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.patch_size = 0
  82                 self.vertices = []
  83
  84
  85 class Face:
  86         def __init__(self, face):
  87                 self.index = face.index
  88                 self.edges = []
  89                 self.edge_keys = face.edge_keys
  90                 self.vertices = face.vertices[:]
  91                 self.loop_indices = face.loop_indices
  92                 self.normal = face.normal
  93                 self.use_smooth = face.use_smooth
  94                 self.material_index = face.material_index
  95                 self.flag = False
  96
  97         def __cmp__(self, other):
  98                 if other is None:
  99                         return 1
 100                 return cmp(self.index, other.index)
 101
 102         def pivot_vertex(self, v):
 103                 n = self.vertices.index(v)
 104                 return [(n+i)%len(self.vertices) for i in range(len(self.vertices))]
 105
 106         def get_loop_index(self, v):
 107                 return self.loop_indices[self.vertices.index(v)]
 108
 109         def get_edge(self, v1, v2):
 110                 key = make_edge_key(v1.index, v2.index)
 111                 for e in self.edges:
 112                         if e.key==key:
 113                                 return e
 114                 raise KeyError("No edge %s"%(key,))
 115
 116         def other_edge(self, e, v):
 117                 for d in self.edges:
 118                         if d!=e and v in d.vertices:
 119                                 return d
 120
 121         def get_neighbors(self):
 122                 neighbors = [e.other_face(self) for e in self.edges]
 123                 return list(filter(bool, neighbors))
 124
 125
 126 class Line:
 127         def __init__(self, e):
 128                 self.edge = e
 129                 self.vertices = e.vertices[:]
 130                 self.flag = False
 131
 132
 133 class UvLayer:
 134         def __init__(self, arg):
 135                 if type(arg)==str:
 136                         self.name = arg
 137                         self.uvs = []
 138                 else:
 139                         self.name = arg.name
 140                         self.uvs = [mathutils.Vector(d.uv) for d in arg.data]
 141
 142                 self.unit = None
 143                 self.hidden = False
 144
 145                 dot = self.name.find('.')
 146                 if dot>=0:
 147                         ext = self.name[dot:]
 148                         if ext.startswith(".unit") and ext[5:].isdigit():
 149                                 self.unit = int(ext[5:])
 150                         elif ext==".hidden":
 151                                 self.hidden = True
 152
 153
 154 class ColorLayer:
 155         def __init__(self, l):
 156                 self.name = l.name
 157                 self.colors = [c.color[:] for c in l.data]
 158
 159
 160 class Mesh:
 161         def __init__(self, mesh):
 162                 self.name = mesh.name
 163
 164                 self.smoothing = mesh.smoothing
 165                 self.use_uv = mesh.use_uv
 166                 self.tangent_uvtex = mesh.tangent_uvtex
 167                 self.use_strips = mesh.use_strips
 168                 self.use_patches = mesh.use_patches
 169                 self.use_lines = mesh.use_lines
 170                 self.vertex_groups = mesh.vertex_groups
 171
 172                 # Clone basic data
 173                 self.vertices = [Vertex(v) for v in mesh.vertices]
 174                 if self.vertex_groups:
 175                         for v in self.vertices:
 176                                 v.groups = [VertexGroup(g) for g in v.groups]
 177
 178                 self.faces = [Face(f) for f in mesh.polygons]
 179                 self.edges = [Edge(e) for e in mesh.edges]
 180                 self.loops = mesh.loops[:]
 181                 self.materials = mesh.materials[:]
 182
 183                 self.use_auto_smooth = mesh.use_auto_smooth
 184                 self.auto_smooth_angle = mesh.auto_smooth_angle
 185                 self.max_groups_per_vertex = mesh.max_groups_per_vertex
 186
 187                 # Clone only the desired UV layers
 188                 if mesh.use_uv=='NONE' or not mesh.uv_layers:
 189                         self.uv_layers = []
 190                 else:
 191                         self.uv_layers = [UvLayer(u) for u in mesh.uv_layers if u.data]
 192
 193                         # Assign texture unit numbers to UV layers that lack one
 194                         missing_unit = [u for u in self.uv_layers if u.unit is None]
