POV-Ray : Newsgroups : povray.binaries.images : Perlin's Improved Noise comparison ... (24K) Server Time
7 Nov 2024 17:32:09 EST (-0500)
  Perlin's Improved Noise comparison ... (24K) (Message 1 to 4 of 4)  
From: Mike Andrews
Subject: Perlin's Improved Noise comparison ... (24K)
Date: 29 Jun 2004 13:45:00
Message: <web.40e1aa39c747073659735c0c0@news.povray.org>
Hi Folks,

I was having another look at Ken Perlin's 'Improved Noise' paper and I
wanted to compare it to the three noise generators currently in PoV. As I
don't have the source for v3.6 yet I thought I'd see if it was possible to
do in SDL.

With a novel (to me at least) use of spline functions I figured out it was.

Anyway, the image shows isosurface superellipsoids with the surface
purturbed by noise generators 1, 2 and 3 (lower right, lower left and top
right respectively) and the improved noise top left.

The three noise generator ones clearly show the inconsistencies in the
second-derivative (lines on the reflections) and this is much reduced in
the 'new' version of the noise.

So, the gist of this is that I hope someone will put the improved noise into
at least the unofficial PoV builds ...

I'll put the scene file in p.b.s-f in case anyone want's to have a look.

Mike.


Post a reply to this message


Attachments:
Download 'noise.jpg' (24 KB)

Preview of image 'noise.jpg'
noise.jpg


 

From: Slime
Subject: Re: Perlin's Improved Noise comparison ... (24K)
Date: 29 Jun 2004 15:51:13
Message: <40e1c831@news.povray.org>
> So, the gist of this is that I hope someone will put the improved noise
into
> at least the unofficial PoV builds ...


I've done this in Slime-POV ( http://www.slimeland.com/slimepov/ ), but that
was based on POV-Ray 3.5.

 - Slime
 [ http://www.slimeland.com/ ]


Post a reply to this message

From: Slime
Subject: Re: Perlin's Improved Noise comparison ... (24K)
Date: 29 Jun 2004 17:22:54
Message: <40e1ddae@news.povray.org>
> I'll put the scene file in p.b.s-f in case anyone want's to have a look.

Woah, you wrote this in SDL? What was the render time like? Was it
acceptable? If so, you should make this into an include file.

 - Slime
 [ http://www.slimeland.com/ ]


Post a reply to this message

From: Mike Andrews
Subject: Re: Perlin's Improved Noise comparison ... (24K)
Date: 30 Jun 2004 05:35:00
Message: <web.40e2890cb1f4587f59735c0c0@news.povray.org>
"Slime" <fak### [at] emailaddress> wrote:
> > I'll put the scene file in p.b.s-f in case anyone want's to have a look.
>
> Woah, you wrote this in SDL? What was the render time like? Was it
> acceptable? If so, you should make this into an include file.
>
>  - Slime
>  [ http://www.slimeland.com/ ]

Yes - SDL. The awkward bit was figuring out how to produce the 3D hashing
function, but then I realised that I could use a spline function for array
lookup; just put the array values at integer points along the spline and
voila!

Render time was 22min on a 1GHz Athlon at 800x600, about 90% of the time
spent on the top half ... so it's not really that useable in real scenes.

Mike.


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.