+
+ @classmethod
+ def _sort_polygon_2d(cls, points):
+ if len(points) <= 3:
+ return points
+ o = sum((Vector(point) for point in points)) / len(points)
+ o = Point(o.coordinates())
+ angles = {}
+ for m in points:
+ om = Vector(o, m)
+ dx, dy = (coordinate for symbol, coordinates in om.coordinates())
+ angle = math.atan2(dy, dx)
+ angles[m] = angle
+ return sorted(points, key=angles.get)
+
+ @classmethod
+ def _sort_polygon_3d(cls, points):
+ if len(points) <= 3:
+ return points
+ o = sum((Vector(point) for point in points)) / len(points)
+ o = Point(o.coordinates())
+ a, b = points[:2]
+ oa = Vector(o, a)
+ ob = Vector(o, b)
+ norm_oa = oa.norm()
+ u = (oa.cross(ob)).asunit()
+ angles = {a: 0.}
+ for m in points[1:]:
+ om = Vector(o, m)
+ normprod = norm_oa * om.norm()
+ cosinus = oa.dot(om) / normprod
+ sinus = u.dot(oa.cross(om)) / normprod
+ angle = math.acos(cosinus)
+ angle = math.copysign(angle, sinus)
+ angles[m] = angle
+ return sorted(points, key=angles.get)
+