blender/io_mspgl/mesh.py

   1 import math
   2 import mathutils
   3 import itertools
   4
   5 def make_edge_key(i1, i2):
   6         return (min(i1, i2), max(i1, i2))
   7
   8 class Edge:
   9         def __init__(self, edge):
  10                 if edge.__class__==Edge:
  11                         self.smooth = edge.smooth
  12                 else:
  13                         self.smooth = False
  14                 if edge:
  15                         self.vertices = edge.vertices[:]
  16                         self.key = edge.key
  17                 else:
  18                         self.vertices = []
  19                         self.key = None
  20                 self.faces = []
  21
  22         def check_smooth(self, limit):
  23                 if len(self.faces)!=2:
  24                         return
  25
  26                 d = self.faces[0].normal.dot(self.faces[1].normal)
  27                 self.smooth = ((d>limit and self.faces[0].use_smooth and self.faces[1].use_smooth) or d>0.99995)
  28
  29         def other_face(self, f):
  30                 if f.index==self.faces[0].index:
  31                         if len(self.faces)>=2:
  32                                 return self.faces[1]
  33                         else:
  34                                 return None
  35                 else:
  36                         return self.faces[0]
  37
  38         def other_vertex(self, v):
  39                 if v.index==self.vertices[0].index:
  40                         return self.vertices[1]
  41                 else:
  42                         return self.vertices[0]
  43
  44
  45 class Vertex:
  46         def __init__(self, vertex):
  47                 if vertex.__class__==Vertex:
  48                         self.uvs = vertex.uvs[:]
  49                         self.tan = vertex.tan
  50                 else:
  51                         self.uvs = []
  52                         self.tan = None
  53                 self.index = vertex.index
  54                 self.co = mathutils.Vector(vertex.co)
  55                 self.normal = mathutils.Vector(vertex.normal)
  56                 self.color = None
  57                 self.flag = False
  58                 self.edges = []
  59                 self.faces = []
  60                 self.groups = vertex.groups[:]
  61
  62         def __cmp__(self, other):
  63                 if other is None:
  64                         return 1
  65                 return cmp(self.index, other.index)
  66
  67
  68 class VertexGroup:
  69         def __init__(self, group):
  70                 if group:
  71                         self.group = group.group
  72                         self.weight = group.weight
  73                 else:
  74                         self.group = 0
  75                         self.weight = 0.0
  76
  77
  78 class Batch:
  79         def __init__(self, pt):
  80                 self.primitive_type = pt
  81                 self.vertices = []
  82
  83
  84 class Face:
  85         def __init__(self, face):
  86                 self.index = face.index
  87                 self.edges = []
  88                 self.edge_keys = face.edge_keys
  89                 self.vertices = face.vertices[:]
  90                 self.loop_indices = face.loop_indices
  91                 self.normal = face.normal
  92                 self.use_smooth = face.use_smooth
  93                 self.material_index = face.material_index
  94                 self.flag = False
  95
  96         def __cmp__(self, other):
  97                 if other is None:
  98                         return 1
  99                 return cmp(self.index, other.index)
 100
 101         def pivot_vertex(self, v):
 102                 n = self.vertices.index(v)
 103                 return [(n+i)%len(self.vertices) for i in range(len(self.vertices))]
 104
 105         def get_loop_index(self, v):
 106                 return self.loop_indices[self.vertices.index(v)]
 107
 108         def get_edge(self, v1, v2):
 109                 key = make_edge_key(v1.index, v2.index)
 110                 for e in self.edges:
 111                         if e.key==key:
 112                                 return e
 113                 raise KeyError("No edge %s"%(key,))
 114
 115         def other_edge(self, e, v):
 116                 for d in self.edges:
 117                         if d!=e and v in d.vertices:
 118                                 return d
 119
 120         def get_neighbors(self):
 121                 neighbors = [e.other_face(self) for e in self.edges]
 122                 return list(filter(bool, neighbors))
 123
 124
 125 class Line:
 126         def __init__(self, e):
 127                 self.edge = e
 128                 self.vertices = e.vertices[:]
 129                 self.flag = False
 130
 131
 132 class UvLayer:
 133         def __init__(self, arg):
 134                 if type(arg)==str:
 135                         self.name = arg
 136                         self.uvs = []
 137                 else:
 138                         self.name = arg.name
 139                         self.uvs = [mathutils.Vector(d.uv) for d in arg.data]
 140
 141                 self.unit = None
 142                 self.hidden = False
 143
 144                 dot = self.name.find('.')
