public override (SurfaceInteraction, double) Sample()
{
// TODO: Implement Sphere sampling
if (Outside)
{
var pObj = this.Radius * Samplers.UniformSampleSphere();
var n = new Vector3(pObj.x, pObj.y, pObj.z);
var pdf = 1 / this.Area();
var dpdu = new Vector3(-pObj.y, pObj.x, 0);
SurfaceInteraction si = new SurfaceInteraction(pObj, n, Vector3.ZeroVector, dpdu, this);
return(ObjectToWorld.Apply(si), pdf);
}
else
{
var pObj = this.Radius * Samplers.UniformSampleSphere();
var n = new Vector3(pObj.x, pObj.y, pObj.z);
var pdf = 1 / this.Area();
var dpdu = new Vector3(-pObj.y, pObj.x, 0);
SurfaceInteraction si = new SurfaceInteraction(pObj, -n, Vector3.ZeroVector, dpdu, this);
return(ObjectToWorld.Apply(si), pdf);
}
// TODO: Return surface interaction and pdf
// A dummy return example
//double dummyPdf = 1.0;
//Vector3 dummyVector = new Vector3(0, 0, 0);
//SurfaceInteraction dummySurfaceInteraction = new SurfaceInteraction(dummyVector, dummyVector, dummyVector, dummyVector, this);
//return (dummySurfaceInteraction, dummyPdf);
}
public override (Spectrum, Vector3, double) Sample_f(Vector3 wo)
{
Vector3 wi = Samplers.CosineSampleHemisphere();
if (wo.z < 0.0)
{
wi.z *= 1.0;
}
return(f(wo, wi), wi, Pdf(wo, wi));
}
public override (SurfaceInteraction, double) Sample()
{
var pObj = Samplers.UniformSampleSphere() * Radius;
pObj *= Radius / pObj.Length(); // refine
var n = pObj.Normalize();
var dpdu = new Vector3(-pObj.y, pObj.x, 0);
var pdf = 1 / Area();
return(ObjectToWorld.Apply(new SurfaceInteraction(pObj, n, Vector3.ZeroVector, dpdu, this)), pdf);
}
public override (Spectrum, Vector3, double) Sample_f(Vector3 wo)
{
var wi = Samplers.CosineSampleHemisphere();
if (wo.z < 0)
{
wi.z *= -1;
}
double pdf = Pdf(wo, wi);
return(f(wo, wi), wi, pdf);
}
public override (SurfaceInteraction, double) Sample()
{
(double x, double y) = Samplers.UniformSampleDisk();
var pObj = new Vector3(x * radius, y * radius, height);
var n = new Vector3(0, 0, 1);
var dpdu = new Vector3(-pObj.y, pObj.x, 0);
double pdf = 1 / Area();
return(ObjectToWorld.Apply(new SurfaceInteraction(pObj, n, Vector3.ZeroVector, dpdu, this)), pdf);
}
public override (SurfaceInteraction, double) Sample()
{
(double x, double y) = Samplers.UniformSampleSquare();
var pObj = new Vector3((x - 0.5) * width, (y - 0.5) * height, 0);
var n = new Vector3(0, 0, 1);
var dpdu = new Vector3(1, 0, 0);
double pdf = 1 / Area();
return(ObjectToWorld.Apply(new SurfaceInteraction(pObj, n, Vector3.ZeroVector, dpdu, this)), pdf);
}
public override (SurfaceInteraction, double) Sample()
{
Vector3 sample = Samplers.UniformSampleSphere();
Vector3 point = sample * Radius;
Vector3 normal = sample;
Vector3 dpdu = new Vector3(-normal.y, normal.x, 0.0);
double pdf = 1.0 / Area();
SurfaceInteraction si = new SurfaceInteraction(point, normal, Vector3.ZeroVector, dpdu, this);
return(ObjectToWorld.Apply(si), pdf);
}
public override (SurfaceInteraction, double) Sample()
{
// TODO: Implement Sphere sampling
