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.color = None
  60                 self.flag = False
  61                 self.edges = []
  62                 self.faces = []
  63                 self.groups = vertex.groups[:]
  64
  65         def __cmp__(self, other):
  66                 if other is None:
  67                         return 1
  68                 return cmp(self.index, other.index)
  69
  70
  71 class VertexGroup:
  72         def __init__(self, group):
  73                 self.group = group.group
  74                 self.weight = group.weight
  75
  76
  77 class Face:
  78         def __init__(self, face):
  79                 self.index = face.index
  80                 self.edges = []
  81                 self.edge_keys = face.edge_keys
  82                 self.vertices = face.vertices[:]
  83                 self.loop_indices = face.loop_indices
  84                 self.normal = face.normal
  85                 self.use_smooth = face.use_smooth
  86                 self.material_index = face.material_index
  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_loop_index(self, v):
  99                 return self.loop_indices[self.vertices.index(v)]
 100
 101         def get_edge(self, v1, v2):
 102                 key = make_edge_key(v1.index, v2.index)
 103                 for e in self.edges:
 104                         if e.key==key:
 105                                 return e
 106                 raise KeyError("No edge %s"%(key,))
 107
 108         def other_edge(self, e, v):
 109                 for d in self.edges:
 110                         if d!=e and v in d.vertices:
 111                                 return d
 112
 113         def get_neighbors(self):
 114                 neighbors = [e.other_face(self) for e in self.edges]
 115                 return list(filter(bool, neighbors))
 116
 117
 118 class Line:
 119         def __init__(self, e):
 120                 self.edge = e
 121                 self.vertices = e.vertices[:]
 122                 self.flag = False
 123
 124
 125 class UvLayer:
 126         def __init__(self, arg):
 127                 if type(arg)==str:
 128                         self.name = arg
 129                         self.uvs = []
 130                 else:
 131                         self.name = arg.name
 132                         self.uvs = [mathutils.Vector(d.uv) for d in arg.data]
 133
 134                 self.unit = None
 135                 self.hidden = False
 136
 137                 dot = self.name.find('.')
 138                 if dot>=0:
 139                         ext = self.name[dot:]
 140                         if ext.startswith(".unit") and ext[5:].isdigit():
 141                                 self.unit = int(ext[5:])
 142                         elif ext==".hidden":
 143                                 self.hidden = True
 144
 145
 146 class ColorLayer:
 147         def __init__(self, l):
 148                 self.name = l.name
 149                 self.colors = [c.color[:] for c in l.data]
 150
 151
 152 class Mesh:
 153         def __init__(self, mesh):
 154                 self.name = mesh.name
 155
 156                 self.winding_test = mesh.winding_test
 157                 self.smoothing = mesh.smoothing
 158                 self.use_uv = mesh.use_uv
 159                 self.tbn_vecs = mesh.tbn_vecs
 160                 self.tbn_uvtex = mesh.tbn_uvtex
 161                 self.vertex_groups = mesh.vertex_groups
 162
 163                 # Clone basic data
 164                 self.vertices = [Vertex(v) for v in mesh.vertices]
 165                 for v in self.vertices:
 166                         v.groups = [VertexGroup(g) for g in v.groups]
 167
 168                 self.faces = [Face(f) for f in mesh.polygons]
 169                 self.edges = [Edge(e) for e in mesh.edges]
 170                 self.loops = mesh.loops[:]
 171                 self.materials = mesh.materials[:]
 172
 173                 self.use_auto_smooth = mesh.use_auto_smooth
 174                 self.auto_smooth_angle = mesh.auto_smooth_angle
 175
 176                 # Clone only the desired UV layers
 177                 if mesh.use_uv=='NONE' or not mesh.uv_layers:
 178                         self.uv_layers = []
 179                 else:
 180                         self.uv_layers = [UvLayer(u) for u in mesh.uv_layers]
 181
 182                         # Assign texture unit numbers to UV layers that lack one
 183                         missing_unit = [u for u in self.uv_layers if u.unit is None]
 184                         if missing_unit:
 185                                 missing_unit = sorted(missing_unit, key=(lambda u: u.name))
 186                                 used_units = [u.unit for u in self.uv_layers if u.unit is not None]
 187                                 for u, n in zip(missing_unit, (i for i in itertools.count() if i not in used_units)):
 188                                         u.unit = n
 189
