/**
* Compute the secondary rays for diffuse reflexion and place them into the subrays
* vector.
* localBasis : the local base on the object at the computation point.
* surfaceCoordinate : the surface coordinate (texture coordinate) of the computation
* point on the object.
* view : the view ray (from the camera or bounced)
* nbRays : the number of wanted ray. It is an indicative information.
* subrays : the vector were the secondaries rays will be put.
* weights : the weights corresponding to the distribution
*/
void RoughLambertianBRDF::getRandomDiffuseRay(const Basis& localBasis, const Point2D& surfaceCoordinate, LightVector& reemitedLight, unsigned int nbRays, std::vector<LightVector>& subrays)
{
Vector normal=localBasis.k;
if(normal.dot(reemitedLight.getRay().v)>0)
normal.mul(-1);
for(unsigned int i=0; i<nbRays; i++)
{
Vector incident;
Real norm2;
Real cosOi;
do{
incident[0]=rand()*2.0/RAND_MAX - 1.0;
incident[1]=rand()*2.0/RAND_MAX - 1.0;
incident[2]=rand()*2.0/RAND_MAX - 1.0;
norm2=incident.square();
incident.normalize();
cosOi=incident.dot(normal);
}while(norm2>cosOi*cosOi || cosOi<=0.0);
LightVector subray;
subray.setRay(localBasis.o, incident);
subray.changeReemitedPolarisationFramework(normal);
subray.initSpectralData(reemitedLight);
subray.setWeight(1.0/M_PI);
subrays.push_back(subray);
}
}
/**
* Compute the secondary rays for diffuse reflexion and place them into the subrays
* vector.
* localBasis : the local base on the object at the computation point.
* surfaceCoordinate : the surface coordinate (texture coordinate) of the computation
* point on the object.
* view : the view ray (from the camera or bounced)
* nbRays : the number of wanted ray. It is an indicative information.
* subrays : the vector were the secondaries rays will be put.
* weights : the weights corresponding to the distribution
*/
void BeckmannBRDF::getRandomDiffuseRay(const Basis& localBasis, const Point2D& surfaceCoordinate, LightVector& reemitedLight, unsigned int nbRays, std::vector<LightVector>& subrays)
{
Vector view = reemitedLight.getRay().v;
view.mul(-1.0);
if(view.dot(localBasis.k)<0)
return;
for(unsigned int i=0; i<nbRays; i++)
{
Vector dir;
Real weight;
BeckmannRoughnessFormula::getBeckmannRandomRay(localBasis, view, _roughness, weight, dir);
LightVector subray;
subray.setRay(localBasis.o, dir);
subray.initSpectralData(reemitedLight);
subray.changeReemitedPolarisationFramework(localBasis.k);
subray.setWeight(weight);
subrays.push_back(subray);
}
}