We don't know what a chameleons inner life is like, but imagine you're in a dark cave and are feeling both sides of it with your hands. They move independently but you're still able to form a pretty good idea of what the space around you is shaped like.

People think of binocular vision as a series of static images we have to integrate before using them, but it's really more of a stream of information we can use on-the-fly as in the cave example.