blender/io_mspgl/export_mesh.py

   1 import itertools
   2 import bpy
   3 import mathutils
   4
   5 class VertexCache:
   6         def __init__(self, size):
   7                 self.size = size
   8                 self.slots = [-1]*self.size
   9
  10         def fetch(self, v):
  11                 hit = v.index in self.slots
  12                 if hit:
  13                         self.slots.remove(v.index)
  14                 self.slots.append(v.index)
  15                 if not hit:
  16                         del self.slots[0]
  17                 return hit
  18
  19         def fetch_strip(self, strip):
  20                 hits = 0
  21                 for v in strip:
  22                         if self.fetch(v):
  23                                 hits += 1
  24                 return hits
  25
  26         def test_strip(self, strip):
  27                 hits = 0
  28                 for i in range(len(strip)):
  29                         if i>=self.size:
  30                                 break
  31                         if strip[i].index in self.slots[i:]:
  32                                 hits += 1
  33                 return hits
  34
  35
  36 class MeshExporter:
  37         def __init__(self):
  38                 self.show_progress = True
  39                 self.use_strips = True
  40                 self.use_degen_tris = False
  41                 self.max_strip_len = 1024
  42                 self.optimize_cache = True
  43                 self.cache_size = 64
  44                 self.material_tex = False
  45
  46         def stripify(self, mesh, progress=None):
  47                 for f in mesh.faces:
  48                         f.flag = False
  49
  50                 faces_done = 0
  51                 strips = []
  52                 loose = []
  53
  54                 cache = None
  55                 if self.optimize_cache:
  56                         cache = VertexCache(self.cache_size)
  57
  58                 island = []
  59                 face_neighbors = []
  60                 island_strips = []
  61                 while 1:
  62                         if not island:
  63                                 # No current island; find any unused face to start from
  64                                 queue = []
  65                                 for f in mesh.faces:
  66                                         if not f.flag:
  67                                                 f.flag = True
  68                                                 queue.append(f)
  69                                                 break
  70
  71                                 if not queue:
  72                                         break
  73
  74                                 # Find all faces connected to the first one
  75                                 while queue:
  76                                         face = queue.pop(0)
  77                                         island.append(face)
  78
  79                                         for n in face.get_neighbors():
  80                                                 if not n.flag:
  81                                                         n.flag = True
  82                                                         queue.append(n)
  83
  84                                 face_neighbors = [f.get_neighbors() for f in island]
  85
  86                                 # Unflag the island for the next phase
  87                                 for f in island:
  88                                         f.flag = False
  89
  90                         # Find an unused face with as few unused neighbors as possible, but
  91                         # at least one.  This heuristic gives a preference to faces in corners
  92                         # or along borders of a non-closed island.
  93                         best = 5
  94                         face = None
  95                         for i, f in enumerate(island):
  96                                 if f.flag:
  97                                         continue
  98
  99                                 score = sum(not n.flag for n in face_neighbors[i])
 100                                 if score>0 and score<best:
 101                                         face = f
 102                                         best = score
 103
 104                         if face:
 105                                 # Create a strip starting from the face.  This will flag the faces.
 106                                 strip = mesh.create_strip(face, self.max_strip_len)
 107                                 if strip:
 108                                         island_strips.append(strip)
 109                                 else:
 110                                         face.flag = True
 111                         else:
 112                                 # Couldn't find a candidate face for starting a strip, so we're
 113                                 # done with this island
 114                                 while island_strips:
 115                                         best = 0
 116                                         if cache:
 117                                                 # Find the strip that benefits the most from the current
 118                                                 # contents of the vertex cache
 119                                                 best_hits = 0
 120                                                 for i in range(len(island_strips)):
 121                                                         hits = cache.test_strip(island_strips[i])
 122                                                         if hits>best_hits:
 123                                                                 best = i
 124                                                                 best_hits = hits
 125
 126                                         strip = island_strips.pop(best)
 127                                         strips.append(strip)
 128
 129                                         if cache:
 130                                                 cache.fetch_strip(strip)
 131
 132                                 faces_done += len(island)
 133                                 progress.set_progress(faces_done/len(mesh.faces))
 134
 135                                 # Collect any faces that weren't used in strips
 136                                 loose += [f for f in island if not f.flag]
 137                                 for f in island:
 138                                         f.flag = True
 139
 140                                 island = []
 141                                 island_strips = []
 142
 143                 if cache:
 144                         cache = VertexCache(self.cache_size)
 145                         total_hits = 0
 146
 147                 if self.use_degen_tris and strips:
 148                         big_strip = []
 149
 150                         for s in strips:
 151                                 if big_strip:
 152                                         # Generate glue elements, ensuring that the next strip begins at
 153                                         # an even position
 154                                         glue = [big_strip[-1], s[0]]
 155                                         if len(big_strip)%2:
 156                                                 glue += [s[0]]
 157
 158                                         big_strip += glue
 159                                         if cache:
 160                                                 total_hits += cache.fetch_strip(glue)
 161
 162                                 big_strip += s
 163                                 if cache:
 164                                         total_hits += cache.fetch_strip(s)
 165
 166                         for f in loose:
 167                                 # Add loose faces to the end.  This wastes space, using five
 168                                 # elements per triangle and six elements per quad.