 195                         if missing_unit:
 196                                 missing_unit = sorted(missing_unit, key=(lambda u: u.name))
 197                                 used_units = [u.unit for u in self.uv_layers if u.unit is not None]
 198                                 for u, n in zip(missing_unit, (i for i in itertools.count() if i not in used_units)):
 199                                         u.unit = n
 200
 201                         self.uv_layers = sorted(self.uv_layers, key=(lambda u: u.unit))
 202
 203                         if mesh.use_uv=='UNIT0' and self.uv_layers:
 204                                 self.uv_layers = [self.uv_layers[0]]
 205                                 if self.uv_layers[0].unit!=0:
 206                                         self.uv_layers = []
 207
 208                 self.colors = None
 209                 if mesh.vertex_colors:
 210                         self.colors = ColorLayer(mesh.vertex_colors[0])
 211
 212                 # Rewrite links between elements to point to cloned data, or create links
 213                 # where they don't exist
 214                 edge_map = {e.key: e for e in self.edges}
 215                 for f in self.faces:
 216                         if len(f.vertices)>4 and not mesh.use.patches:
 217                                 raise ValueError("Unsupported face on mesh {}: N-gon".format(self.name))
 218
 219                         f.vertices = [self.vertices[i] for i in f.vertices]
 220                         for v in f.vertices:
 221                                 v.faces.append(f)
 222
 223                         for k in f.edge_keys:
 224                                 e = edge_map[k]
 225                                 e.faces.append(f)
 226                                 f.edges.append(e)
 227
 228                 for e in self.edges:
 229                         e.vertices = [self.vertices[i] for i in e.vertices]
 230                         for v in e.vertices:
 231                                 v.edges.append(e)
 232
 233                 # Store loose edges as lines
 234                 if mesh.use_lines and not mesh.use_patches:
 235                         self.lines = [Line(e) for e in self.edges if not e.faces]
 236                 else:
 237                         self.lines = []
 238
 239                 # Check if tangent vectors are needed
 240                 if mesh.tangent_vecs=='NO':
 241                         self.tangent_vecs = False
 242                 elif mesh.tangent_vecs=='YES':
 243                         self.tangent_vecs = True
 244                 elif mesh.tangent_vecs=='AUTO':
 245                         from .material import Material
 246                         self.tangent_vecs = False
 247                         for m in self.materials:
 248                                 mat = Material(m)
 249                                 if mat.type=="pbr":
 250                                         normal_prop = next((p for p in mat.properties if p.tex_keyword=="normal_map"), None)
 251                                         if normal_prop and normal_prop.texture:
 252                                                 self.tangent_vecs = True
 253
 254                 self.batches = []
 255
 256         def transform(self, matrix):
 257                 for v in self.vertices:
 258                         v.co = matrix@v.co
 259
 260         def splice(self, other):
 261                 if len(self.uv_layers)!=len(other.uv_layers):
 262                         raise ValueError("Meshes {} and {} have incompatible UV layers".format(self.name, other.name))
 263                 for i, u in enumerate(self.uv_layers):
 264                         if u.name!=other.uv_layers[i].name:
 265                                 raise ValueError("Meshes {} and {} have incompatible UV layers".format(self.name, other.name))
 266
 267                 # Merge materials and form a lookup from source material indices to the
 268                 # merged material list
 269                 material_lookup = []
 270                 for m in other.materials:
 271                         if m in self.materials:
 272                                 material_lookup.append(self.materials.index(m))
 273                         else:
 274                                 material_lookup.append(len(self.materials))
 275                                 self.materials.append(m)
 276
 277                 # Append data and adjust indices where necessary.  Since the data is
 278                 # spliced from the source mesh, rebuilding references is not necessary.
