texture projection onto jit.gl.model

Thanks to an example posted here last week, here's a patch that emulates
texture projection, or more precisely a static projection which is only
projected on objects when they enter a particular part of the screen.

However, the problem I am having is that while torus (jit.gl.gridshape)
updates its texturing information accordingly whenever its position changes
(use fullscreen and drag the object by clicking onto the screen), for the
jit.gl.model, the only way this texturing changes is if the texture is
disabled and reenabled which seems like an awful hack.

Hence, I was wondering if:

1) there is a way to make the jit.gl.gridshape trick work for the
jit.gl.model
2) whether there is a better way of doing the texture projection which would
also avoid texture being wrapped around the object (or projected on both its
sides)? To be more precise here, I am simply looking for a way to project an
invisible video which becomes visible only when an object enters specific
coordinates.

Any help is most appreciated!

Here's the patch in question:

Best wishes,

Ivica Ico Bukvic, D.M.A.
Composition, Music Technology, CCTAD, CHCI
Virginia Tech
Dept. of Music - 0240
Blacksburg, VA 24061
(540) 231-1137
(540) 231-5034 (fax)
ico@vt.edu
http://www.music.vt.edu/people/faculty/bukvic/
http://ico.bukvic.net