 145                 if dot>=0:
 146                         ext = self.name[dot:]
 147                         if ext.startswith(".unit") and ext[5:].isdigit():
 148                                 self.unit = int(ext[5:])
 149                         elif ext==".hidden":
 150                                 self.hidden = True
 151
 152
 153 class ColorLayer:
 154         def __init__(self, l):
 155                 self.name = l.name
 156                 self.colors = [c.color[:] for c in l.data]
 157
 158
 159 class Mesh:
 160         def __init__(self, mesh):
 161                 self.name = mesh.name
 162
 163                 self.smoothing = mesh.smoothing
 164                 self.use_uv = mesh.use_uv
 165                 self.tangent_uvtex = mesh.tangent_uvtex
 166                 self.use_strips = mesh.use_strips
 167                 self.use_lines = mesh.use_lines
 168                 self.vertex_groups = mesh.vertex_groups
 169
 170                 # Clone basic data
 171                 self.vertices = [Vertex(v) for v in mesh.vertices]
 172                 if self.vertex_groups:
 173                         for v in self.vertices:
 174                                 v.groups = [VertexGroup(g) for g in v.groups]
 175
 176                 self.faces = [Face(f) for f in mesh.polygons]
 177                 self.edges = [Edge(e) for e in mesh.edges]
 178                 self.loops = mesh.loops[:]
 179                 self.materials = mesh.materials[:]
 180
 181                 self.use_auto_smooth = mesh.use_auto_smooth
 182                 self.auto_smooth_angle = mesh.auto_smooth_angle
 183                 self.max_groups_per_vertex = mesh.max_groups_per_vertex
 184
 185                 # Clone only the desired UV layers
 186                 if mesh.use_uv=='NONE' or not mesh.uv_layers:
 187                         self.uv_layers = []
 188                 else:
 189                         self.uv_layers = [UvLayer(u) for u in mesh.uv_layers if u.data]
 190
 191                         # Assign texture unit numbers to UV layers that lack one
 192                         missing_unit = [u for u in self.uv_layers if u.unit is None]
 193                         if missing_unit:
 194                                 missing_unit = sorted(missing_unit, key=(lambda u: u.name))
 195                                 used_units = [u.unit for u in self.uv_layers if u.unit is not None]
 196                                 for u, n in zip(missing_unit, (i for i in itertools.count() if i not in used_units)):
 197                                         u.unit = n
 198
 199                         self.uv_layers = sorted(self.uv_layers, key=(lambda u: u.unit))
 200
 201                         if mesh.use_uv=='UNIT0' and self.uv_layers:
 202                                 self.uv_layers = [self.uv_layers[0]]
 203                                 if self.uv_layers[0].unit!=0:
 204                                         self.uv_layers = []
 205
 206                 self.colors = None
 207                 if mesh.vertex_colors:
 208                         self.colors = ColorLayer(mesh.vertex_colors[0])
 209
 210                 # Rewrite links between elements to point to cloned data, or create links
 211                 # where they don't exist
 212                 edge_map = {e.key: e for e in self.edges}
 213                 for f in self.faces:
 214                         if len(f.vertices)>4:
 215                                 raise ValueError("Unsupported face on mesh {}: N-gon".format(self.name))
 216
 217                         f.vertices = [self.vertices[i] for i in f.vertices]
 218                         for v in f.vertices:
 219                                 v.faces.append(f)
 220
 221                         for k in f.edge_keys:
 222                                 e = edge_map[k]
 223                                 e.faces.append(f)
 224                                 f.edges.append(e)
 225
 226                 for e in self.edges:
 227                         e.vertices = [self.vertices[i] for i in e.vertices]
 228                         for v in e.vertices:
 229                                 v.edges.append(e)
 230
 231                 # Store loose edges as lines
 232                 if mesh.use_lines:
 233                         self.lines = [Line(e) for e in self.edges if not e.faces]
 234                 else:
 235                         self.lines = []
 236
 237                 # Check if tangent vectors are needed
 238                 if mesh.tangent_vecs=='NO':
 239                         self.tangent_vecs = False
 240                 elif mesh.tangent_vecs=='YES':
 241                         self.tangent_vecs = True
 242                 elif mesh.tangent_vecs=='AUTO':
 243                         from .material import Material
 244                         self.tangent_vecs = False
