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                 else:
  52                         self.uvs = []
  53                         self.tan = None
  54                 self.index = vertex.index
  55                 self.co = mathutils.Vector(vertex.co)
  56                 self.normal = mathutils.Vector(vertex.normal)
  57                 self.color = None
  58                 self.flag = False
  59                 self.edges = []
  60                 self.faces = []
  61                 self.groups = vertex.groups[:]
  62
  63         def __cmp__(self, other):
  64                 if other is None:
  65                         return 1
  66                 return cmp(self.index, other.index)
  67
  68
  69 class VertexGroup:
  70         def __init__(self, group):
  71                 if group:
  72                         self.group = group.group
  73                         self.weight = group.weight
  74                 else:
  75                         self.group = 0
  76                         self.weight = 0.0
  77
  78
  79 class Face:
  80         def __init__(self, face):
  81                 self.index = face.index
  82                 self.edges = []
  83                 self.edge_keys = face.edge_keys
  84                 self.vertices = face.vertices[:]
  85                 self.loop_indices = face.loop_indices
  86                 self.normal = face.normal
  87                 self.use_smooth = face.use_smooth
  88                 self.material_index = face.material_index
  89                 self.flag = False
  90
  91         def __cmp__(self, other):
  92                 if other is None:
  93                         return 1
  94                 return cmp(self.index, other.index)
  95
  96         def pivot_vertex(self, v):
  97                 n = self.vertices.index(v)
  98                 return [(n+i)%len(self.vertices) for i in range(len(self.vertices))]
  99
 100         def get_loop_index(self, v):
 101                 return self.loop_indices[self.vertices.index(v)]
 102
 103         def get_edge(self, v1, v2):
 104                 key = make_edge_key(v1.index, v2.index)
 105                 for e in self.edges:
 106                         if e.key==key:
 107                                 return e
 108                 raise KeyError("No edge %s"%(key,))
 109
 110         def other_edge(self, e, v):
 111                 for d in self.edges:
 112                         if d!=e and v in d.vertices:
 113                                 return d
 114
 115         def get_neighbors(self):
 116                 neighbors = [e.other_face(self) for e in self.edges]
 117                 return list(filter(bool, neighbors))
 118
 119
 120 class Line:
 121         def __init__(self, e):
 122                 self.edge = e
 123                 self.vertices = e.vertices[:]
 124                 self.flag = False
 125
 126
 127 class UvLayer:
 128         def __init__(self, arg):
 129                 if type(arg)==str:
 130                         self.name = arg
 131                         self.uvs = []
 132                 else:
 133                         self.name = arg.name
 134                         self.uvs = [mathutils.Vector(d.uv) for d in arg.data]
 135
 136                 self.unit = None
 137                 self.hidden = False
 138
 139                 dot = self.name.find('.')
 140                 if dot>=0:
 141                         ext = self.name[dot:]
 142                         if ext.startswith(".unit") and ext[5:].isdigit():
 143                                 self.unit = int(ext[5:])
 144                         elif ext==".hidden":
 145                                 self.hidden = True
 146
 147
 148 class ColorLayer:
 149         def __init__(self, l):
 150                 self.name = l.name
 151                 self.colors = [c.color[:] for c in l.data]
 152
 153
 154 class Mesh:
 155         def __init__(self, mesh):
 156                 self.name = mesh.name
 157
 158                 self.winding_test = mesh.winding_test
 159                 self.smoothing = mesh.smoothing
 160                 self.use_uv = mesh.use_uv
 161                 self.tangent_vecs = mesh.tangent_vecs
 162                 self.tangent_uvtex = mesh.tangent_uvtex
 163                 self.vertex_groups = mesh.vertex_groups
 164
 165                 # Clone basic data
 166                 self.vertices = [Vertex(v) for v in mesh.vertices]
 167                 if self.vertex_groups:
 168                         for v in self.vertices:
 169                                 v.groups = [VertexGroup(g) for g in v.groups]
 170
 171                 self.faces = [Face(f) for f in mesh.polygons]
 172                 self.edges = [Edge(e) for e in mesh.edges]
 173                 self.loops = mesh.loops[:]
 174                 self.materials = mesh.materials[:]
 175
 176                 self.use_auto_smooth = mesh.use_auto_smooth
 177                 self.auto_smooth_angle = mesh.auto_smooth_angle
 178                 self.max_groups_per_vertex = mesh.max_groups_per_vertex
 179
 180                 # Clone only the desired UV layers
 181                 if mesh.use_uv=='NONE' or not mesh.uv_layers:
 182                         self.uv_layers = []
 183                 else:
 184                         self.uv_layers = [UvLayer(u) for u in mesh.uv_layers]
 185
 186                         # Assign texture unit numbers to UV layers that lack one
 187                         missing_unit = [u for u in self.uv_layers if u.unit is None]
 188                         if missing_unit:
 189                                 missing_unit = sorted(missing_unit, key=(lambda u: u.name))
 190                                 used_units = [u.unit for u in self.uv_layers if u.unit is not None]
 191                                 for u, n in zip(missing_unit, (i for i in itertools.count() if i not in used_units)):
 192                                         u.unit = n
 193
 194                         self.uv_layers = sorted(self.uv_layers, key=(lambda u: u.unit))
 195
 196                         if mesh.use_uv=='UNIT0':
 197                                 self.uv_layers = [self.uv_layers[0]]
 198                                 if self.uv_layers[0].unit!=0:
 199                                         self.uv_layers = []
 200
 201                 self.colors = None
 202                 if mesh.vertex_colors:
 203                         self.colors = ColorLayer(mesh.vertex_colors[0])
 204
 205                 # Rewrite links between elements to point to cloned data, or create links
 206                 # where they don't exist
 207                 edge_map = {e.key: e for e in self.edges}
 208                 for f in self.faces:
 209                         if len(f.vertices)>4:
 210                                 raise ValueError("Ngons are not supported")
 211
 212                         f.vertices = [self.vertices[i] for i in f.vertices]
 213                         for v in f.vertices:
 214                                 v.faces.append(f)
 215
 216                         for k in f.edge_keys:
 217                                 e = edge_map[k]
 218                                 e.faces.append(f)
 219                                 f.edges.append(e)
 220
 221                 for e in self.edges:
 222                         e.vertices = [self.vertices[i] for i in e.vertices]
 223                         for v in e.vertices:
 224                                 v.edges.append(e)
 225
 226                 # Store loose edges as lines
 227                 if mesh.use_lines:
 228                         self.lines = [Line(e) for e in self.edges if not e.faces]
 229                 else:
 230                         self.lines = []
 231
 232                 self.vertex_sequence = []
 233
 234         def transform(self, matrix):
 235                 for v in self.vertices:
 236                         v.co = matrix@v.co
 237
 238         def splice(self, other):
 239                 if len(self.uv_layers)!=len(other.uv_layers):
 240                         raise ValueError("Meshes have incompatible UV layers")
 241                 for i, u in enumerate(self.uv_layers):
 242                         if u.name!=other.uv_layers[i].name:
 243                                 raise ValueError("Meshes have incompatible UV layers")
 244
 245                 # Merge materials and form a lookup from source material indices to the
 246                 # merged material list
 247                 material_atlas = []
 248                 for m in other.materials:
 249                         if m in self.materials:
 250                                 material_atlas.append(self.materials.index(m))
 251                         else:
 252                                 material_atlas.append(len(self.materials))
 253                                 self.materials.append(m)
 254
 255                 # Append data and adjust indices where necessary.  Since the data is
 256                 # spliced from the source mesh, rebuilding references is not necessary.
