u: (u.unit or 1000, u.name)))
 190
 191                         if self.use_uv=='UNIT0':
 192                                 self.uv_layers = [self.uv_layers[0]]
 193
 194                         # Assign texture unit numbers to UV layers that lack one
 195                         next_unit = max((u.unit+1 for u in self.uv_layers if u.unit is not None), default=0)
 196                         for u in self.uv_layers:
 197                                 if not u.unit:
 198                                         u.unit = next_unit
 199                                         next_unit += 1
 200
 201                 # Rewrite links between elements to point to cloned data, or create links
 202                 # where they don't exist
 203                 edge_map = {e.key: e for e in self.edges}
 204                 for f in self.faces:
 205                         if len(f.vertices)>4:
 206                                 raise ValueError("Ngons are not supported")
 207
 208                         f.vertices = [self.vertices[i] for i in f.vertices]
 209                         for v in f.vertices:
 210                                 v.faces.append(f)
 211
 212                         for k in f.edge_keys:
 213                                 e = edge_map[k]
 214                                 e.faces.append(f)
 215                                 f.edges.append(e)
 216
 217                 for e in self.edges:
 218                         e.vertices = [self.vertices[i] for i in e.vertices]
 219                         for v in e.vertices:
 220                                 v.edges.append(e)
 221
 222                 # Store loose edges as lines
 223                 if self.use_lines:
 224                         self.lines = [Line(e) for e in self.edges if not e.faces]
 225                 else:
 226                         self.lines = []
 227
 228                 self.vertex_sequence = []
 229
 230         def __getattr__(self, attr):
 231                 return getattr(self._mesh, attr)
 232
 233         def transform(self, matrix):
 234                 for v in self.vertices:
 235                         v.co = matrix*v.co
 236
 237         def splice(self, other):
 238                 if len(self.uv_layers)!=len(other.uv_layers):
 239                         raise ValueError("Meshes have incompatible UV layers")
 240                 for i, u in enumerate(self.uv_layers):
 241                         if u.name!=other.uv_layers[i].name:
 242                                 raise ValueError("Meshes have incompatible UV layers")
 243
 244                 # Merge materials and form a lookup from source material indices to the
 245                 # merged material list
 246                 material_map = []
 247                 for m in other.materials:
 248                         if m in self.materials:
 249                                 material_map.append(self.materials.index(m))
 250                         else:
 251                                 material_map.append(len(self.materials))
 252                                 self.materials.append(m)
 253
 254                 # Append data and adjust indices where necessary.  Since the data is
 255                 # spliced from the source mesh, rebuilding references is not necessary.
 256                 for i, u in enumerate(self.uv_layers):
 257                         u.uvs += other.uv_layers[i].uvs
 258
 259                 offset = len(self.vertices)
 260                 self.vertices += other.vertices
 261                 for v in self.vertices[offset:]:
 262                         v.index += offset
 263
 264                 loop_offset = len(self.loops)
 265                 self.loops += other.loops
 266
 267                 offset = len(self.faces)
 268                 self.faces += other.faces
 269                 for f in self.faces[offset:]:
 270                         f.index += offset
 271                         f.loop_start += loop_offset
 272                         f.loop_indices = range(f.loop_start, f.loop_start+f.loop_total)
 273                         if other.materials:
 274                                 f.material_index = material_map[f.material_index]
 275
 276                 offset = len(self.edges)
 277                 self.edges += other.edges
 278                 for e in self.edges[offset:]:
 279                         e.index += offset
 280                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 281
 282                 self.lines += other.lines
 283
 284         def prepare_triangles(self, progress):
 285                 face_count = len(self.faces)
 286                 for i in range(face_count):
 287                         f = self.faces[i]
 288                         nverts = len(f.vertices)
 289                         if nverts==3:
 290                                 continue
 291
 292                         # Calculate normals at each vertex of the face
