[]最新版本绘制100x100个sprite ios不能显示

/*

        游戏地图

     */

    function GameMap(){



        this.MapRowNum = 100;

        this.MapColNum = 100;



        GameMap.super(this);



        this.init();

    }

    

    Laya.class(GameMap, "GameMap", laya.display.Sprite);



    var _proto = GameMap.prototype;



    _proto.init = function(){

        var boxSp = new laya.display.Sprite();

        // boxSp.cacheAsBitmap = true;

        for(var i = 0; i < this.MapRowNum; i++){

            for(var j = 0; j < this.MapColNum; j++){

                var box = new laya.display.Sprite();

                box.graphics.drawRect(0, 0, 30, 30, null, "#e6e4ef", 1);

                box.x = i * 30;

                box.y = j * 30;

                boxSp.addChild(box);

            }

        }

        boxSp.cacheAs = "bitmap";

        this.addChild(boxSp);



    }

boxSp.cacheAs = "bitmap";
如果去掉这句话可以显示 是内部设置了？？