@Bobsolo1 Please see the documentation for an answer:
http://esotericsoftware.com/spine-cpp#Introduction
"spine-cpp is a generic runtime for integrating Spine animations in game engines and frameworks written in languages that can natively interface with C++."
This Introduction section contains other useful information as well.
If you want to write your own 2D renderer and want to use OpenGL as a rendering backend, you should be able to have a look at any of the existing runtimes using spine-cpp as the generic runtime, like spine-sfml, as an example on how to do what is needed to load, animate and get a mesh to display from a skeleton. If you are not familiar with how to fill and render meshes in OpenGL, you would need to learn that first.