 257                 for i, u in enumerate(self.uv_layers):
 258                         u.uvs += other.uv_layers[i].uvs
 259
 260                 if self.colors:
 261                         if other.colors:
 262                                 self.colors.colors += other.colors.colors
 263                         else:
 264                                 self.colors.colors += [(1.0, 1.0, 1.0, 1.0)]*len(other.loops)
 265                 elif other.colors:
 266                         self.colors = ColorLayer(other.colors.name)
 267                         self.colors.colors = [(1.0, 1.0, 1.0, 1.0)]*len(self.loops)+other.colors.colors
 268
 269                 offset = len(self.vertices)
 270                 self.vertices += other.vertices
 271                 for v in self.vertices[offset:]:
 272                         v.index += offset
 273
 274                 loop_offset = len(self.loops)
 275                 self.loops += other.loops
 276
 277                 offset = len(self.faces)
 278                 self.faces += other.faces
 279                 for f in self.faces[offset:]:
 280                         f.index += offset
 281                         f.loop_indices = range(f.loop_indices.start+offset, f.loop_indices.stop+offset)
 282                         if other.materials:
 283                                 f.material_index = material_atlas[f.material_index]
 284
 285                 offset = len(self.edges)
 286                 self.edges += other.edges
 287                 for e in self.edges[offset:]:
 288                         e.index += offset
 289                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 290
 291                 self.lines += other.lines
 292
 293         def prepare_triangles(self, progress):
 294                 face_count = len(self.faces)
 295                 for i in range(face_count):
 296                         f = self.faces[i]
 297                         nverts = len(f.vertices)
 298                         if nverts==3:
 299                                 continue
 300
 301                         # Calculate normals at each vertex of the face
 302                         edge_vecs = []
 303                         for j in range(nverts):
 304                                 edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
 305
 306                         normals = []
 307                         for j in range(nverts):
 308                                 normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
 309
 310                         # Check which diagonal results in a flatter triangulation
 311                         flatness1 = normals[0].dot(normals[2])
 312                         flatness2 = normals[1].dot(normals[3])
 313                         cut_index = 1 if flatness1>flatness2 else 0
 314
 315                         nf = Face(f)
 316                         nf.index = len(self.faces)
 317                         self.faces.append(nf)
 318
 319                         ne = Edge(None)
 320                         ne.index = len(self.edges)
 321                         self.edges.append(ne)
 322
 323                         nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
 324                         nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
 325                         for v in nf.vertices:
 326                                 v.faces.append(nf)
 327
 328                         ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
 329                         for v in ne.vertices:
 330                                 v.edges.append(ne)
 331                         ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
 332                         ne.smooth = True
 333
 334                         f.vertices[3-cut_index].faces.remove(f)
 335                         del f.vertices[3-cut_index]
 336                         f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
 337
 338                         ne.faces = [f, nf]
 339                         if cut_index==0:
 340                                 nf.edges = [ne, f.edges[2], f.edges[3]]
 341                                 f.edges = [f.edges[0], f.edges[1], ne]
 342                         else:
 343                                 nf.edges = [f.edges[1], f.edges[2], ne]
 344                                 f.edges = [f.edges[0], ne, f.edges[3]]
 345                         for e in nf.edges:
 346                                 if e!=ne:
 347                                         e.faces.remove(f)
 348                                         e.faces.append(nf)
 349
 350                         f.normal = normals[1-cut_index]
 351                         nf.normal = normals[3-cut_index]
 352
 353                         progress.set_progress(i/face_count)
 354
 355         def prepare_smoothing(self, progress):
 356                 smooth_limit = -1
 357                 if self.smoothing=='NONE':
 358                         for f in self.faces:
 359                                 f.use_smooth = False
 360
 361                         smooth_limit = 1
 362                 elif self.use_auto_smooth:
 363                         smooth_limit = math.cos(self.auto_smooth_angle)
 364
 365                 for e in self.edges:
 366                         e.check_smooth(smooth_limit)
 367
 368                 progress.push_task("Sharp edges", 0.0, 0.7)
 369                 self.split_vertices(self.find_smooth_group, progress)
 370
 371                 if self.smoothing!='BLENDER':
 372                         progress.set_task("Updating normals", 0.7, 1.0)
 373                         self.compute_normals(progress)
 374
 375                 progress.pop_task()
 376
 377         def prepare_vertex_groups(self, obj):
 378                 if not self.vertex_groups:
 379                         return
 380
 381                 for v in self.vertices:
 382                         if v.groups:
 383                                 weight_sum = sum(g.weight for g in v.groups)
