Search found 81 matches

by friedlinguini
Wed Jul 25, 2018 3:24 am
Forum: Links & Papers
Topic: Primary Sample Space Path Guiding
Replies: 3
Views: 346

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.
by friedlinguini
Mon Jul 23, 2018 1:44 pm
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 570

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 ...
by friedlinguini
Thu Jun 15, 2017 1:59 pm
Forum: Visuals
Topic: My First Spectral rendering
Replies: 5
Views: 4010

Re: My First Spectral rendering

Whoah, weird. I had thought you could do something very similar, but by adding a random point on the *interior* of a sphere to the normal, rather than on the surface: http://psgraphics.blogspot.com/2014/09/random-diffuse-rays.html. Obviously it would be better to use exactly two random parameters th...
by friedlinguini
Mon Apr 17, 2017 10:30 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 13681

Re: Implementation for Blue-noise Dithered Sampling

The idea ideas not adding a deterministic (blue-noise) number to a random number. In fact, the idea is to get rid of the randomness altogether - you use the deterministic number to post your pattern, instead of using a random number. Right, I was using "random" loosely. My understanding o...
by friedlinguini
Sun Apr 16, 2017 8:34 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 13681

Re: Implementation for Blue-noise Dithered Sampling

sin(2 * pi * (ps - qs)) * 0.5 + 0.5


OK, that makes no sense. I tried to jam a couple of ideas together without making sure that one didn't break the other.

Maybe c * (x - x * x), where x = ps - qs and c is some constant I haven't worked out yet.
by friedlinguini
Sun Apr 16, 2017 2:19 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 13681

Re: Implementation for Blue-noise Dithered Sampling

I was thinking of giving this technique a spin, and I had a couple of random thoughts. 1. The idea is basically to add the pixel-dependent blue-noise shift to a pixel-independent random number, and subtract 1 if necessary to bring things in the range of [0, 1), right? But during tile generation, the...
by friedlinguini
Mon Feb 06, 2017 2:41 pm
Forum: General Development
Topic: Dispersion
Replies: 2
Views: 3487

Re: Dispersion

According to most sources, including https://en.wikipedia.org/wiki/SRGB, the linear RGB values are usually clipped to [0.0, 1.0], with display white represented as (1.0, 1.0, 1.0). It's not entirely clear, but it sounds like you're talking about clamping individual samples. Don't do that. Just aver...
by friedlinguini
Mon Dec 12, 2016 2:58 pm
Forum: General Development
Topic: Multiple Textures CUDA/OpenCL
Replies: 8
Views: 11417

Re: Multiple Textures CUDA/OpenCL

I remember sth. along the lines of the CPU linear filter being 5x slower than nearest filtering. In contrast to that, On the GPU, with HW accelerated filtering, I found there was virtually no difference in performance between nearest and linear filtering. How did you lay out your textures in memory...
by friedlinguini
Tue Dec 06, 2016 1:32 pm
Forum: General Development
Topic: Confused about near-specular reflection that is not energy conserving.
Replies: 4
Views: 3526

Re: Confused about near-specular reflection that is not energy conserving.

There's no reason to give up on point lights; all I was trying to say is that having a BRDF that spikes above 1 is physically plausible. If a point light is bright enough to visibly illuminate a diffuse surface, then it's going to create a very bright highlight on a near-mirror surface. The intensit...
by friedlinguini
Fri Dec 02, 2016 4:17 pm
Forum: General Development
Topic: Confused about near-specular reflection that is not energy conserving.
Replies: 4
Views: 3526

Re: Confused about near-specular reflection that is not energy conserving.

BRDFs can have spikes arbitrarily greater than 1 because you use them by integrating over some finite domain, and the integral should give you something less than one (a surface can't reflect more photons than it receives). Consider also a point light above the ground with an intenty Li. The reflect...

Go to advanced search