Search found 84 matches

by friedlinguini
Thu Aug 01, 2013 11:07 pm
Forum: General Development
Topic: How to flatten a binary bvh to 4ary BVH?
Replies: 4
Views: 3595

Re: How to flatten a binary bvh to 4ary BVH?

I suspect that it means you should discard non-leaf nodes in even layers. The idea is that in a binary tree each node (say, at level 1) has up to two children (level 2), and thus up to four grandchildren (level 3). If you can connect the level 1 node to its level 3 grandchildren you don't need the l...
by friedlinguini
Thu Jul 11, 2013 3:27 pm
Forum: General Development
Topic: Sampling Ashikhmin-Shirley BRDF
Replies: 4
Views: 4358

Re: Sampling Ashikhmin-Shirley BRDF

If you're feeling stingy about generating random numbers, you can reuse a random number that was used to generate a discrete choice. E.g., float r1 = random(); float r2 = random(); if (r1 < diffuseProbability) { r1 = r1 / diffuseProbability; // Do diffuse sampling using r1,r2 } else { r1 = (r1 - dif...
by friedlinguini
Thu Jun 27, 2013 3:53 pm
Forum: My First...
Topic: Low-discrepancy samplers
Replies: 17
Views: 20591

Re: Low-discrepancy samplers

2. (sample the image plane) dimension 0 & dimension 1 for generating the pixel index (basically: pixelX = width * dim[0]; pixelY = height * dim[1];) 3. dimension 2 & dimension 3 for jittering the sample within the pixel Why do you need two steps for this? Why not float fPixelX = width * dim...
by friedlinguini
Mon Jun 24, 2013 7:25 pm
Forum: My First...
Topic: Low-discrepancy samplers
Replies: 17
Views: 20591

Re: Low-discrepancy samplers

Thank you, friedlinguini! That tiny-bit clears things up - but what about, say, stratified sampling? What corresponds to sampling dimension in stratified sampling? I mean, with Halton/Sobol one uses ever higher primes with every light bounce - but in case of stratified sampling..what do the stratas...
by friedlinguini
Mon Jun 24, 2013 2:13 pm
Forum: My First...
Topic: Low-discrepancy samplers
Replies: 17
Views: 20591

Re: Low-discrepancy samplers

Also, why does the SobolGenerator uses so many dimensions (32)? I understand that there might be some case where one needs so high dimensions (like in statistics) but for path-tracing it is way less, no? I mean, I try to use only two (for hemisphere sampling), another two could be used for antialia...
by friedlinguini
Mon May 27, 2013 2:11 pm
Forum: General Development
Topic: artifacts - any idea
Replies: 15
Views: 9791

Re: artifacts - any idea

sajis997, I mean that the caustic is much more visible. I personally think that's a good thing.

yiningkarlli, in the image identified as the "direct lighting only" image (http://imgur.com/EdZ0yza) there is a visible diffuse component to the material.
by friedlinguini
Thu May 16, 2013 11:55 am
Forum: General Development
Topic: artifacts - any idea
Replies: 15
Views: 9791

Re: artifacts - any idea

It looks OK to me. I also note that your elephant has a more pronounced caustic. More importantly, what do you think?
by friedlinguini
Mon May 13, 2013 5:16 pm
Forum: General Development
Topic: artifacts - any idea
Replies: 15
Views: 9791

Re: artifacts - any idea

In a pinch, I think if(generated random number < refractivity coefficient) { Get a refracted ray. refractedColor = trace(refracted ray, depth -1, 1 /* formerly 0 */); } else if(generated random number < reflectivity coefficient) { Get the reflected ray. reflectedColor = trace(reflected ray, depth - ...
by friedlinguini
Thu May 09, 2013 8:49 pm
Forum: General Development
Topic: artifacts - any idea
Replies: 15
Views: 9791

Re: artifacts - any idea

OK, let me put it this way. It looks to me like you're not getting a specular reflection of the light source in the mirror ball. That is, LSE paths (light -> mirror -> eye) are not showing up in your rendering. LDSE paths are showing up (light -> ceiling -> mirror ->eye), so you wind up with a dark ...
by friedlinguini
Thu May 09, 2013 7:01 pm
Forum: General Development
Topic: artifacts - any idea
Replies: 15
Views: 9791

Re: artifacts - any idea

Given that, along with the fact that the specular materials are effectively removed from your direct lighting calculations, wouldn't ... else if(generated random number < reflectivity coefficient) { Get the reflected ray. reflectedColor = trace(reflected ray, depth - 1, 0); } mean no specular highli...

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