3d active stereo patch for DLP

Hi

I am struggling to create an active stereo patch working for my DLP projector / shutterglasses.

(I actually wanted to place the compressed patch in here. but it didnt work, nor did attached file work. so here a dropbox file: https://www.dropbox.com/s/9qjmk29ywigrwt7/3d.maxpat.zip)

This patch has two render-contexts, the first for capturing two cameras for the left and the right, and a second context to display the two textures alternately on a videoplane. When running this patch on my windows machine it kind of works, but after some time it gets out of sync.

And I know from the developer of cosm (http://www.allosphere.ucsb.edu/cosm/) that there is a better way of doing it:

1. set stereo to 1 for both jit.gl.render and jit.window

sending this messages to jit.gl.render
2. draw_buffer back_left
3. erase
4. set the left camera (in this patch applying the left texture to the videoplane)
5. drawswap
6. draw_buffer back_right
7. erase
8. set the right camera (in this patch applying the right texture to the videoplane)
9. bang

but I get errormessages:

first one for setting stereo 1:

jit.gl.render: "viewer" is something other than a jit.matrix, jit.window, jit.pwindow or jit.gl.texture. (Which is already a reported and confirmed issue)

and then for each subsequent bang:

ob3d_draw_preamble camera: GL Error: Invalid operation
ob3d_draw_preamble initial: GL Error: Invalid operation

I am a bit at a loss here now. there is no documentation and no examples to my knowledge. maybe someone has an idea how to apporach the problem?