def schlick(self, incident: 'Vector3', normal: 'Vector3', n1: 'float',
n2: 'float'):
r0 = (n1 - n2) / (n1 + n2)
r0 *= r0
cosX = Vector3.dot(normal, incident)
if n1 > n2:
n = n1 / n2
sinT2 = n * n * (1.0 - cosX * cosX)
if sinT2 > 1.0:
return 1.0
cosX = math.sqrt(1.0 - sinT2)
x = 1.0 - cosX
return r0 + (1.0 - r0) * math.pow(x, 5)
def trilineart_interp(self, c, u, v, w):
uu = u * u * (3 - 2 * u)
vv = v * v * (3 - 2 * v)
ww = w * w * (3 - 2 * w)
accum = 0
for i in range(2):
for j in range(2):
for k in range(2):
weight_v = Vector3(u - i, v - j, w - k)
accum += (i * uu + (1 - i) * (1 - uu)) * \
(j * vv + (1 - j) * (1 - vv)) * \
(k * ww + (1 - k) * (1 - ww)) * Vector3.dot(c[i * 2 + j * 2 + k], weight_v)
return accum
def hit(self, ray: Ray, t_min: float, t_max: float) -> (bool, HitRecord):
"""Checks if the ray 'ray' hits with the sphere between t_min and t_max.
Returns true if there is a collision, false otherwise.
Return the hitRecord information if the collision is true.
"""
current_center = self.get_center(t=ray.time)
oc = ray.origin - current_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(b * b - a * c)) / a
if t_max > temp > t_min:
record = HitRecord()
record.t = temp
record.hit_point = ray.point_at_parameter(record.t)
record.hit_point_normal = (record.hit_point -
current_center) / self._radius
record.u, record.v = self.get_sphere_uv(p=record.hit_point)
record.material = self._material
return True, record
temp = (-b + math.sqrt(b * b - a * c)) / a
if t_max > temp > t_min:
record = HitRecord()
record.t = temp
record.hit_point = ray.point_at_parameter(record.t)
record.hit_point_normal = (record.hit_point -
current_center) / self._radius
record.u, record.v = self.get_sphere_uv(p=record.hit_point)
record.material = self._material
return True, record
return False, None
def value(self, direction: Vector3) -> float:
cosine = Vector3.dot(Vector3.normalize(direction), self._uvw.w())
if cosine > 0:
return cosine / math.pi
else:
return 0