POV-Ray : Newsgroups : povray.binaries.images : Adding black_hole types 2 thru 7 to code branch. Server Time: 27 Jun 2019 04:16:42 GMT
  Adding black_hole types 2 thru 7 to code branch. (Message 1 to 3 of 3)  
From: William F Pokorny
Subject: Adding black_hole types 2 thru 7 to code branch.
Date: 1 Jun 2019 12:17:17
Message: <5cf26ccd$1@news.povray.org>
In addition to type 1 which fixes / clamps the inward black_hole, added 
types 2,3 and 4 which are like type 1 except limiting results to x, y, 
and z coordinate movements, respectively.

New types 5,6 and 7 represent new whirlpool warps around the localized 
spherical coordinates x, y and z axes. The inverse keyword reverses the 
normal direction of rotation. Setting strength 1.0 means a rotation of 
2*pi or a full rotation at the origin - which is a lot. Strengths of 0.5 
perhaps a better starting, half rotation at the local origin.

See branch:

https://github.com/wfpokorny/povray/tree/feature/newBlack_holeTypes

Bill P.


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From: Bald Eagle
Subject: Re: Adding black_hole types 2 thru 7 to code branch.
Date: 1 Jun 2019 14:30:01
Message: <web.5cf28b23748032b44eec112d0@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:

> https://github.com/wfpokorny/povray/tree/feature/newBlack_holeTypes

NICE, Bill.

This hearkens back to
http://news.povray.org/povray.binaries.images/thread/%3C5b492942%40news.povray.org%3E/?mtop=423470

I had made it reasonably far in converting the existing black hole warp source
to SDL and fooling with that, and I think even got some twist in there as well.

I don't know that I ever posted any of those renders.  Probably RL derailed
that.

It's great to read through the source and see how it's all very logically and
methodically laid out.  It would be great to see a few SDL-only scenes that use
"the same coding" to modify a grid of spheres or a square image-map (using
eval_pigment)

Then maybe people would be inspired to play with their own warp patterns and
then they could be adapted to cpp if some really good ones get developed.

(Sometimes it's a bit hard to grasp the context of a small portion of the code,
and some of the cpp stuff still gives me trouble.)


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From: William F Pokorny
Subject: Re: Adding black_hole types 2 thru 7 to code branch.
Date: 2 Jun 2019 10:32:18
Message: <5cf3a5b2$1@news.povray.org>
On 6/1/19 10:26 AM, Bald Eagle wrote:
> William F Pokorny <ano### [at] anonymousorg> wrote:
> 
>> https://github.com/wfpokorny/povray/tree/feature/newBlack_holeTypes
> 
> NICE, Bill.
> 
> This hearkens back to
>
http://news.povray.org/povray.binaries.images/thread/%3C5b492942%40news.povray.org%3E/?mtop=423470
> 
> I had made it reasonably far in converting the existing black hole warp source
> to SDL and fooling with that, and I think even got some twist in there as well.
> 
...

Yes, I vaguely recall folks working on ideas in that thread and it's a 
reason I went after the whirlpool (I see the typo whirpool now in my 
image...) options. I initially was after only the x,y,z only filters.

> 
> It's great to read through the source and see how it's all very logically and
> methodically laid out.  

Often true. Occasionally...(1) ;-)

(1) - Especially my own code/writing read some significant time later!

> It would be great to see a few SDL-only scenes that use
> "the same coding" to modify a grid of spheres or a square image-map (using
> eval_pigment)
> 
> Then maybe people would be inspired to play with their own warp patterns and
> then they could be adapted to cpp if some really good ones get developed.
> 
> (Sometimes it's a bit hard to grasp the context of a small portion of the code,
> and some of the cpp stuff still gives me trouble.)
Same here.

There have been proposals - and there was a patch by someone? - a few 
years back to add warp { function {}... } capability to the warp 
feature. I'd never put the enhancement too near the top of my list as 
you can modify patterns today with functions in that fashion, though, 
less directly. Functions can define patterns directly too.

Thinking about it now though wondering if warp { black_hole function 
{}... } might not be helpful. In addition to built in repeat / random 
placement capabilities, what's useful with the black_hole warp is it 
localizes the manipulations. Strong at the spherical origin fading to 
nothing at the black hole's radius/surface of influence.

Hmm. Perhaps things like "warp { black_hole pattern { } }" or "warp { 
black_hole turbulence { } }" even better... Worth more thinking.

Aside: I wondered as I created the x,y,z filters, if some general 
mechanism filtering all black_hole (or warp{}) results to 
+x,-x,+y,-y,+z,-z might not be the best way to go. But, would need to 
modify a good bit more source code and add SDL syntax to play there.

Bill P.


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