Any clues how to include third-party C++ library to Godot?

Question

I'd like to use a 3rd party library written in C++ and include it in my gdscript in order to control the logic of the game. I've heard about gdnative. How can I use those C++ library files and interface them with the gdscript code without having to modify those file (too many of them) ? What I need is use these library as an API from gdscript.

Something like in the figure.
PS: I read the tutorial here but it talks only about one file with godot headers. But couldn't understand how I can talk with that 3rd party code.

Comments

there are two ways to do it. GDNative or C++ modules

GDNative only exposes a subset of what you can do with c++ modules

you kinda have to be more specific and what classes you wish to touch

http://docs.godotengine.org/en/latest/development/cpp/custom_modules_in_cpp.html

Answer 1

The tutorial in the news is obsolete now. Up to date documentation is pending to be written anytime soon, but in the meantime this example exists: https://github.com/GodotNativeTools/GDNative-demos/tree/master/c/SimpleDemo (that one is in pure C though).

There is also this C++ demo: https://github.com/GodotNativeTools/GDNative-demos/tree/master/cpp/kinematic_character