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22 Jan 2022 18:31:45 EST (-0500)
  A rocky surface (Message 3 to 12 of 12)  
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From: Samuel B 
Subject: Re: A rocky surface
Date: 10 Nov 2021 17:25:00
Message: <web.618c469db5460525cb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 06/11/2021 om 01:58 schreef Samuel B.:
> > Hi,
> >
> > Here's something I was working on a while back. Zoom to 100% to see all the
> > details.
> >
> Impressive indeed. It /looks/ like a seamless image, is that so? Would
> it be possible to introduce some random size variation in terms of
> bigger chunks of rocks contrasted to smaller ones? The present
> impression is of a rather uniform size, overall, which is telltale for a
> non-natural origin. However, well-done indeed.

Thanks, Thomas.

Good eye. The input height map is indeed seamless, but the entire result is not,
since a 1/3 scaled-down copy was layered over the original.

Yeah, the feature sizes are very regular, unfortunately. This is a problem
caused by the CA I used, but also my choice to scale down the layered copy
instead of scaling up. The CA itself can probably be adjusted to produce larger
features, to a point. But the only real way to make something like this work
would be to make a full-on 3d simulation, not 2.5d like this. But I haven't yet
found a good library to evaluate 3d textures, and the only other way I know
(doing it with traditional arrays [on the CPU instead of GPU]) is just too slow.
I could technically do it, but watching the result in real time would not be
possible since I would also have to perform raymarching using the CPU, thus
bogging everything down.

Sam


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From: Norbert Kern
Subject: Re: A rocky surface
Date: 12 Nov 2021 15:55:00
Message: <web.618ed39eb5460525eb56e5a5b7ae6630@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:
> Hi,
>
> Here's something I was working on a while back. Zoom to 100% to see all the
> details.
>
> The height field's map was generated using a cellular automaton in GLSL. For a
> real-time demonstration, see this: https://www.shadertoy.com/view/ftSSDy (Your
> system will need to be able to support pixel shaders.)
>
> In order to be able to save a proper height map, the shader code was ported to a
> Windows GLSL app that supports higher bit output and arbitrary resolutions.
>
> To get deep shadows, a proximity pattern was generated by subtracting a blurred
> copy of the height map from the original using a function. The scene was
> rendered with basic radiosity and low aa settings.
>
> The whole idea behind this was to make height maps that are suitable for
> bedrock, and possibly crystalline surfaces.
>
> Sam


Impressive as usual Sam,

First I thought you used a povray pigment for an isosurface,
so I decided to replicate it with crackle solid form z
offset 5 metric 100000 (averaged, scaled and turbulated of
course), but I didn't get it up to now...


Stay healthy,
Norbert


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From: Paolo Gibellini
Subject: Re: A rocky surface
Date: 12 Nov 2021 17:46:34
Message: <618eeeca$1@news.povray.org>
Il 06/11/2021 01:58, Samuel B. ha scritto:
 > Hi,
 >
 > Here's something I was working on a while back. Zoom to 100% to see
 > all the details.
 >
 > The height field's map was generated using a cellular automaton in
 > GLSL. For a real-time demonstration, see this:
 > https://www.shadertoy.com/view/ftSSDy (Your system will need to be
 > able to support pixel shaders.)
 >
 > In order to be able to save a proper height map, the shader code was
 > ported to a Windows GLSL app that supports higher bit output and
 > arbitrary resolutions.
 >
 > To get deep shadows, a proximity pattern was generated by subtracting
 > a blurred copy of the height map from the original using a function.
 > The scene was rendered with basic radiosity and low aa settings.
 >
 > The whole idea behind this was to make height maps that are suitable
 > for bedrock, and possibly crystalline surfaces.
 >
 > Sam
 >

Really beauty, as always, Sam!

Paolo


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From: Samuel B 
Subject: Re: A rocky surface
Date: 12 Nov 2021 18:25:00
Message: <web.618ef717b5460525cb705ca46e741498@news.povray.org>
"Norbert Kern" <nor### [at] t-onlinede> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> > Hi,
> >
> > Here's something I was working on a while back. Zoom to 100% to see all the
> > details. (...)
>
> Impressive as usual Sam,
>
> First I thought you used a povray pigment for an isosurface,
> so I decided to replicate it with crackle solid form z
> offset 5 metric 100000 (averaged, scaled and turbulated of
> course), but I didn't get it up to now...

Hi Norbert,

I can't remember what offset does, and I have no idea what a metric value of
100k would look like. What was the result like?

I've always liked your images, btw. Natural subjects have always been the
hardest to create.

Sam


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From: Samuel B 
Subject: Re: A rocky surface
Date: 12 Nov 2021 18:25:00
Message: <web.618ef779b5460525cb705ca46e741498@news.povray.org>
Paolo Gibellini <p.g### [at] gmailcom> wrote:
> Il 06/11/2021 01:58, Samuel B. ha scritto:
>  > Hi,
>  >
>  > Here's something I was working on a while back. Zoom to 100% to see
>  > all the details. (...)
>
> Really beauty, as always, Sam!