 279                 for i, u in enumerate(self.uv_layers):
 280                         u.uvs += other.uv_layers[i].uvs
 281
 282                 if self.colors:
 283                         if other.colors:
 284                                 self.colors.colors += other.colors.colors
 285                         else:
 286                                 self.colors.colors += [(1.0, 1.0, 1.0, 1.0)]*len(other.loops)
 287                 elif other.colors:
 288                         self.colors = ColorLayer(other.colors.name)
 289                         self.colors.colors = [(1.0, 1.0, 1.0, 1.0)]*len(self.loops)+other.colors.colors
 290
 291                 offset = len(self.vertices)
 292                 self.vertices += other.vertices
 293                 for v in self.vertices[offset:]:
 294                         v.index += offset
 295
 296                 loop_offset = len(self.loops)
 297                 self.loops += other.loops
 298
 299                 offset = len(self.faces)
 300                 self.faces += other.faces
 301                 for f in self.faces[offset:]:
 302                         f.index += offset
 303                         f.loop_indices = range(f.loop_indices.start+offset, f.loop_indices.stop+offset)
 304                         if other.materials:
 305                                 f.material_index = material_lookup[f.material_index]
 306
 307                 offset = len(self.edges)
 308                 self.edges += other.edges
 309                 for e in self.edges[offset:]:
 310                         e.index += offset
 311                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 312
 313                 self.lines += other.lines
 314
 315         def prepare_triangles(self, task):
 316                 if self.use_patches:
 317                         return
 318
 319                 face_count = len(self.faces)
 320                 for i in range(face_count):
 321                         f = self.faces[i]
 322                         nverts = len(f.vertices)
 323                         if nverts==3:
 324                                 continue
 325
 326                         # Calculate normals at each vertex of the face
 327                         edge_vecs = []
 328                         for j in range(nverts):
 329                                 edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
 330
 331                         normals = []
 332                         for j in range(nverts):
 333                                 normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
 334
 335                         # Check which diagonal results in a flatter triangulation
 336                         flatness1 = normals[0].dot(normals[2])
 337                         flatness2 = normals[1].dot(normals[3])
 338                         cut_index = 1 if flatness1>flatness2 else 0
 339
 340                         nf = Face(f)
 341                         nf.index = len(self.faces)
 342                         self.faces.append(nf)
 343
 344                         ne = Edge(None)
 345                         ne.index = len(self.edges)
 346                         self.edges.append(ne)
 347
 348                         nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
 349                         nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
 350                         for v in nf.vertices:
 351                                 v.faces.append(nf)
 352
 353                         ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
 354                         for v in ne.vertices:
 355                                 v.edges.append(ne)
 356                         ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
 357                         ne.smooth = True
 358
 359                         f.vertices[3-cut_index].faces.remove(f)
 360                         del f.vertices[3-cut_index]
 361                         f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
 362
 363                         ne.faces = [f, nf]
 364                         if cut_index==0:
 365                                 nf.edges = [ne, f.edges[2], f.edges[3]]
 366                                 f.edges = [f.edges[0], f.edges[1], ne]
 367                         else:
 368                                 nf.edges = [f.edges[1], f.edges[2], ne]
 369                                 f.edges = [f.edges[0], ne, f.edges[3]]
 370                         for e in nf.edges:
 371                                 if e!=ne:
 372                                         e.faces.remove(f)
 373                                         e.faces.append(nf)
 374
 375                         f.normal = normals[1-cut_index]
 376                         nf.normal = normals[3-cut_index]
 377
 378                         task.set_progress(i/face_count)
 379
 380         def prepare_smoothing(self, task):
 381                 smooth_limit = -1
 382                 if self.smoothing=='NONE':
 383                         for f in self.faces:
 384                                 f.use_smooth = False
 385
 386                         smooth_limit = 1
 387                 elif self.use_auto_smooth:
 388                         smooth_limit = math.cos(self.auto_smooth_angle)
 389
 390                 for e in self.edges:
 391                         e.check_smooth(smooth_limit)
 392
 393                 subtask = task.task("Sharp edges", 0.7)
 394                 self.split_vertices(self.find_smooth_group, subtask)
 395