 190                         self.uv_layers = sorted(self.uv_layers, key=(lambda u: u.unit))
 191
 192                         if mesh.use_uv=='UNIT0':
 193                                 self.uv_layers = [self.uv_layers[0]]
 194                                 if self.uv_layers[0].unit!=0:
 195                                         self.uv_layers = []
 196
 197                 self.colors = None
 198                 if mesh.vertex_colors:
 199                         self.colors = ColorLayer(mesh.vertex_colors[0])
 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 mesh.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 transform(self, matrix):
 231                 for v in self.vertices:
 232                         v.co = matrix@v.co
 233
 234         def splice(self, other):
 235                 if len(self.uv_layers)!=len(other.uv_layers):
 236                         raise ValueError("Meshes have incompatible UV layers")
 237                 for i, u in enumerate(self.uv_layers):
 238                         if u.name!=other.uv_layers[i].name:
 239                                 raise ValueError("Meshes have incompatible UV layers")
 240
 241                 # Merge materials and form a lookup from source material indices to the
 242                 # merged material list
 243                 material_map = []
 244                 for m in other.materials:
 245                         if m in self.materials:
 246                                 material_map.append(self.materials.index(m))
 247                         else:
 248                                 material_map.append(len(self.materials))
 249                                 self.materials.append(m)
 250
 251                 # Append data and adjust indices where necessary.  Since the data is
 252                 # spliced from the source mesh, rebuilding references is not necessary.
 253                 for i, u in enumerate(self.uv_layers):
 254                         u.uvs += other.uv_layers[i].uvs
 255
 256                 if self.colors:
 257                         if other.colors:
 258                                 self.colors.colors += other.colors.colors
 259                         else:
 260                                 self.colors.colors += [(1.0, 1.0, 1.0, 1.0)]*len(other.loops)
 261                 elif other.colors:
 262                         self.colors = ColorLayer(other.colors.name)
 263                         self.colors.colors = [(1.0, 1.0, 1.0, 1.0)]*len(self.loops)+other.colors.colors
 264
 265                 offset = len(self.vertices)
 266                 self.vertices += other.vertices
 267                 for v in self.vertices[offset:]:
 268                         v.index += offset
 269
 270                 loop_offset = len(self.loops)
 271                 self.loops += other.loops
 272
 273                 offset = len(self.faces)
 274                 self.faces += other.faces
 275                 for f in self.faces[offset:]:
 276                         f.index += offset
 277                         f.loop_indices = range(f.loop_indices.start+offset, f.loop_indices.stop+offset)
 278                         if other.materials:
 279                                 f.material_index = material_map[f.material_index]
 280
 281                 offset = len(self.edges)
 282                 self.edges += other.edges
 283                 for e in self.edges[offset:]:
 284                         e.index += offset
 285                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 286
 287                 self.lines += other.lines
 288
 289         def prepare_triangles(self, progress):
 290                 face_count = len(self.faces)
 291                 for i in range(face_count):
 292                         f = self.faces[i]
 293                         nverts = len(f.vertices)
 294                         if nverts==3:
 295                                 continue
 296
 297                         # Calculate normals at each vertex of the face
 298                         edge_vecs = []
 299                         for j in range(nverts):
 300                                 edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
 301
 302                         normals = []
 303                         for j in range(nverts):
 304                                 normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
 305
 306                         # Check which diagonal results in a flatter triangulation
 307                         flatness1 = normals[0].dot(normals[2])
 308                         flatness2 = normals[1].dot(normals[3])
 309                         cut_index = 1 if flatness1>flatness2 else 0
 310
 311                         nf = Face(f)
 312                         nf.index = len(self.faces)
 313                         self.faces.append(nf)
 314
 315                         ne = Edge(None)
 316                         ne.index = len(self.edges)
 317                         self.edges.append(ne)
