updated the surf.geometry module to better map to blender primatives

surf/geometry.py

@@ -18,6 +18,7 @@ We have chosen to use a winged-edge style mesh for our purpopses.
 
 '''
 
+
 def cross(a, b):
     i = a.y * b.z - a.z * b.y
     j = a.z * b.x - a.x * b.z
@@ -25,14 +26,28 @@ def cross(a, b):
     return Vertex(i, j, k)
 
 
+def _centroid(verts):
+    xs = [vertex.x for vertex in verts]
+    ys = [vertex.y for vertex in verts]
+    zs = [vertex.z for vertex in verts]
+
+    # average each vertex component
+    x = sum(xs) / len(xs)
+    y = sum(ys) / len(ys)
+    z = sum(zs) / len(zs)
+
+    return Vertex(x, y, z)
+
+
 class Vertex(object):
     '''
     A vertex is a position along with other information such as color, normal
     vector and texture coordinates.
+
+    For the sake of our algorithms, we will only worry about the (x, y, z)
+    float positions. Eventually we will also keep track of weights.
     '''
     def __init__(self, x=0.0, y=0.0, z=0.0):
-        '''
-        '''
         self.x = x
         self.y = y
         self.z = z
@@ -71,163 +86,123 @@ class Vertex(object):
         return Vertex(-self.x, -self.y, -self.z)
 
     def __unicode__(self):
-        d = {
+        return pprint.pformat([self.x, self.y, self.z])
-            'id': self.id,
-            'parent_id': self.parent_id,
-            'coords': [self.x, self.y, self.z]
-        }
-        return pprint.pformat(d)
 
     __str__ = __unicode__
     __repr__ = __unicode__
 
 
 class Edge(object):
-    '''
+    def __init__(self, v1, v2):
-    '''
+        self.v1 = v1
-    
+        self.v2 = v2
-    next_id = 0
-    def __init__(self, polygon, parent_id=None, vs=None, es=None, fs=None):
-        '''
-        '''
-        self.polygon = polygon
-        self.parent_id = parent_id
-        self.vertex_ids = vs or []
-        self.edge_ids = es or []
-        self.face_ids = fs or []
-        self.id = Edge.next_id
-        Edge.next_id += 1
-        
-    def neighbor_face_id(self, neighbor_face_id):
-        '''Get neighboring face id
-        '''
-        if neighbor_face_id == self.face_ids[0]:
-            return self.face_ids[1]
-        else:
-            return self.face_ids[0]
-    
-    def __unicode__(self):
-        d = {
-            'id': self.id, 
-            'vertex_ids': self.vertex_ids,
-            'edge_ids': self.edge_ids,
-            'face_ids': self.face_ids,
-        }
-        return pprint.pformat(d)
-    
-    __str__ = __unicode__
-    __repr__ = __unicode__
-    
-    @property
-    def vertices(self):
-        return [self.polygon.vertex(v_id) for v_id in self.vertex_ids]
-    
-    @property
-    def faces(self):
-        return [self.polygon.face(f_id) for f_id in self.face_ids]
-    
-    def winged_edges_at_vertex(self, index):
-        edge_ids = []
-        for edge in self.edges:
-            if self.vertex_ids[index] in edge.vertex_ids:
-                edge_ids.append(edge.id)
-        return edge_ids
-
-class Face(object):
-    '''
-    A face is a closed set of edges,
-    in which a triangle face has three edges,
-    and a quad face has four edges.
-    '''
-    
-    next_id = 0
-    def __init__(self, polygon, parent_id=None, es=None):
-        '''
-        '''
-        self.polygon = polygon
-        self.parent_id = parent_id
-        self.edge_ids = es or []
-        self.id = Face.next_id
-        Face.next_id += 1 
-        
-    def __unicode__(self):
-        d = {'id': self.id, 'edge_ids': self.edge_ids}
-        return pprint.pformat(d)
-    
-    __str__ = __unicode__
-    __repr__ = __unicode__
-
-    def edge(self, edge_id):
-        return self.polygon.edge(edge_id)
-    
-    @property
-    def edges(self):
-        return [self.polygon.edge(e_id) for e_id in self.edge_ids]
-    
-    @property
-    def vertices(self):
-        vertices = []
-        for edge_id in self.edge_ids:
-            edge = self.polygon.edge(edge_id)
-            vertices.extend(edge.vertices)
-        
-        return list(set(vertices))
 
