unity3d Editor LayerMask 编辑器枚举

LayerMask tempMask = EditorGUILayout.MaskField("Mask",InternalEditorUtility.LayerMaskToConcatenatedLayerMask(xxxLayerMask),InternalEditorUtility.layers);
xxxLayerMask = InternalEditorUtility.ConcatenatedLayersMaskToLayerMask(tempMask);