 396                 if self.smoothing!='BLENDER':
 397                         subtask = task.task("Updating normals", 1.0)
 398                         self.compute_normals(subtask)
 399
 400         def prepare_vertex_groups(self, obj):
 401                 if not self.vertex_groups:
 402                         return
 403
 404                 for v in self.vertices:
 405                         if v.groups:
 406                                 weight_sum = sum(g.weight for g in v.groups)
 407                                 v.groups = sorted(v.groups, key=(lambda g: g.weight), reverse=True)[:self.max_groups_per_vertex]
 408                                 weight_scale = weight_sum/sum(g.weight for g in v.groups)
 409                                 for g in v.groups:
 410                                         g.weight *= weight_scale
 411                         while len(v.groups)<self.max_groups_per_vertex:
 412                                 v.groups.append(VertexGroup(None))
 413
 414                 if obj.parent and obj.parent.type=="ARMATURE":
 415                         armature = obj.parent.data
 416                         bone_indices = {b.name: i for i, b in enumerate(armature.bones)}
 417                         group_index_map = {i: i for i in range(len(obj.vertex_groups))}
 418                         for g in first_obj.vertex_groups:
 419                                 if g.name in bone_indices:
 420                                         group_index_map[g.index] = bone_indices[g.name]
 421
 422                         for v in self.vertices:
 423                                 for g in v.groups:
 424                                         g.group = group_index_map[g.group]
 425
 426         def prepare_uv(self, task):
 427                 # Form a list of UV layers referenced by materials with the array atlas
 428                 # property set
 429                 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']
 430                 array_uv_layers = [u for u in self.uv_layers if u.name in array_uv_layers]
 431
 432                 if array_uv_layers:
 433                         for f in self.faces:
 434                                 layer = 0
 435                                 if f.material_index<len(self.materials):
 436                                         mat = self.materials[f.material_index]
 437                                         if mat and mat.array_atlas:
 438                                                 layer = mat.array_layer
 439
 440                                 for l in array_uv_layers:
 441                                         for i in f.loop_indices:
 442                                                 l.uvs[i] = mathutils.Vector((*l.uvs[i], layer))
 443
 444                 # Split by the UV layer used for tangent vectors first so connectivity
 445                 # remains intact for tangent vector computation
 446                 tangent_layer_index = -1
 447                 if self.tangent_vecs:
 448                         if self.tangent_uvtex:
 449                                 uv_names = [u.name for u in self.uv_layers]
 450                                 if self.tangent_uvtex in uv_names:
 451                                         tangent_layer_index = uv_names.index(self.tangent_uvtex)
 452                         elif self.uv_layers[0].unit==0:
 453                                 tangent_layer_index = 0
 454
 455                         if tangent_layer_index<0:
 456                                 raise Exception("Invalid configuration on mesh {}: No tangent UV layer".format(self.name))
 457
 458                 prog_count = len(self.uv_layers)
 459                 if tangent_layer_index>=0:
 460                         prog_count += 1
 461                 task.set_slices(prog_count)
 462
 463                 if tangent_layer_index>=0:
 464                         subtask = task.next_slice("Computing tangents")
 465                         self.split_vertices(self.find_uv_group, subtask, tangent_layer_index)
 466                         subtask = task.next_slice(self.tangent_uvtex)
 467                         self.compute_tangents(tangent_layer_index, subtask)
 468
 469                 # Split by the remaining UV layers
 470                 for i, u in enumerate(self.uv_layers):
 471                         if i==tangent_layer_index:
 472                                 continue
 473
 474                         subtask = task.next_slice(u.name)
 475                         self.split_vertices(self.find_uv_group, subtask, i)
 476
 477                 # Copy UVs from layers to vertices
 478                 for v in self.vertices:
 479                         if v.faces:
 480                                 # All faces still connected to the vertex have the same UV value
 481                                 f = v.faces[0]
 482                                 i = f.get_loop_index(v)
 483                                 v.uvs = [u.uvs[i] for u in self.uv_layers]
 484                         else:
 485                                 v.uvs = [(0.0, 0.0)]*len(self.uv_layers)
 486
 487         def prepare_colors(self, task):
 488                 if not self.colors:
 489                         return
 490
 491                 self.split_vertices(self.find_color_group, task)
 492
 493                 for v in self.vertices:
 494                         if v.faces:
 495                                 f = v.faces[0]
 496                                 v.color = self.colors.colors[f.get_loop_index(v)]
