Compute Pixel footprint using Ray Differentials

[Vrroom]

Dear Professor,

How do we compute the portion of the surface that has a pixel footprint using Ray Differentials? Can you point me to the region in the code for that?

Thanks!!

[Vrroom]

I also had a question about Normal Mapping from your lecture series (Advanced Image Synthesis -- if it wasn't meant to be public, please don't shut it down now!!).

In the first lecture, we saw that we sample rays from the pixel filter distribution (normalized to a distribution) when we want to compute it's color via a change of variables.

In the 5th lecture, the pixel filter kernel is combined with the NDF (so that we can approximate that with a Gaussian). Does that mean that now, we'll sample rays from uniform instead of the pixel filter distribution since it's already accounted for in the NDF' = k * NDF?

Thanks!!!!!