directx9_example/
    DirectX9 example application (Windows).
	
directx11_example/
    DirectX11 example (Windows).
	
opengl_example/
    OpenGL exemple, using fixed pipeline (Windows/OSX/Linux etc., using glfw+glew)
    This is simple and should work for all OpenGL enabled applications.

opengl3_example/
    OpenGL exemple, using programmable pipeline (Windows/OSX/Linux etc., using glfw+glew)
    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 information.