 293                         edge_vecs = []
 294                         for j in range(nverts):
 295                                 edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
 296
 297                         normals = []
 298                         for j in range(nverts):
 299                                 normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
 300
 301                         # Check which diagonal results in a flatter triangulation
 302                         flatness1 = normals[0].dot(normals[2])
 303                         flatness2 = normals[1].dot(normals[3])
 304                         cut_index = 1 if flatness1>flatness2 else 0
 305
 306                         nf = Face(f)
 307                         nf.index = len(self.faces)
 308                         self.faces.append(nf)
 309
 310                         ne = Edge(None)
 311                         ne.index = len(self.edges)
 312                         self.edges.append(ne)
 313
 314                         nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
 315                         nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
 316                         for v in nf.vertices:
 317                                 v.faces.append(nf)
 318
 319                         ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
 320                         for v in ne.vertices:
 321                                 v.edges.append(ne)
 322                         ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
 323                         ne.smooth = True
 324
 325                         f.vertices[3-cut_index].faces.remove(f)
 326                         del f.vertices[3-cut_index]
 327                         f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
 328
 329                         ne.faces = [f, nf]
 330                         if cut_index==0:
 331                                 nf.edges = [ne, f.edges[2], f.edges[3]]
 332                                 f.edges = [f.edges[0], f.edges[1], ne]
 333                         else:
 334                                 nf.edges = [f.edges[1], f.edges[2], ne]
 335                                 f.edges = [f.edges[0], ne, f.edges[3]]
 336                         for e in nf.edges:
 337                                 if e!=ne:
 338                                         e.faces.remove(f)
 339                                         e.faces.append(nf)
 340
 341                         f.normal = normals[1-cut_index]
 342                         nf.normal = normals[3-cut_index]
 343
 344                         progress.set_progress(i/face_count)
 345
 346         def prepare_smoothing(self, progress):
 347                 smooth_limit = -1
 348                 if self.smoothing=='NONE':
 349                         for f in self.faces:
 350                                 f.use_smooth = False
 351
 352                         smooth_limit = 1
 353                 elif self.use_auto_smooth:
 354                         smooth_limit = math.cos(self.auto_smooth_angle)
 355
 356                 for e in self.edges:
 357                         e.check_smooth(smooth_limit)
 358
 359                 progress.push_task("Sharp edges", 0.0, 0.7)
 360                 self.split_vertices(self.find_smooth_group, progress)
 361
 362                 if self.smoothing!='BLENDER':
 363                         progress.set_task("Updating normals", 0.7, 1.0)
 364                         self.compute_normals(progress)
 365
 366                 progress.pop_task()
 367
 368         def prepare_vertex_groups(self, obj):
 369                 for v in self.vertices:
 370                         if v.groups:
 371                                 weight_sum = sum(g.weight for g in v.groups)
 372                                 v.groups = sorted(v.groups, key=(lambda g: g.weight), reverse=True)[:self.max_groups_per_vertex]
 373                                 weight_scale = weight_sum/sum(g.weight for g in v.groups)
 374                                 for g in v.groups:
 375                                         g.weight *= weight_scale
 376
 377                 if obj.parent and obj.parent.type=="ARMATURE":
 378                         armature = obj.parent.data
 379                         bone_indices = {b.name: i for i, b in enumerate(armature.bones)}
 380                         group_index_map = {i: i for i in range(len(obj.vertex_groups))}
 381                         for g in first_obj.vertex_groups:
 382                                 if g.name in bone_indices:
 383                                         group_index_map[g.index] = bone_indices[g.name]
 384
 385                         for v in self.vertices:
 386                                 for g in v.groups:
 387                                         g.group = group_index_map[g.group]
 388
