private void init_render () {
    gl.clear (GL.COLOR_BUFFER_BIT);
    gl.color3f (0.0f, 1.0f, 0.0f);

    gl.capability (GL.BLEND, anti_aliasing);
    gl.capability (GL.CULL_FACE, culling);
    gl.capability (GL.DITHER, dithering);
    gl.capability (GL.POLYGON_SMOOTH, anti_aliasing);

    if (anti_aliasing) gl.blend_func (GL.SRC_ALPHA, GL.ONE);
    gl.cull_face (cull_front ? GL.FRONT : GL.BACK);    
    gl.front_face (winding ? GL.CCW : GL.CW);
    gl.shade_model (shading ? GL.SMOOTH : GL.FLAT);
  }