bool RoughPlasticBsdf::sample(SurfaceScatterEvent &event) const
{
if (event.wi.z() <= 0.0f)
return false;
bool sampleR = event.requestedLobe.test(BsdfLobes::GlossyReflectionLobe);
bool sampleT = event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe);
if (!sampleR && !sampleT)
return false;
const Vec3f &wi = event.wi;
float eta = 1.0f/_ior;
float Fi = Fresnel::dielectricReflectance(eta, wi.z());
float substrateWeight = _substrateWeight*_avgTransmittance*(1.0f - Fi);
float specularWeight = Fi;
float specularProbability = specularWeight/(specularWeight + substrateWeight);
if (sampleR && (event.sampler->nextBoolean(specularProbability) || !sampleT)) {
float roughness = (*_roughness)[*event.info].x();
if (!RoughDielectricBsdf::sampleBase(event, true, false, roughness, _ior, _distribution))
return false;
if (sampleT) {
Vec3f diffuseAlbedo = albedo(event.info);
float Fo = Fresnel::dielectricReflectance(eta, event.wo.z());
Vec3f brdfSubstrate = ((1.0f - Fi)*(1.0f - Fo)*eta*eta)*(diffuseAlbedo/(1.0f - diffuseAlbedo*_diffuseFresnel))*INV_PI*event.wo.z();
Vec3f brdfSpecular = event.weight*event.pdf;
float pdfSubstrate = SampleWarp::cosineHemispherePdf(event.wo)*(1.0f - specularProbability);
float pdfSpecular = event.pdf*specularProbability;
event.weight = (brdfSpecular + brdfSubstrate)/(pdfSpecular + pdfSubstrate);
event.pdf = pdfSpecular + pdfSubstrate;
}
return true;
} else {
Vec3f wo(SampleWarp::cosineHemisphere(event.sampler->next2D()));
float Fo = Fresnel::dielectricReflectance(eta, wo.z());
Vec3f diffuseAlbedo = albedo(event.info);
event.wo = wo;
event.weight = ((1.0f - Fi)*(1.0f - Fo)*eta*eta)*(diffuseAlbedo/(1.0f - diffuseAlbedo*_diffuseFresnel));
if (_scaledSigmaA.max() > 0.0f)
event.weight *= std::exp(_scaledSigmaA*(-1.0f/event.wo.z() - 1.0f/event.wi.z()));
event.pdf = SampleWarp::cosineHemispherePdf(event.wo);
if (sampleR) {
Vec3f brdfSubstrate = event.weight*event.pdf;
float pdfSubstrate = event.pdf*(1.0f - specularProbability);
Vec3f brdfSpecular = RoughDielectricBsdf::evalBase(event, true, false, (*_roughness)[*event.info].x(), _ior, _distribution);
float pdfSpecular = RoughDielectricBsdf::pdfBase(event, true, false, (*_roughness)[*event.info].x(), _ior, _distribution);
pdfSpecular *= specularProbability;
event.weight = (brdfSpecular + brdfSubstrate)/(pdfSpecular + pdfSubstrate);
event.pdf = pdfSpecular + pdfSubstrate;
}
event.sampledLobe = BsdfLobes::DiffuseReflectionLobe;
}
return true;
}
Vec3f RoughPlasticBsdf::eval(const SurfaceScatterEvent &event) const
{
bool sampleR = event.requestedLobe.test(BsdfLobes::GlossyReflectionLobe);
bool sampleT = event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe);
if (!sampleR && !sampleT)
return Vec3f(0.0f);
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
Vec3f glossyR(0.0f);
if (sampleR)
glossyR = RoughDielectricBsdf::evalBase(event, true, false, (*_roughness)[*event.info].x(), _ior, _distribution);
Vec3f diffuseR(0.0f);
if (sampleT) {
float eta = 1.0f/_ior;
float Fi = Fresnel::dielectricReflectance(eta, event.wi.z());
float Fo = Fresnel::dielectricReflectance(eta, event.wo.z());
Vec3f diffuseAlbedo = albedo(event.info);
diffuseR = ((1.0f - Fi)*(1.0f - Fo)*eta*eta*event.wo.z()*INV_PI)*(diffuseAlbedo/(1.0f - diffuseAlbedo*_diffuseFresnel));
if (_scaledSigmaA.max() > 0.0f)
diffuseR *= std::exp(_scaledSigmaA*(-1.0f/event.wo.z() - 1.0f/event.wi.z()));
}
return glossyR + diffuseR;
}
bool MixedBsdf::sample(SurfaceScatterEvent &event) const
{
float ratio;
if (!adjustedRatio(event.requestedLobe, event.info, ratio))
