@Override
    public void display(GLAutoDrawable drawable) {

        int x1 = 0;
        int y1 = 0;
        int x2 = 100;
        int y2 = 100;

        GL2 gl = new DebugGL2(drawable.getGL().getGL2());

        cube(gl, x1, y1, x2, y2);

//        gl.glBegin(gl.GL_QUADS);
//        gl.glVertex2i(x1, y1);
//        gl.glVertex2i(x1, y2);
//        gl.glVertex2i(x2, y2);
//        gl.glVertex2i(x2, y1);
//        gl.glEnd();

//        gl.glCallList();

    }

    private void cube(GL2 gl, int x1, int x2, int y1, int y2) {
        gl.glBegin(gl.GL_QUADS);
        gl.glVertex2i(x1, y1);
        gl.glVertex2i(x1, y2);
        gl.glVertex2i(x2, y2);
        gl.glVertex2i(x2, y1);
        gl.glEnd();
    }