 389         def prepare_uv(self, obj, progress):
 390                 if obj.material_tex and self.use_uv!='NONE':
 391                         layer = UvLayer("material_tex")
 392
 393                         if self.use_uv=='UNIT0':
 394                                 self.uv_layers = [layer]
 395                                 layer.unit = 0
 396                         else:
 397                                 self.uv_layers.append(layer)
 398                                 layer.unit = max((u.unit+1 for u in self.uv_layers if u.unit is not None), default=0)
 399
 400                         layer.uvs = [None]*len(self.loops)
 401                         for f in self.faces:
 402                                 uv = mathutils.Vector(((f.material_index+0.5)/len(self.materials), 0.5))
 403                                 for i in f.loop_indices:
 404                                         layer.uvs[i] = uv
 405
 406                 # Form a list of UV layers referenced by materials with the array atlas
 407                 # property set
 408                 array_uv_layers = [t.uv_layer for m in self.materials if m.array_atlas for t in m.texture_slots if t and t.texture_coords=='UV']
 409                 array_uv_layers = [u for u in self.uv_layers if u.name in array_uv_layers]
 410
 411                 if array_uv_layers:
 412                         for f in self.faces:
 413                                 layer = 0
 414                                 if f.material_index<len(self.materials):
 415                                         mat = self.materials[f.material_index]
 416                                         if mat and mat.array_atlas:
 417                                                 layer = mat.array_layer
 418
 419                                 for l in array_uv_layers:
 420                                         for i in f.loop_indices:
 421                                                 l.uvs[i] = mathutils.Vector((*l.uvs[i], layer))
 422
 423                 # Copy UVs from layers to faces
 424                 for f in self.faces:
 425                         for u in self.uv_layers:
 426                                 f.uvs.append([u.uvs[i] for i in f.loop_indices])
 427
 428                 prog_count = len(self.uv_layers)
 429                 prog_step = 0
 430
 431                 # Split by the UV layer used for TBN vectors first so connectivity
 432                 # remains intact for TBN vector computation
 433                 tbn_layer_index = -1
 434                 if self.tbn_vecs:
 435                         uv_names = [u.name for u in self.uv_layers]
 436                         if self.tbn_uvtex in uv_names:
 437                                 prog_count += 1
 438                                 tbn_layer_index = uv_names.index(self.tbn_uvtex)
 439                                 progress.push_task_slice("Computing TBN", 0, prog_count)
 440                                 self.split_vertices(self.find_uv_group, progress, tbn_layer_index)
 441                                 progress.set_task_slice(self.tbn_uvtex, 1, prog_count)
 442                                 self.compute_tbn(tbn_layer_index, progress)
 443                                 progress.pop_task()
 444                                 prog_step = 2
 445
 446                 # Split by the remaining UV layers
 447                 for i, u in enumerate(self.uv_layers):
 448                         if i==tbn_layer_index:
 449                                 continue
 450
 451                         progress.push_task_slice(u.name, prog_step, prog_count)
 452                         self.split_vertices(self.find_uv_group, progress, i)
 453                         progress.pop_task()
 454                         prog_step += 1
 455
 456                 # Copy UVs from faces to vertices
 457                 for v in self.vertices:
 458                         if v.faces:
 459                                 # All faces still connected to the vertex have the same UV value
 460                                 f = v.faces[0]
 461                                 i = f.vertices.index(v)
 462                                 v.uvs = [u[i] for u in f.uvs]
 463                         else:
 464                                 v.uvs = [(0.0, 0.0)]*len(self.uv_layers)
 465
 466         def split_vertices(self, find_group_func, progress, *args):
 467                 vertex_count = len(self.vertices)
 468                 for i in range(vertex_count):
 469                         v = self.vertices[i]
 470                         for f in v.faces:
 471                                 f.flag = False
 472
 473                         # Find all groups of faces on this vertex
 474                         groups = []
 475                         for f in v.faces:
 476                                 if not f.flag:
 477                                         groups.append(find_group_func(v, f, *args))