 245                         for m in self.materials:
 246                                 mat = Material(m)
 247                                 if mat.type=="pbr":
 248                                         normal_prop = next((p for p in mat.properties if p.tex_keyword=="normal_map"), None)
 249                                         if normal_prop and normal_prop.texture:
 250                                                 self.tangent_vecs = True
 251
 252                 self.batches = []
 253
 254         def transform(self, matrix):
 255                 for v in self.vertices:
 256                         v.co = matrix@v.co
 257
 258         def splice(self, other):
 259                 if len(self.uv_layers)!=len(other.uv_layers):
 260                         raise ValueError("Meshes {} and {} have incompatible UV layers".format(self.name, other.name))
 261                 for i, u in enumerate(self.uv_layers):
 262                         if u.name!=other.uv_layers[i].name:
 263                                 raise ValueError("Meshes {} and {} have incompatible UV layers".format(self.name, other.name))
 264
 265                 # Merge materials and form a lookup from source material indices to the
 266                 # merged material list
 267                 material_lookup = []
 268                 for m in other.materials:
 269                         if m in self.materials:
 270                                 material_lookup.append(self.materials.index(m))
 271                         else:
 272                                 material_lookup.append(len(self.materials))
 273                                 self.materials.append(m)
 274
 275                 # Append data and adjust indices where necessary.  Since the data is
 276                 # spliced from the source mesh, rebuilding references is not necessary.
 277                 for i, u in enumerate(self.uv_layers):
 278                         u.uvs += other.uv_layers[i].uvs
 279
 280                 if self.colors:
 281                         if other.colors:
 282                                 self.colors.colors += other.colors.colors
 283                         else:
 284                                 self.colors.colors += [(1.0, 1.0, 1.0, 1.0)]*len(other.loops)
 285                 elif other.colors:
 286                         self.colors = ColorLayer(other.colors.name)
 287                         self.colors.colors = [(1.0, 1.0, 1.0, 1.0)]*len(self.loops)+other.colors.colors
 288
 289                 offset = len(self.vertices)
 290                 self.vertices += other.vertices
 291                 for v in self.vertices[offset:]:
 292                         v.index += offset
 293
 294                 loop_offset = len(self.loops)
 295                 self.loops += other.loops
 296
 297                 offset = len(self.faces)
 298                 self.faces += other.faces
 299                 for f in self.faces[offset:]:
 300                         f.index += offset
 301                         f.loop_indices = range(f.loop_indices.start+offset, f.loop_indices.stop+offset)
 302                         if other.materials:
 303                                 f.material_index = material_lookup[f.material_index]
 304
 305                 offset = len(self.edges)
 306                 self.edges += other.edges
 307                 for e in self.edges[offset:]:
 308                         e.index += offset
 309                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 310
 311                 self.lines += other.lines
 312
 313         def prepare_triangles(self, task):
 314                 face_count = len(self.faces)
 315                 for i in range(face_count):
 316                         f = self.faces[i]
 317                         nverts = len(f.vertices)
 318                         if nverts==3:
 319                                 continue
 320
 321                         # Calculate normals at each vertex of the face
 322                         edge_vecs = []
 323                         for j in range(nverts):
 324                                 edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
 325
 326                         normals = []
 327                         for j in range(nverts):
 328                                 normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
 329
 330                         # Check which diagonal results in a flatter triangulation
 331                         flatness1 = normals[0].dot(normals[2])
 332                         flatness2 = normals[1].dot(normals[3])
 333                         cut_index = 1 if flatness1>flatness2 else 0
 334
 335                         nf = Face(f)
 336                         nf.index = len(self.faces)
 337                         self.faces.append(nf)
 338
 339                         ne = Edge(None)
 340                         ne.index = len(self.edges)
