Nathan Kopp wrote:
> 
> "Tony[B]" <ben### [at] panamac-comnet> wrote...
> >
> > First, off, thank you for trying to improve something even though everyone
> > else thinks it's working fine already. This kind of experimentation brings
> > new and better things.
> 
> Actually, not everyone thinks it's working.  Check out these posts in
> povray.bugreports:
> "Bug in noise function" dated 8/28/99 by Margus Ramst (this may have been
> fixed already)
	This is the problem I'm addressing... The point is that in most cases,
if this problem manifests itself, you're probably not using noise
correctly. Most of the times it occurs when people translate a noise
pattern to get several different "noises". But noise is actually a
periodic function (it has a period of 4096 in the current
implementations) so you don't need to translate it as much. The problem
should only manifest itself if you zoom out a lot (but then the noise
pattern is not visible anymore). However this is only true for
"straight" noise (as in the bozo pattern) and thing might be different
in other patterns or in turbulence...

> "Bozo "saturation" problem" dated 5/20/99 by Ron Parker (this is "fixed" in
> MegaPov)
> "Spotted normal bug (Jerome M. Berger)" dated 11/22/99 by Peter Popov
> 
	The grid that appears is unfortunately an unavoidable side effect of
the way noise is computed. I don't think this one can be fixed except by
completely replacing the algorithm and I have no idea what could be used
instead :-(

> > The synxtax I see is this: noise {method 0/1/2 fixed_range/range on/off}
> 
> Because this sort of thing affects bozo, spotted, wrinkles, turbulence, and
> a variety of other aspects of POV, the exact way it should be implemented
> may not be this simple.
> 
	True enough. Unfortunately, I have neither the time, nor the overall
knowledge of pov necessary to do it "the right way". Moreover the speed
versus memory parameter should indeed be global anyway. So I think I'll
do it that way (and Tony's keywords look good to me) and let others with
more time/knowledge adapt it if they really think it's necessary (after
all, the problem doesn't occur that often, and people make do very well
with the present limitations)


-- 

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