gsap真是个好东西，有了它，所有的动画都变得那么的优美

gsap.to(this.camera.position, {
        x: 0,
        y: gy,
        z: -1,
        duration: 3,
        ease:"expo.out",
        onUpdate: () => {
          this.camera.lookAt(this.scene.position);
        },
        onComplete: () => {
          this.camera.lookAt(this.scene.position);
        }
      })

TweenMax中文网(GreenSock动画平台,GSAP)

http://www.tweenmax.com.cn/index.html

gasp官网

https://greensock.com/why-gsap/