 341                         self.edges.append(ne)
 342
 343                         nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
 344                         nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
 345                         for v in nf.vertices:
 346                                 v.faces.append(nf)
 347
 348                         ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
 349                         for v in ne.vertices:
 350                                 v.edges.append(ne)
 351                         ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
 352                         ne.smooth = True
 353
 354                         f.vertices[3-cut_index].faces.remove(f)
 355                         del f.vertices[3-cut_index]
 356                         f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
 357
 358                         ne.faces = [f, nf]
 359                         if cut_index==0:
 360                                 nf.edges = [ne, f.edges[2], f.edges[3]]
 361                                 f.edges = [f.edges[0], f.edges[1], ne]
 362                         else:
 363                                 nf.edges = [f.edges[1], f.edges[2], ne]
 364                                 f.edges = [f.edges[0], ne, f.edges[3]]
 365                         for e in nf.edges:
 366                                 if e!=ne:
 367                                         e.faces.remove(f)
 368                                         e.faces.append(nf)
 369
 370                         f.normal = normals[1-cut_index]
 371                         nf.normal = normals[3-cut_index]
 372
 373                         task.set_progress(i/face_count)
 374
 375         def prepare_smoothing(self, task):
 376                 smooth_limit = -1
 377                 if self.smoothing=='NONE':
 378                         for f in self.faces:
 379                                 f.use_smooth = False
 380
 381                         smooth_limit = 1
 382                 elif self.use_auto_smooth:
 383                         smooth_limit = math.cos(self.auto_smooth_angle)
 384
 385                 for e in self.edges:
 386                         e.check_smooth(smooth_limit)
 387
 388                 subtask = task.task("Sharp edges", 0.7)
 389                 self.split_vertices(self.find_smooth_group, subtask)
 390
 391                 if self.smoothing!='BLENDER':
 392                         subtask = task.task("Updating normals", 1.0)
 393                         self.compute_normals(subtask)
 394
 395         def prepare_vertex_groups(self, obj):
 396                 if not self.vertex_groups:
 397                         return
 398
 399                 for v in self.vertices:
 400                         if v.groups:
 401                                 weight_sum = sum(g.weight for g in v.groups)
 402                                 v.groups = sorted(v.groups, key=(lambda g: g.weight), reverse=True)[:self.max_groups_per_vertex]
 403                                 weight_scale = weight_sum/sum(g.weight for g in v.groups)
 404                                 for g in v.groups:
 405                                         g.weight *= weight_scale
 406                         while len(v.groups)<self.max_groups_per_vertex:
 407                                 v.groups.append(VertexGroup(None))
 408
 409                 if obj.parent and obj.parent.type=="ARMATURE":
 410                         armature = obj.parent.data
 411                         bone_indices = {b.name: i for i, b in enumerate(armature.bones)}
 412                         group_index_map = {i: i for i in range(len(obj.vertex_groups))}
 413                         for g in first_obj.vertex_groups:
 414                                 if g.name in bone_indices:
 415                                         group_index_map[g.index] = bone_indices[g.name]
 416
 417                         for v in self.vertices:
 418                                 for g in v.groups:
 419                                         g.group = group_index_map[g.group]
 420
 421         def prepare_uv(self, task):
 422                 # Form a list of UV layers referenced by materials with the array atlas
 423                 # property set
 424                 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']
 425                 array_uv_layers = [u for u in self.uv_layers if u.name in array_uv_layers]
 426
 427                 if array_uv_layers:
 428                         for f in self.faces:
 429                                 layer = 0
 430                                 if f.material_index<len(self.materials):
 431                                         mat = self.materials[f.material_index]
 432                                         if mat and mat.array_atlas:
 433                                                 layer = mat.array_layer