 497                         else:
 498                                 v.color = (1.0, 1.0, 1.0, 1.0)
 499
 500         def split_vertices(self, find_group_func, task, *args):
 501                 vertex_count = len(self.vertices)
 502                 for i in range(vertex_count):
 503                         v = self.vertices[i]
 504                         for f in v.faces:
 505                                 f.flag = False
 506
 507                         # Find all groups of faces on this vertex
 508                         groups = []
 509                         for f in v.faces:
 510                                 if not f.flag:
 511                                         groups.append(find_group_func(v, f, *args))
 512
 513                         # Give groups after the first separate copies of the vertex
 514                         for g in groups[1:]:
 515                                 nv = Vertex(v)
 516                                 nv.index = len(self.vertices)
 517                                 self.vertices.append(nv)
 518
 519                                 for e in v.edges:
 520                                         e_faces_in_g = [f for f in e.faces if f in g]
 521                                         if not e_faces_in_g:
 522                                                 continue
 523
 524                                         if len(e_faces_in_g)<len(e.faces):
 525                                                 # Create a copy of an edge at the boundary of the group
 526                                                 ne = Edge(e)
 527                                                 ne.index = len(self.edges)
 528                                                 self.edges.append(ne)
 529
 530                                                 ne.other_vertex(v).edges.append(ne)
 531
 532                                                 for f in e_faces_in_g:
 533                                                         e.faces.remove(f)
 534                                                         f.edges[f.edges.index(e)] = ne
 535                                                         ne.faces.append(f)
 536
 537                                                 e = ne
 538
 539                                         e.vertices[e.vertices.index(v)] = nv
 540                                         nv.edges.append(e)
 541
 542                                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 543
 544                                 # Filter out any edges that were removed from the original vertex
 545                                 v.edges = [e for e in v.edges if v in e.vertices]
 546
 547                                 for f in g:
 548                                         v.faces.remove(f)
 549                                         f.vertices[f.vertices.index(v)] = nv
 550                                         nv.faces.append(f)
 551
 552                         task.set_progress(i/vertex_count)
 553
 554         def find_smooth_group(self, vertex, face):
 555                 face.flag = True
 556
 557                 edges = [e for e in face.edges if vertex in e.vertices]
 558
 559                 group = [face]
 560                 for e in edges:
 561                         f = face
 562                         while e.smooth:
 563                                 f = e.other_face(f)
 564                                 if not f or f.flag:
 565                                         break
 566
 567                                 f.flag = True
 568                                 group.append(f)
 569                                 e = f.other_edge(e, vertex)
 570
 571                 return group
 572
 573         def find_uv_group(self, vertex, face, index):
 574                 layer = self.uv_layers[index]
 575                 uv = layer.uvs[face.get_loop_index(vertex)]
 576                 face.flag = True
 577
 578                 group = [face]
 579                 for f in vertex.faces:
 580                         if not f.flag and layer.uvs[f.get_loop_index(vertex)]==uv:
 581                                 f.flag = True
 582                                 group.append(f)
 583
 584                 return group
 585
 586         def find_color_group(self, vertex, face):
 587                 color = self.colors.colors[face.get_loop_index(vertex)]
 588                 face.flag = True
 589
 590                 group = [face]
 591                 for f in vertex.faces:
 592                         if not f.flag and self.colors.colors[f.get_loop_index(vertex)]==color:
 593                                 f.flag = True
 594                                 group.append(f)
 595
 596                 return group
 597
 598         def compute_normals(self, task):
 599                 for i, v in enumerate(self.vertices):
 600                         v.normal = mathutils.Vector()
 601                         for f in v.faces:
 602                                 vi = f.pivot_vertex(v)
 603                                 edge1 = f.vertices[vi[1]].co-v.co
 604                                 edge2 = f.vertices[vi[-1]].co-v.co
 605                                 if edge1.length and edge2.length:
 606                                         # Use the angle between edges as a weighting factor.  This gives
 607                                         # more consistent normals on bends with an inequal number of
 608                                         # faces on each side.
