Op 01/06/2021 om 23:40 schreef Bald Eagle:
> "jamesf" <nomail@nomail> wrote:
> 
>> This is a lifting of a "protection" mechanism from the C language (at least
>> that's where I first encountered it).
> 
> .....
> 
> Thanks, James - I have seen that type of thing in the various POV-Ray include
> files, and probably in some source and arduino code.  I thought that's what was
> getting done, but at present it seems that TdG was trying to invoke some kind of
> POV "woo".
> 
>> I'm not aware of any 'magic' that happens in povscript WRT defining a
>> _filename_INC_ variable, but there could be such.
> 
> Yeah - I was stunned that there was some such thing that I had never heard of or
> seen.  On the other hand, it's an interesting concept - maybe a clever macro
> could "search" for all variants of a particular filename...
> 
>> (hope this helps clear up the concept)
> 
> So do I.  The world just keeps getting cloudier, murkier, more opaque, and more
> obscure as time goes on it seems...
> 
> I'm going to sacrifice another lime and offer up a supplication that Thomas gets
> the rest, therapy, - and medication - that he so desperately needs to find
> clarity of mind and inner peace.  We love you, Thomas.   Help is always just a
> forum-post away.   :)
> 
Just got a bootlegged batch of fresh Dried Frog Pills (pale yellow, not 
green) which does seem to do me a lot of good... [kwark!] sorry  ;-)

You know how it works: somebody in some scene uses a "smart" trick, 
which seems to work fine, and you mindlessly copy that into your own 
scenes, and it does seem to work... somehow, and then you tweak that 
"smart" trick to cover another need (close, but different) and lo! it 
just refuses to do what you expected. That is what happened to me. It 
took me an unusual long time to discover that it didn't work because I 
had been so clever as to cover up my tracks in such a way that it always 
"seemed" to work. I was sorely mislead by my tricky mind! One always 
needs a critical mind close by to get you back on the right track. 
Thanks Bill!

-- 
Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:

> You know how it works: somebody in some scene uses a "smart" trick,
> which seems to work fine, and you mindlessly copy that into your own
> scenes, and it does seem to work... somehow, and then you tweak that
> "smart" trick to cover another need (close, but different) and lo! it
> just refuses to do what you expected.

Yes, I have been there on many occasions.  But let's be honest, I've also been
thwarted from time to time by the simplest of stock SDL commands.  :D

> One always
> needs a critical mind close by to get you back on the right track.
> Thanks Bill!
>
> --
> Thomas

Hey - if it somehow "worked", I would have let it slip by for a while too.   I
only noticed it because POV-Ray was squawking about all of that undeclared
identifier stuff.  Damned parser.

Glad you're feeling better.  How many fingers am I holding up?

Post a reply to this message

Op 2-6-2021 om 12:23 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> You know how it works: somebody in some scene uses a "smart" trick,
>> which seems to work fine, and you mindlessly copy that into your own
>> scenes, and it does seem to work... somehow, and then you tweak that
>> "smart" trick to cover another need (close, but different) and lo! it
>> just refuses to do what you expected.
> 
> Yes, I have been there on many occasions.  But let's be honest, I've also been
> thwarted from time to time by the simplest of stock SDL commands.  :D
> 
It is also when you are bending too long over the same bunch of code 
that you get blind to the most obvious things.

>> One always
>> needs a critical mind close by to get you back on the right track.
>> Thanks Bill!
>>
>> --
>> Thomas
> 
> Hey - if it somehow "worked", I would have let it slip by for a while too.   I
> only noticed it because POV-Ray was squawking about all of that undeclared
> identifier stuff.  Damned parser.
> 
> Glad you're feeling better.  How many fingers am I holding up?
> 
hmmm.... fingers...? What do you mean by "fingers"...?

-- 
Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:

> hmmm.... fingers...? What do you mean by "fingers"...?

You are a rather naughty old man.
Clearly I mean the measure of the quantity of tincture of bufo terrestris
americanus in a whiskey glass.  :P


I came across this in my notifications - it's rather old, and sparse, but it has
a list of references that might be of more utility, and act as handles for
searching for newer developments.

https://www.academia.edu/993480/Modeling_Ore_Textures_and_Mineral_Liberation_Using_3D_Voronoi_Diagrams?email_work_card=
view-paper

Post a reply to this message

Op 03/06/2021 om 01:30 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> hmmm.... fingers...? What do you mean by "fingers"...?
> 
> You are a rather naughty old man.
> Clearly I mean the measure of the quantity of tincture of bufo terrestris
> americanus in a whiskey glass.  :P
> 
Why didn't you say so in the first place? Filled my whiskey glass with 
other stuff I am afraid... :-)

> 
> I came across this in my notifications - it's rather old, and sparse, but it has
> a list of references that might be of more utility, and act as handles for
> searching for newer developments.
> 
>
https://www.academia.edu/993480/Modeling_Ore_Textures_and_Mineral_Liberation_Using_3D_Voronoi_Diagrams?email_work_card=
> view-paper
>
Interesting! The use of voronoi diagrams had crossed my mind as an 
alternative. However, I have not the slightest idea how to do that; a 
bit beyond my capacities I am afraid. Still, good to know it has been 
done. Another fork to the exploration rig. Thanks!

