What full featured cross platform GUI toolkit options are there for embedding in an OpenGL app?

I'm writing a fullscreen OpenGL app. Within that I'm going to present a big GL render on the background with a bunch of windows in front, some containing more GL stuff and some containing plain GUI stuff. This sucker needs to run on at least Linux and Windows, Mac would also be nice to have.

What I'm looking for here is GUI toolkit options. I'm after a complete mature system with the full array of widgets, layout helpers, widget focus tracking stuff etc.

My naive notion is to embed something like GTK+, pass it the input events 开发者_Go百科for it's parts of the screen and have it render to buffers that I texture onto GL primitives.

Can GTK+ work like this? What other options are there?

I highly recommend that you check out Qt and its OpenGL module. It's able to do all of the things you described.

Best regards