/// <inheritdoc />
public override Spectrum Sample_Wi(
Interaction it,
Point2D u,
out Vector3D wi,
out double pdf,
out Point2D pRaster,
out VisibilityTester vis)
{
// Uniformly sample a lens interaction _lensIntr_
Point2D pLens = LensRadius * Sampling.ConcentricSampleDisk(u);
Point3D pLensWorld = CameraToWorld.ExecuteTransform(it.Time, new Point3D(pLens.X, pLens.Y, 0.0));
Interaction lensIntr = new Interaction(pLensWorld, it.Time, new MediumInterface(Medium));
lensIntr.N = (CameraToWorld.ExecuteTransform(it.Time, new Point3D(0.0, 0.0, 1.0))).ToVector3D().ToNormal3D();
// Populate arguments and compute the importance value
vis = new VisibilityTester(it, lensIntr);
wi = (lensIntr.P - it.P).ToVector3D();
double dist = wi.Length();
wi /= dist;
// Compute PDF for importance arriving at _ref_
// Compute lens area of perspective camera
double lensArea = LensRadius != 0.0 ? (Math.PI * LensRadius * LensRadius) : 1.0;
pdf = (dist * dist) / (lensIntr.N.AbsDot(wi) * lensArea);
return(We(lensIntr.SpawnRay(-wi), out pRaster));
}
public override Spectrum Sample_Li(Interaction inter, Point2 <float> u, out Vector3 <float> wi, out float pdf, out VisibilityTester vis)
{
Interaction interShape = Shape.Sample(u);
wi = (interShape.P - inter.P).Normalized();
pdf = Shape.Pdf(inter, wi);
vis = new VisibilityTester(inter, interShape);
return(L(interShape, -wi));
}
public override SampledSpectrum Sample(ref Vector3 point, Scene scene, out Vector3 incomingVector,
out VisibilityTester visibilityTester)
{
var direction = point - Position;
incomingVector = direction.Normalized();
visibilityTester = new VisibilityTester(Position, point, scene);
return(Spectrum / direction.LengthSquared);
}
public override Spectrum Sample_Li(Interaction inter, Point2 <float> u, out Vector3 <float> wi, out float pdf, out VisibilityTester visTester)
{
var lightToPoint = position - inter.P;
wi = lightToPoint.Normalized();
pdf = 1.0f;
visTester = new VisibilityTester(inter, new SurfaceInteraction(position));
return(intensity / lightToPoint.LengthSquared());
}
public override Spectrum Sample_Li(Interaction reference,
Point2D u,
out Vector wi,
out float pdf,
out VisibilityTester visibility)
{
wi = (_pLight - reference.P).Normalize();
pdf = 1f;
visibility = new VisibilityTester(reference, new Interaction(_pLight, MediumInterface));
return(_I * Falloff(-wi) / Point.DistanceSqr(_pLight, reference.P));
}
public override Spectrum Sample_Li(Interaction reference,
Point2D u,
out Vector wi,
out float pdf,
out VisibilityTester visibility)
{
wi = (_pLight - reference.P).Normalize();
pdf = 1f;
visibility = new VisibilityTester(reference, new Interaction(_pLight));
var d2 = Point.DistanceSqr(_pLight, reference.P);
return(I / d2);
}
public override SampledSpectrum Sample(ref Vector3 point, Scene scene, out Vector3 incomingVector,
out VisibilityTester visibilityTester)
{
var r1 = StaticRandom.NextFloat() * 2 - 1;
var r2 = StaticRandom.NextFloat() * 2 - 1;
var pointInDiskLocal = new Vector3(r1 * _radius, 0, r2 * _radius);
var pointInDiskWorld = ObjectToWorld.TransformPoint(ref pointInDiskLocal);
incomingVector = point - pointInDiskWorld;
var cosangle = Vector3.Dot(incomingVector.Normalized(), _normal);
visibilityTester = new VisibilityTester(pointInDiskWorld, point, scene);
return(Spectrum * cosangle / incomingVector.Length);
}
