/**
* Compute the diffusely reemited light data and place the result into reemited.
* localBasis : the object localBasis at the computation point.
* surfaceCoordinate : the surface coordinate (texture coordinate) of the computation
* point on the object.
* incident : the incident ray (light ray)
* view : the view ray (from the camera or bounced)
* incidentLight : the incident light comming from the incident ray.
* reemitedLight : the light reemited into the view direction (result will be placed
* here).
*/
void RoughLambertianBRDF::getDiffuseReemited(const Basis& localBasis, const Point2D& surfaceCoordinate, const LightVector& incidentLight, LightVector& reemitedLight)
{
Vector view = reemitedLight.getRay().v;
Vector incident = incidentLight.getRay().v;
Real cosOi = -incident.dot(localBasis.k);
Real cosOv = -view.dot(localBasis.k);
if(cosOi <= 0)
{
reemitedLight.clear();
return;
}
if(cosOi>=1.0)
cosOi=1.0;
if(cosOv>=1.0)
cosOv=1.0;
Real Oi = std::acos(cosOi);
Real Ov = std::acos(cosOv);
Real Pi = std::atan2(incident.dot(localBasis.j), incident.dot(localBasis.i));
Real Pv = std::atan2(view.dot(localBasis.j), view.dot(localBasis.i));
Real factor = OrenNayarFormula::orenNayarReflectance(Oi, Pi, Ov, Pv, _roughness);
for(unsigned int i=0; i<reemitedLight.size(); i++)
reemitedLight[i].setRadiance(incidentLight[i].getRadiance()*_spectrum[incidentLight[i].getIndex()]*factor);
reemitedLight.changeReemitedPolarisationFramework(localBasis.k);
}
/**
* Compute the estimated reflected radiance.
* @param localBasis : the local basis at the computation point.
* @param surfaceCoordinate : the local surface coordinate at the computation point.
* @param object : the surface that reflect the light.
* @param radius : the initial radius search for the nearest photon photon search pass.
* @param nb_poton : the number of nearest pĥoton to take count in the computation.
* @param lightdata : the reflected light data to compute.
*/
inline void MultispectralPhotonMap::getEstimation(const Basis& localBasis, const Point2D& surfaceCoordinate, Object& object, Real radius, int nb_photon, LightVector& lightdata)
{
lightdata.clear();
//Get the nearest photons
std::vector<MultispectralPhoton*> photons;
Real r2 = _tree.getNearestNeighbor(localBasis.o, nb_photon, radius, localBasis.k, photons);
if(r2==0.0)
return;
Real invarea = 1.0/(M_PI*r2);
Real photonPower = _photonPower*invarea;
LightVector incident;
LightVector reemited;
reemited.initGeometricalData(lightdata);
for(unsigned int i=0; i<photons.size(); i++)
{
Real weight = photonPower/std::abs(photons[i]->direction.dot(localBasis.k));
reemited.initSpectralData(lightdata);
incident.initSpectralData(lightdata);
incident.changeReemitedPolarisationFramework(localBasis.k);
for(unsigned int k=0; k<lightdata.size(); k++)
incident[k].setRadiance(weight*photons[i]->radiance[lightdata[k].getIndex()]);
incident.setRay(photons[i]->position, photons[i]->direction);
object.getDiffuseReemited(localBasis, surfaceCoordinate, incident, reemited);
lightdata.add(reemited);
}
lightdata.changeReemitedPolarisationFramework(localBasis.k);
}
void RoughLambertianBRDF::getDiffuseReemitedFromAmbiant(const Basis& localBasis, const Point2D& surfaceCoordinate, LightVector& reemitedLight, const Spectrum& incident)
{
reemitedLight.clear();
reemitedLight.changeReemitedPolarisationFramework(localBasis.k);
//// the same in all directions
//for(unsigned int i=0; i<reemitedLight.size(); i++) {
// reemitedLight[i].setRadiance(incident[i] * _spectrum[i] );
//}
//reemitedLight.changeReemitedPolarisationFramework(localBasis.k);
}
/**
* Compute the diffusely reemited light data and place the result into reemited.
* localBasis : the object localBasis at the computation point.
* surfaceCoordinate : the surface coordinate (texture coordinate) of the computation
* point on the object.
* incident : the incident ray (light ray)
* view : the view ray (from the camera or bounced)
* incidentLight : the incident light comming from the incident ray.
