Color3f Li(const Scene *scene, Sampler *sampler, const Ray3f &ray) const { /* Find the surface that is visible in the requested direction */ Intersection its; //check if the ray intersects the scene if (!scene->rayIntersect(ray, its)) { //check if a distant disk light is set const Emitter* distantsDisk = scene->getDistantEmitter(); if(distantsDisk == nullptr ) return Color3f(0.0f); //sample the distant disk light Vector3f d = ray.d; return distantsDisk->sampleL(d); } //get the Number of lights from the scene const std::vector<Emitter *> lights = scene->getEmitters(); uint32_t nLights = lights.size(); Color3f tp(1.0f, 1.0f, 1.0f); Color3f L(0.0f, 0.0f, 0.0f); Ray3f pathRay(ray.o, ray.d); bool deltaFlag = true; while(true) { if (its.mesh->isEmitter() && deltaFlag) { const Emitter* areaLightEM = its.mesh->getEmitter(); const areaLight* aEM = static_cast<const areaLight *> (areaLightEM); L += tp * aEM->sampleL(-pathRay.d, its.shFrame.n, its); } //Light sampling //randomly select a lightsource uint32_t var = uint32_t(std::min(sampler->next1D()*nLights, float(nLights) - 1.0f)); //init the light color Color3f Li(0.0f, 0.0f, 0.0f); Color3f Ld(1.0f, 1.0f, 1.0f); //create a sample for the light const BSDF* curBSDF = its.mesh->getBSDF(); const Point2f lightSample = sampler->next2D(); VisibilityTester vis; Vector3f wo; float lightpdf; float bsdfpdf; Normal3f n = its.shFrame.n; deltaFlag = curBSDF->isDeltaBSDF(); //sample the light { Li = lights[var]->sampleL(its.p, Epsilon, lightSample , &wo, &lightpdf, &vis); lightpdf /= float(nLights); //check if the pdf of the sample is greater than 0 and if the color is not black if(lightpdf > 0 && Li.maxCoeff() != 0.0f) { //calculate the cosine term wi in my case the vector to the light float cosTerm = std::abs(n.dot(wo)); const BSDFQueryRecord queryEM = BSDFQueryRecord(its.toLocal(- pathRay.d), its.toLocal(wo), EMeasure::ESolidAngle, sampler); Color3f f = curBSDF->eval(queryEM); if(f.maxCoeff() > 0.0f && f.minCoeff() >= 0.0f && vis.Unoccluded(scene)) { bsdfpdf = curBSDF->pdf(queryEM); float weight = BalanceHeuristic(float(1), lightpdf, float(1), bsdfpdf); if(curBSDF->isDeltaBSDF()) weight = 1.0f; if(bsdfpdf > 0.0f) { Ld = (weight * f * Li * cosTerm) / lightpdf; L += tp * Ld; } else { //cout << "bsdfpdf = " << bsdfpdf << endl; //cout << "f = " << f << endl; } } } } //Material part BSDFQueryRecord queryMats = BSDFQueryRecord(its.toLocal(-pathRay.d), Vector3f(0.0f), EMeasure::ESolidAngle, sampler); Color3f fi = curBSDF->sample(queryMats, sampler->next2D()); bsdfpdf = curBSDF->pdf(queryMats); lightpdf = 0.0f; if(fi.maxCoeff() > 0.0f && fi.minCoeff() >= 0.0f) { if(bsdfpdf > 0.0f) { Ray3f shadowRay(its.p, its.toWorld(queryMats.wo)); Intersection lightIsect; if (scene->rayIntersect(shadowRay, lightIsect)) { if(lightIsect.mesh->isEmitter()){ const Emitter* areaLightEMcur = lightIsect.mesh->getEmitter(); const areaLight* aEMcur = static_cast<const areaLight *> (areaLightEMcur); Li = aEMcur->sampleL(-shadowRay.d, lightIsect.shFrame.n, lightIsect); lightpdf = aEMcur->pdf(its.p, (lightIsect.p - its.p).normalized(), lightIsect.p, Normal3f(lightIsect.shFrame.n)); } } else { const Emitter* distantsDisk = scene->getDistantEmitter(); if(distantsDisk != nullptr ) { //check if THIS is right! Li = distantsDisk->sampleL(lightIsect.toWorld(queryMats.wo)); lightpdf = distantsDisk->pdf(Point3f(0.0f), wo, Point3f(0.0f), Normal3f(0.0f)); } } lightpdf /= float(nLights); //calculate the weights float weight = BalanceHeuristic(float(1), bsdfpdf, float(1), lightpdf); //check if the lightcolor is not black if(Li.maxCoeff() > 0.0f && lightpdf > 0.0f ) { //wo in my case the vector to the light Ld = weight * Li * fi; L += tp * Ld; } } tp *= fi; } else { break; } wo = its.toWorld(queryMats.wo); pathRay = Ray3f(its.p, wo); if (!scene->rayIntersect(pathRay, its)) { const Emitter* distantsDisk = scene->getDistantEmitter(); if(distantsDisk != nullptr ) { //sample the distant disk light Vector3f d = pathRay.d; L += tp * distantsDisk->sampleL(d); } break; } float maxCoeff = tp.maxCoeff(); float q = std::min(0.99f, maxCoeff); if(q < sampler->next1D()){ break; } tp /= q; } return L; }