def when_convex_mirror_is_constructed(self):
self.mirror = SphericalMirror(
placement=self.placement,
diameter=self.diameter,
focal_length=-self.focal_length
)
class TestSphericalMirror(unittest.TestCase):
"""
Test SphericalMirror class
"""
def clean_state(self):
self.mirror = None
self.aperture = None
self.diameter = None
self.aperture_origin = None
self.aperture_direction = None
self.aperture_normal = None
self.orthogonal_directions = None
self.placement = None
self.ray_location = None
self.orthogonal_direction = None
self.scale_factor = None
self.test_ray_distance = None
self.test_ray = None
self.initial_wavefront = None
self.filtered_wavefront = None
self.test_directions = None
self.test_direction = None
self.test_point = None
def setUp(self):
self.clean_state()
self.diameter = 10.0
self.focal_length = 50.0
self.aperture_origin = Position.from_xyz((10.0, 20.0, 30.0))
self.aperture_direction = Direction.from_xyz((1.0, 2.0, 3.0))
self.aperture_normal = self.aperture_direction.normalized()
self.placement = Ray(self.aperture_origin, self.aperture_normal)
self.orthogonal_directions = [
self.aperture_direction.cross(Direction.right).normalized(),
self.aperture_direction.cross(Direction.forward).normalized(),
self.aperture_direction.cross(Direction.backward).normalized(),
]
self.test_directions = [self.aperture_normal.add(
orthogonal_direction.scale(0.1)).normalized() for orthogonal_direction in self.orthogonal_directions]
def tearDown(self):
self.clean_state()
def test_positive_focal_length_is_concave(self):
self.when_concave_mirror_is_constructed()
self.then_mirror_is_concave()
def when_concave_mirror_is_constructed(self):
self.mirror = SphericalMirror(
placement=self.placement,
diameter=self.diameter,
focal_length=self.focal_length
)
def then_mirror_is_concave(self):
self.assertFalse(self.mirror.is_convex)
self.assertTrue(self.mirror.is_concave)
def test_negative_focal_length_is_concave(self):
self.when_convex_mirror_is_constructed()
self.then_mirror_is_convex()
def when_convex_mirror_is_constructed(self):
self.mirror = SphericalMirror(
placement=self.placement,
diameter=self.diameter,
focal_length=-self.focal_length
)
def then_mirror_is_convex(self):
self.assertTrue(self.mirror.is_convex)
self.assertFalse(self.mirror.is_concave)
def test_spherical_radius_is_correct(self):
self.when_concave_mirror_is_constructed()
self.then_spherical_radius_is_twice_focal_length()
self.when_convex_mirror_is_constructed()
self.then_spherical_radius_is_twice_focal_length()
def then_spherical_radius_is_twice_focal_length(self):
spherical_radius = self.mirror.sphere.radius
self.assertAlmostEqual(2.0 * math.fabs(self.focal_length), spherical_radius)
def test_aperture_circle_lies_on_sphere(self):
self.when_concave_mirror_is_constructed()
self.then_aperture_circle_lies_on_sphere()
self.when_convex_mirror_is_constructed()
self.then_aperture_circle_lies_on_sphere()
def then_aperture_circle_lies_on_sphere(self):
for self.orthogonal_direction in self.orthogonal_directions:
self.when_aperture_circle_point_is_constructed()
self.then_aperture_circle_point_lies_on_sphere()
def when_aperture_circle_point_is_constructed(self):
self.test_direction = self.orthogonal_direction.scale(self.diameter * 0.5)
self.test_point = self.aperture_origin.add(self.test_direction)
def then_aperture_circle_point_lies_on_sphere(self):
actual_elevation = self.mirror.sphere.elevation(self.test_point)
self.assertAlmostEqual(0.0, actual_elevation)
def test_rays_from_center_of_sphere_reflect_back(self):
self.when_concave_mirror_is_constructed()
self.when_test_rays_are_positioned_at_sphere_center()
self.then_test_rays_reflect_back()
def when_test_rays_are_positioned_at_sphere_center(self):
self.test_center_position = self.mirror.sphere.center_position
self.when_test_rays_are_constructed()
def when_test_rays_are_constructed(self):
self.test_rays = [Ray(self.test_center_position, test_direction)
for test_direction in self.test_directions]
def then_test_rays_reflect_back(self):
for self.test_ray in self.test_rays:
self.when_test_ray_is_reflected()
self.then_reflected_ray_is_opposite_of_test_ray()
def when_test_ray_is_reflected(self):
self.reflected_ray = self.mirror.reflect(self.test_ray)
def then_reflected_ray_is_opposite_of_test_ray(self):
dotProduct = vector_dot_product(self.test_ray.direction.xyz, self.reflected_ray.direction.xyz)
self.assertAlmostEqual(-1.0, dotProduct)
def test_rays_from_focal_point_of_sphere_reflect_parallel(self):
self.when_concave_mirror_is_constructed()
self.when_test_rays_are_positioned_at_focal_point()
self.then_test_rays_reflect_parallel()
def when_test_rays_are_positioned_at_focal_point(self):
self.test_center_position = self.mirror.sphere.center_position.add(
self.aperture_normal.scale(self.focal_length)
)
self.when_test_rays_are_constructed()
def then_test_rays_reflect_parallel(self):
for self.test_ray in self.test_rays:
self.when_test_ray_is_reflected()
self.then_reflected_ray_is_opposite_of_aperture_normal()
def then_reflected_ray_is_opposite_of_aperture_normal(self):
dotProduct = vector_dot_product(self.aperture_normal.xyz, self.reflected_ray.direction.xyz)
self.assertAlmostEqual(-1.0, dotProduct)
