def testTransformation(self):
sphere = Sphere(transformation=translation(Vec(10.0, 0.0, 0.0)))
ray1 = Ray(origin=Point(10, 0, 2), dir=-VEC_Z)
intersection1 = sphere.ray_intersection(ray1)
assert intersection1
assert HitRecord(
world_point=Point(10.0, 0.0, 1.0),
normal=Normal(0.0, 0.0, 1.0),
surface_point=Vec2d(0.0, 0.0),
t=1.0,
ray=ray1,
material=sphere.material,
).is_close(intersection1)
ray2 = Ray(origin=Point(13, 0, 0), dir=-VEC_X)
intersection2 = sphere.ray_intersection(ray2)
assert intersection2
assert HitRecord(
world_point=Point(11.0, 0.0, 0.0),
normal=Normal(1.0, 0.0, 0.0),
surface_point=Vec2d(0.0, 0.5),
t=2.0,
ray=ray2,
material=sphere.material,
).is_close(intersection2)
# Check if the sphere failed to move by trying to hit the untransformed shape
assert not sphere.ray_intersection(
Ray(origin=Point(0, 0, 2), dir=-VEC_Z))
# Check if the *inverse* transformation was wrongly applied
assert not sphere.ray_intersection(
Ray(origin=Point(-10, 0, 0), dir=-VEC_Z))
def testHit(self):
sphere = Sphere()
ray1 = Ray(origin=Point(0, 0, 2), dir=-VEC_Z)
intersection1 = sphere.ray_intersection(ray1)
assert intersection1
assert HitRecord(
world_point=Point(0.0, 0.0, 1.0),
normal=Normal(0.0, 0.0, 1.0),
surface_point=Vec2d(0.0, 0.0),
t=1.0,
ray=ray1,
material=sphere.material,
).is_close(intersection1)
ray2 = Ray(origin=Point(3, 0, 0), dir=-VEC_X)
intersection2 = sphere.ray_intersection(ray2)
assert intersection2
assert HitRecord(
world_point=Point(1.0, 0.0, 0.0),
normal=Normal(1.0, 0.0, 0.0),
surface_point=Vec2d(0.0, 0.5),
t=2.0,
ray=ray2,
material=sphere.material,
).is_close(intersection2)
assert not sphere.ray_intersection(
Ray(origin=Point(0, 10, 2), dir=-VEC_Z))
def testNormals(self):
sphere = Sphere(transformation=scaling(Vec(2.0, 1.0, 1.0)))
ray = Ray(origin=Point(1.0, 1.0, 0.0), dir=Vec(-1.0, -1.0))
intersection = sphere.ray_intersection(ray)
# We normalize "intersection.normal", as we are not interested in its length
assert intersection.normal.normalize().is_close(
Normal(1.0, 4.0, 0.0).normalize())
def testNormalDirection(self):
# Scaling a sphere by -1 keeps the sphere the same but reverses its
# reference frame
sphere = Sphere(transformation=scaling(Vec(-1.0, -1.0, -1.0)))
ray = Ray(origin=Point(0.0, 2.0, 0.0), dir=-VEC_Y)
intersection = sphere.ray_intersection(ray)
# We normalize "intersection.normal", as we are not interested in its length
assert intersection.normal.normalize().is_close(
Normal(0.0, 1.0, 0.0).normalize())
def testInnerHit(self):
sphere = Sphere()
ray = Ray(origin=Point(0, 0, 0), dir=VEC_X)
intersection = sphere.ray_intersection(ray)
assert intersection
assert HitRecord(
world_point=Point(1.0, 0.0, 0.0),
normal=Normal(-1.0, 0.0, 0.0),
surface_point=Vec2d(0.0, 0.5),
t=1.0,
ray=ray,
).is_close(intersection)
def testUVCoordinates(self):
sphere = Sphere()
# The first four rays hit the unit sphere at the
# points P1, P2, P3, and P4.
#
# ^ y
# | P2
# , - ~ * ~ - ,
# , ' | ' ,
# , | ,
# , | ,
# , | , P1
# -----*-------------+-------------*---------> x
# P3 , | ,
# , | ,
# , | ,
# , | , '
# ' - , _ * _ , '
# | P4
#
# P5 and P6 are aligned along the x axis and are displaced
# along z (ray5 in the positive direction, ray6 in the negative
# direction).
ray1 = Ray(origin=Point(2.0, 0.0, 0.0), dir=-VEC_X)
assert sphere.ray_intersection(ray1).surface_point.is_close(
Vec2d(0.0, 0.5))
ray2 = Ray(origin=Point(0.0, 2.0, 0.0), dir=-VEC_Y)
assert sphere.ray_intersection(ray2).surface_point.is_close(
Vec2d(0.25, 0.5))
ray3 = Ray(origin=Point(-2.0, 0.0, 0.0), dir=VEC_X)
assert sphere.ray_intersection(ray3).surface_point.is_close(
Vec2d(0.5, 0.5))
ray4 = Ray(origin=Point(0.0, -2.0, 0.0), dir=VEC_Y)
assert sphere.ray_intersection(ray4).surface_point.is_close(
Vec2d(0.75, 0.5))
ray5 = Ray(origin=Point(2.0, 0.0, 0.5), dir=-VEC_X)
assert sphere.ray_intersection(ray5).surface_point.is_close(
Vec2d(0.0, 1 / 3))
ray6 = Ray(origin=Point(2.0, 0.0, -0.5), dir=-VEC_X)
assert sphere.ray_intersection(ray6).surface_point.is_close(
Vec2d(0.0, 2 / 3))