opengl_example/
OpenGL example, using GLFW + fixed pipeline.
This is simple and should work for all OpenGL enabled applications.
Prefer following this example since it is the shortest one!
opengl3_example/
OpenGL exemple, using GLFW/GL3W + programmable pipeline.
This uses more modern calls and custom shaders.
I don't think there is an advantage using this over the simpler example, but it is provided for reference.
directx9_example/
DirectX9 example, Windows only.
directx11_example/
DirectX11 example, Windows only.
This is quite long and tedious, because: DirectX11.