POV-Ray : Newsgroups : povray.pov4.discussion.general : Ideas. Updated f_wood(). povr branch. : Re: Ideas. Updated f_wood(). povr branch. Server Time
24 Oct 2021 02:54:40 EDT (-0400)
  Re: Ideas. Updated f_wood(). povr branch.  
From: William F Pokorny
Date: 19 Sep 2021 06:29:58
Message: <61471126$1@news.povray.org>
On 9/19/21 4:22 AM, jr wrote:
> thinking aloud about the simulation, and not having used 'f_wood()' yet, as user
> I think I'd like one simple (wrapper) function/macro where, ideally, I'd only
> provide an "age" (ie #rings) and some average "annual" growth value to obtain a
> pattern, and maybe a rand seed.  (I guess all eight parameters will be needed
> when "tuning" some aspect(s) of the render)

FYI - I've not published a povr version with f_wood().

Yes, a simpler interface would likely be the more common use case in 
practice. With many of new inbuilt functions, I'm trying out and tuning 
ideas. I want knobs and switches and expect further change

In fact With f_wood been thinking about additional return value pairs... 
Internally, we are always tracking a previous positional sum for ring 
count and the the next sum - so we can do a linear interpolation at the 
value between the two value 'positions.'

My thinking is we can probably create some interesting isosurface 
ladder/net/web like structures by using the leg positions of the ladder 
as seeds and, local to the value, four corner positions. Maybe connect 
up TOK's point to point linear sweeps on the fly.

> 
> unrelated, but I've only found out about two_exciting_  Tcl extensions; thinking
> that when 'povr'/POV-Ray compiles, the "library" of backend stuff which is
> linked late in the process, I'm fairly certain, could be (mis-)used;-)  with
> either of these:
> <https://wiki.tcl-lang.org/page/Ffidl>
> <https://cffi.magicsplat.com/>

Thanks for the pointers. The first rings no bells, but I see from my 
notes I've stumbled across the second site at some point.

I played some - looks like now, way back in 2019 :-| - with:

https://github.com/flightaware/cpptcl

which is based on a much earlier tcl function wrapper package that's 
15-20 years older IIRC. There is too, of course, swig.

With tcl wrappers of C++, I always seem to get as far as a few examples, 
but never much more before I drop the effort for other - less painful - 
play. Someday...

On the practical side, I find I often drop back to to extracting enough 
of the POV-Ray header structure to compile tiny c++ programs when first 
trying bits of code. The compile / link loop is then really quick even 
if I happen to be playing also with the headers. I've got an older two 
core i3. Even with 'make -j4', changed header compiles take a while.

Bill P.


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