     @property
     def centroid(self):
-        '''
+        return _centroid([self.v1, self.v2])
-        '''
-    
-        # gather all face vertex coords
-        face_vertices = self.vertices
-        
-        xs = [vertex.x for vertex in face_vertices]
-        ys = [vertex.y for vertex in face_vertices]
-        zs = [vertex.z for vertex in face_vertices]
-
-        # average each vertex component
-        x = sum(xs) / len(xs)
-        y = sum(ys) / len(ys)
-        z = sum(zs) / len(zs)
-        
-        return [x, y, z]
-
-    
-class Polygon(object):
-    '''
-    '''
-    
-    def __init__(self, vs=None, es=None, fs=None):
-        self.vertices = vs or []
-        self.edges = es or []
-        self.faces = fs or []
-    
-    def face(self, face_id):
-        for face in self.faces:
-            if face.id == face_id:
-                return face
-        return None
-    
-    def edge(self, edge_id):
-        for edge in self.edges:
-            if edge.id == edge_id:
-                return edge
-        return None
-    
-    def vertex(self, vertex_id):
-        for vertex in self.vertices:
-            if vertex.id == vertex_id:
-                return vertex
-        return None
-
-    def edge_ids_with_parent(self, parent_edge_id):
-        child_edge_ids = []
-        for edge in self.edges:
-            if edge.parent_id == parent_edge_id:
-                child_edge_ids.append(edge.id)
-        return child_edge_ids
 
     def __unicode__(self):
+        return pprint.pformat((self.v1, self.v2))
+
+    __str__ = __unicode__
+    __repr__ = __unicode__
+
+
+class Face(object):
+    '''
+    A face is a closed set of edges, in which a triangle face has three edges,
+    and a quad face has four edges. Blender stores a face as a collection of
+    the verts that compose it, so we shall store them thusly as well.
+
+    Blender historicaly only supported faces with an edge count of three or
+    four. We will cross the N-gon bridge in the future.
+    '''
+
+    def __init__(self, verts=None):
+        self.verts = verts or []
+
+    def __unicode__(self):
+        return pprint.pformat(self.verts)
+
+    __str__ = __unicode__
+    __repr__ = __unicode__
+
+    @property
+    def centroid(self):
+        return _centroid(self.verts)
+
+
+class PolygonMesh(object):
+    '''
+    A polygon object is a collection of the following lists:
+
+    - a list containing the 3-space vertex information
+    - a list containing the edge indices ([0, 1] means first and second
+      elements of the vertices list)
+    - a list of the faces (indices of the vertices in a given face)
+
+    - connectivity information (eventually will be calculated given the verts,
+      edges, and faces)
+    '''
+
+    def __init__(self, *args, **kwargs):
+        self.vertices = kwargs['vertices']
+        self.edges = kwargs['edges']
+        self.faces = kwargs['faces']
+
+        # the strategy for the following members involves lazy-instantiating
+        # them if they weren't passing them in:
+        self._faces_for_edge = kwargs.get('faces for edge', None)
+        self._edges_for_face = kwargs.get('edges for face', None)
+        self._edges_for_vert = kwargs.get('edges for vert', None)
+        self._faces_for_vert = kwargs.get('faces for vert', None)
+
+    @property
+    def faces_for_edge(self):
+        """returns a list of face indices for a given edge index.
+
+        Intended to be used in the following way:
+
+        >>> # vs, es, fs, ffe, eff, efv, ffv from blender or similar
+        >>> mesh =  Polygon(vs, es, fs, ffe, eff, efv, ffv)
+        >>> mesh.faces_for_edge[0]
+        [0, 1]
+        >>> [self.face[i] for i in mesh.faces_for_edge[1]]
+        [<Face 0>, <Face 1>]
+
+        where 0 and 1 are indices into the face list
+        """
+        if self._faces_for_edge is None:
+            # TODO: eventually support generating this ourselves ...
+            raise AttributeError("Not yet implemented if you don't explicitly pass this in")
+        return self._faces_for_edge
+
+    @property
+    def edges_for_face(self):
+        """returns a list of edge indices for a given face index."""
+        if self._edges_for_face is None:
+            # TODO: eventually support generating this ourselves ...
+            raise AttributeError("Not yet implemented if you don't explicitly pass this in")
+        return self._edges_for_face
+
+    @property
+    def edges_for_vert(self):
+        """returns a list of edge indices for a given vertex index."""
+        if self._edges_for_vert is None:
+            # TODO: eventually support generating this ourselves ...
+            raise AttributeError("Not yet implemented if you don't explicitly pass this in")
+        return self._edges_for_vert
+
+    @property
+    def faces_for_vert(self):
+        """returns a list of face indices for a given vert index."""
+        if self._faces_for_vert is None:
+            # TODO: eventually support generating this ourselves ...
+            raise AttributeError("Not yet implemented if you don't explicitly pass this in")
+        return self._faces_for_vert
+
+    def __unicode__(self):
+        # TODO: perhaps also add connectivity here?
         d = {
             'vertices': self.vertices,
             'edges': self.edges,
@@ -237,4 +212,3 @@ class Polygon(object):
 
     __str__ = __unicode__
     __repr__ = __unicode__
-