def Sample1(self, u: (float, float), n: Normal) -> Point3d:
b1, b2 = UniformSampleTriangle(u)
# Get triangle vertices in _p1_, _p2_, and _p3_
p1_index = self.mesh.index[self.triangle_index*3 + 0]
p2_index = self.mesh.index[self.triangle_index*3 + 2]
p3_index = self.mesh.index[self.triangle_index*3 + 1]
p1 = self.mesh.points[p1_index]
p2 = self.mesh.points[p2_index]
p3 = self.mesh.points[p3_index]
p = p1 * b1 + p2 * b2 + p3 * (1.0 - b1 - b2)
n.Set(Normal.create_from_vector3d(Vector3d.cross(p2-p1, p3-p1)).get_normalized())
#todo if (ReverseOrientation) *Ns *= -1.f;
return p
def get_intersection(self, ray: Ray, dg: DifferentialGeometry) -> (bool, float):
p1_index = self.mesh.index[self.triangle_index*3 + 0]
p2_index = self.mesh.index[self.triangle_index*3 + 2]
p3_index = self.mesh.index[self.triangle_index*3 + 1]
p1 = self.mesh.points[p1_index]
p2 = self.mesh.points[p2_index]
p3 = self.mesh.points[p3_index]
e1 = p2 - p1
e2 = p3 - p1
s1 = Vector3d.cross(ray.direction, e2)
divisor = Vector3d.dot(s1, e1)
if divisor == 0.0:
return False, 0.0
invDivisor = 1.0 / divisor
# Compute first barycentric coordinate
d = ray.origin - p1
b1 = Vector3d.dot(d, s1) * invDivisor
if b1 < 0.0 or b1 > 1.0:
return False, 0.0
#Compute second barycentric coordinate
s2 = Vector3d.cross(d, e1)
b2 = Vector3d.dot(ray.direction, s2) * invDivisor
if b2 < 0.0 or (b1 + b2) > 1.0:
return False, 0.0
# Compute _t_ to intersection point
t = Vector3d.dot(e2, s2) * invDivisor
if t < ray.min_t or t > ray.max_t:
return False, 0.0
dg.shape = self
dg.point = ray.get_at(t)
dg.normal = Normal.create_from_vector3d( Vector3d.cross(e1, e2).get_normalized())
return True, t
def Sample_L2(self, scene: Scene, ls: LightSample, u: (float, float), n: Normal, ray: Ray, time: float) -> (
Spectrum, float):
ray = Ray(self.lightPos, UniformSampleSphere(ls.uPos), 0.0, infinity_max_f, time)
n.Set(Normal.create_from_vector3d(ray.direction))
return self.intensity, UniformSpherePdf()