def test_a_scaling_matrix_applied_to_a_vecor():
transform = transformations.scaling(2, 3, 4)
v = vector(-4, 6, 8)
expected_vector = vector(-8, 18, 32)
with tf.Session() as sess:
[expected, actual] = sess.run([expected_vector, transform(v)])
assert((expected == actual).all())
def test_a_scaling_matrix_applied_to_a_point():
transform = transformations.scaling(2, 3, 4)
p = point(-4, 6, 8)
expected_point = point(-8, 18, 32)
with tf.Session() as sess:
[expected, actual] = sess.run([expected_point, transform(p)])
assert((expected == actual).all())
def test_multiplying_the_inverse_of_a_scaling_matrix():
transform = transformations.scaling(2, 3, 4)
inverse = transformations.invert(transform)
v = vector(-4, 6, 8)
expected_vector = vector(-2, 2, 2)
with tf.Session() as sess:
[expected, actual] = sess.run([expected_vector, inverse(v)])
assert((expected == actual).all())
def test_intersecting_a_scaled_sphere_with_a_ray():
r = Ray(point(0., 0., -5.), vector(0., 0., 1.))
s = Sphere(transformations.scaling(2, 2, 2))
xs = s.intersect(r)
with tf.Session() as sess:
actual_xs = sess.run(xs)
assert (len(actual_xs) == 2)
assert (actual_xs[0] == 3)
assert (actual_xs[1] == 7)
def test_chained_transofrmations_must_be_applied_in_reverse_order():
p = point(1, 0, 1)
A = transformations.rotation_x(math.pi/2)
B = transformations.scaling(5, 5, 5)
C = transformations.translation(10, 5, 7)
CBA = transformations.concat(C, B, A)
with tf.Session() as sess:
[expected, actual] = sess.run([point(15, 0, 7), CBA(p)])
assert(np.allclose(expected, actual))
def test_individual_transformations_are_applied_in_sequence():
p = point(1, 0, 1)
A = transformations.rotation_x(math.pi/2)
B = transformations.scaling(5, 5, 5)
C = transformations.translation(10, 5, 7)
with tf.Session() as sess:
[expected_p2, expected_p3, expected_p4, actual_p2, actual_p3, actual_p4] = sess.run(
[point(1, -1, 0), point(5, -5, 0), point(15, 0, 7), A(p), B(A(p)), C(B(A(p)))])
assert(np.allclose(expected_p2, actual_p2))
assert(np.allclose(expected_p3, actual_p3))
assert(np.allclose(expected_p4, actual_p4))