io_mesh_stl/blender_utils.py

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   3 #  This program is free software; you can redistribute it and/or
   4 #  modify it under the terms of the GNU General Public License
   5 #  as published by the Free Software Foundation; either version 2
   6 #  of the License, or (at your option) any later version.
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   8 #  This program is distributed in the hope that it will be useful,
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  10 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 #  GNU General Public License for more details.
  12 #
  13 #  You should have received a copy of the GNU General Public License
  14 #  along with this program; if not, write to the Free Software Foundation,
  15 #  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16 #
  17 # ##### END GPL LICENSE BLOCK #####
  18
  19 # <pep8 compliant>
  20
  21 import bpy
  22 import array
  23 from itertools import chain
  24
  25
  26 def create_and_link_mesh(name, faces, face_nors, points, global_matrix):
  27     """
  28     Create a blender mesh and object called name from a list of
  29     *points* and *faces* and link it in the current scene.
  30     """
  31
  32     mesh = bpy.data.meshes.new(name)
  33     mesh.from_pydata(points, [], faces)
  34
  35     if face_nors:
  36         # Note: we store 'temp' normals in loops, since validate() may alter final mesh,
  37         #       we can only set custom lnors *after* calling it.
  38         mesh.create_normals_split()
  39         lnors = tuple(chain(*chain(*zip(face_nors, face_nors, face_nors))))
  40         mesh.loops.foreach_set("normal", lnors)
  41
  42     mesh.transform(global_matrix)
  43
  44     # update mesh to allow proper display
  45     mesh.validate(clean_customdata=False)  # *Very* important to not remove lnors here!
  46
  47     if face_nors:
  48         clnors = array.array('f', [0.0] * (len(mesh.loops) * 3))
  49         mesh.loops.foreach_get("normal", clnors)
  50
  51         mesh.polygons.foreach_set("use_smooth", [True] * len(mesh.polygons))
  52
  53         mesh.normals_split_custom_set(tuple(zip(*(iter(clnors),) * 3)))
  54         mesh.use_auto_smooth = True
  55         mesh.show_edge_sharp = True
  56         mesh.free_normals_split()
  57
  58     mesh.update()
  59
  60     scene = bpy.context.scene
  61
  62     obj = bpy.data.objects.new(name, mesh)
  63     scene.objects.link(obj)
  64     scene.objects.active = obj
  65     obj.select = True
  66
  67
  68 def faces_from_mesh(ob, global_matrix, use_mesh_modifiers=False, triangulate=True):
  69     """
  70     From an object, return a generator over a list of faces.
  71
  72     Each faces is a list of his vertexes. Each vertex is a tuple of
  73     his coordinate.
  74
  75     use_mesh_modifiers
  76         Apply the preview modifier to the returned liste
  77
  78     triangulate
  79         Split the quad into two triangles
  80     """
  81
  82     # get the editmode data
  83     ob.update_from_editmode()
  84
  85     # get the modifiers
  86     try:
  87         mesh = ob.to_mesh(bpy.context.scene, use_mesh_modifiers, "PREVIEW")
  88     except RuntimeError:
  89         raise StopIteration
  90
  91     mat = global_matrix * ob.matrix_world
  92     mesh.transform(mat)
  93     if mat.is_negative:
  94         mesh.flip_normals()
  95         mesh.calc_tessface()
  96
  97     if triangulate:
  98         # From a list of faces, return the face triangulated if needed.
  99         def iter_face_index():
 100             for face in mesh.tessfaces:
 101                 vertices = face.vertices[:]
 102                 if len(vertices) == 4:
 103                     yield vertices[0], vertices[1], vertices[2]
 104                     yield vertices[2], vertices[3], vertices[0]
 105                 else:
 106                     yield vertices
 107     else:
 108         def iter_face_index():
 109             for face in mesh.tessfaces:
 110                 yield face.vertices[:]
 111
 112     vertices = mesh.vertices
 113
 114     for indexes in iter_face_index():
 115         yield [vertices[index].co.copy() for index in indexes]
 116
 117     bpy.data.meshes.remove(mesh)