 318
 319                         nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
 320                         nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
 321                         for v in nf.vertices:
 322                                 v.faces.append(nf)
 323
 324                         ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
 325                         for v in ne.vertices:
 326                                 v.edges.append(ne)
 327                         ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
 328                         ne.smooth = True
 329
 330                         f.vertices[3-cut_index].faces.remove(f)
 331                         del f.vertices[3-cut_index]
 332                         f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
 333
 334                         ne.faces = [f, nf]
 335                         if cut_index==0:
 336                                 nf.edges = [ne, f.edges[2], f.edges[3]]
 337                                 f.edges = [f.edges[0], f.edges[1], ne]
 338                         else:
 339                                 nf.edges = [f.edges[1], f.edges[2], ne]
 340                                 f.edges = [f.edges[0], ne, f.edges[3]]
 341                         for e in nf.edges:
 342                                 if e!=ne:
 343                                         e.faces.remove(f)
 344                                         e.faces.append(nf)
 345
 346                         f.normal = normals[1-cut_index]
 347                         nf.normal = normals[3-cut_index]
 348
 349                         progress.set_progress(i/face_count)
 350
 351         def prepare_smoothing(self, progress):
 352                 smooth_limit = -1
 353                 if self.smoothing=='NONE':
 354                         for f in self.faces:
 355                                 f.use_smooth = False
 356
 357                         smooth_limit = 1
 358                 elif self.use_auto_smooth:
 359                         smooth_limit = math.cos(self.auto_smooth_angle)
 360
 361                 for e in self.edges:
 362                         e.check_smooth(smooth_limit)
 363
 364                 progress.push_task("Sharp edges", 0.0, 0.7)
 365                 self.split_vertices(self.find_smooth_group, progress)
 366
 367                 if self.smoothing!='BLENDER':
 368                         progress.set_task("Updating normals", 0.7, 1.0)
 369                         self.compute_normals(progress)
 370
 371                 progress.pop_task()
 372
 373         def prepare_vertex_groups(self, obj):
 374                 for v in self.vertices:
 375                         if v.groups:
 376                                 weight_sum = sum(g.weight for g in v.groups)
 377                                 v.groups = sorted(v.groups, key=(lambda g: g.weight), reverse=True)[:self.max_groups_per_vertex]
 378                                 weight_scale = weight_sum/sum(g.weight for g in v.groups)
 379                                 for g in v.groups:
 380                                         g.weight *= weight_scale
 381
 382                 if obj.parent and obj.parent.type=="ARMATURE":
 383                         armature = obj.parent.data
 384                         bone_indices = {b.name: i for i, b in enumerate(armature.bones)}
 385                         group_index_map = {i: i for i in range(len(obj.vertex_groups))}
 386                         for g in first_obj.vertex_groups:
 387                                 if g.name in bone_indices:
 388                                         group_index_map[g.index] = bone_indices[g.name]
 389
 390                         for v in self.vertices:
 391                                 for g in v.groups:
 392                                         g.group = group_index_map[g.group]
 393
 394         def apply_material_map(self, material_map):
 395                 for m in self.materials:
 396                         if m.name not in material_map.material_names:
 397                                 raise Exception("Material map is not compatible with Mesh")
 398
 399                 if self.use_uv=='NONE':
 400                         return
 401
 402                 layer = UvLayer("material_map")
 403                 if self.use_uv=='UNIT0':
 404                         self.uv_layers = [layer]
 405                         layer.unit = 0
 406                 else:
 407                         self.uv_layers.append(layer)
 408                         used_units = [u.unit for u in self.uv_layers]
 409                         layer.unit = next(i for i in itertools.count() if i not in used_units)
 410                         self.uv_layers.sort(key=lambda u: u.unit)
 411
 412                 layer.uvs = [(0.0, 0.0)]*len(self.loops)
 413                 for f in self.faces:
 414                         uv = material_map.get_material_uv(self.materials[f.material_index])