 434
 435                                 for l in array_uv_layers:
 436                                         for i in f.loop_indices:
 437                                                 l.uvs[i] = mathutils.Vector((*l.uvs[i], layer))
 438
 439                 # Split by the UV layer used for tangent vectors first so connectivity
 440                 # remains intact for tangent vector computation
 441                 tangent_layer_index = -1
 442                 if self.tangent_vecs:
 443                         if self.tangent_uvtex:
 444                                 uv_names = [u.name for u in self.uv_layers]
 445                                 if self.tangent_uvtex in uv_names:
 446                                         tangent_layer_index = uv_names.index(self.tangent_uvtex)
 447                         elif self.uv_layers[0].unit==0:
 448                                 tangent_layer_index = 0
 449
 450                         if tangent_layer_index<0:
 451                                 raise Exception("Invalid configuration on mesh {}: No tangent UV layer".format(self.name))
 452
 453                 prog_count = len(self.uv_layers)
 454                 if tangent_layer_index>=0:
 455                         prog_count += 1
 456                 task.set_slices(prog_count)
 457
 458                 if tangent_layer_index>=0:
 459                         subtask = task.next_slice("Computing tangents")
 460                         self.split_vertices(self.find_uv_group, subtask, tangent_layer_index)
 461                         subtask = task.next_slice(self.tangent_uvtex)
 462                         self.compute_tangents(tangent_layer_index, subtask)
 463
 464                 # Split by the remaining UV layers
 465                 for i, u in enumerate(self.uv_layers):
 466                         if i==tangent_layer_index:
 467                                 continue
 468
 469                         subtask = task.next_slice(u.name)
 470                         self.split_vertices(self.find_uv_group, subtask, i)
 471
 472                 # Copy UVs from layers to vertices
 473                 for v in self.vertices:
 474                         if v.faces:
 475                                 # All faces still connected to the vertex have the same UV value
 476                                 f = v.faces[0]
 477                                 i = f.get_loop_index(v)
 478                                 v.uvs = [u.uvs[i] for u in self.uv_layers]
 479                         else:
 480                                 v.uvs = [(0.0, 0.0)]*len(self.uv_layers)
 481
 482         def prepare_colors(self, task):
 483                 if not self.colors:
 484                         return
 485
 486                 self.split_vertices(self.find_color_group, task)
 487
 488                 for v in self.vertices:
 489                         if v.faces:
 490                                 f = v.faces[0]
 491                                 v.color = self.colors.colors[f.get_loop_index(v)]
 492                         else:
 493                                 v.color = (1.0, 1.0, 1.0, 1.0)
 494
 495         def split_vertices(self, find_group_func, task, *args):
 496                 vertex_count = len(self.vertices)
 497                 for i in range(vertex_count):
 498                         v = self.vertices[i]
 499                         for f in v.faces:
 500                                 f.flag = False
 501
 502                         # Find all groups of faces on this vertex
 503                         groups = []
 504                         for f in v.faces:
 505                                 if not f.flag:
 506                                         groups.append(find_group_func(v, f, *args))
 507
 508                         # Give groups after the first separate copies of the vertex
 509                         for g in groups[1:]:
 510                                 nv = Vertex(v)
 511                                 nv.index = len(self.vertices)
 512                                 self.vertices.append(nv)
 513
 514                                 for e in v.edges:
 515                                         e_faces_in_g = [f for f in e.faces if f in g]
 516                                         if not e_faces_in_g:
 517                                                 continue
 518
 519                                         if len(e_faces_in_g)<len(e.faces):
 520                                                 # Create a copy of an edge at the boundary of the group
 521                                                 ne = Edge(e)
 522                                                 ne.index = len(self.edges)
 523                                                 self.edges.append(ne)
 524
 525                                                 ne.other_vertex(v).edges.append(ne)
 526
