three.js 匀速动画(向量表示速度)

效果：

代码：

<template>
  <div>
    <el-container>
      <el-main>
        <div class="box-card-left">
          <div id="threejs" style="border: 1px solid red"></div>1. 匀速动画(向量表示速度)
        </div>
      </el-main>
    </el-container>
  </div>
</template>
<script>
// 引入轨道控制器扩展库OrbitControls.js
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls.js";
import { GLTFLoader } from "three/examples/jsm/loaders/GLTFLoader.js";
// 效果制作器
import { EffectComposer } from "three/examples/jsm/postprocessing/EffectComposer.js";
// 渲染通道
import { RenderPass } from "three/examples/jsm/postprocessing/RenderPass.js";
// 发光描边OutlinePass
import { OutlinePass } from "three/examples/jsm/postprocessing/OutlinePass.js";
import {
  CSS2DObject,
  CSS2DRenderer,
} from "three/examples/jsm/renderers/CSS2DRenderer.js";
import TWEEN from "@tweenjs/tween.js";
// TextGeometry 是一个附加组件，必须显式导入。 three/examples/jsm/geometries
import { TextGeometry } from 'three/examples/jsm/geometries/TextGeometry.js';
// FontLoader 是一个附加组件，必须显式导入。
import { FontLoader } from "three/examples/jsm/loaders/FontLoader.js";
export default {
  data() {
    return {
      textGeometry: null,
      group: null,
      camera: null,
      box: null,
      renderer: null,
      clock: null,
      sudu: null,
      mesh: null,
      group: null,
      flag: true
    };
  },
  created() {},
  mounted() {
    this.name = this.$route.query.name;
    this.init();
  },
  methods: {
    goBack() {
      this.$router.go(-1);
    },
    // 1. 匀速动画(向量表示速度)
    init() {
      // 创建场景对象
      this.scene = new this.$three.Scene();
        const axesHelper = new this.$three.AxesHelper(200);
        this.scene.add(axesHelper);
      const ambientLight = new this.$three.AmbientLight(0xffffff, 1);
      this.scene.add(ambientLight);
      this.clock = new this.$three.Clock();
      this.sudu = new this.$three.Vector3(0,0,10);//物体运动速度
      // 创建文本模型对象
      /**
       * TextGeometry(text, parameters)
       *  text: 要显示的文字
       *  parameters: {
       *   font -- THREE.字体
       *   size -- Float.大小
       *   height -- Float.字体厚度， 默认是50
       *   curveSegments — Integer. 曲线上点的数量. 默认值为12.
            bevelEnabled — Boolean. 是否打开斜面. 默认值为False.
            bevelThickness — Float. 文本斜面的深度. 默认值为10.
            bevelSize — Float. 斜面离轮廓的距离. 默认值为8.
       * 
       * }
       */
      this.box = new this.$three.Box3();

      const fontLoader = new FontLoader();
      fontLoader.load("/fonts/Fontquan-XinYiJiXiangSong_Regular.json", font => {
        const mesh = this.createText(font, 0xFB0606);
        const mesh2 = this.createText(font,0xF84949);
  
        mesh2.rotateX(Math.PI);
        mesh2.translateY(-this.box.min.y + 10)
        mesh2.translateZ(-10)

        
        this.group = new this.$three.Group();
        this.group.add(mesh,mesh2);
        this.scene.add(this.group);

        this.camera = new this.$three.PerspectiveCamera();
        this.camera.position.set(0,30,500);
        this.camera.lookAt(0,0,0);
        this.renderer = new this.$three.WebGLRenderer();
        this.renderer.setSize(1000,800);
        this.renderer.render(this.scene, this.camera);
        window.document.getElementById("threejs").appendChild(this.renderer.domElement);
        const controls = new OrbitControls(this.camera, this.renderer.domElement);
        controls.addEventListener("change", e => {
          this.renderer.render(this.scene, this.camera);
        })
        this.loopFun();
      })
    },
    loopFun() {
      const spt = this.clock.getDelta() * 2;
      const dis = this.sudu.clone().multiplyScalar(spt);
      this.group.position.add(dis);
      this.renderer.render(this.scene, this.camera);
      requestAnimationFrame(this.loopFun);
    },
    createText(font, color) {
      const textGeometry = new TextGeometry('龙年大吉', { font: font, size:50, height: 10});
        const material = new this.$three.MeshLambertMaterial({color: color});
        const mesh = new this.$three.Mesh(textGeometry, material);
        this.box.expandByObject(mesh);
        const move_x = (this.box.max.x - this.box.min.x) / 2;
        mesh.translateX(-move_x)
        mesh.translateZ(-5)
        mesh.translateY(-this.box.min.y+ 0)
        return mesh;
    }
  },
};
</script>
//
<style lang="less" scoped>
.box-card-left {
  display: flex;
  align-items: flex-start;
  flex-direction: row;

  width: 100%;

  .box-right {
    img {
      width: 500px;
      user-select: none;
    }
  }
}
</style>