 478
 479                         # Give groups after the first separate copies of the vertex
 480                         for g in groups[1:]:
 481                                 nv = Vertex(v)
 482                                 nv.index = len(self.vertices)
 483                                 self.vertices.append(nv)
 484
 485                                 for e in v.edges:
 486                                         e_faces_in_g = [f for f in e.faces if f in g]
 487                                         if not e_faces_in_g:
 488                                                 continue
 489
 490                                         if len(e_faces_in_g)<len(e.faces):
 491                                                 # Create a copy of an edge at the boundary of the group
 492                                                 ne = Edge(e)
 493                                                 ne.index = len(self.edges)
 494                                                 self.edges.append(ne)
 495
 496                                                 ne.other_vertex(v).edges.append(ne)
 497
 498                                                 for f in e_faces_in_g:
 499                                                         e.faces.remove(f)
 500                                                         f.edges[f.edges.index(e)] = ne
 501                                                         ne.faces.append(f)
 502
 503                                                 e = ne
 504
 505                                         e.vertices[e.vertices.index(v)] = nv
 506                                         nv.edges.append(e)
 507
 508                                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 509
 510                                 # Filter out any edges that were removed from the original vertex
 511                                 v.edges = [e for e in v.edges if v in e.vertices]
 512
 513                                 for f in g:
 514                                         v.faces.remove(f)
 515                                         f.vertices[f.vertices.index(v)] = nv
 516                                         nv.faces.append(f)
 517
 518                         progress.set_progress(i/vertex_count)
 519
 520         def find_smooth_group(self, vertex, face):
 521                 face.flag = True
 522
 523                 edges = [e for e in face.edges if vertex in e.vertices]
 524
 525                 group = [face]
 526                 for e in edges:
 527                         f = face
 528                         while e.smooth:
 529                                 f = e.other_face(f)
 530                                 if not f or f.flag:
 531                                         break
 532
 533                                 f.flag = True
 534                                 group.append(f)
 535                                 e = f.other_edge(e, vertex)
 536
 537                 return group
 538
 539         def find_uv_group(self, vertex, face, index):
 540                 uv = face.uvs[index][face.vertices.index(vertex)]
 541                 face.flag = True
 542
 543                 group = [face]
 544                 for f in vertex.faces:
 545                         if not f.flag and f.uvs[index][f.vertices.index(vertex)]==uv:
 546                                 f.flag = True
 547                                 group.append(f)
 548
 549                 return group
 550
 551         def compute_normals(self, progress):
 552                 for i, v in enumerate(self.vertices):
 553                         v.normal = mathutils.Vector()
 554                         for f in v.faces:
 555                                 fv = f.pivot_vertices(v)
 556                                 edge1 = fv[1].co-fv[0].co
 557                                 edge2 = fv[-1].co-fv[0].co
 558                                 if edge1.length and edge2.length:
 559                                         # Use the angle between edges as a weighting factor.  This gives
 560                                         # more consistent normals on bends with an inequal number of
 561                                         # faces on each side.
 562                                         v.normal += f.normal*edge1.angle(edge2)
 563
 564                         if v.normal.length:
 565                                 v.normal.normalize()
 566                         else:
 567                                 v.normal = mathutils.Vector((0, 0, 1))
 568
 569                         progress.set_progress(i/len(self.vertices))
 570
 571         def compute_tbn(self, index, progress):
 572                 # This function is called at an early stage during UV preparation when
 573                 # face UVs are not available yet
 574                 layer_uvs = self.uv_layers[index].uvs
 575