 527                                                 for f in e_faces_in_g:
 528                                                         e.faces.remove(f)
 529                                                         f.edges[f.edges.index(e)] = ne
 530                                                         ne.faces.append(f)
 531
 532                                                 e = ne
 533
 534                                         e.vertices[e.vertices.index(v)] = nv
 535                                         nv.edges.append(e)
 536
 537                                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 538
 539                                 # Filter out any edges that were removed from the original vertex
 540                                 v.edges = [e for e in v.edges if v in e.vertices]
 541
 542                                 for f in g:
 543                                         v.faces.remove(f)
 544                                         f.vertices[f.vertices.index(v)] = nv
 545                                         nv.faces.append(f)
 546
 547                         task.set_progress(i/vertex_count)
 548
 549         def find_smooth_group(self, vertex, face):
 550                 face.flag = True
 551
 552                 edges = [e for e in face.edges if vertex in e.vertices]
 553
 554                 group = [face]
 555                 for e in edges:
 556                         f = face
 557                         while e.smooth:
 558                                 f = e.other_face(f)
 559                                 if not f or f.flag:
 560                                         break
 561
 562                                 f.flag = True
 563                                 group.append(f)
 564                                 e = f.other_edge(e, vertex)
 565
 566                 return group
 567
 568         def find_uv_group(self, vertex, face, index):
 569                 layer = self.uv_layers[index]
 570                 uv = layer.uvs[face.get_loop_index(vertex)]
 571                 face.flag = True
 572
 573                 group = [face]
 574                 for f in vertex.faces:
 575                         if not f.flag and layer.uvs[f.get_loop_index(vertex)]==uv:
 576                                 f.flag = True
 577                                 group.append(f)
 578
 579                 return group
 580
 581         def find_color_group(self, vertex, face):
 582                 color = self.colors.colors[face.get_loop_index(vertex)]
 583                 face.flag = True
 584
 585                 group = [face]
 586                 for f in vertex.faces:
 587                         if not f.flag and self.colors.colors[f.get_loop_index(vertex)]==color:
 588                                 f.flag = True
 589                                 group.append(f)
 590
 591                 return group
 592
 593         def compute_normals(self, task):
 594                 for i, v in enumerate(self.vertices):
 595                         v.normal = mathutils.Vector()
 596                         for f in v.faces:
 597                                 vi = f.pivot_vertex(v)
 598                                 edge1 = f.vertices[vi[1]].co-v.co
 599                                 edge2 = f.vertices[vi[-1]].co-v.co
 600                                 if edge1.length and edge2.length:
 601                                         # Use the angle between edges as a weighting factor.  This gives
 602                                         # more consistent normals on bends with an inequal number of
 603                                         # faces on each side.
 604                                         v.normal += f.normal*edge1.angle(edge2)
 605
 606                         if v.normal.length:
 607                                 v.normal.normalize()
 608                         else:
 609                                 v.normal = mathutils.Vector((0, 0, 1))
 610
 611                         task.set_progress(i/len(self.vertices))
 612
 613         def compute_tangents(self, index, task):
 614                 layer_uvs = self.uv_layers[index].uvs
 615
 616                 for i, v in enumerate(self.vertices):
 617                         v.tan = mathutils.Vector()
 618                         for f in v.faces:
 619                                 vi = f.pivot_vertex(v)
 620                                 uv0 = layer_uvs[f.loop_indices[vi[0]]]
 621                                 uv1 = layer_uvs[f.loop_indices[vi[1]]]
 622                                 uv2 = layer_uvs[f.loop_indices[vi[-1]]]
 623                                 du1 = uv1[0]-uv0[0]
 624                                 du2 = uv2[0]-uv0[0]
 625                                 dv1 = uv1[1]-uv0[1]
 626                                 dv2 = uv2[1]-uv0[1]
 627                                 edge1 = f.vertices[vi[1]].co-f.vertices[vi[0]].co
