The scripting code doesn't work in a 64-bit build, which seriously hampers my ability to test this stuff out, but I managed to track down the problem in this case using Windows builds running with Wine.
I confirmed that the RTT code works perfectly, so that wasn't the cause of the problem. It turns out to be a culling issue. The calls to drawRectangle() in the script end up turning on culling (not a scripting related problem, just the result of bad drawing code) and the RTT texture simply gets culled away. It still draws fine as far as the game is concerned, but the hardware will cull it out. I made some changes to gr_set_cull() so that we can restore the original cull state rather than just forcing it on/off blindly. I'll have to do some testing to make sure this change doesn't break anything else, but I think this should solve the remaining RTT issues (along with the other code in the Xt builds).
I'll make a new test build tomorrow so that you can confirm it all works for you Nuke, and then we can consider this fixed.
