瓦片地图不显示求助

Cocos2d-x
#1 
bool MainScene::init()
{
    if ( !Scene::init() ){return false;}
    log("init  MainScene Start...");
    
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();

    Layer* layer = Layer::create();

    tileMap = TMXTiledMap::create("tm_outside.tmx");
    layer->addChild(tileMap, 0, "tm_outside");
    addChild(tileMap,-1);
    addChild(layer,-1);

    Size CC_UNUSED s = tileMap->getContentSize();
    CCLOG("ContentSize: %f, %f", s.width, s.height);

    Size size = tileMap->getTileSize();
    log("TileSize:%f,%f", size.width, size.height);

    Size size2 = tileMap->getMapSize();
    log("MapSize:%f,%f", size2.width, size2.height);

//    TMXLayer* background = tileMap->getLayer("background");
//    layer->addChild(background);
}

```



输出：
init  MainScene Start...
ContentSize: 0.000000, 0.000000
TileSize:32.000000,32.000000
MapSize:27.000000,28.000000



瓦片地图显示不出来，但是好像读取到了数据，contentSize数字不对，是不是哪里路径写错了没加载到图片？
#2

是不能用png图片格式，换了jpg的瓦片地图就可以了。。