return false;
if (event.sampler->nextBoolean(ratio)) {
if (!_bsdf0->sample(event))
return false;
float pdf0 = event.pdf*ratio;
float pdf1 = _bsdf1->pdf(event)*(1.0f - ratio);
Vec3f f = event.weight*event.pdf*ratio + _bsdf1->eval(event)*(1.0f - ratio);
event.pdf = pdf0 + pdf1;
event.weight = f/event.pdf;
} else {
if (!_bsdf1->sample(event))
return false;
float pdf0 = _bsdf0->pdf(event)*ratio;
float pdf1 = event.pdf*(1.0f - ratio);
Vec3f f = _bsdf0->eval(event)*ratio + event.weight*event.pdf*(1.0f - ratio);
event.pdf = pdf0 + pdf1;
event.weight = f/event.pdf;
}
event.weight *= albedo(event.info);
return true;
}
Vec3f PlasticBsdf::eval(const SurfaceScatterEvent &event) const
{
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
bool evalR = event.requestedLobe.test(BsdfLobes::SpecularReflectionLobe);
bool evalT = event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe);
float eta = 1.0f/_ior;
float Fi = Fresnel::dielectricReflectance(eta, event.wi.z());
float Fo = Fresnel::dielectricReflectance(eta, event.wo.z());
if (evalR && checkReflectionConstraint(event.wi, event.wo)) {
return Vec3f(Fi);
} else if (evalT) {
Vec3f diffuseAlbedo = albedo(event.info);
Vec3f brdf = ((1.0f - Fi)*(1.0f - Fo)*eta*eta*event.wo.z()*INV_PI)*
(diffuseAlbedo/(1.0f - diffuseAlbedo*_diffuseFresnel));
if (_scaledSigmaA.max() > 0.0f)
brdf *= std::exp(_scaledSigmaA*(-1.0f/event.wo.z() - 1.0f/event.wi.z()));
return brdf;
} else {
return Vec3f(0.0f);
}
}
bool RoughConductorBsdf::sample(SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::GlossyReflectionLobe))
return false;
if (event.wi.z() <= 0.0f)
return false;
// TODO Re-enable this?
//float sampleRoughness = (1.2f - 0.2f*std::sqrt(std::abs(event.wi.z())))*_roughness;
float roughness = (*_roughness)[*event.info].x();
float sampleRoughness = roughness;
float alpha = Microfacet::roughnessToAlpha(_distribution, roughness);
float sampleAlpha = Microfacet::roughnessToAlpha(_distribution, sampleRoughness);
Vec3f m = Microfacet::sample(_distribution, sampleAlpha, event.sampler->next2D(BsdfSample));
float wiDotM = event.wi.dot(m);
event.wo = 2.0f*wiDotM*m - event.wi;
if (wiDotM <= 0.0f || event.wo.z() <= 0.0f)
return false;
float G = Microfacet::G(_distribution, alpha, event.wi, event.wo, m);
float D = Microfacet::D(_distribution, alpha, m);
float mPdf = Microfacet::pdf(_distribution, sampleAlpha, m);
float pdf = mPdf*0.25f/wiDotM;
float weight = wiDotM*G*D/(event.wi.z()*mPdf);
Vec3f F = Fresnel::conductorReflectance(_eta, _k, wiDotM);
event.pdf = pdf;
event.weight = albedo(event.info)*(F*weight);
event.sampledLobe = BsdfLobes::GlossyReflectionLobe;
return true;
}
Vec3f ConductorBsdf::eval(const SurfaceScatterEvent &event) const
{
bool evalR = event.requestedLobe.test(BsdfLobes::SpecularReflectionLobe);
if (evalR && checkReflectionConstraint(event.wi, event.wo))
return albedo(event.info)*Fresnel::conductorReflectance(_eta, _k, event.wi.z());
else
return Vec3f(0.0f);
}
Vec3f LambertBsdf::eval(const SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe))
return Vec3f(0.0f);
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
return albedo(event.info)*INV_PI*event.wo.z();
}
bool ConductorBsdf::sample(SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::SpecularReflectionLobe))
return false;
event.wo = Vec3f(-event.wi.x(), -event.wi.y(), event.wi.z());
event.pdf = 1.0f;
event.weight = albedo(event.info)*Fresnel::conductorReflectance(_eta, _k, event.wi.z());
event.sampledLobe = BsdfLobes::SpecularReflectionLobe;
return true;
}