-- 
Thomas

Post a reply to this message

Op 03/06/2021 om 08:39 schreef Thomas de Groot:
> Interesting! The use of voronoi diagrams had crossed my mind as an 
> alternative. However, I have not the slightest idea how to do that; a 
> bit beyond my capacities I am afraid. Still, good to know it has been 
> done. Another fork to the exploration rig. Thanks!
> 
Which reminded me of an old program I played with in the past: 
Tesselsphere. On Sourceforge, there are other utilities too using 
voronoi diagrams.

https://sourceforge.net/directory/os:windows/?q=voronoi

-- 
Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:

> Interesting! The use of voronoi diagrams had crossed my mind as an
> alternative. However, I have not the slightest idea how to do that; a
> bit beyond my capacities I am afraid. Still, good to know it has been
> done. Another fork to the exploration rig. Thanks!

Good heavens, lad!  You're already doing it.
Crackle IS Voronoi - and you're using crackle {solid} which is 3D Voronoi.

Stop being so modest.  :)

Post a reply to this message

Op 3-6-2021 om 12:16 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> Interesting! The use of voronoi diagrams had crossed my mind as an
>> alternative. However, I have not the slightest idea how to do that; a
>> bit beyond my capacities I am afraid. Still, good to know it has been
>> done. Another fork to the exploration rig. Thanks!
> 
> Good heavens, lad!  You're already doing it.
> Crackle IS Voronoi - and you're using crackle {solid} which is 3D Voronoi.
> 
> Stop being so modest.  :)
> 
>
LOL! I completely forgot about that aspect of crackle!


Gentilhomme" where de main character, wanting to get access to the upper 
echelons of society, starts to "educate" himself with the help of 
"teachers" (more interested in money) and so is delighted to learn that 
he has been speaking "prose" all his life without knowing it.

https://en.wikipedia.org/wiki/Le_Bourgeois_gentilhomme

[Admire my latest portrait on the site above. I think it is particularly 
well done and life-like] :-)

-- 
Thomas

Post a reply to this message

Op 03/06/2021 om 13:27 schreef Thomas de Groot:
> Op 3-6-2021 om 12:16 schreef Bald Eagle:
>> Thomas de Groot <tho### [at] degrootorg> wrote:
>>
>>> Interesting! The use of voronoi diagrams had crossed my mind as an
>>> alternative. However, I have not the slightest idea how to do that; a
>>> bit beyond my capacities I am afraid. Still, good to know it has been
>>> done. Another fork to the exploration rig. Thanks!
>>

>> Crackle IS Voronoi - and you're using crackle {solid} which is 3D 
>> Voronoi.
>>

>>
>>
> LOL! I completely forgot about that aspect of crackle!
> 

...but seriously, I would be interested to know how to use voronoi 
diagrams for this particular project, apart from the crackles pattern. 
Something where the individual cells (and distribution of them) would be 
more "controlled" by the user. Beyond the "using voronoi without knowing 
it", that would completely change the whole granite setup I think. At 
this moment, beyond the beta and beyond the final version.

-- 
Thomas

Post a reply to this message

Thomas de Groot <tho### [at] degrootorg> wrote:

> ...but seriously, I would be interested to know how to use voronoi
> diagrams for this particular project, apart from the crackles pattern.
> Something where the individual cells (and distribution of them) would be
> more "controlled" by the user. Beyond the "using voronoi without knowing
> it", that would completely change the whole granite setup I think.

Correct, and there has been some interest in exactly that for quite some time.

I have 2 or 3 implementations of Voronoi algorithms coded in GLSL/Shadertoy that
I've been meaning to start converting to SDL, in the hopes that I could get
something reasonably functional.



I didn't get to spend ANY POV-time yesterday, but I was thinking about exactly
what you're talking about, and it occurred to me that one thing we could
probably do is plug crackle into a function and then operate on the function
coordinates - like I did with the vortex.  That would give spatial control.

Then the whole bricks pattern trick would give further control over the
coloring.

And, of course Jerome Grimbert has already addressed this in hgpovray38
https://wiki.povray.org/content/User:Le_Forgeron#voronoi

I mean, even for now, we could probably just add some gentle black hole warps or
other warps to the basic granite pattern and introduce a little bit of
variation.  I'm bad at implementing warps, but maybe the quartz veins could
benefit from some clever application of them.

> At
> this moment, beyond the beta and beyond the final version.

Yes, just looking at the POV-Ray source code for the crackle and other
voronoi-based pattern shows it to be a little complex, and IIRC, the problem was
really that it's one of those things that you can do fairly straightforwardly
with an algorithm when directly shading pixels, but would be difficult or
impossible to do with straight SDL functions.

https://thebookofshaders.com/12/
https://iquilezles.org/www/articles/voronoilines/voronoilines.htm
https://iquilezles.org/www/articles/smoothvoronoi/smoothvoronoi.htm
https://iquilezles.org/www/articles/voronoise/voronoise.htm

Post a reply to this message