 415                         for i in f.loop_indices:
 416                                 layer.uvs[i] = uv
 417
 418         def prepare_uv(self, progress):
 419                 # Form a list of UV layers referenced by materials with the array atlas
 420                 # property set
 421                 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']
 422                 array_uv_layers = [u for u in self.uv_layers if u.name in array_uv_layers]
 423
 424                 if array_uv_layers:
 425                         for f in self.faces:
 426                                 layer = 0
 427                                 if f.material_index<len(self.materials):
 428                                         mat = self.materials[f.material_index]
 429                                         if mat and mat.array_atlas:
 430                                                 layer = mat.array_layer
 431
 432                                 for l in array_uv_layers:
 433                                         for i in f.loop_indices:
 434                                                 l.uvs[i] = mathutils.Vector((*l.uvs[i], layer))
 435
 436                 prog_count = len(self.uv_layers)
 437                 prog_step = 0
 438
 439                 # Split by the UV layer used for TBN vectors first so connectivity
 440                 # remains intact for TBN vector computation
 441                 tbn_layer_index = -1
 442                 if self.tbn_vecs:
 443                         uv_names = [u.name for u in self.uv_layers]
 444                         if self.tbn_uvtex in uv_names:
 445                                 prog_count += 1
 446                                 tbn_layer_index = uv_names.index(self.tbn_uvtex)
 447                                 progress.push_task_slice("Computing TBN", 0, prog_count)
 448                                 self.split_vertices(self.find_uv_group, progress, tbn_layer_index)
 449                                 progress.set_task_slice(self.tbn_uvtex, 1, prog_count)
 450                                 self.compute_tbn(tbn_layer_index, progress)
 451                                 progress.pop_task()
 452                                 prog_step = 2
 453                         else:
 454                                 raise Exception("TBN UV layer not found")
 455
 456                 # Split by the remaining UV layers
 457                 for i, u in enumerate(self.uv_layers):
 458                         if i==tbn_layer_index:
 459                                 continue
 460
 461                         progress.push_task_slice(u.name, prog_step, prog_count)
 462                         self.split_vertices(self.find_uv_group, progress, i)
 463                         progress.pop_task()
 464                         prog_step += 1
 465
 466                 # Copy UVs from layers to vertices
 467                 for v in self.vertices:
 468                         if v.faces:
 469                                 # All faces still connected to the vertex have the same UV value
 470                                 f = v.faces[0]
 471                                 i = f.get_loop_index(v)
 472                                 v.uvs = [u.uvs[i] for u in self.uv_layers]
 473                         else:
 474                                 v.uvs = [(0.0, 0.0)]*len(self.uv_layers)
 475
 476         def prepare_colors(self, progress):
 477                 if not self.colors:
 478                         return
 479
 480                 self.split_vertices(self.find_color_group, progress)
 481
 482                 for v in self.vertices:
 483                         if v.faces:
 484                                 f = v.faces[0]
 485                                 v.color = self.colors.colors[f.get_loop_index(v)]
 486                         else:
 487                                 v.color = (1.0, 1.0, 1.0, 1.0)
 488
 489         def split_vertices(self, find_group_func, progress, *args):
 490                 vertex_count = len(self.vertices)
 491                 for i in range(vertex_count):
 492                         v = self.vertices[i]
 493                         for f in v.faces:
 494                                 f.flag = False
 495
 496                         # Find all groups of faces on this vertex
 497                         groups = []
 498                         for f in v.faces:
 499                                 if not f.flag:
 500                                         groups.append(find_group_func(v, f, *args))
 501
 502                         # Give groups after the first separate copies of the vertex
 503                         for g in groups[1:]:
 504                                 nv = Vertex(v)
 505                                 nv.index = len(self.vertices)
 506                                 self.vertices.append(nv)
 507
 508                                 for e in v.edges:
