As my raytracer is getting more and more complex with lots of dynamic options and movement controls trying to remember keypresses from a command window to turn things off and on is getting increasingly difficult.
The time has come to build a proper interface for the rendering window. Now as I dont want to spend too much time developing this from scratch I thought I'd have another look at Qt (pronounced cute). Its been quite a while and a good few versions since I last used it, and am pleasently surprised at the improvements and additions. As it does offer openGL widget / rendering it is the perfect library to use for my raytracer. Using openGL and Qt still gives me the option of going cross-platform on the raytracer and as the memory handling / page locked mem is faster on linux this could give a few more fps :)
In short, if you are looking at a C++ friendly interface designer you could do a lot worse than using the new Qt. (http://www.qtsoftware.com/)