Voronoi ISL Shader

General questions about Indigo, the scene format, rendering etc...
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Meelis
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Re: Voronoi ISL Shader

Post by Meelis » Tue Mar 29, 2011 10:13 pm

I think i was wrong about the tiling, probably the tile got soo small i can't see it from noise.
Need to move camera closer.

1'st uv layout:
Image

10x 10y times larger uv than 1'st
Image
galinette wrote:There is a UV mapping issue : the UV mapping from both sides are not the same, generating two superimposed stained glass cell patterns
The random color is not working for photo collage. Did the not matching 2 sides got fixed, will it work if i duplicate 1 plane and change normals outside and move over the glass medium. Then i make glass parts to diffuse transmitter to speed up if it helps.

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galinette
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Re: Voronoi ISL Shader

Post by galinette » Wed Mar 30, 2011 12:18 am

So it seems to work as expected, for infinite non repeating mapping! That's the beauty of procedural materials.

In the above picture, it seems you have two different UV sizes for the two faces?

The photo collage is not made with the database material. It was a custom one.
The mismatching UV was only a problem of modelling and not a problem of material definition. It's only because I messed up the UV in sketchup (which I don't like for UV mapping). Should not happen with the DB material.

I'll try posting a picture collage material when I have some time (which is very rare for a few months... :( ). First I need to finish the stone wall requested by whaat!


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Meelis
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Re: Voronoi ISL Shader

Post by Meelis » Wed Mar 30, 2011 12:43 am

:) Okay

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CTZn
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Re: Voronoi ISL Shader

Post by CTZn » Wed Mar 30, 2011 1:13 am

Hi Etienne,
galinette wrote: I wanted to use real volume absorbance for tinting the glass, but as far as I know, it's not possible yet to use shaders for the volumic absorbance.
Ono demonstrated otherwise !
http://www.indigorenderer.com/forum/vie ... 069#p96069
http://www.indigorenderer.com/forum/vie ... 601#p89601
galinette wrote:It would also be tricky, as I suppose that absorbance shader will use "pos" and no UV coordinates, whereas bump uses only UV and no "pos".
Good point. I guess that you could use a closest UV from pos function, is this correct ?

Given a position within a volumetric shader, it would returne the UV coordinates of the closest point on the surface containing the medium. However, as I am understanding it, this may require to return an array or stuff when multiple UV sets are present, but that's just me telling ;)

edit: ah, scratch the limitation I'm talking about; the queried index could be one of the two arguments provided, the function would then return a single vec2.
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Meelis
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Re: Voronoi ISL Shader

Post by Meelis » Wed Mar 30, 2011 1:49 am

Stained Glass volumic absorbance with dispersion sounds nice :roll:
Maybe some displacement for wavy old running glass too.

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Re: Voronoi ISL Shader

Post by galinette » Wed Mar 30, 2011 8:05 pm

CTZn wrote:Good point. I guess that you could use a closest UV from pos function, is this correct ?
Yes, this would be interesting. Would this not be very expensive to compute? Because if the absorbance varies spacially, you have to recompute it with small steps (finite elements integration) when crossing the medium (argh)

There would be two other interesting features related to this:
- Use of pos in bump shaders! Missing this is a shame. I can understand this is messy in displacement shaders (but there are workarounds to enable it), I can't understand for bump!!
- Possibility to use the Indigo UV generation not only for vertices but also for the volumetric shader pos>UV conversion
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CTZn
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Re: Voronoi ISL Shader

Post by CTZn » Thu Mar 31, 2011 2:03 am

galinette wrote:
CTZn wrote:Good point. I guess that you could use a closest UV from pos function, is this correct ?
Yes, this would be interesting. Would this not be very expensive to compute?
You tell me. I guess it would, as you are explaining.
galinette wrote:There would be two other interesting features related to this:
- Use of pos in bump shaders! Missing this is a shame. I can understand this is messy in displacement shaders (but there are workarounds to enable it), I can't understand for bump!!
- Possibility to use the Indigo UV generation not only for vertices but also for the volumetric shader pos>UV conversion
To start with I'll point Ono to this post of yours, should the busy man miss it. Eventually I can push the requests to an higher level, but as far as I am concerned you would have to elaborate a bit more on those.

One thing I can not do is to change Ono's priorities ;)
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galinette
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Re: Voronoi ISL Shader

Post by galinette » Tue Apr 12, 2011 9:24 am

Hi whaat,

I started working again at that shader. Here is the last weird result! Still needs some tweaking...
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stones2.png
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Re: Voronoi ISL Shader

Post by StompinTom » Wed Apr 13, 2011 3:57 am

galinette wrote:Hi whaat,

I started working again at that shader. Here is the last weird result! Still needs some tweaking...
Sheesh, I should just hire you to make all my materials for me.

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Whaat
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Re: Voronoi ISL Shader

Post by Whaat » Thu Apr 14, 2011 5:16 pm

Well I think Glare should hire him. :)

We all appreciate your efforts on this material! Thanks!

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Re: Voronoi ISL Shader

Post by OnoSendai » Tue May 31, 2011 4:25 am

Bumping this thread..
If anyone can tell me the specs/interface for a voronoi function I can add it to the std ISL library.

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Re: Voronoi ISL Shader

Post by Zom-B » Tue May 31, 2011 5:16 am

Direct ISL veronoi would make things esier for the User, so thumbsup"

>> http://en.wikipedia.org/wiki/Voronoi_diagram

The External Links on the bottom should provide quite neat extra information not covered by the article.
polygonmanufaktur.de

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CTZn
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Re: Voronoi ISL Shader

Post by CTZn » Tue May 31, 2011 8:29 am

Found this, this special case is also of graphical interest*:

http://www.math.psu.edu/qdu/Res/Pre/dfg99sirv.pdf

* In two dimensions the basic cell for the optimal CVT is a regular hexagon

What if I already had a set of points ready to use :?: with eventual absorbtion data for each 8)

I guess, galinette knows all about that...
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Re: Voronoi ISL Shader

Post by OnoSendai » Tue May 31, 2011 11:36 am

Implemented a basic Voronoi function.
Messing around with it:
The ones with rings are based on pulse()ing the distance from the voronoi cell points. There's also 4 scales of Voronoi regions mixed together :)
Attachments
voronoi_shader_test4.jpg
voronoi_shader_test3.jpg
voronoi_shader_test2.jpg
voronoi_shader_test1.jpg

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Re: Voronoi ISL Shader

Post by fused » Tue May 31, 2011 11:50 am

Cool!

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