public override float Pdf(ref Vector wo, ref Vector wi, BxDFTypes bxDFType)
{
if(!SameHemisphere(ref wo, ref wi))
return 0f;
return distr.Pdf(ref wo, ref wi);
}
public RgbSpectrum rho(Vector wo, BxDFTypes flags)
{
RgbSpectrum ret = new RgbSpectrum();
for (int i = 0; i < bxdfs.Count; ++i)
if (BxDF.MatchesFlags(bxdfs[i], flags))
ret += bxdfs[i].Rho(wo);
return ret;
}
public override float Pdf(ref Vector wo, ref Vector wi, BxDFTypes bxDFType)
{
return 1f;
}
public float Pdf(ref Vector woW, ref Vector wiW, BxDFTypes flags)
{
if (bxdfs.Count == 0) return 0f;
Vector wo = WorldToLocal(ref woW);
var wi = WorldToLocal(ref wiW);
float pdf = 0f;
int matchingComps = 0;
for (int i = 0; i < bxdfs.Count; ++i)
if (BxDF.MatchesFlags(bxdfs[i], flags))
{
++matchingComps;
pdf += bxdfs[i].Pdf(ref wo, ref wi);
}
return matchingComps > 0 ? pdf / matchingComps : 0f;
}
public RgbSpectrum f(ref Vector woW, ref Vector wiW, BxDFTypes flags)
{
Vector wi = WorldToLocal(ref wiW);
var wo = WorldToLocal(ref woW);
if ((wiW & ng) * (woW & ng) > 0)
// ignore BTDFs
flags = flags & ~BxDFTypes.BSDF_TRANSMISSION;
else
// ignore BRDFs
flags = flags & ~BxDFTypes.BSDF_REFLECTION;
RgbSpectrum f = RgbSpectrum.ZeroSpectrum();
for (int i = 0; i < bxdfs.Count; ++i)
if (BxDF.MatchesFlags(bxdfs[i], flags))
f += bxdfs[i].F(ref wo, ref wi);
return f;
}
public int NumComponents(BxDFTypes flags)
{
var res = bxdfs.Count(p => BxDF.MatchesFlags(p, flags));
return res;
}
public RgbSpectrum Sample_f(ref Vector woW, out Vector wiW,
float u1, float u2, float u3, out float pdf, out BxDFTypes? sampled,
BxDFTypes flags = BxDFTypes.BSDF_ALL,
BxDFTypes? sampledType = null)
{
BxDFTypes fl = flags;
int matchingComps = NumComponents(fl);
if (matchingComps == 0)
{
pdf = 0f;
wiW = Vector.Zero;
sampled = null;
return new RgbSpectrum(0f);
}
int which = (int)Math.Min((u3 * matchingComps),
matchingComps - 1);
BxDF bxdf = null;
int count = which;
for (int i = 0; i < bxdfs.Count; ++i)
if (BxDF.MatchesFlags(bxdfs[i], fl))
if (count-- == 0)
{
bxdf = bxdfs[i];
break;
}
Vector wi = new Vector();
Vector wo = WorldToLocal(ref woW);
wiW = Vector.Zero;
pdf = 0f;
bool specularBounce;
RgbSpectrum f = bxdf.Sample(ref wo, out wi, u1, u2, out pdf, out specularBounce);
sampled = bxdf.Type;
if (pdf > 0f && pdf < MathLab.Epsilon) return RgbSpectrum.ZeroSpectrum();
if (sampledType != null) sampledType = bxdf.Type;
wiW = LocalToWorld(wi);
if ((!BxDF.MatchesFlags(bxdf, BxDFTypes.BSDF_SPECULAR)) && matchingComps > 1)
{
for (int i = 0; i < bxdfs.Count; ++i)
{
if (bxdfs[i] != bxdf &&
BxDF.MatchesFlags(bxdfs[i], fl))
pdf += bxdfs[i].Pdf(ref wo, ref wi);
}
}
if (matchingComps > 1) pdf /= matchingComps;
// Compute value of BSDF for sampled direction
if (BxDF.MatchesFlags(bxdf, BxDFTypes.BSDF_SPECULAR))
//if ((bxdf.Type & BxDFType.BSDF_SPECULAR) == 0)
{
f = RgbSpectrum.ZeroSpectrum();
if ((wiW & ng) * (woW & ng) > 0f)
// ignore BTDFs
{
fl = fl & ~BxDFTypes.BSDF_TRANSMISSION;
}
else
// ignore BRDFs
fl = (fl & ~BxDFTypes.BSDF_REFLECTION);
for (int i = 0; i < bxdfs.Count; ++i)
if (BxDF.MatchesFlags(bxdfs[i], fl))
f += bxdfs[i].F(ref wo, ref wi);
f = f / pdf;
}
return f;
}
internal RgbSpectrum Sample_f(Vector wo, ref Vector wi, float bs1, float bs2, float bcs, out float bsdfPdf, BxDFTypes flags)
{
throw new NotImplementedException();
}
public static bool MatchesFlags(BxDF obj, BxDFTypes flags)
{
return (flags & obj.type).Equals(flags) || (flags & obj.type).Equals(obj.type);
}
public BxDF(BxDFTypes t)
{
type = t;
}
public override float Pdf(ref Vector wo, ref Vector wi, BxDFTypes bxDFType)
{
return mattePdf * mirrorPdf;
}
public virtual float Pdf(ref Vector wo, ref Vector wi, BxDFTypes bxDFType)
{
return wi.z*MathLab.INVPI;
}
