def Sample2(self, p: Point3d, u: (float, float), Ns: Normal) -> Point3d:
# Compute coordinate system for sphere sampling
Pcenter = Point3d(0, 0, 0) * self.objectToWorld
wc = (Pcenter - p).get_normalized()
wcX, wcY = Transform.create_coordinateSystem(wc)
# Sample uniformly on sphere if $\pt{}$ is inside it
if (p - Pcenter).get_length_squared() - self.radius * self.radius < 1e-40:
return self.Sample1(u, Ns)
# Sample sphere uniformly inside subtended cone
sinThetaMax2 = self.radius * self.radius / (p - Pcenter).get_length_squared()
cosThetaMax = math.sqrt(max(0.0, 1.0 - sinThetaMax2))
dgSphere = DifferentialGeometry()
thit = 1.0
r = Ray(p, UniformSampleCone2(u, cosThetaMax, wcX, wcY, wc), 1e-3)
b, t = self.get_intersection(r, dgSphere)
# if not b:
#bug
thit = Vector3d.dot(Pcenter - p, r.direction.get_normalized())
ps = r.get_at(thit)
nn = (ps - Pcenter).get_normalized()
Ns.Set(nn)
# if (ReverseOrientation) *ns *= -1.f;
return ps
def get_is_intersected(self, ray: Ray) -> bool:
# Check ray against overall grid bounds
if self.bounds.get_is_point_inside(ray.get_at(ray.min_t)):
rayT = ray.min_t
else:
rayT, tmp = self.bounds.get_intersect(ray)
if rayT is None:
return False
gridIntersect = ray.get_at(rayT)
# Set up 3D DDA for ray
NextCrossingT = [float] * 3
DeltaT = [float] * 3
Step = [int] * 3
Out = [int] * 3
Pos = [int] * 3
for axis in range(3):
# Compute current voxel for axis
Pos[axis] = self.get_pos_to_voxel(gridIntersect, axis)
if ray.direction[axis] >= 0:
# Handle ray with positive direction for voxel stepping
NextCrossingT[axis] = rayT + (self.get_voxel_to_pos(Pos[axis] + 1, axis) - gridIntersect[axis]) / \
ray.direction[axis]
DeltaT[axis] = self.width[axis] / ray.direction[axis]
Step[axis] = 1
Out[axis] = self.nVoxels[axis]
else:
# Handle ray with negative direction for voxel stepping
NextCrossingT[axis] = rayT + (self.get_voxel_to_pos(Pos[axis], axis) - gridIntersect[axis]) / \
ray.direction[axis]
DeltaT[axis] = -self.width[axis] / ray.direction[axis]
Step[axis] = -1
Out[axis] = -1
#Walk grid for shadow ray
while True:
o = self.get_offset(Pos[0], Pos[1], Pos[2])
voxel = self.voxels[o]
if voxel is not None:
if voxel.get_is_intersected(ray):
return True
# Advance to next voxel
# Find _stepAxis_ for stepping to next voxel
bits = ((NextCrossingT[0] < NextCrossingT[1]) << 2) + ((NextCrossingT[0] < NextCrossingT[2]) << 1) + (
(NextCrossingT[1] < NextCrossingT[2]))
cmpToAxis = [2, 1, 2, 1, 2, 2, 0, 0]
stepAxis = cmpToAxis[bits]
if ray.max_t < NextCrossingT[stepAxis]:
break
Pos[stepAxis] += Step[stepAxis]
if Pos[stepAxis] == Out[stepAxis]:
break
NextCrossingT[stepAxis] += DeltaT[stepAxis]
return False
def generate_ray(self, sample:CameraSample)->Ray:
point_camera = Point3d(sample.image_xy[0], sample.image_xy[1], 0.0) * self.rasterToCamera
direction = Vector3d(0.0, 0.0, 1.0)
r = Ray(point_camera, direction, 0.0, infinity_max_f)
if self.lensRadius>0.0:
pass
#todo
r.time = sample.time
return r * self.camera_to_world
def generate_ray(self, sample:CameraSample)->Ray:
camera_point = Point3d(sample.image_xy[0], sample.image_xy[1], 0.0) * self.rasterToCamera
camera_direction = Vector3d(camera_point.x, camera_point.y, camera_point.z).get_normalized()
r = Ray(camera_point, camera_direction, 0.0, infinity_max_f)
if self.lensRadius>0.0:
pass
#todo
r.time = sample.time
return r * self.camera_to_world
def Pdf2(self, p: Point3d, wi: Vector3d)->float:
# Intersect sample ray with area light geometry
dgLight = DifferentialGeometry()
ray = Ray(p, wi, 1e-3)
ray.depth = -1 # temporary hack to ignore alpha mask
b, thit =self.get_intersection(ray, dgLight)
if not b:
return 0.0
# Convert light sample weight to solid angle measure
pdf = (p - ray.get_at(thit)).get_length_squared() / (math.fabs(Vector3d.dot(dgLight.normal, -wi) * self.Area()))
if math.isinf(pdf):
pdf = 0.0
return pdf
def scatter(self, ray, hit_record):
target = hit_record.point + hit_record.normal + random_in_unit_sphere()
self.scattered = Ray(hit_record.point, target - hit_record.point,
ray.time)
self.attenuation = self.albedo
return True
def Sample1(self, p: Point3d, ls: LightSample, Ns: Normal)->Point3d:
pdf, sn = self.areaDistribution.SampleDiscrete(ls.uComponent)
pt = self.shapes[sn].Sample2(p, ls.uPos, Ns)
# Find closest intersection of ray with shapes in _ShapeSet_
r = Ray(p, (pt-p).get_normalized(), 1e-3, infinity_max_f)
anyHit = False
thit = 1.0
dg = DifferentialGeometry()
for i in range(len(self.shapes)):
anyHit_b, thit_f = self.shapes[i].get_intersection(r, dg)
if anyHit_b:
anyHit = True
thit = thit_f
if anyHit:
Ns.Set(dg.normal)
return r.get_at(thit)
def scatter(self, ray, hit_record):
reflected = reflect(unit_vector(ray.direction), hit_record.normal)
self.scattered = Ray(hit_record.point,
reflected + self.fuzzy * random_in_unit_sphere(),
ray.time)
self.attenuation = self.albedo
return np.dot(self.scattered.direction, hit_record.normal) > 0.
def get_intersection(self, ray: Ray, intersection: Intersection) -> bool:
hit, thit = self.shape.get_intersection(ray, intersection.differentialGeometry)
if not hit:
return False
intersection.primitive = self
intersection.WorldToObject = self.shape.objectToWorld
intersection.ObjectToWorld = self.shape.objectToWorld
ray.max_t = thit
return True
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
