ompf2.com

Does anyone know if the product of two microfacet distributions (specifically GGX) is also a microfacet distribution and how to compute the alpha of the new distribution? I found some conversion from alpha to standard deviation and used that along with the product of two gaussian distributions to de...

Fantastic, then I have an idea about what to expect from it.

And thanks for opening up your renderer.

Could you elaborate a bit on the RNG used? In preperation for denoising in my own renderer I'm looking into different random number generators to get a decent set of samples pr pixel and ideally different samples for neighbouring pixels. I see that yours uses what looks like several sets of blue noi...

If you already have the VNDF sampling from the 2014 paper then implementing the new is trivial. It's the same set of samples with the same PDF, so you just have to copy paste the reference sample method and then you'll have faster GGX sampling

Messed up a transform while cleaning up my implementation of A Spherical Cap Preserving Parameterization for Spherical Distributions. I call it the Blackhole Sun effect.

Looks like a made up term that he doesn't bother to define.

Alright. That's basically what I want to do at some point for my own path tracer as well in interactive scenarios. I don't think I've ever read anything about it, since it should be fairly trivial, but http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.155.326&rep=rep1&type=pdf and https://gra...

Yea, that really doesn't explain it. Now it sounds a bit more like (path) filtering, but a bounce count in the range of thousands (at least per individual path) is generally a bit silly.
If it's filtering, then there' been a ton of work done in that field.

What exactly do you mean by progressive depth? Render one bounce at a time and defer the next bounces (if any) to the next render call / frame? If so then I haven't seen anything directly related to that, but there are papers that sort the rays pr bounce, so visualizing them as well is fairly trivia...

Interesting. I guess I must do it slightly different then, because I just tested mine with MIS and MIS + 3 light RIS (or whatever warped self-rolled version of RIS I'm using) and there is no difference. I don't scale the PDF though when evaluating multiple light sources. I simply leave the light PDF...