def __init__(self, vertices, center=None):
Surface.__init__(self)
c = center or _center_of_point_cloud(vertices)
self.center = c
num_vertices = len(vertices)
if len(vertices) < 2:
raise Exception('insufficient vertices')
normal = self._compute_normal(c, vertices)
v1 = vertices[0]
i = Vector(v1.x - c.x, v1.y - c.y, v1.z - c.z)
j = i.cross(normal)
vertices = vertices[:]
vertices.append(vertices[0])
s = Surface()
for index in xrange(num_vertices):
a = vertices[index]
b = vertices[index+1]
a1 = Vector(a.x - c.x, a.y - c.y, a.z - c.z)
a.tcoord = (a1.dot(i), a1.dot(j))
face = Face(Edge(c, a), Edge(a, b), Edge(b, c))
s.add(face)
self.add(s)
def _compute_normal(self, center, vertices):
normals = []
c = center
v1 = vertices[0]
v1 = Vector(v1.x - c.x, v1.y - c.y, v1.z - c.z)
for v in vertices[1:2]:
v = Vector(v.x - c.x, v.y - c.y, v.z - c.z)
n = v1.cross(v)
normals.append(n.normalize())
normal = Vector()
for _n in normals:
normal = normal + _n
return normal.normalize()
