object CharlatanoOverlay : GLEventListener {
    
    private val WINDOW_WIDTH = 500
    private val WINDOW_HEIGHT = 500
    private val FPS = 60
    
    val window = GLWindow.create(GLCapabilities(null))
    
    init {
        GLProfile.initSingleton()
    }
    
    fun open(width: Int = WINDOW_WIDTH, height: Int = WINDOW_HEIGHT, x: Int = 100, y: Int = 1000) {
        val animator = FPSAnimator(window, FPS, true)
        
        window.addWindowListener(object : WindowAdapter() {
            override fun windowDestroyNotify(e: WindowEvent) {
                thread {
                    if (animator.isStarted)
                        animator.stop()
                    exitProcess(0)
                }.start()
            }
        })
        
        window.addGLEventListener(this)
        window.setSize(width, height)
        window.setPosition(x, y)
        window.title = "Hello world"
        window.isVisible = true
        animator.start()
    }
    
    val g = GLGraphics2D() //Create GL2D wrapper
    
    override fun display(gLDrawable: GLAutoDrawable) {
        val gl2 = gLDrawable.gl.gL2
        
        gl2.glClear(GL.GL_COLOR_BUFFER_BIT)
        
        g.prePaint(gLDrawable.context) //Updated wrapper to latest glContext
        
        g.color = Color.RED
        g.drawRect(0, 0, 200, 200)
        g.color = Color.YELLOW
        g.drawLine(0, 0, 100, 100)
        g.color = Color.CYAN
        g.drawString("OpenGL 2D Made Easy! :D", 100, 100)
    }
    
    override fun init(glDrawable: GLAutoDrawable) {
    }
    
    override fun reshape(gLDrawable: GLAutoDrawable, x: Int, y: Int, width: Int, height: Int) {
        val gl = gLDrawable.gl.gL2
        gl.glViewport(0, 0, width, height)
    }
    
    override fun dispose(gLDrawable: GLAutoDrawable) {
        g.glDispose()
    }
}