 628                                 edge2 = f.vertices[vi[-1]].co-f.vertices[vi[0]].co
 629                                 div = (du1*dv2-du2*dv1)
 630                                 if div:
 631                                         mul = edge1.angle(edge2)/div
 632                                         v.tan += (edge1*dv2-edge2*dv1)*mul
 633
 634                         if v.tan.length:
 635                                 v.tan.normalize()
 636
 637                         task.set_progress(i/len(self.vertices))
 638
 639         def prepare_sequence(self, task):
 640                 subtask = task.task("Reordering faces", 0.5)
 641                 self.reorder_faces(subtask)
 642
 643                 subtask = task.task("Building sequence", 1.0)
 644                 if self.use_strips:
 645                         self.build_tristrip_sequence(subtask)
 646                 else:
 647                         self.build_triangle_sequence(subtask)
 648
 649                 if self.use_lines:
 650                         self.build_line_sequence()
 651
 652                 self.reorder_vertices()
 653
 654         def build_tristrip_sequence(self, task):
 655                 sequence = None
 656                 for i, f in enumerate(self.faces):
 657                         if sequence:
 658                                 if len(sequence)==3:
 659                                         # Rotate the first three vertices so that the new face can be added
 660                                         if sequence[0] in f.vertices and sequence[1] not in f.vertices:
 661                                                 sequence.append(sequence[0])
 662                                                 del sequence[0]
 663                                         elif sequence[2] not in f.vertices and sequence[1] in f.vertices:
 664                                                 sequence.insert(0, sequence[-1])
 665                                                 del sequence[-1]
 666
 667                                 if sequence[-1] not in f.vertices:
 668                                         sequence = None
 669                                 else:
 670                                         to_add = [v for v in f.vertices if v!=sequence[-1] and v!=sequence[-2]]
 671                                         if len(to_add)==2:
 672                                                 if (f.vertices[1]==sequence[-1]) != (len(sequence)%2==1):
 673                                                         to_add.reverse()
 674                                                 sequence.append(sequence[-1])
 675                                         sequence += to_add
 676
 677                         if not sequence:
 678                                 self.batches.append(Batch("TRIANGLE_STRIP"))
 679                                 sequence = self.batches[-1].vertices
 680                                 sequence += f.vertices
 681
 682                         task.set_progress(i/len(self.faces))
 683
 684         def build_triangle_sequence(self, task):
 685                 batch = Batch("TRIANGLES")
 686                 for f in self.faces:
 687                         batch.vertices += f.vertices
 688                 self.batches.append(batch)
 689
 690         def build_line_sequence(self):
 691                 batch = Batch("LINES")
 692                 for l in self.lines:
 693                         batch.vertices += l.vertices
 694                 self.batches.append(batch)
 695
 696                 self.reorder_vertices()
 697
 698         def reorder_faces(self, task):
 699                 # Tom Forsyth's vertex cache optimization algorithm
 700                 # http://eelpi.gotdns.org/papers/fast_vert_cache_opt.html
 701
 702                 for f in self.faces:
 703                         f.flag = False
 704
 705                 last_triangle_score = 0.75
 706                 cache_decay_power = 1.5
 707                 valence_boost_scale = 2.0
 708                 valence_boost_power = -0.5
 709
 710                 max_cache_size = 32
 711                 cached_vertices = []
 712
 713                 # Keep track of the score and number of unused faces for each vertex
 714                 vertex_info = [[0, len(v.faces)] for v in self.vertices]
 715                 for vi in vertex_info:
 716                         if vi[1]:
 717                                 vi[0] = valence_boost_scale*(vi[1]**valence_boost_power)
 718
 719                 face = None
 720                 reordered_faces = []
 721
 722                 n_processed = 0
 723                 while 1:
 724                         if not face:
 725                                 # Previous iteration gave no candidate for best face (or this is
 726                                 # the first iteration).  Scan all faces for the highest score.
