Has anyone else noticed that the bozo pigment tends to "saturate" at 
the low and high ends of the scale?  It seems as though the pattern
values regularly go outside the [0..1] boundaries, but the color_map
ends up clipping them, leaving large unsightly areas of solid color
in any bozo-based pigment.  Is there any solution for this that 
wouldn't kill backward-compatibility?  Perhaps an extension of the
various maps beyond the [0..1] range?  Maybe new keywords to perform
a linear transform on the output of the pattern function before the
color map is applied?  This issue also tends to affect the new options
to the crackle pattern that I added in the superpatch, so a general-
purpose solution for all pigments would be best.

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Ron Parker <par### [at] fwicom> wrote:
: Has anyone else noticed that the bozo pigment tends to "saturate" at 
: the low and high ends of the scale?

  Yes. I have noticed this when I make heightfield images with the bozo
patterns. There are annoying planes at the top and the bottom of the
heightfield.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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On 21 May 1999 08:54:07 -0500, Nieminen Mika wrote:
>Ron Parker <par### [at] fwicom> wrote:
>: Has anyone else noticed that the bozo pigment tends to "saturate" at 
>: the low and high ends of the scale?
>
>  Yes. I have noticed this when I make heightfield images with the bozo
>patterns. There are annoying planes at the top and the bottom of the
>heightfield.

Funny you should mention that, as that's what first brought it to my
attention.  I was using bozo as an isosurface with the new "pigment"
function in the 3.1e superpatch.  I can code up an unofficial fix for
it, of course, and I probably will.

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Wow, great, a fix can be done huh? I too noticed this happens in the
creation of a height_field, but it wasn't the 'bozo' pattern, it was
'spotted'. It isn't as noticeable when used only as a pigment, but I had
wondered about this "mesa" effect before.


Ron Parker wrote:
> 
> On 21 May 1999 08:54:07 -0500, Nieminen Mika wrote:
> >Ron Parker <par### [at] fwicom> wrote:
> >: Has anyone else noticed that the bozo pigment tends to "saturate" at
> >: the low and high ends of the scale?
> >
> >  Yes. I have noticed this when I make heightfield images with the bozo
> >patterns. There are annoying planes at the top and the bottom of the
> >heightfield.
> 
> Funny you should mention that, as that's what first brought it to my
> attention.  I was using bozo as an isosurface with the new "pigment"
> function in the 3.1e superpatch.  I can code up an unofficial fix for
> it, of course, and I probably will.

-- 
 omniVERSE: beyond the universe
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 mailto://inversez@aol.com?Subject=PoV-News

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I was looking at a Perlin Noise function which used a type of cubic
interpolation as well as cosine interpolation to produce noise. The
cubic interpolation went above the highest points(look at the site to
see what I mean), but the cosine interpolation didn't. If POV-Ray uses
cubic interpolation in this way and clips it to the range from 0 to 1,
this would explain the "mesas".
The web site was:
http://freespace.virgin.net/hugo.elias/m_perlin.htm

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