my cockpit demo now supports a more dynamic way of handling render targets, meaning you can have as many displays as you want. of course there is a hardware limit of how many render buffers you can have, modern video cards support at least 8, mind you some of these are used by the game. one is used up by your frame buffer (maybe two), and there may be others used as well. i figure your typical cockpit should use no more than 5 (1 instrument panel, 1 hud, 1 video display, and 2 mirrors).
i haven't fully implemented mirrors yet, thats gonna be fun, both to code and setup. they will take your main view info into consideration, so you can move your head around and use them to see behind you at varying angles. i smashed a bug with my gatling turrets (the one where they like to open fire immediately entering a game). though i think i (or one of my cats) introduced a bug in my multitargeting system. still need a way to configure the scripted gauges. still its worthy of me updating my svn repo with the working version.
i have yet another idea about drawing the entire hud to a render target. i need to dip into c again and create pre and post draw hooks for the hud, in the former you set a render target and adjust the fov of your camera so that the corners of the hud polygon intersect the corners of the view frustum (this sets up certain functions that the hud uses to draw things like lead indicators correctly). then in the latter you reset it to screen, the resulting texture should contain transparent hud info. unfortunately i cant get rtt to work in the alpha-supporting build at all. if the alpha build can be made to work i may just use hud polygons for important stuff like targeting features, without any c code.