 169                                 if len(big_strip)%2:
 170                                         order = (-1, -2, 0, 1)
 171                                 else:
 172                                         order = (0, 1, -1, -2)
 173                                 vertices = [f.vertices[i] for i in order[:len(f.vertices)]]
 174
 175                                 if big_strip:
 176                                         glue = [big_strip[-1], vertices[0]]
 177                                         big_strip += glue
 178                                         if cache:
 179                                                 total_hits += cache.fetch_strip(glue)
 180
 181                                 big_strip += vertices
 182                                 if cache:
 183                                         total_hits += cache.fetch_strip(vertices)
 184
 185                         strips = [big_strip]
 186                         loose = []
 187
 188                 return strips, loose
 189
 190         def export(self, context, out_file, obj=None, progress=None):
 191                 if obj is None:
 192                         obj = context.active_object
 193
 194                 from .mesh import create_mesh_from_object
 195                 from .util import Progress
 196
 197                 if not progress:
 198                         progress = Progress(self.show_progress and context)
 199                 progress.push_task("", 0.0, 0.65)
 200
 201                 mesh = create_mesh_from_object(context, obj, progress)
 202
 203                 strips = []
 204                 loose = mesh.faces
 205                 if self.use_strips:
 206                         progress.set_task("Creating strips", 0.65, 0.95)
 207                         strips, loose = self.stripify(mesh, progress)
 208
 209                 progress.set_task("Writing file", 0.95, 1.0)
 210
 211                 from .outfile import open_output
 212                 out_file = open_output(out_file)
 213
 214                 fmt = ["NORMAL3"]
 215                 if mesh.uv_layers:
 216                         for u in mesh.uv_layers:
 217                                 size = str(len(u.uvs[0]))
 218                                 if u.unit==0:
 219                                         fmt.append("TEXCOORD"+size)
 220                                 else:
 221                                         fmt.append("TEXCOORD%s_%d"%(size, u.unit))
 222                         if mesh.tbn_vecs:
 223                                 fmt += ["TANGENT3", "BINORMAL3"]
 224                 if mesh.vertex_groups:
 225                         fmt.append("ATTRIB%d_5"%(mesh.max_groups_per_vertex*2))
 226                 fmt.append("VERTEX3")
 227                 out_file.begin("vertices", *fmt)
 228                 normal = None
 229                 uvs = {}
 230                 tan = None
 231                 bino = None
 232                 group = None
 233                 for v in mesh.vertices:
 234                         if v.normal!=normal:
 235                                 out_file.write("normal3", *v.normal)
 236                                 normal = v.normal
 237                         for i, u in enumerate(mesh.uv_layers):
 238                                 if v.uvs[i]!=uvs.get(i):
 239                                         size = str(len(v.uvs[i]))
 240                                         if u.unit==0:
 241                                                 out_file.write("texcoord"+size, *v.uvs[i])
 242                                         else:
 243                                                 out_file.write("multitexcoord"+size, u.unit, *v.uvs[i])
 244                                         uvs[i] = v.uvs[i]
 245                         if mesh.tbn_vecs:
 246                                 if v.tan!=tan:
 247                                         out_file.write("tangent3", *v.tan)
 248                                         tan = v.tan
 249                                 if v.bino!=bino:
 250                                         out_file.write("binormal3", *v.bino)
 251                                         bino = v.bino
 252                         if mesh.vertex_groups:
 253                                 group_attr = [(group_index_map[g.group], g.weight*v.group_weight_scale) for g in v.groups[:mesh.max_groups_per_vertex]]
 254                                 while len(group_attr)<mesh.max_groups_per_vertex:
 255                                         group_attr.append((0, 0.0))
 256                                 group_attr = list(itertools.chain(*group_attr))
 257                                 if group_attr!=group:
 258                                         out_file.write("attrib%d"%len(group_attr), 5, *group_attr)
 259                                         group = group_attr
 260                         out_file.write("vertex3", *v.co)
 261                 out_file.end()
 262                 for s in strips:
 263                         out_file.begin("batch", "TRIANGLE_STRIP")
 264                         indices = []
 265                         n = 0
 266                         for v in s:
 267                                 indices.append(v.index)
 268                                 if len(indices)>=32:
 269                                         out_file.write("indices", *indices)
 270                                         indices = []
 271                         if indices:
 272                                 out_file.write("indices", *indices)
 273                         out_file.end()
 274
 275                 if loose:
 276                         out_file.begin("batch", "TRIANGLES")
 277                         for f in loose:
 278                                 for i in range(2, len(f.vertices)):
 279                                         out_file.write("indices", f.vertices[0].index, f.vertices[i-1].index, f.vertices[i].index)
 280                         out_file.end()
 281
 282                 if mesh.lines:
 283                         out_file.begin("batch", "LINES")
 284                         for l in mesh.lines:
 285                                 out_file.write("indices", l.vertices[0].index, l.vertices[1].index)
 286                         out_file.end()
 287
 288                 if mesh.winding_test:
 289                         out_file.write("winding", "COUNTERCLOCKWISE")
 290
 291                 progress.pop_task()
 292
 293                 return mesh