The quickest way is by using jit.gl.asyncread. If realtime performance is of concern you should consider keeping it in the GL realm, though your monitoring window will have to be a jit.window instead of a pwindow.

This could give some inspiration: https://cycling74.com/forums/sharing-triplehead2go-rendering-setup-updated-for-max6-and-jit-gl-node

if performance is an issue and you are on a mac, you could make a seperate player standalone application and a seperate interface standalone application. (they could communicate via osc) send the player ouput texture with the external "jit.gl.syphonclient.mxo". receive the texture with the external jit.gl.syphonserver.mxo at your interface application.

this method has a bit overhead, but was the most efficient way i figured out. also it is not trivial to build a standalone with the syphon externals. perhaps this will be more comfortable in future versions.

tt

Thanks for the responses guys! I have both methods up and running, will see if the payoff for performance is worth it with the standalone.