What is the purpose of 'framebuffer' when setting up a GL context?

Question

In this example code it deals with framebuffers before setting up the context.

I've read the man pages of the functions, but I still don't understand exactly what's going on.

So my question is, what exactly is a framebuffer in GLX and how significant is configuring it?

Answer 1

A framebuffer is an area of memory that holds a displayable image. You need one when creating an OpenGL context so that OpenGL has a place to store the image it renders.