def test_a_ray_strikes_a_cylinder1(self):
cyl = Cylinder()
direction = Vector(0, 0, 1).normalize()
r = Ray(Point(1, 0, -5), direction)
xs = cyl.local_intersect(r)
self.assertEqual(2, xs.count)
self.assertTrue(equals(5.0, xs[0].t))
self.assertTrue(equals(5.0, xs[1].t))
def test_a_ray_strikes_a_cylinder3(self):
cyl = Cylinder()
direction = Vector(0.1, 1, 1).normalize()
r = Ray(Point(0.5, 0, -5), direction)
xs = cyl.local_intersect(r)
self.assertEqual(2, xs.count)
self.assertTrue(equals(6.80798, xs[0].t))
self.assertTrue(equals(7.08872, xs[1].t))
def test_ray_misses_cylinder(self):
cyl = Cylinder()
rays = [
Ray(Point(1, 0, 0), Vector(0, 1, 0)),
Ray(Point(0, 0, 0), Vector(0, 1, 0)),
Ray(Point(0, 0, -5), Vector(1, 1, 1))
]
for ray in rays:
direction = Vector.normalize(ray.direction)
r = Ray(ray.origin, direction)
xs = cyl.local_intersect(r)
self.assertEqual(len(xs), 0)
def test_intersect_constrained_cylinder(self):
cyl = Cylinder()
cyl.minimum = 1
cyl.maximum = 2
CylinderIntersection = namedtuple("CyliderIntersection",
["point", "direction", "count"])
cylinder_intersections = [
CylinderIntersection(Point(0, 1.5, 0), Vector(0.1, 1, 0), 0),
CylinderIntersection(Point(0, 3, -5), Vector(0, 0, 1), 0),
CylinderIntersection(Point(0, 0, -5), Vector(0, 0, 1), 0),
CylinderIntersection(Point(0, 2, -5), Vector(0, 0, 1), 0),
CylinderIntersection(Point(0, 1, -5), Vector(0, 0, 1), 0),
CylinderIntersection(Point(0, 1.5, -2), Vector(0, 0, 1), 2)
]
for cylinder_intersection in cylinder_intersections:
direction = Vector.normalize(cylinder_intersection.direction)
r = Ray(cylinder_intersection.point, direction)
xs = cyl.local_intersect(r)
self.assertEqual(len(xs), cylinder_intersection.count)
def test_ray_strikes_cylinder(self):
cyl = Cylinder()
RayIntersection = namedtuple("RayIntersection",
["origin", "direction", "t0", "t1"])
ray_intersections = [
RayIntersection(Point(1, 0, -5), Vector(0, 0, 1), 5, 5),
RayIntersection(Point(0, 0, -5), Vector(0, 0, 1), 4, 6),
RayIntersection(Point(0.5, 0, -5), Vector(0.1, 1, 1), 6.80798,
7.08872)
]
for ray_intersection in ray_intersections:
direction = Vector.normalize(ray_intersection.direction)
r = Ray(ray_intersection.origin, direction)
xs = cyl.local_intersect(r)
self.assertEqual(len(xs), 2)
self.assertAlmostEqual(xs[0].t,
ray_intersection.t0,
delta=Constants.epsilon)
self.assertAlmostEqual(xs[1].t,
ray_intersection.t1,
delta=Constants.epsilon)
def test_interserct_caps_of_closed_cylinder(self):
cyl = Cylinder()
cyl.minimum = 1
cyl.maximum = 2
cyl.closed = True
cyl.maximum = 2
CylinderIntersection = namedtuple("CyliderIntersection",
["point", "direction", "count"])
cylinder_intersections = [
CylinderIntersection(Point(0, 3, 0), Vector(0, -1, 0), 2),
CylinderIntersection(Point(0, 3, -2), Vector(0, -1, 2), 2),
CylinderIntersection(Point(0, 4, -2), Vector(0, -1, 1),
2), # corner case
CylinderIntersection(Point(0, 0, -2), Vector(0, 1, 2), 2),
CylinderIntersection(Point(0, -1, -2), Vector(0, 1, 1),
2) # corner case
]
for cylinder_intersection in cylinder_intersections:
direction = Vector.normalize(cylinder_intersection.direction)
r = Ray(cylinder_intersection.point, direction)
xs = cyl.local_intersect(r)
self.assertEqual(len(xs), cylinder_intersection.count)
def test_intersecting_a_constrained_cylinder(self):
cyl = Cylinder(1, 2)
direction = Vector(0.1, 1, 0)
r = Ray(Point(0, 1.5, 0), direction)
xs = cyl.local_intersect(r)
self.assertEqual(xs.count, 0)
def test_a_ray_misses_a_cylinder3(self):
cyl = Cylinder()
direction = Vector(1, 1, 1).normalize()
r = Ray(Point(0, 0, -5), direction)
xs = cyl.local_intersect(r)
self.assertEqual(0, xs.count)