 509                                         e_faces_in_g = [f for f in e.faces if f in g]
 510                                         if not e_faces_in_g:
 511                                                 continue
 512
 513                                         if len(e_faces_in_g)<len(e.faces):
 514                                                 # Create a copy of an edge at the boundary of the group
 515                                                 ne = Edge(e)
 516                                                 ne.index = len(self.edges)
 517                                                 self.edges.append(ne)
 518
 519                                                 ne.other_vertex(v).edges.append(ne)
 520
 521                                                 for f in e_faces_in_g:
 522                                                         e.faces.remove(f)
 523                                                         f.edges[f.edges.index(e)] = ne
 524                                                         ne.faces.append(f)
 525
 526                                                 e = ne
 527
 528                                         e.vertices[e.vertices.index(v)] = nv
 529                                         nv.edges.append(e)
 530
 531                                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 532
 533                                 # Filter out any edges that were removed from the original vertex
 534                                 v.edges = [e for e in v.edges if v in e.vertices]
 535
 536                                 for f in g:
 537                                         v.faces.remove(f)
 538                                         f.vertices[f.vertices.index(v)] = nv
 539                                         nv.faces.append(f)
 540
 541                         progress.set_progress(i/vertex_count)
 542
 543         def find_smooth_group(self, vertex, face):
 544                 face.flag = True
 545
 546                 edges = [e for e in face.edges if vertex in e.vertices]
 547
 548                 group = [face]
 549                 for e in edges:
 550                         f = face
 551                         while e.smooth:
 552                                 f = e.other_face(f)
 553                                 if not f or f.flag:
 554                                         break
 555
 556                                 f.flag = True
 557                                 group.append(f)
 558                                 e = f.other_edge(e, vertex)
 559
 560                 return group
 561
 562         def find_uv_group(self, vertex, face, index):
 563                 layer = self.uv_layers[index]
 564                 uv = layer.uvs[face.get_loop_index(vertex)]
 565                 face.flag = True
 566
 567                 group = [face]
 568                 for f in vertex.faces:
 569                         if not f.flag and layer.uvs[f.get_loop_index(vertex)]==uv:
 570                                 f.flag = True
 571                                 group.append(f)
 572
 573                 return group
 574
 575         def find_color_group(self, vertex, face):
 576                 color = self.colors.colors[face.get_loop_index(vertex)]
 577                 face.flag = True
 578
 579                 group = [face]
 580                 for f in vertex.faces:
 581                         if not f.flag and self.colors.colors[f.get_loop_index(vertex)]==color:
 582                                 f.flag = True
 583                                 group.append(f)
 584
 585                 return group
 586
 587         def compute_normals(self, progress):
 588                 for i, v in enumerate(self.vertices):
 589                         v.normal = mathutils.Vector()
 590                         for f in v.faces:
 591                                 vi = f.pivot_vertex(v)
 592                                 edge1 = f.vertices[vi[1]].co-v.co
 593                                 edge2 = f.vertices[vi[-1]].co-v.co
 594                                 if edge1.length and edge2.length:
 595                                         # Use the angle between edges as a weighting factor.  This gives
 596                                         # more consistent normals on bends with an inequal number of
 597                                         # faces on each side.
 598                                         v.normal += f.normal*edge1.angle(edge2)
 599
 600                         if v.normal.length:
 601                                 v.normal.normalize()
 602                         else:
 603                                 v.normal = mathutils.Vector((0, 0, 1))
 604
 605                         progress.set_progress(i/len(self.vertices))
 606
 607         def compute_tbn(self, index, progress):
 608                 # This function is called at an early stage during UV preparation when
 609                 # face UVs are not available yet
