glm::vec3 BidirectionalIntegrator::TraceRay(Ray r, unsigned int depth)
{
Intersection isx = intersection_engine->GetIntersection(r);
if(isx.t < 0)
return glm::vec3(0);
else if(isx.object_hit->material->is_light_source)
{
return isx.object_hit->material->base_color * isx.texture_color;
}
glm::vec3 resultColor(0);
for(Geometry* light : scene->lights)
{
std::vector<PathNode> eyePath = generateEyePath(r);
std::vector<PathNode> lightPath = generateLightPath(light);
if(!eyePath.empty() && !lightPath.empty())
{
PathNode* node = &lightPath[0];
float lightPdf = light->RayPDF(node->isx,Ray(node->isx.point,node->dirIn_world));
glm::vec3 Le(0);
if(lightPdf != 0)
Le = light->material->base_color * light->material->intensity / lightPdf;
glm::vec3 directWt(1.0f);
for(int i=1;i<=eyePath.size();i++)
{
node = &eyePath[i-1];
Ray ray(light->transform.position(), - node->dirIn_world);
resultColor += directWt * EstimateDirectLight(node->isx, ray, light) / WeightPath(i,0);
directWt *= node->F * glm::abs(glm::dot(node->dirOut_world,node->isx.normal)) / node->pdf;
for(int j=1;j<=lightPath.size();j++)
{
resultColor += Le * EvaluatePath(eyePath,i,lightPath,j) / WeightPath(i,j);
}
}
}
else
{
continue;
}
}
return resultColor;
}
Spectrum VolumePatIntegrator::UniformSampleLight(const Scene *scene,
const Renderer *renderer, MemoryArena &arena, const Point &p,
const Normal &n, const Vector &wo, float rayEpsilon, float time, RNG &rng) const {
// Randomly choose a single light to sample, _light_
int nLights = int(scene->lights.size());
if (nLights == 0) return Spectrum(0.);
int lightNum;
lightNum = Floor2Int(rng.RandomFloat() * nLights);
lightNum = min(lightNum, nLights-1);
Light *light = scene->lights[lightNum];
// Initialize light sample for single light sampling
LightSample lightSample(rng);
return (float) nLights * EstimateDirectLight(scene, renderer, arena,
light, p, n, wo, rayEpsilon, time, rng, lightSample);
}
