static Color3 finalGathering(KdTree<Photon> *map , Scene& scene ,
Intersection& inter , RNG& rng , const Vector3& wo ,
int gatherSamples , int knn , Real maxSqrDis)
{
Color3 res = Color3(0.0 , 0.0 , 0.0);
for (int i = 0; i < gatherSamples; i++)
{
Real pdf;
Vector3 wi = sampleCosHemisphere(rng.randVector3() , &pdf);
Ray ray = Ray(inter.p + wi * EPS , wi);
Intersection _inter;
Geometry *_g = scene.intersect(ray , _inter);
if (_g == NULL)
continue;
Color3 tmp = estimate(map , 0 , knn , scene , _inter , -wi , maxSqrDis);
BSDF bsdf(wi , _inter , scene);
Real cosine , bsdfPdf;
Color3 brdf = bsdf.f(scene , wo , cosine , &bsdfPdf);
if (brdf.isBlack())
continue;
pdf *= bsdfPdf;
res = res + (tmp | brdf) * (cosine / pdf);
}
res = res / gatherSamples;
return res;
}
static Color3 directIllumination(Scene& scene , Intersection& inter ,
RNG& rng , const Vector3& visionDir)
{
Color3 res = Color3(0.0 , 0.0 , 0.0);
Vector3 lightDir;
Real cosine;
Color3 brdf;
Ray ray;
BSDF bsdf(visionDir , inter , scene);
int N = 1;
for (int i = 0; i < N; i++)
{
int k = rand() % scene.lights.size();
AbstractLight *l = scene.lights[k];
Vector3 dirToLight;
Real dist , directPdf;
Color3 illu = l->illuminance(scene.sceneSphere , inter.p , rng.randVector3() ,
dirToLight , dist , directPdf);
illu = illu / (directPdf / scene.lights.size());
if (scene.occluded(inter.p + dirToLight * EPS , dirToLight ,
inter.p + dirToLight * (inter.t - EPS)))
continue;
Real bsdfPdf;
brdf = bsdf.f(scene , dirToLight , cosine , &bsdfPdf);
if (brdf.isBlack())
continue;
res = res + (illu | brdf) * (cosine / bsdfPdf);
}
res = res / N;
return res;
}