 727                                 best_score = 0
 728                                 for f in self.faces:
 729                                         if f.flag:
 730                                                 continue
 731
 732                                         score = sum(vertex_info[v.index][0] for v in f.vertices)
 733                                         if score>best_score:
 734                                                 best_score = score
 735                                                 face = f
 736
 737                         if not face:
 738                                 break
 739
 740                         reordered_faces.append(face)
 741                         face.flag = True
 742
 743                         for v in face.vertices:
 744                                 vertex_info[v.index][1] -= 1
 745
 746                                 # Shuffle the vertex into the front of the cache
 747                                 if v in cached_vertices:
 748                                         cached_vertices.remove(v)
 749                                 cached_vertices.insert(0, v)
 750
 751                         # Update scores for all vertices in the cache
 752                         for i, v in enumerate(cached_vertices):
 753                                 score = 0
 754                                 if i<3:
 755                                         score += last_triangle_score
 756                                 elif i<max_cache_size:
 757                                         score += (1-(i-3)/(max_cache_size-3))**cache_decay_power
 758                                 if vertex_info[v.index][1]:
 759                                         score += valence_boost_scale*(vertex_info[v.index][1]**valence_boost_power)
 760                                 vertex_info[v.index][0] = score
 761
 762                         face = None
 763                         best_score = 0
 764                         for v in cached_vertices:
 765                                 for f in v.faces:
 766                                         if not f.flag:
 767                                                 score = sum(vertex_info[fv.index][0] for fv in f.vertices)
 768                                                 if score>best_score:
 769                                                         best_score = score
 770                                                         face = f
 771
 772                         del cached_vertices[max_cache_size:]
 773
 774                         n_processed += 1
 775                         task.set_progress(n_processed/len(self.faces))
 776
 777                 self.faces = reordered_faces
 778                 for i, f in enumerate(self.faces):
 779                         f.index = i
 780
 781         def reorder_vertices(self):
 782                 for v in self.vertices:
 783                         v.index = -1
 784
 785                 reordered_vertices = []
 786                 for b in self.batches:
 787                         for v in b.vertices:
 788                                 if v.index<0:
 789                                         v.index = len(reordered_vertices)
 790                                         reordered_vertices.append(v)
 791
 792                 for v in self.vertices:
 793                         if v.index<0:
 794                                 v.index = len(reordered_vertices)
 795                                 reordered_vertices.append(v)
 796
 797                 self.vertices = reordered_vertices
 798
 799                 for e in self.edges:
 800                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 801
 802
 803 def create_mesh_from_object(ctx, obj):
 804         if obj.type!="MESH":
 805                 raise Exception("Object {} is not a mesh".format(obj.name))
 806
 807         task = ctx.task("Collecting mesh data", 0.2)
 808
 809         objs = [(obj, mathutils.Matrix())]
 810         i = 0
 811         while i<len(objs):
 812                 o, m = objs[i]
 813                 i += 1
 814                 for c in o.children:
 815                         if c.type=="MESH" and c.compound:
 816                                 objs.append((c, m*c.matrix_local))
 817
 818         dg = ctx.context.evaluated_depsgraph_get()
 819
 820         mesh = None
 821         for o, m in objs:
 822                 eval_obj = o.evaluated_get(dg)
 823                 bmesh = eval_obj.to_mesh()
 824
 825                 # Object.to_mesh does not copy custom properties
 826                 bmesh.smoothing = o.data.smoothing
 827                 bmesh.use_lines = o.data.use_lines
 828                 bmesh.vertex_groups = o.data.vertex_groups
 829                 bmesh.max_groups_per_vertex = o.data.max_groups_per_vertex
 830                 bmesh.use_uv = o.data.use_uv
 831                 bmesh.tangent_vecs = o.data.tangent_vecs
 832                 bmesh.tangent_uvtex = o.data.tangent_uvtex
 833
 834                 me = Mesh(bmesh)
 835                 me.transform(m)
 836
 837                 for i, s in enumerate(eval_obj.material_slots):
 838                         if s.link=='OBJECT':
 839                                 me.materials[i] = s.material
 840
 841                 if mesh:
 842                         mesh.splice(me)
 843                 else:
 844                         mesh = me
 845
 846         mesh.name = obj.data.name
 847
 848         task = ctx.task("Triangulating", 0.3)
 849         mesh.prepare_triangles(task)
 850         task = ctx.task("Smoothing", 0.5)
 851         mesh.prepare_smoothing(task)
 852         task = ctx.task("Vertex groups", 0.6)
 853         mesh.prepare_vertex_groups(obj)
 854         task = ctx.task("Preparing UVs", 0.75)
 855         mesh.prepare_uv(task)
 856         task = ctx.task("Preparing vertex colors", 0.85)
 857         mesh.prepare_colors(task)
 858         task = ctx.task("Render sequence", 1.0)
 859         mesh.prepare_sequence(task)
 860
 861         return mesh