bool LambertBsdf::sample(SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe))
return false;
if (event.wi.z() <= 0.0f)
return false;
event.wo = SampleWarp::cosineHemisphere(event.sampler->next2D());
event.pdf = SampleWarp::cosineHemispherePdf(event.wo);
event.weight = albedo(event.info);
event.sampledLobe = BsdfLobes::DiffuseReflectionLobe;
return true;
}
Vec3f RoughWireBcsdf::eval(const SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::GlossyLobe) || event.wo.z() == 0.0f)
return Vec3f(0.0f);
float sinThetaI = event.wi.y();
float sinThetaO = event.wo.y();
float cosThetaI = trigInverse(sinThetaI);
float cosThetaO = trigInverse(sinThetaO);
float cosPhi = event.wo.z()/std::sqrt(event.wo.x()*event.wo.x() + event.wo.z()*event.wo.z());
Vec3f attenuation = albedo(event.info)*Fresnel::conductorReflectance(_eta, _k, trigHalfAngle(event.wi.dot(event.wo)));
return attenuation*N(cosPhi)*M(_v, sinThetaI, sinThetaO, cosThetaI, cosThetaO);
}
bool PlasticBsdf::sample(SurfaceScatterEvent &event) const
{
if (event.wi.z() <= 0.0f)
return false;
bool sampleR = event.requestedLobe.test(BsdfLobes::SpecularReflectionLobe);
bool sampleT = event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe);
const Vec3f &wi = event.wi;
float eta = 1.0f/_ior;
float Fi = Fresnel::dielectricReflectance(eta, wi.z());
float substrateWeight = _avgTransmittance*(1.0f - Fi);
float specularWeight = Fi;
float specularProbability;
if (sampleR && sampleT)
specularProbability = specularWeight/(specularWeight + substrateWeight);
else if (sampleR)
specularProbability = 1.0f;
else if (sampleT)
specularProbability = 0.0f;
else
return false;
if (sampleR && event.sampler->nextBoolean(specularProbability)) {
event.wo = Vec3f(-wi.x(), -wi.y(), wi.z());
event.pdf = specularProbability;
event.weight = Vec3f(Fi/specularProbability);
event.sampledLobe = BsdfLobes::SpecularReflectionLobe;
} else {
Vec3f wo(SampleWarp::cosineHemisphere(event.sampler->next2D()));
float Fo = Fresnel::dielectricReflectance(eta, wo.z());
Vec3f diffuseAlbedo = albedo(event.info);
event.wo = wo;
event.weight = ((1.0f - Fi)*(1.0f - Fo)*eta*eta)*(diffuseAlbedo/(1.0f - diffuseAlbedo*_diffuseFresnel));
if (_scaledSigmaA.max() > 0.0f)
event.weight *= std::exp(_scaledSigmaA*(-1.0f/event.wo.z() - 1.0f/event.wi.z()));
event.pdf = SampleWarp::cosineHemispherePdf(event.wo)*(1.0f - specularProbability);
event.weight /= 1.0f - specularProbability;
event.sampledLobe = BsdfLobes::DiffuseReflectionLobe;
}
return true;
}
Vec3f RoughConductorBsdf::eval(const SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::GlossyReflectionLobe))
return Vec3f(0.0f);
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
float roughness = (*_roughness)[*event.info].x();
float alpha = Microfacet::roughnessToAlpha(_distribution, roughness);
Vec3f hr = (event.wi + event.wo).normalized();
float cosThetaM = event.wi.dot(hr);
Vec3f F = Fresnel::conductorReflectance(_eta, _k, cosThetaM);
float G = Microfacet::G(_distribution, alpha, event.wi, event.wo, hr);
float D = Microfacet::D(_distribution, alpha, hr);
float fr = (G*D*0.25f)/event.wi.z();
return albedo(event.info)*(F*fr);
}
Vec3f PhongBsdf::eval(const SurfaceScatterEvent &event) const
{
bool evalGlossy = event.requestedLobe.test(BsdfLobes::GlossyReflectionLobe);
bool evalDiffuse = event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe);
if (!evalGlossy && !evalDiffuse)
return Vec3f(0.0f);
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
float result = 0.0f;
if (evalDiffuse)
result += _diffuseRatio*INV_PI;
