def UniformSampleOneLight(scene: Scene, renderer: Renderer, p: Point3d, n: Normal, wo: Vector3d,
time: float, bsdf: BSDF, sample: Sample,
lightSampleOffsets: [LightSampleOffsets]=None, bsdfSampleOffsets: [BSDFSampleOffsets]=None,
lightNumOffset: int=-1) -> Spectrum:
L = Spectrum(0.0)
nLights = int(len(scene.lights))
if nLights == 0:
return Spectrum(0.0)
if lightNumOffset != -1:
lightNum = int((sample.values_array_1d[lightNumOffset][0] * nLights)) # todo floor to int
else:
lightNum = int((random() * nLights)) # todo floor to int
lightNum = min(lightNum, nLights - 1)
light = scene.lights[lightNum]
# Initialize light and bsdf samples for single light sample
if lightSampleOffsets is not None and bsdfSampleOffsets is not None:
lightSample = LightSample.create_from_sample(sample, lightSampleOffsets, 0)
bsdfSample = BSDFSample.create_from_sample(sample, bsdfSampleOffsets, 0)
else:
lightSample = LightSample.create_from_random()
bsdfSample = BSDFSample.create_from_random()
Ld = EstimateDirect(scene, renderer, light, p, n, wo, time, bsdf, lightSample, bsdfSample,
BxDFType.BSDF_ALL & ~BxDFType.BSDF_SPECULAR)
return Ld * float(nLights)
def UniformSampleAllLights(scene: Scene, renderer: Renderer, p: Point3d, n: Normal, wo: Vector3d,
time: float, bsdf: BSDF, sample: Sample,
lightSampleOffsets: [LightSampleOffsets],
bsdfSampleOffsets: [BSDFSampleOffsets]) -> Spectrum:
L = Spectrum(0.0)
for i in range(len(scene.lights)):
light = scene.lights[i]
if lightSampleOffsets is None:
nSamples = 1
else:
nSamples = lightSampleOffsets[i].nSamples
# Estimate direct lighting from _light_ samples
Ld = Spectrum(0.0)
for j in range(nSamples):
# Find light and BSDF sample values for direct lighting estimate
if lightSampleOffsets is not None and bsdfSampleOffsets is not None:
lightSample = LightSample.create_from_sample(sample, lightSampleOffsets[i], j)
bsdfSample = BSDFSample.create_from_sample(sample, bsdfSampleOffsets[i], j)
else:
lightSample = LightSample.create_from_random()
bsdfSample = BSDFSample.create_from_random()
Ld += EstimateDirect(scene, renderer, light, p, n, wo, time, bsdf, lightSample, bsdfSample,
BxDFType.BSDF_ALL & ~BxDFType.BSDF_SPECULAR)
L += Ld / nSamples
return L
def Li(self, scene, renderer: Renderer, r: Ray, intersection: Intersection, sample: Sample) -> Spectrum:
# Declare common path integration variables
pathThroughput = Spectrum(1.0)
L = Spectrum(0.0)
ray = deepcopy(r)
specularBounce = False
localIsect = Intersection()
isectp = intersection
bounces = 0
while True:
# Possibly add emitted light at path vertex
if bounces == 0 or specularBounce:
L += pathThroughput * isectp.Le(-ray.direction)
# Sample illumination from lights to find path contribution
bsdf = isectp.get_bsdf(ray)
p = bsdf.dgShading.point
n = bsdf.dgShading.normal
wo = -ray.direction
if bounces < self.maxDepth:
L += pathThroughput * UniformSampleOneLight(scene, renderer, p, n, wo, ray.time, bsdf, sample,
self.lightSampleOffsets[bounces],
self.bsdfSampleOffsets[bounces],
self.lightNumOffset[bounces])
else:
L += pathThroughput * UniformSampleOneLight(scene, renderer, p, n, wo, ray.time, bsdf, sample)
# Sample BSDF to get new path direction
# Get _outgoingBSDFSample_ for sampling new path direction
if bounces < self.maxDepth:
outgoingBSDFSample = BSDFSample.create_from_sample(sample, self.pathSampleOffsets[bounces], 0)
else:
outgoingBSDFSample = BSDFSample.create_from_random()
wi, pdf, flags, f = bsdf.Sample_f(wo, outgoingBSDFSample, BxDFType.BSDF_ALL)
if f.get_is_black() or pdf == 0.0:
break
specularBounce = (flags & BxDFType.BSDF_SPECULAR) != 0
pathThroughput *= f * math.fabs(Vector3d.dot(wi, n)) / pdf
ray = Ray(p, wi, 0.01, ray.max_t)
# Possibly terminate the path
if bounces > 3:
continueProbability = min(0.5, pathThroughput.y())
if random() > continueProbability:
break
pathThroughput /= continueProbability
if bounces == self.maxDepth:
break
# Find next vertex of path
if not scene.get_intersection(ray, localIsect):
if specularBounce:
for i in range(scene.lights.size()):
L += pathThroughput * scene.lights[i].get_Le(ray)
break
# pathThroughput *= renderer->Transmittance(scene, ray, NULL, rng, arena);
isectp = localIsect
bounces += 1
return L