指定模型高亮功能，附带设置背景颜色，获取随机数方法。
百度查看说是gltf格式的模型可以携带PBR材质信息，如果可以这样，那就完全可以在blender中配置好材质导出了，也就不需要像在unity中调整参数了。

import * as THREE from 'three'
import { OutlinePass } from 'three/examples/jsm/postprocessing/OutlinePass';
import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer';
import { RenderPass } from 'three/examples/jsm/postprocessing/RenderPass';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

//创建场景
const scene = new THREE.Scene();
//配置相机
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
//创建渲染器
const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
//动态创建的cube模型
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshBasicMaterial({ color: 0x0000FF });
const cube = new THREE.Mesh(geometry, material);
cube.position.x += 4;
scene.add(cube);

// 加载模型文件  模型在工程根目录
loadModelGLB('../testmodel.glb', loadModelSucceed, loadModelFail);
var cube2 = new THREE.Mesh(geometry, material);
cube2.position.x -= 2.5;
scene.add(cube2);

camera.position.z = 5;

//================================指定模型边缘高亮=================================================
let composer;
//创建高亮组件
var outlinePass = new OutlinePass(new THREE.Vector2(window.innerWidth, window.innerHeight), scene, camera);
//封装的指定模型高亮方法
function outlineObj(obj) {
  // 描边
  composer = new EffectComposer(renderer);
  const renderPass = new RenderPass(scene, camera);
  composer.addPass(renderPass);
  //模型描边颜色，默认白色         
  outlinePass.visibleEdgeColor.set(0xffff00);
  //高亮发光描边厚度
  outlinePass.edgeThickness = 4;
  //高亮描边发光强度
  outlinePass.edgeStrength = 6;
  //模型闪烁频率控制，默认0不闪烁 猜测是插值控制显色，数字是变化的时间
  outlinePass.pulsePeriod = 1;
  composer.addPass(outlinePass);
  // 将描边模型添加进去
  outlinePass.selectedObjects.push(obj);
}
//================================指定模型边缘高亮 END=================================================

//计时器
const clock = new THREE.Clock();
let timer = 0;
function animate() {
  requestAnimationFrame(animate);

  cube.rotation.x += 0.01;
  cube.rotation.y += 0.01;
  
  //使用高亮组件必须使用此函数
  composer.render();
  //renderer.render(scene, camera);

  timer += clock.getDelta();
  //每一秒变换一次背景颜色
  if (timer >= 1) {
    timer = 0;
    scene.background = new THREE.Color(getRandomColorValue());//设置背景色
  }

}
//获取随机颜色值
function getRandomColorValue() {
  var red = Math.round(Math.random() * 255); // 生成0-255之间的随机整数作为红色分量
  var green = Math.round(Math.random() * 255); // 生成0-255之间的随机整数作为绿色分量
  var blue = Math.round(Math.random() * 255); // 生成0-255之间的随机整数作为蓝色分量

  return "rgb(" + red + ", " + green + ", " + blue + ")"; // 返回RGB格式的随机颜色值
}

outlineObj(cube2);
outlineObj(cube);
animate();



//==============================加载模型================================================
//加载GLB模型，传入路径、加载完成的回调、加载失败的回调
function loadModelGLB(path, succeed, fail) {
  const loader = new GLTFLoader();
  loader.load(path, function (gltf) {
    succeed(gltf);
  }, undefined, function (error) {
    fail(error);
  });
}

//加载完成的回调
function loadModelSucceed(gltf) {
  let returnGltf = gltf.scene;
  returnGltf.rotation.y += 2;
  //配置加载的模型设置
  returnGltf.traverse(function (child) {
    if (child.isMesh) {
        child.frustumCulled = false;
        //模型阴影
        child.castShadow = true;
        //模型自发光
        child.material.emissive = child.material.color;
        child.material.emissiveMap = child.material.map;
    }
});

  scene.add(returnGltf);
  outlineObj(returnGltf);

}
//加载失败回调
function loadModelFail(msg) {
  console.error(msg);
}
//==============================加载模型 END================================================