Thanks, Paolo! I thought I'd post the result, even if it doesn't make its way
into a scene someday.

Sam


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From: nemesis
Subject: Re: A rocky surface
Date: 19 Nov 2021 13:55:00
Message: <web.6197f274b54605256eb44466112415a2@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:
> Hi,
>
> Here's something I was working on a while back. Zoom to 100% to see all the
> details.
>
> The height field's map was generated using a cellular automaton in GLSL. For a
> real-time demonstration, see this: https://www.shadertoy.com/view/ftSSDy (Your
> system will need to be able to support pixel shaders.)
>
> In order to be able to save a proper height map, the shader code was ported to a
> Windows GLSL app that supports higher bit output and arbitrary resolutions.
>
> To get deep shadows, a proximity pattern was generated by subtracting a blurred
> copy of the height map from the original using a function. The scene was
> rendered with basic radiosity and low aa settings.
>
> The whole idea behind this was to make height maps that are suitable for
> bedrock, and possibly crystalline surfaces.
>
> Sam

oh, you already deal with GLSL...


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From: Bald Eagle
Subject: Re: A rocky surface
Date: 20 Nov 2021 10:45:00
Message: <web.61991743b54605251f9dae3025979125@news.povray.org>
"nemesis" <nam### [at] gmailcom> wrote:
> I think you povray folks would like something like this:
>
> https://twitter.com/zozuar/status/1461524656532471811

That is some CRAZY stuff right there...  :O
Converting that to an isosurface is likely entirely possible, and would give me
a huge headache.

Also, what you're basically saying is that Detroit, MI is a fractal computer
simulation...

> oh, you already deal with GLSL...

Yes - Sam is responsible in large part for turning me on to the magic of
ShaderToy.  Super fun and educational.  :)


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From: nemesis
Subject: Re: A rocky surface
Date: 21 Nov 2021 23:15:00
Message: <web.619b1823b5460525279eb8f7112415a2@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "nemesis" <nam### [at] gmailcom> wrote:
> > I think you povray folks would like something like this:
> >
> > https://twitter.com/zozuar/status/1461524656532471811
>
> That is some CRAZY stuff right there...  :O
> Converting that to an isosurface is likely entirely possible, and would give me
> a huge headache.
>
> Also, what you're basically saying is that Detroit, MI is a fractal computer
> simulation...
>
> > oh, you already deal with GLSL...
>
> Yes - Sam is responsible in large part for turning me on to the magic of
> ShaderToy.  Super fun and educational.  :)

we're living in the future, guys. Modeling scenes entirely in VR is pretty
mind-blowing too.


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From: Samuel B 
Subject: Re: A rocky surface
Date: 23 Nov 2021 20:20:00
Message: <web.619d9282b5460525cb705ca46e741498@news.povray.org>
"nemesis" <nam### [at] gmailcom> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> (...)
> > The height field's map was generated using a cellular automaton in GLSL.
> (...)
>
> oh, you already deal with GLSL...

Yeah, I started getting into it back when Winamp and Milkdrop had already gained
a bit of steam. It was kind of mind blowing to discover full-screen cellular
automata was possible.

Sam


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From: Samuel B 
Subject: Re: A rocky surface
Date: 23 Nov 2021 20:35:00
Message: <web.619d961fb5460525cb705ca46e741498@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "nemesis" <nam### [at] gmailcom> wrote:
> > I think you povray folks would like something like this:
> >
> > https://twitter.com/zozuar/status/1461524656532471811
>
> That is some CRAZY stuff right there...  :O
> Converting that to an isosurface is likely entirely possible, and would give me
> a huge headache.

Technically, what you're seeing in that video /is/ an isosurface, so the same
thing can made in POV-Ray as well.

I did manage to make a kaleidoscopic iterated function systems (KIFS) in POV-Ray
a while back, but never managed to get the symmetries for the Menger sponge
working correctly (it was doubled along one axis, iirc). I think my Menger
sponge failed due to how I was repeating the signed distance function (sdf)... I
was probably comibing functions and patters, and using warp{repeat x flip x} or
something, instead of using pure functions and only using abs() for mirroring.

> > oh, you already deal with GLSL...
>
> Yes - Sam is responsible in large part for turning me on to the magic of
> ShaderToy.  Super fun and educational.  :)

Oh, that's great :) Shaders are wonderful things... you aren't bound by the
usual constraints. You create images using of pure math, even to the point of
making your own 3d renderers from scratch. You can make ray marchers
(isosurfaces from SDFs), raytracers, voxel tracers... But shaders are also
limited in ways other environments aren't. For instance, in POV-Ray you can
write a loop to display millions of objects and have it render in less than a
minute. Doing the exactly same thing in shaders is likely to crash the context
(or maybe even the operating system) you are running it in. Different tools for
different things :D

Sam


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