def test_intersecting_a_ray_with_a_nonempty_group():
# Given
g = Group()
s1 = Sphere()
s2 = Sphere()
s2.transform = translation(0, 0, -3)
s3 = Sphere()
s3.transform = translation(5, 0, 0)
g.add_child(s1)
g.add_child(s2)
g.add_child(s3)
# When
r = Ray(Point(0, 0, -5), Vector(0, 0, 1))
xs = g.local_intersect(r)
# Then
assert len(xs) == 4
assert xs[0].object == s2
assert xs[1].object == s2
assert xs[2].object == s1
assert xs[3].object == s1
def test_the_hit_should_offset_the_point():
# Given
r = Ray(Point(0, 0, -5), Vector(0, 0, 1))
shape = Sphere()
shape.transform = translation(0, 0, 1)
i = Intersection(5, shape)
# When
comps = i.prepare_computations(r)
# Then
assert comps.over_point.z < -EPSILON / 2
assert comps.point.z > comps.over_point.z
def test_intersecting_a_transformed_group():
# Given
g = Group()
g.transform = scaling(2, 2, 2)
s = Sphere()
s.transform = translation(5, 0, 0)
g.add_child(s)
# When
r = Ray(Point(10, 0, -10), Vector(0, 0, 1))
xs = g.intersect(r)
# Then
assert len(xs) == 2
def default_world():
light = PointLight(Point(-10, 10, -10), Color(1, 1, 1))
s1 = Sphere()
s1.material.color = Color(0.8, 1.0, 0.6)
s1.material.diffuse = 0.7
s1.material.specular = 0.2
s2 = Sphere()
s2.transform = scaling(0.5, 0.5, 0.5)
w = World()
w.light = light
w.objects = [s1, s2]
return w
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)
def test_default_world():
# Given
light = PointLight(Point(-10, 10, -10), Color(1, 1, 1))
s1 = Sphere()
s1.material.color = Color(0.8, 1.0, 0.6)
s1.material.diffuse = 0.7
s1.material.specular = 0.2
s2 = Sphere()
s2.transform = scaling(0.5, 0.5, 0.5)
# When
w = default_world()
# Then
assert w.light == light
assert s1 in w.objects
assert s2 in w.objects
def test__shade_hit__is_given_an_intersection_in_shadow():
# Given
w = World()
w.light = PointLight(Point(0, 0, -10), Color(1, 1, 1))
s1 = Sphere()
w.objects.append(s1)
s2 = Sphere()
s2.transform = translation(0, 0, 10)
w.objects.append(s2)
r = Ray(Point(0, 0, 5), Vector(0, 0, 1))
i = Intersection(4, s2)
# When
comps = i.prepare_computations(r)
c = w.shade_hit(comps)
# Then
assert c == Color(0.1, 0.1, 0.1)
def test__shade_hit__with_a_transparent_material():
# Given
w = default_world()
floor = Plane()
floor.transform = translation(0, -1, 0)
floor.material.transparency = 0.5
floor.material.refractive_index = 1.5
w.objects.append(floor)
ball = Sphere()
ball.material.color = Color(1, 0, 0)
ball.material.ambient = 0.5
ball.transform = translation(0, -3.5, -0.5)
w.objects.append(ball)
r = Ray(Point(0, 0, -3), Vector(0, -sqrt(2) / 2, sqrt(2) / 2))
xs = Intersections(Intersection(sqrt(2), floor))
# When
comps = xs[0].prepare_computations(r, xs)
color = w.shade_hit(comps, 5)
# Then
assert color == Color(0.93642, 0.68642, 0.68642)
