POV-Ray : Newsgroups : povray.binaries.images : Crackle : Re: Crackle Server Time
30 Jan 2023 10:08:22 EST (-0500)
  Re: Crackle  
From: Chris R
Date: 16 Nov 2022 15:10:00
Message: <web.637542cb302862a47aaec48e5cc1b6e@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > Next stage would be to code it using only functions, and then it could be used
> > as a pigment pattern.
> Indeed.   If I knew how this all worked and could code it right.  <eyeroll>
> Also, these things are SLOW.
> I thought the function version would be faster, but this small render took 23.75
> min.
> My initial frustration with trying to make one of these things was the nested
> loops, but I figured I could "unroll" that and just daisy chain the functions.
> Which I did, and it works - sorta.
> But it's 102 functions, and for some reason it looks like I got the color code
> wrong too.
> It also look like there are different methods for generating the Voronoi
> pattern, and this one is (obviously) grid based, like POV-Ray's.   I'll have to
> try my hand at one with a much more arbitrary data set.
> Also: Chris R - are you aware that you can get a Voronoi pattern just using
> overlapping cones?  Depending on what you're planning to do with it, that would
> be both super easy and FAST.  And from what I understand, it's actually a
> legitimate Voronoi result.
> https://smathermather.com/2012/01/20/fast-calculation-of-voronoi-polygons-in-povray/

Thanks for the pointers.  I'll check them out.

Most of my work is done with isosurfaces, especially for close-up views of
objects.  I end up coding the basic shape of the object I want as a function and
then apply perturbations using noise generators and pigment patterns to get the
"texture" I want on the surface of the object.  I then apply an SDL texture to
get the color and finish look to the object.

For the tiled floors, and some of my brick wall work, I have to find ways to
make the pigment pattern I use to generate the surface texture to match up with
the pigment pattern I use to generate the colors and finishes.  So, the crackle
pigment pattern works well that way, now that you have shown me how to get a
consistent texture to apply to the cells.  If I need more variability between
cells I'll just have to play with the texture maps and randomize them more.

-- Chris R.

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