 609                                         v.normal += f.normal*edge1.angle(edge2)
 610
 611                         if v.normal.length:
 612                                 v.normal.normalize()
 613                         else:
 614                                 v.normal = mathutils.Vector((0, 0, 1))
 615
 616                         task.set_progress(i/len(self.vertices))
 617
 618         def compute_tangents(self, index, task):
 619                 layer_uvs = self.uv_layers[index].uvs
 620
 621                 for i, v in enumerate(self.vertices):
 622                         v.tan = mathutils.Vector()
 623                         for f in v.faces:
 624                                 vi = f.pivot_vertex(v)
 625                                 uv0 = layer_uvs[f.loop_indices[vi[0]]]
 626                                 uv1 = layer_uvs[f.loop_indices[vi[1]]]
 627                                 uv2 = layer_uvs[f.loop_indices[vi[-1]]]
 628                                 du1 = uv1[0]-uv0[0]
 629                                 du2 = uv2[0]-uv0[0]
 630                                 dv1 = uv1[1]-uv0[1]
 631                                 dv2 = uv2[1]-uv0[1]
 632                                 edge1 = f.vertices[vi[1]].co-f.vertices[vi[0]].co
 633                                 edge2 = f.vertices[vi[-1]].co-f.vertices[vi[0]].co
 634                                 div = (du1*dv2-du2*dv1)
 635                                 if div:
 636                                         mul = edge1.angle(edge2)/div
 637                                         v.tan += (edge1*dv2-edge2*dv1)*mul
 638
 639                         if v.tan.length:
 640                                 v.tan.normalize()
 641
 642                         task.set_progress(i/len(self.vertices))
 643
 644         def prepare_sequence(self, task):
 645                 if self.use_patches:
 646                         subtask = task.task("Reordering patches", 0.5)
 647                         self.reorder_patches(subtask)
 648
 649                         subtask = task.task("Building sequence", 1.0)
 650                         self.build_patch_sequence(subtask)
 651                 else:
 652                         subtask = task.task("Reordering faces", 0.5)
 653                         self.reorder_faces(subtask)
 654
 655                         subtask = task.task("Building sequence", 1.0)
 656                         if self.use_strips:
 657                                 self.build_tristrip_sequence(subtask)
 658                         else:
 659                                 self.build_triangle_sequence(subtask)
 660
 661                         if self.use_lines:
 662                                 self.build_line_sequence()
 663
 664                 self.reorder_vertices()
 665
 666         def build_tristrip_sequence(self, task):
 667                 sequence = None
 668                 for i, f in enumerate(self.faces):
 669                         if sequence:
 670                                 if len(sequence)==3:
 671                                         # Rotate the first three vertices so that the new face can be added
 672                                         if sequence[0] in f.vertices and sequence[1] not in f.vertices:
 673                                                 sequence.append(sequence[0])
 674                                                 del sequence[0]
 675                                         elif sequence[2] not in f.vertices and sequence[1] in f.vertices:
 676                                                 sequence.insert(0, sequence[-1])
 677                                                 del sequence[-1]
 678
 679                                 if sequence[-1] not in f.vertices:
 680                                         sequence = None
 681                                 else:
 682                                         to_add = [v for v in f.vertices if v!=sequence[-1] and v!=sequence[-2]]
 683                                         if len(to_add)==2:
 684                                                 if (f.vertices[1]==sequence[-1]) != (len(sequence)%2==1):
 685                                                         to_add.reverse()
 686                                                 sequence.append(sequence[-1])
 687                                         sequence += to_add
 688
 689                         if not sequence:
 690                                 self.batches.append(Batch("TRIANGLE_STRIP"))
 691                                 sequence = self.batches[-1].vertices
 692                                 sequence += f.vertices
 693
 694                         task.set_progress(i/len(self.faces))
 695
 696         def build_triangle_sequence(self, task):
