public static Spectrum SpecularReflect(RayDifferential ray, BSDF bsdf, Intersection isect, IRenderer renderer, Scene scene, Sample sample)
{
Vector wo = -ray.Direction, wi = new Vector ();
double pdf = 0.0;
Point p = bsdf.dgShading.p;
Normal n = bsdf.dgShading.n;
Spectrum f = bsdf.SampleF (wo, ref wi, new BSDFSample (), ref pdf, BxDFType.BSDF_REFLECTION | BxDFType.BSDF_SPECULAR);
Spectrum L = new Spectrum ();
if (pdf > 0.0 && !f.IsBlack && Util.AbsDot (wi, n) != 0.0)
{
RayDifferential rd = new RayDifferential (p, wi, ray, isect.RayEpsilon);
if (ray.HasDifferentials)
{
rd.HasDifferentials = true;
rd.RxOrigin = p + isect.dg.dpdx;
rd.RyOrigin = p + isect.dg.dpdy;
Normal dndx = bsdf.dgShading.dndu * bsdf.dgShading.dudx + bsdf.dgShading.dndv * bsdf.dgShading.dvdx;
Normal dndy = bsdf.dgShading.dndu * bsdf.dgShading.dudy + bsdf.dgShading.dndv * bsdf.dgShading.dvdy;
Vector dwodx = -ray.RxDirection - wo, dwody = -ray.Direction - wo;
double dDNdx = (dwodx ^ n) + (wo ^ dndx);
double dDNdy = (dwody ^ n) + (wo ^ dndy);
rd.RxDirection = wi - dwodx + 2 * new Vector ((wo ^ n) * dndx + dDNdx * n);
rd.RyDirection = wi - dwody + 2 * new Vector ((wo ^ n) * dndy + dDNdy * n);
}
Spectrum Li = renderer.Li (scene, rd, sample);
L = f * Li * Util.AbsDot (wi, n) / pdf;
}
return L;
}
public override BSDF GetBsdf(DifferentialGeometry dgGeom, DifferentialGeometry dgShading)
{
DifferentialGeometry dgs = new DifferentialGeometry ();
if (BumpMap != null)
Bump (BumpMap, dgGeom, dgShading, ref dgs);
else
dgs = new DifferentialGeometry (dgShading);
BSDF bsdf = new BSDF (dgs, dgGeom.n);
Spectrum R = Kr.Evaluate (dgs).Clamp ();
double e = Eta.Evaluate (dgs);
if (!R.IsBlack)
bsdf.Add (new SpecularReflection (R, new FresnelDielectric (1.0, e)));
return bsdf;
}
public override BSDF GetBsdf(DifferentialGeometry dgGeom, DifferentialGeometry dgShading)
{
DifferentialGeometry dgs = new DifferentialGeometry ();
if (BumpMap != null)
Bump (BumpMap, dgGeom, dgShading, ref dgs);
else
dgs = new DifferentialGeometry (dgShading);
BSDF bsdf = new BSDF (dgs, dgGeom.n);
Spectrum r = Kd.Evaluate (dgs).Clamp ();
double sig = Util.Clamp (Sigma.Evaluate (dgs), 0.0, 90.0);
if (sig == 0.0)
bsdf.Add (new Lambertian (r));
else
bsdf.Add (new OrenNayar (r, sig));
return bsdf;
}
public static Spectrum SpecularTransmit(RayDifferential ray, BSDF bsdf, Intersection isect, IRenderer renderer, Scene scene, Sample sample)
{
Vector wo = -ray.Direction, wi = new Vector ();
double pdf = 0.0;
Point p = bsdf.dgShading.p;
Normal n = bsdf.dgShading.n;
Spectrum f = bsdf.SampleF (wo, ref wi, new BSDFSample (), ref pdf, BxDFType.BSDF_TRANSMISSION | BxDFType.BSDF_SPECULAR);
Spectrum L = new Spectrum ();
if (pdf > 0.0 && !f.IsBlack && Util.AbsDot (wi, n) != 0.0)
{
RayDifferential rd = new RayDifferential (p, wi, ray, isect.RayEpsilon);
if (ray.HasDifferentials)
{
rd.HasDifferentials = true;
rd.RxOrigin = p + isect.dg.dpdx;
rd.RyOrigin = p + isect.dg.dpdy;
double eta = bsdf.Eta;
Vector w = -wo;
if ((wo ^ n) < 0.0)
eta = 1.0 / eta;
Normal dndx = bsdf.dgShading.dndu * bsdf.dgShading.dudx + bsdf.dgShading.dndv * bsdf.dgShading.dvdx;
Normal dndy = bsdf.dgShading.dndu * bsdf.dgShading.dudy + bsdf.dgShading.dndv * bsdf.dgShading.dvdy;
Vector dwodx = -ray.RxDirection - wo, dwody = -ray.RyDirection - wo;
double dDNdx = (dwodx ^ n) + (wo ^ dndx);
double dDNdy = (dwody ^ n) + (wo ^ dndy);
double mu = eta * (w ^ n) - (wi ^ n);
double dmudx = (eta - (eta * eta * (w ^ n)) / (wi ^ n)) * dDNdx;
double dmudy = (eta - (eta * eta * (w ^ n)) / (wi ^ n)) * dDNdy;
rd.RxDirection = wi + eta * dwodx - new Vector (mu * dndx + dmudx * n);
rd.RyDirection = wi + eta * dwody - new Vector (mu * dndy + dmudy * n);
}
Spectrum Li = renderer.Li (scene, rd, sample);
L = f * Li * Util.AbsDot (wi, n) / pdf;
}
return L;
}