Hey there gang. I've been doing some local mods of Flightgear for a university research group, and am now about to take a fairly hefty step in the project, so I was hoping to get some advice and find some direction.

I'm using Flightgear as a means of showing what a UAV is doing, is it is a much more natural display mode than simply seeing some telemetry numbers, and a map-view flight plan. Thus far, I've painted over the flightgear graphics with a video stream taken from the plane, and a HUD which displays needed information. It also highlights potential collision threats. All this has been simple enough, as it's all simply painting over the screen with 2D graphics.

The next step is more involved. I'd like to add things to the simulated world, things that aren't actually there, such as the waypoints that the plane is flying towards, flightpaths that should be taken for a landing, or any other usefull things that come up. For these items to be useful, they'd have to be classified as something different than the terrain scenery, so when the video is painted on the screen, these artificial objects could then be rendered over the video.

So really, I'm just looking for any hint as to where I should even start with this design. Something like a landing path should be tied permanantly into a given runway, but something like waypoints should be able to be handed in dynamically on the fly through some sort of bridge program. Most of my familiarity with the internal working of flightgear is specifically in the renderer code. What else should I be boning up on? Presumably somethings in the way it handles navigation, as I could simply tie all extra objects to perticular positions, and have OpenGL draw them as/when needed. Thanks for any help to this far too open ended question!
-cullam