[]图集动画没有显示

Laya.init(1600, 1400, Laya.WebGL);
var AniConfPath = 'res/atlas/cloud.json';
Laya.loader.load(AniConfPath, Laya.Handler.create(this, this.createAnimation), null, Laya.loader.ATLAS);
function createAnimation() {
var ani = new Laya.Animation();
ani.loadAtlas(AniConfPath);
ani.interval = 30;
ani.index = 1;
ani.play();
Laya.stage.addChild(ani);
}