 384                                 v.groups = sorted(v.groups, key=(lambda g: g.weight), reverse=True)[:self.max_groups_per_vertex]
 385                                 weight_scale = weight_sum/sum(g.weight for g in v.groups)
 386                                 for g in v.groups:
 387                                         g.weight *= weight_scale
 388                         while len(v.groups)<self.max_groups_per_vertex:
 389                                 v.groups.append(VertexGroup(None))
 390
 391                 if obj.parent and obj.parent.type=="ARMATURE":
 392                         armature = obj.parent.data
 393                         bone_indices = {b.name: i for i, b in enumerate(armature.bones)}
 394                         group_index_map = {i: i for i in range(len(obj.vertex_groups))}
 395                         for g in first_obj.vertex_groups:
 396                                 if g.name in bone_indices:
 397                                         group_index_map[g.index] = bone_indices[g.name]
 398
 399                         for v in self.vertices:
 400                                 for g in v.groups:
 401                                         g.group = group_index_map[g.group]
 402
 403         def apply_material_atlas(self, material_atlas):
 404                 for m in self.materials:
 405                         if m.name not in material_atlas.material_names:
 406                                 raise Exception("Material atlas is not compatible with Mesh")
 407
 408                 if self.use_uv=='NONE':
 409                         return
 410
 411                 layer = UvLayer("material_atlas")
 412                 if self.use_uv=='UNIT0':
 413                         self.uv_layers = [layer]
 414                         layer.unit = 0
 415                 else:
 416                         self.uv_layers.append(layer)
 417                         used_units = [u.unit for u in self.uv_layers]
 418                         layer.unit = next(i for i in itertools.count() if i not in used_units)
 419                         self.uv_layers.sort(key=lambda u: u.unit)
 420
 421                 layer.uvs = [(0.0, 0.0)]*len(self.loops)
 422                 for f in self.faces:
 423                         uv = material_atlas.get_material_uv(self.materials[f.material_index])
 424                         for i in f.loop_indices:
 425                                 layer.uvs[i] = uv
 426
 427         def prepare_uv(self, progress):
 428                 # Form a list of UV layers referenced by materials with the array atlas
 429                 # property set
 430                 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']
 431                 array_uv_layers = [u for u in self.uv_layers if u.name in array_uv_layers]
 432
 433                 if array_uv_layers:
 434                         for f in self.faces:
 435                                 layer = 0
 436                                 if f.material_index<len(self.materials):
 437                                         mat = self.materials[f.material_index]
 438                                         if mat and mat.array_atlas:
 439                                                 layer = mat.array_layer
 440
 441                                 for l in array_uv_layers:
 442                                         for i in f.loop_indices:
 443                                                 l.uvs[i] = mathutils.Vector((*l.uvs[i], layer))
 444
 445                 prog_count = len(self.uv_layers)
 446                 prog_step = 0
 447
 448                 # Split by the UV layer used for tangent vectors first so connectivity
 449                 # remains intact for tangent vector computation
 450                 tangent_layer_index = -1
 451                 if self.tangent_vecs:
 452                         if self.tangent_uvtex:
 453                                 uv_names = [u.name for u in self.uv_layers]
 454                                 if self.tangent_uvtex in uv_names:
 455                                         tangent_layer_index = uv_names.index(self.tangent_uvtex)
 456                         elif self.uv_layers[0].unit==0:
 457                                 tangent_layer_index = 0
 458
 459                         if tangent_layer_index>=0:
 460                                 prog_count += 1
 461                                 progress.push_task_slice("Computing tangents", 0, prog_count)
 462                                 self.split_vertices(self.find_uv_group, progress, tangent_layer_index)
 463                                 progress.set_task_slice(self.tangent_uvtex, 1, prog_count)
 464                                 self.compute_tangents(tangent_layer_index, progress)
 465                                 progress.pop_task()
 466                                 prog_step = 2
 467                         else:
 468                                 raise Exception("Tangent UV layer not found")
 469
 470                 # Split by the remaining UV layers
 471                 for i, u in enumerate(self.uv_layers):
 472                         if i==tangent_layer_index:
 473                                 continue
 474
 475                         progress.push_task_slice(u.name, prog_step, prog_count)
 476                         self.split_vertices(self.find_uv_group, progress, i)
 477                         progress.pop_task()
 478                         prog_step += 1
 479
 480                 # Copy UVs from layers to vertices
 481                 for v in self.vertices:
 482                         if v.faces:
 483                                 # All faces still connected to the vertex have the same UV value
 484                                 f = v.faces[0]
 485                                 i = f.get_loop_index(v)
 486                                 v.uvs = [u.uvs[i] for u in self.uv_layers]
 487                         else:
 488                                 v.uvs = [(0.0, 0.0)]*len(self.uv_layers)