* reemitedLight : the light reemited into the view direction (result will be placed
* here).
*/
void BeckmannBRDF::getDiffuseReemited(const Basis& localBasis, const Point2D& surfaceCoordinate, const LightVector& incidentLight, LightVector& reemitedLight)
{
const Vector& incident = incidentLight.getRay().v;
const Vector& view = reemitedLight.getRay().v;
//Computing the micro normal
Vector microNormal;
microNormal.setsum(incident, view);
microNormal.mul(-1.0);
microNormal.normalize();
//Computing some cosinuses and sinuses
Real cosLN = -localBasis.k.dot(incident); // incident and normal
Real cosVN = -localBasis.k.dot(view); // view and normal
Real cosHN = localBasis.k.dot(microNormal); // micro normal and normal
Real cosLH = -microNormal.dot(incident); // incident and micro normal
Real cosVH = -microNormal.dot(view); // view and micro normal
//Compute Beckmann and Shadowing&masking coeficients
Real beckmann = BeckmannRoughnessFormula::BeckmannDistribution(cosHN,
_roughness);
Real shadmask = BeckmannRoughnessFormula::BeckmannShadowMasking(cosLN,
cosVN,
cosVH,
cosHN);
//Setting the polarisation framework
LightVector localIncidentLight(incidentLight);
localIncidentLight.changeIncidentPolarisationFramework(microNormal);
localIncidentLight.flip();
reemitedLight.changeReemitedPolarisationFramework(microNormal);
if(cosVN <=0.001 || cosLN <=0.001)
{
reemitedLight.clear();
return;
}
//Computing reflectances for each wavelength
for(unsigned int i=0; i<localIncidentLight.size(); i++)
{
Real ROrth, RPara;
getReflectance(cosLH, localIncidentLight[i].getIndex(), ROrth, RPara);
reemitedLight[i].applyReflectance(localIncidentLight[i], RPara*beckmann*shadmask, ROrth*beckmann*shadmask);
}
}
void BeckmannBRDF::getDiffuseReemitedFromAmbiant(const Basis& localBasis, const Point2D& surfaceCoordinate, LightVector& reemitedLight, const Spectrum& incident)
{
const Vector& light = localBasis.k;
const Vector& view = reemitedLight.getRay().v;
//Computing the micro normal
Vector microNormal;
microNormal.setsum(light, view);
microNormal.mul(-1.0);
microNormal.normalize();
//Computing some cosinuses and sinuses
Real cosLN = -localBasis.k.dot(light); // light and normal
Real cosVN = -localBasis.k.dot(view); // view and normal
Real cosHN = localBasis.k.dot(microNormal); // micro normal and normal
Real cosLH = -microNormal.dot(light); // light and micro normal
Real cosVH = -microNormal.dot(view); // view and micro normal
//Compute Beckmann and Shadowing&masking coeficients
Real beckmann = BeckmannRoughnessFormula::BeckmannDistribution(cosHN,
_roughness);
Real shadmask = BeckmannRoughnessFormula::BeckmannShadowMasking(cosLN,
cosVN,
cosVH,
cosHN);
if(cosVN <=0.001 )
{
reemitedLight.clear();
return;
}
for(unsigned int wl=0; wl < reemitedLight.size(); wl++) {
Real ROrth, RPara;
getReflectance(cosLH, wl, ROrth, RPara);
ROrth *= beckmann * shadmask;
RPara *= beckmann * shadmask;
reemitedLight[wl].setRadiance(incident[wl] /** cosVN*/ * 0.5 * (ROrth + RPara));
}
reemitedLight.changeReemitedPolarisationFramework(microNormal);
}
/**
* Compute the absorption of a light ray through the medium.
*/
inline void Medium::transportLight(LightVector& light) const
{
if(isOpaque)
{
light.clear();
return;
}
if(useLambertianModel)
{
for(unsigned int i=0; i<light.size(); i++)
light[i].mul(t[light[i].getIndex()]);
}
if(useFresnelModel)
{
for(unsigned int i=0; i<light.size(); i++)
{
Real a = DielectricFormula::dielectricAbsorption(light.getDistance(), GlobalSpectrum::getWaveLength(light[i].getIndex())*1E-9, k[light[i].getIndex()]);
light[i].mul(a);
}
}
}