oblack_btn.addEventListener(MouseEvent.CLICK,oblack_col);

function oblack_col(e:MouseEvent)

{

        var colorTrans:ColorTransform = walls.transform.colorTransform;

 

        colorTrans.redOffset = 0;

        colorTrans.greenOffset =0;

        colorTrans.blueOffset =0;

        walls.transform.colorTransform = colorTrans;

}