 576                 for i, v in enumerate(self.vertices):
 577                         v.tan = mathutils.Vector()
 578                         v.bino = mathutils.Vector()
 579                         for f in v.faces:
 580                                 vi = f.pivot_vertex(v)
 581                                 uv0 = layer_uvs[f.loop_indices[vi[0]]]
 582                                 uv1 = layer_uvs[f.loop_indices[vi[1]]]
 583                                 uv2 = layer_uvs[f.loop_indices[vi[-1]]]
 584                                 du1 = uv1[0]-uv0[0]
 585                                 du2 = uv2[0]-uv0[0]
 586                                 dv1 = uv1[1]-uv0[1]
 587                                 dv2 = uv2[1]-uv0[1]
 588                                 edge1 = f.vertices[vi[1]].co-f.vertices[vi[0]].co
 589                                 edge2 = f.vertices[vi[-1]].co-f.vertices[vi[0]].co
 590                                 div = (du1*dv2-du2*dv1)
 591                                 if div:
 592                                         mul = edge1.angle(edge2)/div
 593                                         v.tan += (edge1*dv2-edge2*dv1)*mul
 594                                         v.bino += (edge2*du1-edge1*du2)*mul
 595
 596                         if v.tan.length:
 597                                 v.tan.normalize()
 598                         if v.bino.length:
 599                                 v.bino.normalize()
 600
 601                         progress.set_progress(i/len(self.vertices))
 602
 603         def prepare_sequence(self, progress):
 604                 progress.push_task("Reordering faces", 0.0, 0.5)
 605                 self.reorder_faces(progress)
 606
 607                 progress.set_task("Building sequence", 0.5, 1.0)
 608                 sequence = None
 609                 for i, f in enumerate(self.faces):
 610                         if sequence:
 611                                 if len(sequence)==3:
 612                                         # Rotate the first three vertices so that the new face can be added
 613                                         if sequence[0] in f.vertices and sequence[1] not in f.vertices:
 614                                                 sequence.append(sequence[0])
 615                                                 del sequence[0]
 616                                         elif sequence[2] not in f.vertices and sequence[1] in f.vertices:
 617                                                 sequence.insert(0, sequence[-1])
 618                                                 del sequence[-1]
 619
 620                                 if sequence[-1] not in f.vertices:
 621                                         sequence = None
 622                                 else:
 623                                         to_add = [v for v in f.vertices if v!=sequence[-1] and v!=sequence[-2]]
 624                                         if len(to_add)==2:
 625                                                 if (f.vertices[1]==sequence[-1]) != (len(sequence)%2==1):
 626                                                         to_add.reverse()
 627                                                 sequence.append(sequence[-1])
 628                                         sequence += to_add
 629
 630                         if not sequence:
 631                                 sequence = f.vertices[:]
 632                                 self.vertex_sequence.append(sequence)
 633
 634                         progress.set_progress(i/len(self.faces))
 635
 636                 progress.pop_task()
 637
 638                 self.reorder_vertices()
 639
 640         def reorder_faces(self, progress):
 641                 # Tom Forsyth's vertex cache optimization algorithm
 642                 # http://eelpi.gotdns.org/papers/fast_vert_cache_opt.html
 643
 644                 for f in self.faces:
 645                         f.flag = False
 646
 647                 last_triangle_score = 0.75
 648                 cache_decay_power = 1.5
 649                 valence_boost_scale = 2.0
 650                 valence_boost_power = -0.5
 651
 652                 max_cache_size = 32
 653                 cached_vertices = []
 654
 655                 # Keep track of the score and number of unused faces for each vertex
 656                 vertex_info = [[0, len(v.faces)] for v in self.vertices]
 657                 for vi in vertex_info:
 658                         vi[0] = valence_boost_scale*(vi[1]**valence_boost_power)
 659
 660                 face = None
 661                 reordered_faces = []
 662
 663                 n_processed = 0
 664                 while 1:
 665                         if not face:
 666                                 # Previous iteration gave no candidate for best face (or this is
 667                                 # the first iteration).  Scan all faces for the highest score.
