/// <inheritdoc />
public override double GenerateRay(CameraSample sample, out Ray ray)
{
//ProfilePhase prof(Prof::GenerateCameraRay);
// Compute raster and camera sample positions
Point3D pFilm = new Point3D(sample.FilmPoint.X, sample.FilmPoint.Y, 0.0);
Point3D pCamera = RasterToCamera.AtPoint(pFilm);
ray = new Ray(new Point3D(0.0, 0.0, 0.0), pCamera.ToVector3D().Normalize());
// Modify ray for depth of field
if (LensRadius > 0.0)
{
// Sample point on lens
Point2D pLens = LensRadius * Sampling.ConcentricSampleDisk(sample.LensPoint);
// Compute point on plane of focus
double ft = FocalDistance / ray.Direction.Z;
Point3D pFocus = ray.AtPoint(ft);
// Update ray for effect of lens
ray.Origin = new Point3D(pLens.X, pLens.Y, 0.0);
ray.Direction = (pFocus - ray.Origin).ToVector3D().Normalize();
}
ray.Time = PbrtMath.Lerp(sample.Time, ShutterOpen, ShutterClose);
ray.Medium = Medium;
ray = CameraToWorld.ExecuteTransform(ray);
return(1.0);
}
/// <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));
}
/// <inheritdoc />
public override double GenerateRayDifferential(CameraSample sample, out RayDifferential ray)
{
//ProfilePhase prof(Prof::GenerateCameraRay);
// Compute raster and camera sample positions
Point3D pFilm = new Point3D(sample.FilmPoint.X, sample.FilmPoint.Y, 0.0);
Point3D pCamera = RasterToCamera.ExecuteTransform(pFilm);
Vector3D dir = new Vector3D(pCamera.X, pCamera.Y, pCamera.Z).Normalize();
ray = new RayDifferential(new Point3D(0.0, 0.0, 0.0), dir);
// Modify ray for depth of field
if (LensRadius > 0.0)
{
// Sample point on lens
Point2D pLens = LensRadius * Sampling.ConcentricSampleDisk(sample.LensPoint);
// Compute point on plane of focus
double ft = FocalDistance / ray.Direction.Z;
Point3D pFocus = ray.AtPoint(ft);
// Update ray for effect of lens
ray.Origin = new Point3D(pLens.X, pLens.Y, 0.0);
ray.Direction = (pFocus - ray.Origin).ToVector3D().Normalize();
}
// Compute offset rays for _PerspectiveCamera_ ray differentials
if (LensRadius > 0.0)
{
// Compute _PerspectiveCamera_ ray differentials accounting for lens
// Sample point on lens
Point2D pLens = LensRadius * Sampling.ConcentricSampleDisk(sample.LensPoint);
Vector3D dx = (pCamera.ToVector3D() + _dxCamera).Normalize();
double ft = FocalDistance / dx.Z;
Point3D pFocus = new Point3D(0.0, 0.0, 0.0) + (ft * dx).ToPoint3D();
ray.RxOrigin = new Point3D(pLens.X, pLens.Y, 0.0);
ray.RxDirection = (pFocus - ray.RxOrigin).ToVector3D().Normalize();
Vector3D dy = (pCamera.ToVector3D() + _dyCamera).Normalize();
ft = FocalDistance / dy.Z;
pFocus = new Point3D(0.0, 0.0, 0.0) + (ft * dy).ToPoint3D();
ray.RyOrigin = new Point3D(pLens.X, pLens.Y, 0.0);
ray.RyDirection = (pFocus - ray.RyOrigin).ToVector3D().Normalize();
}
else
{
ray.RxOrigin = ray.RyOrigin = ray.Origin;
ray.RxDirection = (pCamera.ToVector3D() + _dxCamera).Normalize();
ray.RyDirection = (pCamera.ToVector3D() + _dyCamera).Normalize();
}
ray.Time = PbrtMath.Lerp(sample.Time, ShutterOpen, ShutterClose);
ray.Medium = Medium;
ray = new RayDifferential(CameraToWorld.ExecuteTransform(ray))
{
HasDifferentials = true
};
return(1.0);
}