def test_rotating_a_point_around_the_y_axis():
# Given
p = Point(0, 0, 1)
half_quarter = rotation_y(pi / 4)
full_quarter = rotation_y(pi / 2)
# Then
assert half_quarter * p == Point(sqrt(2) / 2, 0, sqrt(2) / 2)
assert full_quarter * p == Point(1, 0, 0)
def test_constructing_a_ray_when_the_camera_is_transformed():
# Given
c = Camera(201, 101, pi / 2)
# When
c.transform = rotation_y(pi / 4) * translation(0, -2, 5)
r = c.ray_for_pixel(100, 50)
# Then
assert r.origin == Point(0, 2, -5)
assert r.direction == Vector(sqrt(2) / 2, 0, -sqrt(2) / 2)
def test_finding_the_normal_on_a_child_object():
# Given
g1 = Group()
g1.transform = rotation_y(pi / 2)
g2 = Group()
g2.transform = scaling(1, 2, 3)
g1.add_child(g2)
s = Sphere()
s.transform = translation(5, 0, 0)
g2.add_child(s)
# When
n = s.normal_at(Point(1.7321, 1.1547, -5.5774))
# Then
assert n == Vector(0.2857, 0.42854, -0.85716)
def test_converting_a_normal_from_object_to_world_space():
# Given
g1 = Group()
g1.transform = rotation_y(pi / 2)
g2 = Group()
g2.transform = scaling(1, 2, 3)
g1.add_child(g2)
s = Sphere()
s.transform = translation(5, 0, 0)
g2.add_child(s)
# When
n = s.normal_to_world(Vector(sqrt(3) / 3, sqrt(3) / 3, sqrt(3) / 3))
# Then
assert n == Vector(0.28571, 0.42857, -0.85714)
def test_converting_a_point_from_world_to_object_space():
# Given
g1 = Group()
g1.transform = rotation_y(pi / 2)
g2 = Group()
g2.transform = scaling(2, 2, 2)
g1.add_child(g2)
s = Sphere()
s.transform = translation(5, 0, 0)
g2.add_child(s)
# When
p = s.world_to_object(Point(-2, 0, -10))
# Then
assert p == Point(0, 0, -1)
if __name__ == "__main__":
# pattern = StripePattern(Color(1, 0, 0), Color(1, 1, 1))
# pattern = CheckersPattern(Color(1, 0, 0), Color(1, 1, 1))
pattern = GradientPattern(Color(1, 0, 0), Color(1, 1, 1))
# pattern = RingPattern(Color(1, 0, 0), Color(1, 1, 1))
pattern.transform = scaling(0.2, 0.2, 0.2)
floor = Plane()
floor.material = Material()
floor.material.color = Color(1, 0.9, 0.9)
# floor.material.pattern = pattern
backdrop = Plane()
backdrop.transform = \
rotation_y(pi / 3) * translation(0, 0, 5) * rotation_x(pi / 2)
backdrop2 = Plane()
backdrop2.transform = \
rotation_y(-pi / 3) * translation(0, 0, 5) * rotation_x(pi / 2)
middle = Sphere()
# middle = glass_sphere()
middle.transform = translation(-0.5, 1, 0.5)
# middle.reflective = 1.0
middle.material = Material()
middle.material.color = Color(0.1, 1, 0.5)
# middle.material.pattern = pattern
middle.material.diffuse = 0.7
middle.material.specular = 0.3
# middle.material.reflective = 1.0