if (evalGlossy) {
float cosTheta = Vec3f(-event.wi.x(), -event.wi.y(), event.wi.z()).dot(event.wo);
if (cosTheta > 0.0f)
result += std::pow(cosTheta, _exponent)*_brdfFactor*(1.0f - _diffuseRatio);
}
return albedo(event.info)*event.wo.z()*result;
}
Vec3f OrenNayarBsdf::eval(const SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::DiffuseReflectionLobe))
return Vec3f(0.0f);
if (event.wi.z() <= 0.0f || event.wo.z() <= 0.0f)
return Vec3f(0.0f);
const Vec3f &wi = event.wi;
const Vec3f &wo = event.wo;
float thetaR = std::acos(event.wo.z());
float thetaI = std::acos(event.wi.z());
float alpha = max(thetaR, thetaI);
float beta = min(thetaR, thetaI);
float sinAlpha = std::sin(alpha);
float denom = (wi.x()*wi.x() + wi.y()*wi.y())*(wo.x()*wo.x() + wo.y()*wo.y());
float cosDeltaPhi;
if (denom == 0.0f)
cosDeltaPhi = 1.0f;
else
cosDeltaPhi = (wi.x()*wo.x() + wi.y()*wo.y())/std::sqrt(denom);
const float RoughnessToSigma = 1.0f/std::sqrt(2.0f);
float sigma = RoughnessToSigma*(*_roughness)[*event.info].x();
float sigmaSq = sigma*sigma;
float C1 = 1.0f - 0.5f*sigmaSq/(sigmaSq + 0.33f);
float C2 = 0.45f*sigmaSq/(sigmaSq + 0.09f);
if (cosDeltaPhi >= 0.0f)
C2 *= sinAlpha;
else
C2 *= sinAlpha - cube((2.0f*INV_PI)*beta);
float C3 = 0.125f*(sigmaSq/(sigmaSq + 0.09f))*sqr((4.0f*INV_PI*INV_PI)*alpha*beta);
float fr1 = (C1 + cosDeltaPhi*C2*std::tan(beta) + (1.0f - std::abs(cosDeltaPhi))*C3*std::tan(0.5f*(alpha + beta)));
float fr2 = 0.17f*sigmaSq/(sigmaSq + 0.13f)*(1.0f - cosDeltaPhi*sqr((2.0f*INV_PI)*beta));
Vec3f diffuseAlbedo = albedo(event.info);
return (diffuseAlbedo*fr1 + diffuseAlbedo*diffuseAlbedo*fr2)*wo.z()*INV_PI;
}
void
Vegetation::output (Log& log) const
{
output_value (N (), "N", log);
output_value (N_fixated (), "N_fixated", log);
output_value (LAI (), "LAI", log);
output_value (height (), "height", log);
output_value (cover (), "cover", log);
output_value (LAIvsH (), "LAIvsH", log);
output_value (HvsLAI (), "HvsLAI", log);
output_value (ACExt_PAR (), "ACExt_PAR", log);
output_value (ACRef_PAR (), "ACRef_PAR", log);
output_value (ACExt_NIR (), "ACExt_NIR", log);
output_value (ACRef_NIR (), "ACRef_NIR", log);
output_value (ARExt (), "ARExt", log);
output_value (EpFactorDry (), "EpFactorDry", log);
output_value (EpFactorWet (), "EpFactorWet", log);
output_value (albedo (), "albedo", log);
output_value (interception_capacity (), "interception_capacity", log);
output_value (shadow_stomata_conductance (),
"shadow_stomata_conductance", log);
output_value (sunlit_stomata_conductance (),
"sunlit_stomata_conductance", log);
}
bool RoughWireBcsdf::sample(SurfaceScatterEvent &event) const
{
if (!event.requestedLobe.test(BsdfLobes::GlossyLobe))
return false;
float xi1 = event.sampler->next1D();
Vec2f xi23 = event.sampler->next2D();
float sinThetaI = event.wi.y();
float cosThetaI = trigInverse(sinThetaI);
float sinPhi = sampleN(xi1);
float sinThetaO = sampleM(_v, sinThetaI, cosThetaI, xi23.x(), xi23.y());
float cosPhi = trigInverse(sinPhi);
float cosThetaO = trigInverse(sinThetaO);
event.wo = Vec3f(sinPhi*cosThetaO, sinThetaO, cosPhi*cosThetaO);
event.pdf = N(cosPhi)*M(_v, sinThetaI, sinThetaO, cosThetaI, cosThetaO);
event.weight = albedo(event.info)*Fresnel::conductorReflectance(_eta, _k, trigHalfAngle(event.wi.dot(event.wo)));
event.sampledLobe = BsdfLobes::GlossyLobe;
return true;
}
Vec3f MixedBsdf::eval(const SurfaceScatterEvent &event) const
{
float ratio = (*_ratio)[*event.info].x();
return albedo(event.info)*(_bsdf0->eval(event)*ratio + _bsdf1->eval(event)*(1.0f - ratio));
}
