William F Pokorny <ano### [at] anonymousorg> wrote:

> One thing long on my todo list is to dive into core isosurface code. Not
> sure how it today handles the normals, though I can imagine ways to do it.

Indeed.  I may look into the gradient functions and see what lies therein.
I scored some code from a ShaderToy script and watched some painfully presented
CalcIII lectures.   Confident I'll get it soon enough.


> Yes, think you are right on this. I'd not been burned by the default
> color maps on the block patterns. I happened to see the brick colors at
> ag2.2 while removing maps from continuous patterns.
>
> I have it in my head unless accessing the color channels with .red or
> whatever we do today get the pattern's value back

It would be lovely to get some code to handle vector functions.
Curious if your reading of the present scalar function source code gives you an
idea about how much extra work that would be to implement.

Also of interest would be some extra dot notations to rearrange vectors.
So if Vector = <x, y, z>, then Vector.yzx would give <y, z, x>.

> Reminds me, our .grey and general color to grey conversion also has
> issues with being - off standard, I guess. A question on my - think more
> deeply about it someday - list, is whether on the fly color to grey
> conversion should get pulled from povr. I have this feeling it isn't
> 'really' necessary today.

I suppose - though I see no harm either.
Now, having brought that up, it reminds me that all 3 channels get combined into
a single scalar output.
If that could be done in a deterministic manner such that the channels could be
extracted back out (albeit with lower, but usable precision) then it would be a
nice way to cheat / work-around vector function output.
"Pairing functions" could be used, and maybe there are other better ways...
https://stackoverflow.com/questions/919612/mapping-two-integers-to-one-in-a-unique-and-deterministic-way


> I don't have much for free bandwidth beyond what I'm trying to do
> currently, but, is your email as used in your posts to the news groups
> one I can use?

Yes.  :)

I only mention it because sometime it helps to have things brought up at the
outset, rather than the ole' "Oh!  I wish I had known about that before ..."


> Your posts, John Greenwood's on the -1 to 1 blobbing, and many others
> over the years, all influencing to some degree whatever hacking I'm
> doing, not doing or might do in povr.

Well, I'm glad that you get something out of it.   I think we all get to the
point where our experiments serve to inspire each other to experiment, push the
envelope, and try things we might not ever have thought of doing.

I of course have learned much from your experience and informative posts, as
well as so many others.

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