def scatter(self, ray_in: Ray, hit_record: hit_record):
outward_normal = Vector3(1, 1, 1)
reflected = ray_in.direction().reflect(hit_record.normal)
ni_over_nt = 0
attenuation = Vector3(1, 1, 1)
scattered = Vector3(0, 0, 0)
reflect_prob = 0
cosine = 0
if (ray_in.direction().dot(hit_record.normal) > 0):
outward_normal = Vector3(0, 0, 0) - hit_record.normal
ni_over_nt = self.ref_idx
cosine = self.ref_idx * ray_in.direction().dot(
hit_record.normal) / ray_in.direction().length()
else:
outward_normal = hit_record.normal
ni_over_nt = 1 / self.ref_idx
cosine = -ray_in.direction().dot(
hit_record.normal) / ray_in.direction().length()
is_scattered, refracted = refract(ray_in.direction(), outward_normal,
ni_over_nt)
if (is_scattered):
reflect_prob = schlick(cosine, self.ref_idx)
else:
scattered = Ray(hit_record.p, reflected)
reflect_prob = 1.0
if (random.uniform(0, 1) < reflect_prob):
scattered = Ray(hit_record.p, reflected)
else:
scattered = Ray(hit_record.p, refracted)
return (True, scattered, attenuation)
def random_in_unit_disk():
p = Vector3(0,0,0)
while (p.dot(p) >= 1.0):
p = Vector3(random.uniform(0,1), random.uniform(0,1), 0).scalar_mul(2.0) - Vector3(1,1,0)
return p
def random_in_unit_sphere():
p = Vector3(random.uniform(0, 1), random.uniform(0, 1), random.uniform(
0, 1)).scalar_mul(2.0) - Vector3(1, 1, 1)
while (p.squared_length() >= 1.0):
p = Vector3(random.uniform(0, 1), random.uniform(0, 1),
random.uniform(0, 1)).scalar_mul(2.0) - Vector3(1, 1, 1)
return p
def refract(v: Vector3, n: Vector3, ni_over_nt: float):
uv = v.normalize()
dt = uv.dot(n)
discriminant = 1.0 - ni_over_nt * ni_over_nt * (1 - dt * dt)
if (discriminant > 0):
refracted = (uv -
n.scalar_mul(dt)).scalar_mul(ni_over_nt) - n.scalar_mul(
math.sqrt(discriminant))
return (True, refracted)
return (False, Vector3(0, 0, 0))
def hit(self, ray: Ray, t_min: float, t_max: float):
temp_rec = hit_record(0, Vector3(0, 0, 0), Vector3(0, 0, 0),
Material())
hit_anything = False
closest_so_far = t_max
for item in self.list:
if (item.hit(ray, t_min, closest_so_far, temp_rec)):
hit_anything = True
closest_so_far = temp_rec.t
temp_rec.material = item.material
return (hit_anything, temp_rec)
def __init__(self, lookfrom: Vector3, lookat: Vector3, vup: Vector3, fov, aspect, aperture, focus_dist):
theta = fov * (3.145 / 180.0)
half_height = math.tan(theta/2.0)
half_width = aspect * half_height
self.origin = lookfrom
self.w = (lookfrom - lookat).normalize()
self.u = vup.cross(self.w).normalize()
self.v = self.w.cross(self.u)
self.lower_left_corner = self.origin - self.u.scalar_mul(half_width) - self.v.scalar_mul(half_height * focus_dist) - self.w.scalar_mul(focus_dist)
self.horizontal = self.u.scalar_mul(2 * half_width * focus_dist)
self.vertical = self.v.scalar_mul(2 * half_height * focus_dist)
self.lens_radius = 0.0
def hit(self, ray: Ray, t_min: float, t_max: float, rec: hit_record):
oc = ray.origin() - self.center
a = Vector3.dot(ray.direction(), ray.direction())
b = Vector3.dot(oc, ray.direction())
c = Vector3.dot(oc, oc) - self.radius * self.radius
discriminant = b * b - a * c
if (discriminant > 0):
temp = (-b - math.sqrt(discriminant)) / a
if (temp < t_max and temp > t_min):
rec.t = temp
rec.p = ray.point_at_parameter(rec.t)
rec.normal = (rec.p - self.center).scalar_div(self.radius)
return True
temp = (-b + math.sqrt(discriminant)) / a
if (temp < t_max and temp > t_min):
rec.t = temp
rec.p = ray.point_at_parameter(rec.t)
rec.normal = (rec.p - self.center).scalar_div(self.radius)
return True
return False
def scatter(self, ray_in: Ray, rec):
return (False, Ray(Vector3(0, 0, 0), Vector3(0, 0, 0)))