OK, I'm starting to ponder UI options. The UI is actually quite complicated (several windows, complex widgets), so I'm weighing up a couple of options; Option 1 is to go with an OpenGL rendering UI toolkit like Crazy Eddy's. This has the downside that I'll have to implement some complex widgets -- none of the libraries I've see have them. Option 2 is to use Qt and put the GL renderings into windows and have the game as a desktop app. I still have to implement some of the more complex widgets but I've got a fairly rich starting point and experience with Qt. Option 3 is that I already HAVE implementations of most of the widgets as raw X11 stuff from a previous project. I could retarget that to draw into RGBA textures fairly easily. However, I'm not sure how people implement those latter sorts of systems; I can think of two approaches; one is to have a separate texture for each window, which are drawn as quads onto the display. The other is to have one massive texture which covers the screen and draw my windows into that (redrawing things when they move). So my question is -- what approaches do other people take to put window-system-like HUDs over the display?

My single concern with using Qt and running the game as a regular windowed application is user acceptance.

Users are used to games that take over the screen and fill the monitor. Although using regular normal window components would make the game a lot easier to write, I'm wondering if it won't (to users) seem like "not a proper game" in some way.

There is actually an advantage -- if I'm putting the OpenGL into windows, I can put more than one view on-screen and hence watch what's going on in more than one place..