def test_intersecting_translated_sphere_with_ray(self):
r = Ray(point(0, 0, -5), vector(0, 0, 1))
s = Sphere()
s.set_transform(translation(5, 0, 0))
xs = s.intersect(r)
self.assertEqual(0, len(xs))
def test_sphere_behind_ray(self):
r = Ray(point(0, 0, 5), vector(0, 0, 1))
s = Sphere()
xs = s.intersect(r)
self.assertEqual(2, len(xs))
self.assertEqual(-6, xs[0].t)
self.assertEqual(-4, xs[1].t)
def test_ray_originates_inside_sphere(self):
r = Ray(point(0, 0, 0), vector(0, 0, 1))
s = Sphere()
xs = s.intersect(r)
self.assertEqual(2, len(xs))
self.assertEqual(-1, xs[0].t)
self.assertEqual(1, xs[1].t)
def test_ray_intersects_sphere_at_tangent(self):
r = Ray(point(0, 1, -5), vector(0, 0, 1))
s = Sphere()
xs = s.intersect(r)
self.assertEqual(2, len(xs))
self.assertEqual(5, xs[0].t)
self.assertEqual(5, xs[1].t)
def test_intersecting_scaled_sphere_with_ray(self):
r = Ray(point(0, 0, -5), vector(0, 0, 1))
s = Sphere()
s.set_transform(scaling(2, 2, 2))
xs = s.intersect(r)
self.assertEqual(2, len(xs))
self.assertEqual(3, xs[0].t)
self.assertEqual(7, xs[1].t)
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_ray_misses_sphere(self):
r = Ray(point(0, 2, -5), vector(0, 0, 1))
s = Sphere()
xs = s.intersect(r)
self.assertEqual(0, len(xs))