[PD] GEM- simple img texturing into a circle

[B. Bogart]

Hi Jamie,

Why not:

a. texture a large plane with a circular alpha channel hole

b. model a large plane with a circular hole.

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

.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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