Search found 89 matches

Fri Apr 26, 2019 9:34 pm
Forum: General Development
Topic: Point lights and non-diffuse brdfs
Replies: 9
Views: 2925

Re: Point lights and non-diffuse brdfs

The issue is that I am not convinced that it is well-defined, hence why I want to see a formal proof (be it through measure theory, differential geometry, or even starting with Maxwell's equations). For one thing the brdf is defined in terms of radiance, not in terms of intensity. And if it is inde...
Fri Apr 26, 2019 6:51 pm
Forum: General Development
Topic: Point lights and non-diffuse brdfs
Replies: 9
Views: 2925

Re: Point lights and non-diffuse brdfs

PBRT doesn't really go much further beyond implementation details, most of the arguments are of "an intuitive" nature, I want something a bit more formal. The closest thing I could find on the topic was from: http://www.oceanopticsbook.info/view/light_and_radiometry/level_2/the_limitations_of_radia...
Fri Apr 26, 2019 1:12 pm
Forum: General Development
Topic: Point lights and non-diffuse brdfs
Replies: 9
Views: 2925

Re: Point lights and non-diffuse brdfs

Do you have a reference for the part where you mention that you're replacing the radiance with a delta function? Well, you have an integral over an angle that is non-zero if and only if it includes a singular direction. That's a delta function, isn't it? If you really need academic respectability t...
Tue Mar 26, 2019 1:33 pm
Forum: General Development
Topic: Path tracing in games
Replies: 26
Views: 23827

Re: Path tracing in games

I think the hope is that it will follow roughly the same trajectory as programmable shading, which was also once an extravagant feature from the offline world. Unlike with Cg, I think there’s a bit more of a push for multi-vendor adoption of the interface as seen from getting it in DirectX early, al...
Mon Mar 04, 2019 1:09 pm
Forum: ompf2
Topic: Moving ompf2 to a new host
Replies: 6
Views: 1812

Re: Moving ompf2 to a new host

Thanks for this, Jacco, and for all of your other hard work on the forum!
Sun Feb 10, 2019 2:51 pm
Forum: General Development
Topic: Performance issues with Wald&havran's nlogn kdtree construction
Replies: 5
Views: 2703

Re: Performance issues with Wald&havran's nlogn kdtree construction

Calculating a median can be O(n) (see std::nth_element, median-of-median algorithm, etc), so the overall algorithm I described should run in O(n log n).

If you’re using a language that doesn’t have a linear median/partition library function, then that can be a bit of a rabbit hole.
Fri Feb 08, 2019 2:01 am
Forum: General Development
Topic: Performance issues with Wald&havran's nlogn kdtree construction
Replies: 5
Views: 2703

Re: Performance issues with Wald&havran's nlogn kdtree construction

Seems like unnecessary complexity to use a SAH construction algorithm just to organize a point cloud. Especially if the heuristic is just a median split. That means you don't need to do a plane sweep or a full sort. I'd also get rid of mixing component values from different dimensions. As you've not...
Thu Sep 20, 2018 3:19 pm
Topic: CUDA 10 available
Replies: 6
Views: 11725

Re: CUDA 10 available

I don't think CUDA itself has been advertised with ray-tracing goodness; it's all delegated to OptiX, DirectX, and Vulkan.
Wed Jul 25, 2018 3:24 am
Topic: Primary Sample Space Path Guiding
Replies: 3
Views: 2915

Re: Primary Sample Space Path Guiding

It seemed to have a lot of the same ideas as multidimensional adaptive sampling (https://www.ci.i.u-tokyo.ac.jp/~hachisuka/mdas.pdf), and also the same weaknesses.
Mon Jul 23, 2018 1:44 pm
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 4668

Re: Emissive surfaces and visibility term

I'd say no. Without explicit light source sampling, all geometric factors relating to the light source--surface area, distance, and cosine term--are accounted for in the probability of a ray hitting the light source "by accident." For example, if the geometric normal of a triangular light source is ...