blender/io_mspgl/mesh.py

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