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Re: Perlin and simplex noise

From: Erik Dahlstrom <ed@opera.com>
Date: Fri, 31 Aug 2012 10:57:39 +0200
To: www-svg@w3.org
Cc: "public-fx@w3.org" <public-fx@w3.org>
Message-ID: <op.wjwdudkegeuyw5@gnorps>
On Thu, 30 Aug 2012 18:51:32 +0200, David Dailey  
<ddailey@zoominternet.net> wrote:

> I know you all found the concepts of declarative randomness a bit
> distasteful (we're giving a talk on it at the conference in Switzerland,
> soon) and given the history of society's reaction to randomness, one can
> perhaps understand if not appreciate that reaction.
> However, I wondered if thought has been given to Simplex noise in  
> addition
> to Perlin noise[1]?

Some thought has gone into that[2], but there's no concrete proposal for  
it yet. It's listed as issue 15 in the filter draft [3].

I would like to see a more hardware friendly noise algorithm in the spec,  
e.g simplex noise (or something with the same characteristics), but if we  
want existing content to look the same we can't just switch the algorithm  
in feTurbulence since the algorithm in the spec and the simplex algorithm  
generate slightly different results. But, it may well be that the  
differences are small enough that it would be acceptable, anyhow I think  
that needs to be investigated.

What do other people think? The computational cost of the noise algorithm  
in SVG 1.1 is fairly high, and that does limit what you can use it for in  
practice. If we chose to go for a new noise algorithm I would also like to  
be able to animate the noise continously (I think this means we'd need the  
3d version of the algorithm). That is, I'd like to simulate say fire or  
smoke, and link the z dimension in the noise algorithm to the time  
dimension so that the animation is continous (without strange gaps and  
without it looking like the result is scrolled along either or both of the  
x and y-axis).

[1] http://en.wikipedia.org/wiki/Simplex_noise
[2] http://www.w3.org/2009/02/05-svg-minutes.html#item01

Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog: http://my.opera.com/macdev_ed
Received on Friday, 31 August 2012 08:58:17 UTC

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