 610                 layer_uvs = self.uv_layers[index].uvs
 611
 612                 for i, v in enumerate(self.vertices):
 613                         v.tan = mathutils.Vector()
 614                         v.bino = mathutils.Vector()
 615                         for f in v.faces:
 616                                 vi = f.pivot_vertex(v)
 617                                 uv0 = layer_uvs[f.loop_indices[vi[0]]]
 618                                 uv1 = layer_uvs[f.loop_indices[vi[1]]]
 619                                 uv2 = layer_uvs[f.loop_indices[vi[-1]]]
 620                                 du1 = uv1[0]-uv0[0]
 621                                 du2 = uv2[0]-uv0[0]
 622                                 dv1 = uv1[1]-uv0[1]
 623                                 dv2 = uv2[1]-uv0[1]
 624                                 edge1 = f.vertices[vi[1]].co-f.vertices[vi[0]].co
 625                                 edge2 = f.vertices[vi[-1]].co-f.vertices[vi[0]].co
 626                                 div = (du1*dv2-du2*dv1)
 627                                 if div:
 628                                         mul = edge1.angle(edge2)/div
 629                                         v.tan += (edge1*dv2-edge2*dv1)*mul
 630                                         v.bino += (edge2*du1-edge1*du2)*mul
 631
 632                         if v.tan.length:
 633                                 v.tan.normalize()
 634                         if v.bino.length:
 635                                 v.bino.normalize()
 636
 637                         progress.set_progress(i/len(self.vertices))
 638
 639         def prepare_sequence(self, progress):
 640                 progress.push_task("Reordering faces", 0.0, 0.5)
 641                 self.reorder_faces(progress)
 642
 643                 progress.set_task("Building sequence", 0.5, 1.0)
 644                 sequence = None
 645                 for i, f in enumerate(self.faces):
 646                         if sequence:
 647                                 if len(sequence)==3:
 648                                         # Rotate the first three vertices so that the new face can be added
 649                                         if sequence[0] in f.vertices and sequence[1] not in f.vertices:
 650                                                 sequence.append(sequence[0])
 651                                                 del sequence[0]
 652                                         elif sequence[2] not in f.vertices and sequence[1] in f.vertices:
 653                                                 sequence.insert(0, sequence[-1])
 654                                                 del sequence[-1]
 655
 656                                 if sequence[-1] not in f.vertices:
 657                                         sequence = None
 658                                 else:
 659                                         to_add = [v for v in f.vertices if v!=sequence[-1] and v!=sequence[-2]]
 660                                         if len(to_add)==2:
 661                                                 if (f.vertices[1]==sequence[-1]) != (len(sequence)%2==1):
 662                                                         to_add.reverse()
 663                                                 sequence.append(sequence[-1])
 664                                         sequence += to_add
 665
 666                         if not sequence:
 667                                 sequence = f.vertices[:]
 668                                 self.vertex_sequence.append(sequence)
 669
 670                         progress.set_progress(i/len(self.faces))
 671
 672                 progress.pop_task()
 673
 674                 self.reorder_vertices()
 675
 676         def reorder_faces(self, progress):
 677                 # Tom Forsyth's vertex cache optimization algorithm
 678                 # http://eelpi.gotdns.org/papers/fast_vert_cache_opt.html
 679
 680                 for f in self.faces:
 681                         f.flag = False
 682
 683                 last_triangle_score = 0.75
 684                 cache_decay_power = 1.5
 685                 valence_boost_scale = 2.0
 686                 valence_boost_power = -0.5
 687
 688                 max_cache_size = 32
 689                 cached_vertices = []
 690
 691                 # Keep track of the score and number of unused faces for each vertex
 692                 vertex_info = [[0, len(v.faces)] for v in self.vertices]
 693                 for vi in vertex_info:
 694                         vi[0] = valence_boost_scale*(vi[1]**valence_boost_power)
 695
 696                 face = None
 697                 reordered_faces = []
 698
 699                 n_processed = 0
 700                 while 1:
 701                         if not face:
 702                                 # Previous iteration gave no candidate for best face (or this is
 703                                 # the first iteration).  Scan all faces for the highest score.
