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Member Since 06 Sep 2002
Offline Last Active Apr 21 2016 05:18 AM

Posts I've Made

In Topic: "Random Digit Scrambling" for quasi montecarlo sampling

24 October 2014 - 04:06 AM

It looks like you are trying to understand someone else's code without understanding, or even reading, the paper: it is clearly stated in section 7 that


Randomized digit scrambling (section 3.2.3) is realized by just calling the routines with a random integer instead of the default parameter uint r = 0.

Hammersley sequences or the like are a higher level construct than radical inverse functions (in fact the "end product" of the whole algorithm), not a low-level primitive.


I read the paper and don't understand how they combine the routines to get their RDS. 

The scrambled part still makes sense to me.

func ScrambledHammersley(i, numSamples, r uint32) Vector2 {
	return MakeVector2(float32(i) / float32(numSamples), ScrambledRadicalInverse_vdC(i, r))

But apparently they are combining all of the three radical inverse functions to get some result.

In Topic: Decouple simulation and rendering: Interpolate particles

04 June 2014 - 01:28 AM

I see. Thanks for the input!

In Topic: OpenGL 4.4 render to SNORM

31 May 2014 - 04:53 AM



Maybe the easiest thing is to render to UNORM and map [-1, 1] to [0, 1] in the shader. Not really a big deal, but I wanted to find out what the problem is.

In Topic: OpenGL 4.4 render to SNORM

30 May 2014 - 05:41 AM

Yes, I'm checking for completeness. The behavior I get is completely identical to just using a UNORM target, so it seems to be silently converting to that. I also don't get any debug output from OpenGL.


This is with a GeForce GTX 570, driver 331.38 on Ubuntu.


Do you have experience with rendering to this format?

In Topic: OpenGL 4.4 render to SNORM

29 May 2014 - 10:15 AM

I don't know. It says:


We are silent about requiring R, RG, RBA and RGBA rendering. This is an implementation choice.


As the hardware seems to perfectly capable of rendering to SNORM I expect that it is implemented for all drivers.

Has someone here successfully rendered to SNORM with OpenGL?




This OpenGL 4.4 core spec document also does not mark the SNORM formats as something that must be supported for a color target. Maybe it is really not supported to render to SNORM. Can anybody confirm this?