 489
 490         def prepare_colors(self, progress):
 491                 if not self.colors:
 492                         return
 493
 494                 self.split_vertices(self.find_color_group, progress)
 495
 496                 for v in self.vertices:
 497                         if v.faces:
 498                                 f = v.faces[0]
 499                                 v.color = self.colors.colors[f.get_loop_index(v)]
 500                         else:
 501                                 v.color = (1.0, 1.0, 1.0, 1.0)
 502
 503         def split_vertices(self, find_group_func, progress, *args):
 504                 vertex_count = len(self.vertices)
 505                 for i in range(vertex_count):
 506                         v = self.vertices[i]
 507                         for f in v.faces:
 508                                 f.flag = False
 509
 510                         # Find all groups of faces on this vertex
 511                         groups = []
 512                         for f in v.faces:
 513                                 if not f.flag:
 514                                         groups.append(find_group_func(v, f, *args))
 515
 516                         # Give groups after the first separate copies of the vertex
 517                         for g in groups[1:]:
 518                                 nv = Vertex(v)
 519                                 nv.index = len(self.vertices)
 520                                 self.vertices.append(nv)
 521
 522                                 for e in v.edges:
 523                                         e_faces_in_g = [f for f in e.faces if f in g]
 524                                         if not e_faces_in_g:
 525                                                 continue
 526
 527                                         if len(e_faces_in_g)<len(e.faces):
 528                                                 # Create a copy of an edge at the boundary of the group
 529                                                 ne = Edge(e)
 530                                                 ne.index = len(self.edges)
 531                                                 self.edges.append(ne)
 532
 533                                                 ne.other_vertex(v).edges.append(ne)
 534
 535                                                 for f in e_faces_in_g:
 536                                                         e.faces.remove(f)
 537                                                         f.edges[f.edges.index(e)] = ne
 538                                                         ne.faces.append(f)
 539
 540                                                 e = ne
 541
 542                                         e.vertices[e.vertices.index(v)] = nv
 543                                         nv.edges.append(e)
 544
 545                                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 546
 547                                 # Filter out any edges that were removed from the original vertex
 548                                 v.edges = [e for e in v.edges if v in e.vertices]
 549
 550                                 for f in g:
 551                                         v.faces.remove(f)
 552                                         f.vertices[f.vertices.index(v)] = nv
 553                                         nv.faces.append(f)
 554
 555                         progress.set_progress(i/vertex_count)
 556
 557         def find_smooth_group(self, vertex, face):
 558                 face.flag = True
 559
 560                 edges = [e for e in face.edges if vertex in e.vertices]
 561
 562                 group = [face]
 563                 for e in edges:
 564                         f = face
 565                         while e.smooth:
 566                                 f = e.other_face(f)
 567                                 if not f or f.flag:
 568                                         break
 569
 570                                 f.flag = True
 571                                 group.append(f)
 572                                 e = f.other_edge(e, vertex)
 573
 574                 return group
 575
 576         def find_uv_group(self, vertex, face, index):
 577                 layer = self.uv_layers[index]
 578                 uv = layer.uvs[face.get_loop_index(vertex)]
 579                 face.flag = True
 580
 581                 group = [face]
 582                 for f in vertex.faces:
 583                         if not f.flag and layer.uvs[f.get_loop_index(vertex)]==uv:
 584                                 f.flag = True
 585                                 group.append(f)
 586
 587                 return group
 588
 589         def find_color_group(self, vertex, face):
 590                 color = self.colors.colors[face.get_loop_index(vertex)]
 591                 face.flag = True
 592
 593                 group = [face]
 594                 for f in vertex.faces:
 595                         if not f.flag and self.colors.colors[f.get_loop_index(vertex)]==color:
 596                                 f.flag = True
 597                                 group.append(f)
 598
 599                 return group
 600
 601         def compute_normals(self, progress):
 602                 for i, v in enumerate(self.vertices):
 603                         v.normal = mathutils.Vector()
 604                         for f in v.faces:
 605                                 vi = f.pivot_vertex(v)
 606                                 edge1 = f.vertices[vi[1]].co-v.co
 607                                 edge2 = f.vertices[vi[-1]].co-v.co
 608                                 if edge1.length and edge2.length:
 609                                         # Use the angle between edges as a weighting factor.  This gives
 610                                         # more consistent normals on bends with an inequal number of
 611                                         # faces on each side.
