public override void Sample_f(ShadePointInfo pt, float u0, float u1, float u2, out Vector vector, out float radiancePdf,
out float pdf1, out BsdfEvent @event)
{
float c = 1f - Vector.Dot(ref pt.IncomingDirection, ref pt.ShadingNormal);
float Re = R0 + (1f - R0) * c * c * c * c * c;
float P = .25f + .5f * Re;
if ((u2 < P && reflectionSpecularBounce))
{//onlySpecular ||
vector = MetalBrdf.GlossyReflection(ref pt.IncomingDirection, exponent, ref pt.ShadingNormal, u0, u1);
pdf1 = P / Re;
@event = BsdfEvent.Specular;
radiancePdf = Re;
}
else
{
Vector dir = MC.CosineSampleHemisphere(u0, u1);
pdf1 = dir.z * MathLab.INVPI;
/*
Vector v1, v2;
*
dir =
Vector.CoordinateSystem(ref shadeN, out v1, out v2);
dir = new Vector(
v1.x * dir.x + v2.x * dir.y + shadeN.x * dir.z,
v1.y * dir.x + v2.y * dir.y + shadeN.y * dir.z,
v1.z * dir.x + v2.z * dir.y + shadeN.z * dir.z);*/
ONB fm = new ONB(ref pt.ShadingNormal);
var wi = fm.ToWorld(ref dir);//pt.Frame
float dp = Vector.Dot(ref pt.ShadingNormal, ref wi);
// Using 0.0001 instead of 0.0 to cut down fireflies
if (dp <= 0.0001f)
{
pdf1 = 0f;
}
pdf1 /= dp;
float iRe = 1f - Re;
pdf1 *= (1f - P) / iRe;
@event = BsdfEvent.Glossy | BsdfEvent.Diffuse;
vector = wi;
radiancePdf = iRe;
}
}