def angle_for_vertex(self, v: Vertex):
"""
Returns plane angle at the given vertex v,
or raises an Error if such vertex is not in the face
"""
# p1 ---> p2
# p1 ---> p3
i = self.vertices.index(v)
p1 = self.vertices[i]
p2 = self.vertices[(i + 1) % len(self.vertices)]
p3 = self.vertices[(i + 2) % len(self.vertices)]
return vector_angle(vector_from_to(p1.pos, p2.pos),
vector_from_to(p1.pos, p3.pos))
def test_zero_angle(self):
v1 = Vector3(0, 0, 3)
v2 = Vector3(0, 0, 12)
angle = vector_angle(v2, v1)
self.assertEqual(angle, 0)
def test_180_angle(self):
v1 = Vector3(1, 1, 3)
v2 = Vector3(-1, -1, -3)
angle = vector_angle(v2, v1)
self.assertEqual(angle, math.pi)
def test_opposite_positive_angle(self):
v1 = Vector3(0, 0, 3)
v2 = Vector3(1, -3, 0)
angle = vector_angle(v2, v1)
self.assertEqual(angle, math.pi / 2)