directx9_example/
    DirectX9 example (Windows only).
	
directx11_example/
    DirectX11 example (Windows only).
	
opengl_example/
    OpenGL example, using GLFW + fixed pipeline.
    This is simple and should work for all OpenGL enabled applications.

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.