[PD] GEM- simple img texturing into a circle

[Jaime Oliver]

Hi Ben

>
> Why not:
>
> a. texture a large plane with a circular alpha channel hole
>
> b. model a large plane with a circular hole.


I'll give that a try, I think i'll need some more flexibility since i need
to have other polygons in the same patch... but maybe i can solve it in a
different way...

>
> Both would be a mask that show through what is rendered behind them,
> should be very fast, but not as flexible, as your ideas.


Being fast is definitely going to be a requirement.
Now, in this context, is flexibility a synonym for madness? or more
precisely, is this approach too slow?

best,

J

>
> .b.
>
> Jaime Oliver wrote:
> > Hello all, I am trying to do something which should be fairly easy: I am
> > trying to see a circle that let's through an image that is behind it.
> > (As if through a telescope...) So my attempt so far consists of
> > texturing this image into a circle and compensate changes in translation
> > and size of the circle with the pix_coordinate object. I have managed to
> > do this with rectangles and triangles, but can't a find a way around
> > circles. The main idea is the next:
> >
> > pix_image
> > |
> > pix_texture   coordinate-mess
> > |                   /
> > pix_coordinate
> > |
> > rotateXYZ
> > |
> > translateXYZ
> > |
> > circle
> >
> > The coordinate message has this behaviour:
> > -the 1st two floats don't have any effect.
> > -the 3rd one compresses/expands left-right,
> > -the 4th one compresses/expands up-down,
> > -the 5th doesn't do anything,
> > -the 6th one seems to offest the vertical compression/expanssion
> > -any succesive floats have no effect.
> >
> > So my problem is that without any horixontal offest i can't compensate
> > for size/transaltion values. If i had that i think i could do some math
> > to do this....
> >
> > Anyone has any suggestions? Is this the wrong approach??
> >
> > I am attaching the patch if anyone want's to test this and I am also
> > attaching an example of how i am compensating this for a polygon 3
> >
> > best,
> >
> > J
> >
> >
> > --
> > Jaime E Oliver LR
> >
> > joliverl at ucsd.edu <mailto:joliverl at ucsd.edu>
> > www.realidadvisual.org/jaimeoliver
> > <http://www.realidadvisual.org/jaimeoliver>
> > www-crca.ucsd.edu/ <http://www-crca.ucsd.edu/>
> > www.realidadvisual.org <http://www.realidadvisual.org>
> >
> > 9168 Regents Rd. Apt. G
> > La Jolla, CA 92037
> > USA
> >
> >
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> >
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-- 
Jaime E Oliver LR

joliverl at ucsd.edu
www.realidadvisual.org/jaimeoliver
www-crca.ucsd.edu/
www.realidadvisual.org

9168 Regents Rd. Apt. G
La Jolla, CA 92037
USA
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