 668                                 best_score = 0
 669                                 for f in self.faces:
 670                                         if f.flag:
 671                                                 continue
 672
 673                                         score = sum(vertex_info[v.index][0] for v in f.vertices)
 674                                         if score>best_score:
 675                                                 best_score = score
 676                                                 face = f
 677
 678                         if not face:
 679                                 break
 680
 681                         reordered_faces.append(face)
 682                         face.flag = True
 683
 684                         for v in face.vertices:
 685                                 vertex_info[v.index][1] -= 1
 686
 687                                 # Shuffle the vertex into the front of the cache
 688                                 if v in cached_vertices:
 689                                         cached_vertices.remove(v)
 690                                 cached_vertices.insert(0, v)
 691
 692                         # Update scores for all vertices in the cache
 693                         for i, v in enumerate(cached_vertices):
 694                                 score = 0
 695                                 if i<3:
 696                                         score += last_triangle_score
 697                                 elif i<max_cache_size:
 698                                         score += (1-(i-3)/(max_cache_size-3))**cache_decay_power
 699                                 if vertex_info[v.index][1]:
 700                                         score += valence_boost_scale*(vertex_info[v.index][1]**valence_boost_power)
 701                                 vertex_info[v.index][0] = score
 702
 703                         face = None
 704                         best_score = 0
 705                         for v in cached_vertices:
 706                                 for f in v.faces:
 707                                         if not f.flag:
 708                                                 score = sum(vertex_info[fv.index][0] for fv in f.vertices)
 709                                                 if score>best_score:
 710                                                         best_score = score
 711                                                         face = f
 712
 713                         del cached_vertices[max_cache_size:]
 714
 715                         n_processed += 1
 716                         progress.set_progress(n_processed/len(self.faces))
 717
 718                 self.faces = reordered_faces
 719                 for i, f in enumerate(self.faces):
 720                         f.index = i
 721
 722         def reorder_vertices(self):
 723                 for v in self.vertices:
 724                         v.index = -1
 725
 726                 reordered_vertices = []
 727                 for s in self.vertex_sequence:
 728                         for v in s:
 729                                 if v.index<0:
 730                                         v.index = len(reordered_vertices)
 731                                         reordered_vertices.append(v)
 732
 733                 self.vertices = reordered_vertices
 734
 735                 for e in self.edges:
 736                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 737
 738         def drop_references(self):
 739                 for v in self.vertices:
 740                         v._vertex = None
 741                         for g in v.groups:
 742                                 g._group = None
 743                 for e in self.edges:
 744                         e._edge = None
 745                 for f in self.faces:
 746                         f._face = None
 747                 for u in self.uv_layers:
 748                         u._layer = None
 749                 self._mesh = None
 750
 751
 752 def create_mesh_from_object(context, obj, progress):
 753         if obj.type!="MESH":
 754                 raise Exception("Object is not a mesh")
 755
 756         progress.push_task("Preparing mesh", 0.0, 0.2)
 757
 758         objs = [(obj, mathutils.Matrix())]
 759         i = 0
 760         while i<len(objs):
 761                 o, m = objs[i]
 762                 i += 1
 763                 for c in o.children:
 764                         if c.type=="MESH" and c.compound:
 765                                 objs.append((c, m*c.matrix_local))
 766
 767         mesh = None
 768         bmeshes = []
 769         for o, m in objs:
 770                 bmesh = o.to_mesh(context.scene, True, "PREVIEW")
 771                 bmeshes.append(bmesh)
 772
 773                 # Object.to_mesh does not copy custom properties
 774                 bmesh.winding_test = o.data.winding_test
 775                 bmesh.smoothing = o.data.smoothing
 776                 bmesh.use_lines = o.data.use_lines
 777                 bmesh.vertex_groups = o.data.vertex_groups
 778                 bmesh.max_groups_per_vertex = o.data.max_groups_per_vertex
 779                 bmesh.use_uv = o.data.use_uv
 780                 bmesh.tbn_vecs = o.data.tbn_vecs
 781                 bmesh.tbn_uvtex = o.data.tbn_uvtex
 782
 783                 me = Mesh(bmesh)
 784                 me.transform(m)
 785
 786                 if mesh:
 787                         mesh.splice(me)
 788                 else:
 789                         mesh = me
 790
 791         progress.set_task("Triangulating", 0.2, 0.3)
 792         mesh.prepare_triangles(progress)
 793         progress.set_task("Smoothing", 0.3, 0.5)
 794         mesh.prepare_smoothing(progress)
 795         progress.set_task("Vertex groups", 0.5, 0.6)
 796         mesh.prepare_vertex_groups(obj)
 797         progress.set_task("Preparing UVs", 0.6, 0.8)
 798         mesh.prepare_uv(obj, progress)
 799         progress.set_task("Render sequence", 0.8, 1.0)
 800         mesh.prepare_sequence(progress)
 801
 802         # Discard the temporary Blender meshes after making sure there's no
 803         # references to the data
 804         mesh.drop_references()
 805         for m in bmeshes:
 806                 bpy.data.meshes.remove(m)
 807
 808         progress.pop_task()
 809
 810         return mesh