public virtual float GenerateRayDifferential(CameraSample sample, out RayDifferential rd)
{
Ray ray;
float wt = GenerateRay(sample, out ray);
rd = RayDifferential.FromRay(ray);
// Find ray after shifting one pixel in the $x$ direction
CameraSample sshift = sample;
++(sshift.ImageX);
Ray rx;
float wtx = GenerateRay(sshift, out rx);
rd.RxOrigin = rx.Origin;
rd.RxDirection = rx.Direction;
// Find ray after shifting one pixel in the $y$ direction
--(sshift.ImageX);
++(sshift.ImageY);
Ray ry;
float wty = GenerateRay(sshift, out ry);
rd.RyOrigin = ry.Origin;
rd.RyDirection = ry.Direction;
if (wtx == 0.0f || wty == 0.0f)
{
return(0.0f);
}
rd.HasDifferentials = true;
return(wt);
}
public Spectrum Transmittance(Scene scene, Renderer renderer,
Sample sample, Random rng)
{
return(renderer.Transmittance(
scene, RayDifferential.FromRay(Ray),
sample, rng));
}