 697                 batch = Batch("TRIANGLES")
 698                 for f in self.faces:
 699                         batch.vertices += f.vertices
 700                 self.batches.append(batch)
 701
 702         def build_line_sequence(self):
 703                 batch = Batch("LINES")
 704                 for l in self.lines:
 705                         batch.vertices += l.vertices
 706                 self.batches.append(batch)
 707
 708         def build_patch_sequence(self, task):
 709                 current_size = 0
 710                 sequence = None
 711                 for f in self.faces:
 712                         if len(f.vertices)!=current_size:
 713                                 current_size = len(f.vertices)
 714                                 self.batches.append(Batch("PATCHES"))
 715                                 self.batches[-1].patch_size = current_size
 716                                 sequence = self.batches[-1].vertices
 717
 718                         sequence += f.vertices
 719
 720         def reorder_faces(self, task):
 721                 # Tom Forsyth's vertex cache optimization algorithm
 722                 # http://eelpi.gotdns.org/papers/fast_vert_cache_opt.html
 723
 724                 for f in self.faces:
 725                         f.flag = False
 726
 727                 last_triangle_score = 0.75
 728                 cache_decay_power = 1.5
 729                 valence_boost_scale = 2.0
 730                 valence_boost_power = -0.5
 731
 732                 max_cache_size = 32
 733                 cached_vertices = []
 734
 735                 # Keep track of the score and number of unused faces for each vertex
 736                 vertex_info = [[0, len(v.faces)] for v in self.vertices]
 737                 for vi in vertex_info:
 738                         if vi[1]:
 739                                 vi[0] = valence_boost_scale*(vi[1]**valence_boost_power)
 740
 741                 face = None
 742                 reordered_faces = []
 743
 744                 n_processed = 0
 745                 while 1:
 746                         if not face:
 747                                 # Previous iteration gave no candidate for best face (or this is
 748                                 # the first iteration).  Scan all faces for the highest score.
 749                                 best_score = 0
 750                                 for f in self.faces:
 751                                         if f.flag:
 752                                                 continue
 753
 754                                         score = sum(vertex_info[v.index][0] for v in f.vertices)
 755                                         if score>best_score:
 756                                                 best_score = score
 757                                                 face = f
 758
 759                         if not face:
 760                                 break
 761
 762                         reordered_faces.append(face)
 763                         face.flag = True
 764
 765                         for v in face.vertices:
 766                                 vertex_info[v.index][1] -= 1
 767
 768                                 # Shuffle the vertex into the front of the cache
 769                                 if v in cached_vertices:
 770                                         cached_vertices.remove(v)
 771                                 cached_vertices.insert(0, v)
 772
 773                         # Update scores for all vertices in the cache
 774                         for i, v in enumerate(cached_vertices):
 775                                 score = 0
 776                                 if i<3:
 777                                         score += last_triangle_score
 778                                 elif i<max_cache_size:
 779                                         score += (1-(i-3)/(max_cache_size-3))**cache_decay_power
 780                                 if vertex_info[v.index][1]:
 781                                         score += valence_boost_scale*(vertex_info[v.index][1]**valence_boost_power)
 782                                 vertex_info[v.index][0] = score
 783
 784                         face = None
 785                         best_score = 0
 786                         for v in cached_vertices:
 787                                 for f in v.faces:
 788                                         if not f.flag:
 789                                                 score = sum(vertex_info[fv.index][0] for fv in f.vertices)
 790                                                 if score>best_score:
 791                                                         best_score = score
