map exploring

How do you add a new section to a backround image without redrawing the whole image on top of it? I’m looking for the most efficent way to do this. My collage advisior just stuck me with this problem and I have only been working with openGL for about a week. PLEASE HELP!! I’m working using C or C++.

Some more context would be nice - what exactly are you doing?

There are very, very few universal “right answers” in graphics, and I can guarantee this isn’t one of them.