def test_orthogonal_camera(self):
cam = OrthogonalCamera(aspect_ratio=2.0)
# Fire one ray for each corner of the image plane
ray1 = cam.fire_ray(0.0, 0.0)
ray2 = cam.fire_ray(1.0, 0.0)
ray3 = cam.fire_ray(0.0, 1.0)
ray4 = cam.fire_ray(1.0, 1.0)
# Verify that the rays are parallel by verifying that cross-products vanish
assert are_close(0.0, ray1.dir.cross(ray2.dir).squared_norm())
assert are_close(0.0, ray1.dir.cross(ray3.dir).squared_norm())
assert are_close(0.0, ray1.dir.cross(ray4.dir).squared_norm())
# Verify that the ray hitting the corners have the right coordinates
assert ray1.at(1.0).is_close(Point(0.0, 2.0, -1.0))
assert ray2.at(1.0).is_close(Point(0.0, -2.0, -1.0))
assert ray3.at(1.0).is_close(Point(0.0, 2.0, 1.0))
assert ray4.at(1.0).is_close(Point(0.0, -2.0, 1.0))
def is_close(self, other, epsilon=1e-6):
"""Return True if the three RGB components of two colors are close by less than `epsilon`"""
return (are_close(self.r, other.r, epsilon=epsilon)
and are_close(self.g, other.g, epsilon=epsilon)
and are_close(self.b, other.b, epsilon=epsilon))
def _are_xyz_close(a, b, epsilon=1e-5):
# This works thanks to Python's duck typing. In C++ and other languages
# you should probably rely on function templates or something like
return (are_close(a.x, b.x, epsilon=epsilon)
and are_close(a.y, b.y, epsilon=epsilon)
and are_close(a.z, b.z, epsilon=epsilon))