What is layering??

Hello, I have lot of confusions about layering… First of all what is layering?? what it will do?? now i am using open gl(safety critical) it support only 97 APIs… how can i do layering with this??

Layering means different things in different contexts. Here’s one:

It might be more useful if you explain what you’re trying to do, so folks could help you map that to what techniques might be useful.

This appears to be a re-run of this thread.