截屏保存的图片是全白的

Cocos2d-x JavaScript
#1 
/**
     * capture screen shot .
     * @param imgName  String]  file name , not include dir
     * @param callback  function arg count = 1 ; @sub param path  file path
     * @returns {Boolean}
     */
    screenShot: function (imgName,callback) {
        var renderTexture = new cc.RenderTexture(cc.visibleRect.width, cc.visibleRect.height, 0, 0);
        (renderTexture.getSprite()).setAnchorPoint(cc.p(0.5, 0.5));
        renderTexture.setPosition(cc.p(cc.visibleRect.width / 2, cc.visibleRect.height / 2));
        renderTexture.setAnchorPoint(cc.p(0.5, 0.5));
        var runningNode = cc.director.getRunningScene();
        renderTexture.begin();
        runningNode.visit();
        renderTexture.end();
        var ok = renderTexture.saveToFile(imgName, cc.IMAGE_FORMAT_JPEG, false);
        if(!ok) return ok;
        //jsb.reflection.callStaticMethod("org/cocos2dx/javascript/AppActivity", "closeWeb", "()V");
        var act = new cc.Sequence(new cc.DelayTime(0.1),new cc.CallFunc(function(){
            if(callback){
                var path = jsb.fileUtils.getWritablePath() + imgName;
                callback(path);
            }
        },null,null));
        runningNode.runAction(act);
        return  ok;
    },


```

保存的图片是片白色的图，要怎么弄
#2

请问楼主有解决么？怎么解决的？我遇到同样的问题。。