glutAddMenuEntry( "Sub menu A3 (03)", 13 );
glutMenuDestroyFunc ( MenuDestroy ); /* callback specific to this menu */
glutAddMenuEntry( "Sub menu A3 (03)", 13 );
glutMenuDestroyFunc ( MenuDestroy ); /* callback specific to this menu */
subMenuB = glutCreateMenu( MenuCallback );
glutAddMenuEntry( "Sub menu B1 (04)", 14 );
glutAddMenuEntry( "Sub menu B2 (05)", 15 );
subMenuB = glutCreateMenu( MenuCallback );
glutAddMenuEntry( "Sub menu B1 (04)", 14 );
glutAddMenuEntry( "Sub menu B2 (05)", 15 );
glutMenuDestroyFunc ( MenuDestroy ); /* callback specific to this menu */
glutAttachMenu( GLUT_LEFT_BUTTON );
glutMenuDestroyFunc ( MenuDestroy ); /* callback specific to this menu */
glutAttachMenu( GLUT_LEFT_BUTTON );