 612                                         v.normal += f.normal*edge1.angle(edge2)
 613
 614                         if v.normal.length:
 615                                 v.normal.normalize()
 616                         else:
 617                                 v.normal = mathutils.Vector((0, 0, 1))
 618
 619                         progress.set_progress(i/len(self.vertices))
 620
 621         def compute_tangents(self, index, progress):
 622                 layer_uvs = self.uv_layers[index].uvs
 623
 624                 for i, v in enumerate(self.vertices):
 625                         v.tan = mathutils.Vector()
 626                         for f in v.faces:
 627                                 vi = f.pivot_vertex(v)
 628                                 uv0 = layer_uvs[f.loop_indices[vi[0]]]
 629                                 uv1 = layer_uvs[f.loop_indices[vi[1]]]
 630                                 uv2 = layer_uvs[f.loop_indices[vi[-1]]]
 631                                 du1 = uv1[0]-uv0[0]
 632                                 du2 = uv2[0]-uv0[0]
 633                                 dv1 = uv1[1]-uv0[1]
 634                                 dv2 = uv2[1]-uv0[1]
 635                                 edge1 = f.vertices[vi[1]].co-f.vertices[vi[0]].co
 636                                 edge2 = f.vertices[vi[-1]].co-f.vertices[vi[0]].co
 637                                 div = (du1*dv2-du2*dv1)
 638                                 if div:
 639                                         mul = edge1.angle(edge2)/div
 640                                         v.tan += (edge1*dv2-edge2*dv1)*mul
 641
 642                         if v.tan.length:
 643                                 v.tan.normalize()
 644
 645                         progress.set_progress(i/len(self.vertices))
 646
 647         def prepare_sequence(self, progress):
 648                 progress.push_task("Reordering faces", 0.0, 0.5)
 649                 self.reorder_faces(progress)
 650
 651                 progress.set_task("Building sequence", 0.5, 1.0)
 652                 sequence = None
 653                 for i, f in enumerate(self.faces):
 654                         if sequence:
 655                                 if len(sequence)==3:
 656                                         # Rotate the first three vertices so that the new face can be added
 657                                         if sequence[0] in f.vertices and sequence[1] not in f.vertices:
 658                                                 sequence.append(sequence[0])
 659                                                 del sequence[0]
 660                                         elif sequence[2] not in f.vertices and sequence[1] in f.vertices:
 661                                                 sequence.insert(0, sequence[-1])
 662                                                 del sequence[-1]
 663
 664                                 if sequence[-1] not in f.vertices:
 665                                         sequence = None
 666                                 else:
 667                                         to_add = [v for v in f.vertices if v!=sequence[-1] and v!=sequence[-2]]
 668                                         if len(to_add)==2:
 669                                                 if (f.vertices[1]==sequence[-1]) != (len(sequence)%2==1):
 670                                                         to_add.reverse()
 671                                                 sequence.append(sequence[-1])
 672                                         sequence += to_add
 673
 674                         if not sequence:
 675                                 sequence = f.vertices[:]
 676                                 self.vertex_sequence.append(sequence)
 677
 678                         progress.set_progress(i/len(self.faces))
 679
 680                 progress.pop_task()
 681
 682                 self.reorder_vertices()
 683
 684         def reorder_faces(self, progress):
 685                 # Tom Forsyth's vertex cache optimization algorithm
 686                 # http://eelpi.gotdns.org/papers/fast_vert_cache_opt.html
 687
 688                 for f in self.faces:
 689                         f.flag = False
 690
 691                 last_triangle_score = 0.75
 692                 cache_decay_power = 1.5
 693                 valence_boost_scale = 2.0
 694                 valence_boost_power = -0.5
 695
 696                 max_cache_size = 32
 697                 cached_vertices = []
 698
 699                 # Keep track of the score and number of unused faces for each vertex
 700                 vertex_info = [[0, len(v.faces)] for v in self.vertices]
 701                 for vi in vertex_info:
 702                         vi[0] = valence_boost_scale*(vi[1]**valence_boost_power)
 703
 704                 face = None
 705                 reordered_faces = []
 706
 707                 n_processed = 0
 708                 while 1:
 709                         if not face:
 710                                 # Previous iteration gave no candidate for best face (or this is
 711                                 # the first iteration).  Scan all faces for the highest score.