//Vector3 pObj = Samplers.CosineSampleHemisphere() * Radius;
Vector3 pObj = Samplers.UniformSampleSphere() * Radius;
pObj = pObj * (Radius / pObj.Length());
// TODO: Return surface interaction and pdf
var dpdu = new Vector3(-pObj.y, pObj.x, 0);
double pdf = 1 / Area(); // a je kle inv 4 PI (1/Math.PI/4)
return(ObjectToWorld.Apply(new SurfaceInteraction(pObj, ObjectToWorld.ApplyNormal(pObj), Vector3.ZeroVector, dpdu, this)), pdf);
}
public override double Pdf(SurfaceInteraction _si, Vector3 wi)
{
SurfaceInteraction si = WorldToObject.Apply(_si);
double dist2 = si.Point.LengthSquared();
if (dist2 <= Radius * Radius)
{
// Point inside sphere
return(base.Pdf(_si, wi));
}
// Point outside sphere
double sinThetaMax = Radius / Math.Sqrt(dist2);
double cosThetaMax = Utils.SinToCos(sinThetaMax);
return(Samplers.UniformConePdf(cosThetaMax));
}
public override (SurfaceInteraction, double) Sample(SurfaceInteraction _si)
{
SurfaceInteraction si = WorldToObject.Apply(_si);
double dc2 = si.Point.LengthSquared();
if (dc2 <= Radius * Radius)
{
// Point inside sphere
return(base.Sample(_si));
}
// Point outside sphere
double dc = Math.Sqrt(dc2);
double sinThetaMax = Radius / dc;
double cosThetaMax = Utils.SinToCos(sinThetaMax);
// Determine theta and phi for uniform cone sampling
double cosTheta = (cosThetaMax - 1) * Samplers.ThreadSafeRandom.NextDouble() + 1;
double sinTheta = Utils.CosToSin(cosTheta);
double phi = Samplers.ThreadSafeRandom.NextDouble() * 2.0 * Math.PI;
// Distance between reference point and sample point on sphere
double ds = dc * cosTheta - Math.Sqrt(Math.Max(0, Radius * Radius - dc2 * sinTheta * sinTheta));
// Kosinusni zakon
double cosAlpha = (dc2 + Radius * Radius - ds * ds) / (2 * dc * Radius);
double sinAlpha = Utils.CosToSin(cosAlpha);
// Construct coordinate system and use phi and theta as spherical coordinates to get point on sphere
Vector3 wcZ = si.Point.Clone().Normalize();
(Vector3 wcX, Vector3 wcY) = Utils.CoordinateSystem(wcZ);
Vector3 nObj = Utils.SphericalDirection(sinAlpha, cosAlpha, phi, wcX, wcY, wcZ);
Vector3 pObj = nObj * Radius;
// Surface interaction
Vector3 dpdu = new Vector3(-nObj.y, nObj.x, 0.0);
SurfaceInteraction siSample = new SurfaceInteraction(pObj, nObj, Vector3.ZeroVector, dpdu, this);
// Uniform cone PDF
double pdf = Samplers.UniformConePdf(cosThetaMax);
return(ObjectToWorld.Apply(siSample), pdf);
}
public override (SurfaceInteraction, double) Sample()
{
// TODO: Implement Sphere sampling
var center = new Vector3(0, 0, 0);
var point = center + Radius * Samplers.UniformSampleSphere();
var normal = point.Normalize();
if (innerOrientation)
{
normal = -normal;
}
point *= Radius / (center - point).Length();
var wo = point;
var dpdu = Dpdu(point);
var interaction = new SurfaceInteraction(point, normal, wo, dpdu, this);
return(ObjectToWorld.Apply(interaction), Pdf(interaction, point));
}
public override double Pdf(Vector3 wo, Vector3 wi)
{
//return Samplers.UniformHemispherePdf();
return(Samplers.CosineHemispherePdf(wo, wi));
}
