POV-Ray : Newsgroups : povray.pov4.discussion.general : On triangle and smooth_triangle shapes. : Re: On triangle and smooth_triangle shapes. Server Time
16 Apr 2024 07:42:56 EDT (-0400)
  Re: On triangle and smooth_triangle shapes.  
From: Bald Eagle
Date: 13 Nov 2023 07:15:00
Message: <web.655212913d3331871f9dae3025979125@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:
> On 11/12/23 22:09, Bald Eagle wrote:
> > I'm guessing that you'll likely have to implement some debugging capability to
> > output or make visible the normal vectors.
>
> As always. Thanks for the references! Yes, related.

You're welcome.   And thanks for confirming.

> Yes, your debugging capability for normals. It's been on my todo list
> for a while. I plan to implement it as a special pattern so I can return
> the perturbed normals in addition to the raw normals.
>
> I've already modified the yuqk aoi pattern to work with the full range
> -1 to +1 possible perturbed normals. I should try that now actually on
> the black ones... Ah, it didn't offer clue why things go black in the
> degenerate case - things are still black.
>
> I'll need to do some debugging I guess.

While you're in there digging around in the normal code,  perhaps you can make
some notes about exactly HOW that all works.  Normals seem to me like they'd
need a 2D modification (theta, r) rather than just a single scalar value.
That whole weird tetrahedron thing....

https://news.povray.org/5c45e632%241%40news.povray.org

I also had a link to an external site/article, but can't find it atm.

A useful pattern would be something that would allow a function to return the
normal as a vector (and doesn't require the prior existence of an object surface
to work).

Also reminds me of the problem I still have to solve/work-around here:
https://news.povray.org/povray.unofficial.patches/thread/%3C60a268da%241%40news.povray.org%3E/


Speaking of functions, I just threw up my hands and gave up on converting a
"simple" shader, because trying to convert that into SDL with functions blows up
into over 1000 lines of bloated code.  As you know, there's a long list of
things that make the function parser unusable in such circumstances, so I won't
get into it .... here.   ;)

- BW


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