def prepare_computations(intersection, ray, xs=None):
c = comps()
c.t = intersection.t
c.object = intersection.object
c.point = position(ray, c.t)
c.eyev = -ray.direction
c.normalv = normal_at(c.object, c.point)
if dot(c.normalv, c.eyev) < 0:
c.inside = True
c.normalv = -c.normalv
else:
c.inside = False
c.over_point = c.point + c.normalv * EPSILON
c.under_point = c.point - c.normalv * EPSILON
c.reflectv = reflect(ray.direction, c.normalv)
containers = []
if xs:
for i in xs:
if i == intersection:
if len(containers) == 0:
c.n1 = 1.0
else:
c.n1 = containers[-1].material.refractive_index
if i.object in containers:
containers.remove(i.object)
else:
containers.append(i.object)
if i == intersection:
if len(containers) == 0:
c.n2 = 1.0
else:
c.n2 = containers[-1].material.refractive_index
break
return c
print("Starting render...")
for y in range(canvas_pixels):
world_y = half - pixel_size * y
for x in range(canvas_pixels):
world_x = -half + pixel_size * x
pos = point(world_x, world_y, wall_z)
r = ray(ray_origin, normalize(pos - ray_origin))
xs = intersect(shape, r)
if hit(xs) is not None:
pnt = position(r, xs[0].t)
normal = normal_at(xs[0].object, pnt)
eye = -r.direction
color = lighting(xs[0].object.material, xs[0].object, light,
pnt, eye, normal)
write_pixel(canvas, x, y, color)
end = time.time()
print("Finished render.")
print(str(round(end - start, 2)) + "s")
start = time.time()
print("Start writing file...")
canvas_to_ppm(canvas).write_file("images/sphere.ppm")
end = time.time()
print("Finished writing file.")
def step_impl(context):
assert position(context.r, -1) == point(1, 3, 4)
def step_impl(context):
assert position(context.r, 2.5) == point(4.5, 3, 4)
def step_impl(context):
assert position(context.r, 0) == point(2, 3, 4)