def intersect_lights(scene, lights, pos, normal):
# scene, light, vector -> float
color = 1
for light in lights:
dirn = vr.normalize(vr.sub_vector(lt.get_pos(light), pos))
new_ray = ry.make_ray(pos, dirn)
t, n = intersect_scene(scene, new_ray)
if not t:
dot_or_0 = max([vr.dot_prod(dirn, normal), 0])
incr = dot_or_0 * lt.get_brightness(light)
color += incr
if color:
return min([8, color])
def intersect_sphere(sphere, ray):
# sphere a, ray a -> Maybe int
dirn = ry.get_dirn(ray)
pos = ry.get_pos(ray)
center = get_center(sphere)
to_center = vr.sub_vector(pos, center)
a = vr.dot_prod(dirn, dirn)
b = 2*vr.dot_prod(dirn, to_center)
c = vr.dot_prod(to_center, to_center) - get_radius(sphere) ** 2
det = b ** 2 - 4 * a * c
if det < 0:
return None
else:
t1 = (-b + math.sqrt(det)) / (2*a)
t2 = (-b - math.sqrt(det)) / (2*a)
return min([t1, t2])
def sphere_normal(sphere, pt):
return vr.normalize(vr.sub_vector(pt, get_center(sphere)))
def make_view_geometry(eye, up, center):
# (vector a) ** 3 -> seq (vector a)
forward = vr.normalize(vr.sub_vector(center, eye))
side = vr.normalize(vr.cross_prod(forward, up))
up = vr.normalize(vr.cross_prod(side, forward))
return [forward, side, up]