 704                                 best_score = 0
 705                                 for f in self.faces:
 706                                         if f.flag:
 707                                                 continue
 708
 709                                         score = sum(vertex_info[v.index][0] for v in f.vertices)
 710                                         if score>best_score:
 711                                                 best_score = score
 712                                                 face = f
 713
 714                         if not face:
 715                                 break
 716
 717                         reordered_faces.append(face)
 718                         face.flag = True
 719
 720                         for v in face.vertices:
 721                                 vertex_info[v.index][1] -= 1
 722
 723                                 # Shuffle the vertex into the front of the cache
 724                                 if v in cached_vertices:
 725                                         cached_vertices.remove(v)
 726                                 cached_vertices.insert(0, v)
 727
 728                         # Update scores for all vertices in the cache
 729                         for i, v in enumerate(cached_vertices):
 730                                 score = 0
 731                                 if i<3:
 732                                         score += last_triangle_score
 733                                 elif i<max_cache_size:
 734                                         score += (1-(i-3)/(max_cache_size-3))**cache_decay_power
 735                                 if vertex_info[v.index][1]:
 736                                         score += valence_boost_scale*(vertex_info[v.index][1]**valence_boost_power)
 737                                 vertex_info[v.index][0] = score
 738
 739                         face = None
 740                         best_score = 0
 741                         for v in cached_vertices:
 742                                 for f in v.faces:
 743                                         if not f.flag:
 744                                                 score = sum(vertex_info[fv.index][0] for fv in f.vertices)
 745                                                 if score>best_score:
 746                                                         best_score = score
 747                                                         face = f
 748
 749                         del cached_vertices[max_cache_size:]
 750
 751                         n_processed += 1
 752                         progress.set_progress(n_processed/len(self.faces))
 753
 754                 self.faces = reordered_faces
 755                 for i, f in enumerate(self.faces):
 756                         f.index = i
 757
 758         def reorder_vertices(self):
 759                 for v in self.vertices:
 760                         v.index = -1
 761
 762                 reordered_vertices = []
 763                 for s in self.vertex_sequence:
 764                         for v in s:
 765                                 if v.index<0:
 766                                         v.index = len(reordered_vertices)
 767                                         reordered_vertices.append(v)
 768
 769                 self.vertices = reordered_vertices
 770
 771                 for e in self.edges:
 772                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 773
 774
 775 def create_mesh_from_object(context, obj, progress, *, material_map=None):
 776         if obj.type!="MESH":
 777                 raise Exception("Object is not a mesh")
 778
 779         progress.push_task("Preparing mesh", 0.0, 0.2)
 780
 781         objs = [(obj, mathutils.Matrix())]
 782         i = 0
 783         while i<len(objs):
 784                 o, m = objs[i]
 785                 i += 1
 786                 for c in o.children:
 787                         if c.type=="MESH" and c.compound:
 788                                 objs.append((c, m*c.matrix_local))
 789
 790         dg = context.evaluated_depsgraph_get()
 791
 792         mesh = None
 793         for o, m in objs:
 794                 eval_obj = o.evaluated_get(dg)
 795                 bmesh = eval_obj.to_mesh()
 796
 797                 # Object.to_mesh does not copy custom properties
 798                 bmesh.winding_test = o.data.winding_test
 799                 bmesh.smoothing = o.data.smoothing
 800                 bmesh.use_lines = o.data.use_lines
 801                 bmesh.vertex_groups = o.data.vertex_groups
 802                 bmesh.max_groups_per_vertex = o.data.max_groups_per_vertex
 803                 bmesh.use_uv = o.data.use_uv
 804                 bmesh.tbn_vecs = o.data.tbn_vecs
 805                 bmesh.tbn_uvtex = o.data.tbn_uvtex
 806
 807                 me = Mesh(bmesh)
 808                 me.transform(m)
 809
 810                 for i, s in enumerate(eval_obj.material_slots):
 811                         if s.link=='OBJECT':
 812                                 me.materials[i] = s.material
 813
 814                 if mesh:
 815                         mesh.splice(me)
 816                 else:
 817                         mesh = me
 818
 819         mesh.name = obj.data.name
 820
 821         if material_map:
 822                 mesh.apply_material_map(material_map)
 823
 824         progress.set_task("Triangulating", 0.2, 0.3)
 825         mesh.prepare_triangles(progress)
 826         progress.set_task("Smoothing", 0.3, 0.5)
 827         mesh.prepare_smoothing(progress)
 828         progress.set_task("Vertex groups", 0.5, 0.6)
 829         mesh.prepare_vertex_groups(obj)
 830         progress.set_task("Preparing UVs", 0.6, 0.75)
 831         mesh.prepare_uv(progress)
 832         progress.set_task("Preparing vertex colors", 0.75, 0.85)
 833         mesh.prepare_colors(progress)
 834         progress.set_task("Render sequence", 0.85, 1.0)
 835         mesh.prepare_sequence(progress)
 836
 837         progress.pop_task()
 838
 839         return mesh