 712                                 best_score = 0
 713                                 for f in self.faces:
 714                                         if f.flag:
 715                                                 continue
 716
 717                                         score = sum(vertex_info[v.index][0] for v in f.vertices)
 718                                         if score>best_score:
 719                                                 best_score = score
 720                                                 face = f
 721
 722                         if not face:
 723                                 break
 724
 725                         reordered_faces.append(face)
 726                         face.flag = True
 727
 728                         for v in face.vertices:
 729                                 vertex_info[v.index][1] -= 1
 730
 731                                 # Shuffle the vertex into the front of the cache
 732                                 if v in cached_vertices:
 733                                         cached_vertices.remove(v)
 734                                 cached_vertices.insert(0, v)
 735
 736                         # Update scores for all vertices in the cache
 737                         for i, v in enumerate(cached_vertices):
 738                                 score = 0
 739                                 if i<3:
 740                                         score += last_triangle_score
 741                                 elif i<max_cache_size:
 742                                         score += (1-(i-3)/(max_cache_size-3))**cache_decay_power
 743                                 if vertex_info[v.index][1]:
 744                                         score += valence_boost_scale*(vertex_info[v.index][1]**valence_boost_power)
 745                                 vertex_info[v.index][0] = score
 746
 747                         face = None
 748                         best_score = 0
 749                         for v in cached_vertices:
 750                                 for f in v.faces:
 751                                         if not f.flag:
 752                                                 score = sum(vertex_info[fv.index][0] for fv in f.vertices)
 753                                                 if score>best_score:
 754                                                         best_score = score
 755                                                         face = f
 756
 757                         del cached_vertices[max_cache_size:]
 758
 759                         n_processed += 1
 760                         progress.set_progress(n_processed/len(self.faces))
 761
 762                 self.faces = reordered_faces
 763                 for i, f in enumerate(self.faces):
 764                         f.index = i
 765
 766         def reorder_vertices(self):
 767                 for v in self.vertices:
 768                         v.index = -1
 769
 770                 reordered_vertices = []
 771                 for s in self.vertex_sequence:
 772                         for v in s:
 773                                 if v.index<0:
 774                                         v.index = len(reordered_vertices)
 775                                         reordered_vertices.append(v)
 776
 777                 self.vertices = reordered_vertices
 778
 779                 for e in self.edges:
 780                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 781
 782
 783 def create_mesh_from_object(context, obj, progress, *, material_atlas=None):
 784         if obj.type!="MESH":
 785                 raise Exception("Object is not a mesh")
 786
 787         progress.push_task("Preparing mesh", 0.0, 0.2)
 788
 789         objs = [(obj, mathutils.Matrix())]
 790         i = 0
 791         while i<len(objs):
 792                 o, m = objs[i]
 793                 i += 1
 794                 for c in o.children:
 795                         if c.type=="MESH" and c.compound:
 796                                 objs.append((c, m*c.matrix_local))
 797
 798         dg = context.evaluated_depsgraph_get()
 799
 800         mesh = None
 801         for o, m in objs:
 802                 eval_obj = o.evaluated_get(dg)
 803                 bmesh = eval_obj.to_mesh()
 804
 805                 # Object.to_mesh does not copy custom properties
 806                 bmesh.winding_test = o.data.winding_test
 807                 bmesh.smoothing = o.data.smoothing
 808                 bmesh.use_lines = o.data.use_lines
 809                 bmesh.vertex_groups = o.data.vertex_groups
 810                 bmesh.max_groups_per_vertex = o.data.max_groups_per_vertex
 811                 bmesh.use_uv = o.data.use_uv
 812                 bmesh.tangent_vecs = o.data.tangent_vecs
 813                 bmesh.tangent_uvtex = o.data.tangent_uvtex
 814
 815                 me = Mesh(bmesh)
 816                 me.transform(m)
 817
 818                 for i, s in enumerate(eval_obj.material_slots):
 819                         if s.link=='OBJECT':
 820                                 me.materials[i] = s.material
 821
 822                 if mesh:
 823                         mesh.splice(me)
 824                 else:
 825                         mesh = me
 826
 827         mesh.name = obj.data.name
 828
 829         if material_atlas:
 830                 mesh.apply_material_atlas(material_atlas)
 831
 832         progress.set_task("Triangulating", 0.2, 0.3)
 833         mesh.prepare_triangles(progress)
 834         progress.set_task("Smoothing", 0.3, 0.5)
 835         mesh.prepare_smoothing(progress)
 836         progress.set_task("Vertex groups", 0.5, 0.6)
 837         mesh.prepare_vertex_groups(obj)
 838         progress.set_task("Preparing UVs", 0.6, 0.75)
 839         mesh.prepare_uv(progress)
 840         progress.set_task("Preparing vertex colors", 0.75, 0.85)
 841         mesh.prepare_colors(progress)
 842         progress.set_task("Render sequence", 0.85, 1.0)
 843         mesh.prepare_sequence(progress)
 844
 845         progress.pop_task()
 846
 847         return mesh