def test_computing_normal_on_scaled_sphere(self):
s = Sphere()
s.set_transform(scaling(1, 0.5, 1))
n = s.normal_at(point(0, math.sqrt(2) / 2, -math.sqrt(2) / 2))
self.assert_tuple_equals(vector(0, 0.97014, -0.24254), n, 0.001)
def test_computing_normal_on_translated_sphere(self):
s = Sphere()
s.set_transform(translation(0, 1, 0))
n = s.normal_at(point(0, 1.70711, -0.70711))
self.assert_tuple_equals(vector(0, 0.70711, -0.70711), n, 0.001)
def test_normal_is_normalized_vector(self):
s = Sphere()
n = s.normal_at(
point(math.sqrt(3) / 3,
math.sqrt(3) / 3,
math.sqrt(3) / 3))
self.assertEqual(n.normalize(), n)
def test_normal_on_sphere_at_point_on_none_axial_point(self):
s = Sphere()
n = s.normal_at(
point(math.sqrt(3) / 3,
math.sqrt(3) / 3,
math.sqrt(3) / 3))
self.assertEqual(n.normalize(), n)
wall_size = 7.0
canvas_pixels = 1000
pixel_size = wall_size / canvas_pixels
half = wall_size / 2
c = Canvas(canvas_pixels, canvas_pixels)
col = color(1, 0, 0)
start_time = time.time()
for y in range(canvas_pixels):
elapsed_time = time.time() - start_time
if elapsed_time > 0 and y > 0:
print("time_to_finish: " + str(1.0 * (canvas_pixels - y) /
(1.0 * y / elapsed_time)))
world_y = half - pixel_size * y
for x in range(canvas_pixels):
world_x = -half + pixel_size * x
position = point(world_x, world_y, wall_z)
ray = Ray(ray_origin, (position - ray_origin).normalize())
xs = s.intersect(ray)
if hit(xs):
hit_point = ray.position(hit(xs).t)
norma_at_hit_point = s.normal_at(hit_point)
eye = -ray.direction
color = s.material.lighting(light, hit_point, eye,
norma_at_hit_point)
c.write_pixel(x, y, color)
c.save_to_file('sphere6.ppm')
def test_normal_on_sphere_at_point_on_y_axis(self):
s = Sphere()
n = s.normal_at(point(0, 1, 0))
self.assertEqual(vector(0, 1, 0), n)
