三个JS -如何在运行时将材质上的Lambert更改为Phong？

// 创建场景、相机和渲染器
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

// 加载模型
var loader = new THREE.OBJLoader();
loader.load('model.obj', function (object) {
    scene.add(object);
});

// 创建光源
var light = new THREE.DirectionalLight(0xffffff, 1);
light.position.set(1, 1, 1).normalize();
scene.add(light);

// 创建Lambert材质
var material = new THREE.MeshLambertMaterial({ color: 0x00ff00 });

// 将材质应用到模型上
object.traverse(function (child) {
    if (child instanceof THREE.Mesh) {
        child.material = material;
    }
});

// 在运行时将材质从Lambert更改为Phong
object.traverse(function (child) {
    if (child instanceof THREE.Mesh) {
        child.material = new THREE.MeshPhongMaterial({ color: 0x00ff00 });
    }
});

// 渲染场景
function animate() {
    requestAnimationFrame(animate);
    renderer.render(scene, camera);
}
animate();