# ##### BEGIN GPL LICENSE BLOCK #####
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####

# <pep8 compliant>

import bpy


def create_and_link_mesh(name, faces, points):
    '''
    Create a blender mesh and object called name from a list of
    *points* and *faces* and link it in the current scene.
    '''

    mesh = bpy.data.meshes.new(name)
    mesh.from_pydata(points, [], faces)

    ob = bpy.data.objects.new(name, mesh)
    bpy.context.scene.objects.link(ob)

    # update mesh to allow proper display
    mesh.validate()
    mesh.update()


def faces_from_mesh(ob, apply_modifier=False, triangulate=True):
    '''
    From an object, return a generator over a list of faces.

    Each faces is a list of his vertexes. Each vertex is a tuple of
    his coordinate.

    apply_modifier
        Apply the preview modifier to the returned liste

    triangulate
        Split the quad into two triangles
    '''

    # get the modifiers
    try:
        mesh = ob.to_mesh(bpy.context.scene, apply_modifier, "PREVIEW")
    except RuntimeError:
        return ()

    if triangulate:
        # From a list of faces, return the face triangulated if needed.
        def iter_face_index():
            for face in mesh.faces:
                vertices = face.vertices[:]
                if len(vertices) == 4:
                    yield vertices[0], vertices[1], vertices[2]
                    yield vertices[2], vertices[3], vertices[0]
                else:
                    yield vertices
    else:
        def iter_face_index():
            for face in mesh.faces:
                yield face.vertices[:]

    return ([(mesh.vertices[index].co * ob.matrix_world)[:]
             for index in indexes] for indexes in iter_face_index())
