But in SpriteBatchNode::init(), it will create a new texture and pass through it
`bool SpriteBatchNode::init()
  {
      Texture2D * texture = new Texture2D();
      texture->autorelease();
      return this->initWithTexture(texture, 0);
  }`
so tex won't be nullptr, and _textureAtlas is created, so `if ( !_textureAtlas ) { return; }` won't work, and the `_tileSet` is nullptr, it crashes because of the bad access.