[]关于Matter的初始化问题

var engine = Matter.Engine.create({
enableSleeping: true
});
Matter.Engine.run(engine);

var render = LayaRender.create(
{
engine: engine,
width: GAME_CONFIG.WIDTH,
height: GAME_CONFIG.HEIGHT,
options:
{
wireframes: false
}
});
LayaRender.run(render);

代码是官方的。
以下这段是源码
function createContainer(render)
{
var con = render.container;

spriteCon = new Laya.Sprite();
graphicsCon = new Laya.Sprite();

render.spriteContainer = spriteCon;
render.graphicsContainer = graphicsCon;

con.addChild(spriteCon);
con.addChild(graphicsCon);

graphics = graphicsCon.graphics;
}
现在con这个是undefined的。请问这个在哪来赋值哦。看了半天没看懂