i'm developing an editor programming. it uses opengl for the rendering, with multiple contexts for multiple windows. i don't need to render at 60fps, in fact i really only want to render when necessary. right now i just render on mouse movement, so i can easily run my mouse over it and see what it is, but what would be the best way to render only when the display needs updating?

you could render to a texture and, until the view needs to change, just rerender the image each frame instead.

This is about the lowest overhead you'll get I guess.