 792                                                         face = f
 793
 794                         del cached_vertices[max_cache_size:]
 795
 796                         n_processed += 1
 797                         task.set_progress(n_processed/len(self.faces))
 798
 799                 self.faces = reordered_faces
 800                 for i, f in enumerate(self.faces):
 801                         f.index = i
 802
 803         def reorder_patches(self, task):
 804                 for f in self.faces:
 805                         f.flag = False
 806
 807                 reordered_faces = []
 808                 n_processed = 0
 809
 810                 while 1:
 811                         current_size = 0
 812
 813                         for f in self.faces:
 814                                 if f.flag:
 815                                         continue
 816
 817                                 if not current_size:
 818                                         current_size = len(f.vertices)
 819                                 elif len(f.vertices)!=current_size:
 820                                         continue
 821
 822                                 reordered_faces.append(f)
 823                                 f.flag = True
 824
 825                                 n_processed += 1
 826                                 task.set_progress(n_processed/len(self.faces))
 827
 828                         if not current_size:
 829                                 break
 830
 831         def reorder_vertices(self):
 832                 for v in self.vertices:
 833                         v.index = -1
 834
 835                 reordered_vertices = []
 836                 for b in self.batches:
 837                         for v in b.vertices:
 838                                 if v.index<0:
 839                                         v.index = len(reordered_vertices)
 840                                         reordered_vertices.append(v)
 841
 842                 for v in self.vertices:
 843                         if v.index<0:
 844                                 v.index = len(reordered_vertices)
 845                                 reordered_vertices.append(v)
 846
 847                 self.vertices = reordered_vertices
 848
 849                 for e in self.edges:
 850                         e.key = make_edge_key(e.vertices[0].index, e.vertices[1].index)
 851
 852
 853 def create_mesh_from_object(ctx, obj):
 854         if obj.type!="MESH":
 855                 raise Exception("Object {} is not a mesh".format(obj.name))
 856
 857         task = ctx.task("Collecting mesh data", 0.2)
 858
 859         objs = [(obj, mathutils.Matrix())]
 860         i = 0
 861         while i<len(objs):
 862                 o, m = objs[i]
 863                 i += 1
 864                 for c in o.children:
 865                         if c.type=="MESH" and c.compound:
 866                                 objs.append((c, m*c.matrix_local))
 867
 868         dg = ctx.context.evaluated_depsgraph_get()
 869
 870         mesh = None
 871         for o, m in objs:
 872                 eval_obj = o.evaluated_get(dg)
 873                 bmesh = eval_obj.to_mesh()
 874
 875                 # Object.to_mesh does not copy custom properties
 876                 bmesh.smoothing = o.data.smoothing
 877                 bmesh.use_lines = o.data.use_lines
 878                 bmesh.vertex_groups = o.data.vertex_groups
 879                 bmesh.max_groups_per_vertex = o.data.max_groups_per_vertex
 880                 bmesh.use_uv = o.data.use_uv
 881                 bmesh.tangent_vecs = o.data.tangent_vecs
 882                 bmesh.tangent_uvtex = o.data.tangent_uvtex
 883
 884                 me = Mesh(bmesh)
 885                 me.transform(m)
 886
 887                 for i, s in enumerate(eval_obj.material_slots):
 888                         if s.link=='OBJECT':
 889                                 me.materials[i] = s.material
 890
 891                 if mesh:
 892                         mesh.splice(me)
 893                 else:
 894                         mesh = me
 895
 896         mesh.name = obj.data.name
 897
 898         task = ctx.task("Triangulating", 0.3)
 899         mesh.prepare_triangles(task)
 900         task = ctx.task("Smoothing", 0.5)
 901         mesh.prepare_smoothing(task)
 902         task = ctx.task("Vertex groups", 0.6)
 903         mesh.prepare_vertex_groups(obj)
 904         task = ctx.task("Preparing UVs", 0.75)
 905         mesh.prepare_uv(task)
 906         task = ctx.task("Preparing vertex colors", 0.85)
 907         mesh.prepare_colors(task)
 908         task = ctx.task("Render sequence", 1.0)
 909         mesh.prepare_sequence(task)
 910
 911         return mesh