def EstimateDirect(scene: Scene, renderer: Renderer, light: Light, p: Point3d, n: Normal, wo: Vector3d,
time: float, bsdf: BSDF, lightSample: LightSample, bsdfSample: BSDFSample,
BxDFTypeFlag: int) -> Spectrum:
Ld = Spectrum(0.0)
visibility = VisibilityTester()
wi, Li, lightPdf = light.Sample_L1(p, lightSample, time, visibility)
if lightPdf > 0.0 and not Li.get_is_black():
f = bsdf.f(wo, wi, BxDFTypeFlag)
if not f.get_is_black() and visibility.Unoccluded(scene):
# Add light's contribution to reflected radiance
#Li *= visibility.Transmittance(scene, renderer, None)
inv_lightPdf = 1.0 / lightPdf
if light.get_is_delta_light():
Ld += f * Li * math.fabs(Vector3d.dot(wi, n)) * inv_lightPdf
else:
bsdfPdf = bsdf.get_Pdf(wo, wi, BxDFTypeFlag)
weight = PowerHeuristic(1, lightPdf, 1, bsdfPdf)
Ld += f * Li * math.fabs(Vector3d.dot(wi, n)) * weight * inv_lightPdf
# Sample BSDF with multiple importance sampling
if not light.get_is_delta_light():
wi, bsdfPdf, sampledType, f = bsdf.Sample_f(wo, bsdfSample, BxDFTypeFlag)
if not f.get_is_black() and bsdfPdf > 0.0:
weight = 1.0
if not (BxDFTypeFlag & BxDFType.BSDF_SPECULAR):
lightPdf = light.get_pdf(p, wi)
if lightPdf == 0.0:
return Ld
weight = PowerHeuristic(1, bsdfPdf, 1, lightPdf)
# Add light contribution from BSDF sampling
lightIsect = Intersection()
Li = Spectrum(0.0)
ray = Ray(p, wi, 1e-3, infinity_max_f, time)
if scene.get_intersection(ray, lightIsect):
if lightIsect.primitive.GetAreaLight() == light:
Li = lightIsect.Le(-wi)
else:
Li = light.Le(ray)
if not Li.get_is_black():
Li *= 1.0 #todo renderer.Transmittance(scene, ray, None)
Ld += f * Li * math.fabs(Vector3d.dot(wi, n)) * weight / bsdfPdf
return Ld
