/**
* Computes the radiance returned by tracing the ray r.
*/
void PhotonMapper::trace(const Ray& ray, int depth, const Color& flux)
{
Intersection is;
Color lIndirect = Color(0.0f, 0.0f, 0.0f);
if (mScene->intersect(ray, is)){
if (depth != 0){
Hitpoint hp;
hitpointBVH.intersect(is, flux);
float type = uniform();
float reflectivity = is.mMaterial->getReflectivity(is);
float transparency = is.mMaterial->getTransparency(is);
if (type <= reflectivity){
trace(is.getReflectedRay(), depth + 1, flux);
return;
}
else if (type - reflectivity <= transparency){
trace(is.getRefractedRay(), depth + 1, flux);
return;
}
}
if (depth < maxDepth || uniform() > p_abs){
float theta = acos(sqrt(1 - uniform()));
float phi = 2 * M_PI * uniform();
float x = sin(theta) * cos(phi);
float y = sin(theta) * sin(phi);
float z = cos(theta);
Vector3D nvec(1.0f, 0.0f, 0.0f);
Vector3D mvec(0.0f, 1.0f, 0.0f);
Vector3D W = is.mNormal;
W.normalize();
Vector3D U = nvec % W;
if (U.length() < 0.01f)
U = mvec % W;
Vector3D V = W % U;
Vector3D dir = x * U + y * V + z * W;
Ray ray2;
ray2.orig = is.mPosition;
ray2.dir = dir;
Color addFlux = M_PI * is.mMaterial->evalBRDF(is, ray.dir) * flux * (is.mNormal * dir);
if (depth >= maxDepth)
addFlux *= abs_factor;
trace(ray2, depth + 1, addFlux);
}
}
}
void PhotonMapper::forwardPassRay(Ray ray, int x, int y, float weight, int depth){
Intersection is;
if (weight > 0 && depth < maxForwardPassDepth && mScene->intersect(ray, is)){
Hitpoint* hp = new Hitpoint();
hp->pixelX = x;
hp->pixelY = y;
hp->is = is;
hp->radius = startRadius;
Color reflectedC, refractedC, emittedC;
Material* m = is.mMaterial;
float reflectivity = m->getReflectivity(is);
float transparency = m->getTransparency(is);
float diffuse = (1.0f - reflectivity - transparency)*weight;
hp->pixelWeight = (1.0f - reflectivity - transparency) * weight;
if (reflectivity > 0.0f) {
Ray reflectedRay = is.getReflectedRay();
forwardPassRay(reflectedRay, x, y, reflectivity * weight, depth+1);
}
if (transparency > 0.0f) {
Ray refractedRay = is.getRefractedRay();
forwardPassRay(refractedRay, x, y, transparency * weight, depth+1);
}
if (diffuse){
for (int i = 0; i < mScene->getNumberOfLights(); ++i){
PointLight* l = mScene->getLight(i);
if (!mScene->intersect(is.getShadowRay(l))){
Vector3D lightVec = l->getWorldPosition() - is.mPosition;
float d2 = lightVec.length2();
lightVec.normalize();
Color radiance = l->getRadiance();
Color brdf = is.mMaterial->evalBRDF(is, lightVec);
float angle = max(lightVec * is.mNormal, 0.0f);
hp->directIllumination += radiance * brdf * angle / d2;
}
}
vec.push_back(hp);
}
}
}
