"Bald Eagle" <cre### [at] netscapenet> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
>
> > It's not always easy to port shader code to POV-Ray script. It can be done, but
> > things often have to be nested in a funny way.
>
> I've had a lot of success following along with MS and IQ, as well as others.
> Sometimes it takes a few tries to get things to all fit together properly, and
> get the correct syntax for all of the functions.
>
> The real value is to see how all of the pieces of what makes the scene - the
> camera, geometry, lighting, shadows, reflections, etc are all governed by their
> respective formulas, and all get linked together to produce the final image.
> None of it exists - but it all works together to produce an image that is the
> result of the evaluation of a single formula - the same formula - for every
> pixel, based only on the uv coordinates of the pixel.

Yeah, one of the funniest aspects of shaders is how each pixel is the
culmination of every function fed into it. POV-Ray is like this too, but it's
more pronounced in shaders. Functions are probably the closest analog in
POV-Ray.

Unfortunately, shaders are bottlenecked by memory, and also by the fact that
each pixel calculates everything. In POV-Ray, you can do a bunch of calculations
during parsing, and everything after that shares a pool of memory. Not so with
shaders.

(On a related note, I've been wondering how difficult it would be to write a
raymarcher using POV-Ray functions.)

> That, Bill Pokorny's tutelage in using POV-Ray's functions, and Jerome
> Grimbert's excellent and myriad examples of patterns really helped me understand
> the underpinnings and ways to structure shapes and patterns, which helped me
> understand and solve some long standing problems and then proceed to stretch out
> and explore some really cool extensions to those basic principles.  Tor Olav
> Kristensen's mentoring me in using macros to assemble complex functions, using
> Bernstein polynomials, full-color patterns, and many other cool tips and tricks
> over the years have allowed me to explore even more territory in terms of
> constructing custom functions, crafting complex geometry, and better
> understanding how to manually create triangle meshes, work with surface normals,
> and tons of other stuff.   jr is a wizard at coding a diverse range of
> algorithms, and using dictionaries and macros to achieve amazing levels of
> complexity in projects with real utility.
> And of course the innumerable contributions of clipka, TdG, Friedrich
> Lohmueller, and many many others.

Yeah, there has been a lot of important work made by many people. But much of it
is hard to find now, unfortunately.

> I have learned SO much over the years, and overall, it is something that still
> remains fun, and retains the magic and excitement of discovery and exploration
> of new territoy.
> [...]

I feel that way too, but I'm finding it harder and harder to build up the energy
needed as time goes on :/

> > I'm not familiar with Martijn S. but I know about IQ, having been into shaders
> > for a while now. [...]
>
> Martijn runs "The Art of Code"
> https://www.youtube.com/@TheArtofCodeIsCool/videos
>
> Great live coding sessions.

Ah yes, I have heard of the channel.

> IQ is obviously busy with family - I hope he starts posting new material
> sometime soon.  SO much to learn from him.

He has still been posting an occasional surface definition function here and
there.

> And thank you, Sam, for all of your cool little projects that you bring to us
> here, and for turning me on to Shadertoy - it's made a HUGE difference in how I
> approach things, and has allowed some of my projects to be really fun successes,
> whereas without what I learned from Shadertoy, they would have been frustrating
> or impossible.
>
> - BW

Hey, thanks. We all learn from others. Shaders are definitely are great tool for
grasping ideas, since it's all pure math at that point.

Not sure if I mentioned this before, but if you use a mobile device there is an
app called "Shader Editor" on the playstore. Not as good as Shadertoy, but very
useful if you want to make shaders away from a laptop or desktop environment.
It's got a bunch of inputs available such as camera, orientation, textures, etc.
(It can even be useful. For instance, I made a level with it and calibrated it
to my phone, so I can use my phone as an actual level.)

Sam

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