three.js变形动画-使用MorphAnimMesh制作奔跑的小马动画(vue中使用three.js67)

1.demo效果

2.变形动画介绍

变形动画就像老实的胶片电影，每一个动作有若干个分步帧，把这些帧串联起来，不断切换就实现动画效果，这里给每个分步起了一个名字叫 关键帧 或者 变形目标，使用这种方法制作动画的好处是，可以为所有顶点指定每个关键位置，但同时会带来不足，对于大型网格制作的动画，模型文件会非常大，因为每个关键帧上所有的顶点都要保存下来

3. 实现要点

3.1 加载模型文件

这里需要说明一下，最新的three.js没有JSONLoader加载器，这个demo需要用到，于是在 public目录下的index.html 文件中引入旧版three.js

<script type="text/javascript" src="./libs/three.js"></script>

在当前vue文件中注释掉引入本地依赖的代码

// import * as THREE from 'three'

然后就可以愉快的使用了

const publicPath = process.env.BASE_URL
const loader = new THREE.JSONLoader()
loader.load(`${publicPath}models/horse.js`,(geometry, mat) => {//加载完成后回调处理
})

3.2 创建MorphAnimMesh变形动画网格

创建变形动画网格，这里需要注意几点

• 保证使用的材质中的 morphTargets 属性为true，否则网格不会动
• 创建MorphAnimMesh对象前，一定要调用几何体的 computeMorphNormals() 方法，用来计算变形目标的法向量
• 计算变形目标的颜色，使用辅助函数 morphColorsToFaceColors

//创建右侧奔跑的马
const mat1 = new THREE.MeshLambertMaterial({morphTargets: true,vertexColors: THREE.FaceColors
})THIS.morphColorsToFaceColors(geometry) //计算几何体表面颜色
geometry.computeVertexNormals() //计算顶点法向量
geometry.computeFaceNormals() //计算表面法向量
geometry.computeMorphNormals() //计算变形目标法向量// 创建变形动画网格对象并添加到场景
THIS.meshAnim = new THREE.MorphAnimMesh(geometry, mat1)
THIS.meshAnim.duration = 1000
THIS.meshAnim.position.x = 200
THIS.meshAnim.position.z = 0
this.scene.add(THIS.meshAnim)

// 取morph颜色设置到几何体面颜色
morphColorsToFaceColors(geometry) {if (geometry.morphColors && geometry.morphColors.length) {const colorMap = geometry.morphColors[0]for (let i = 0; i < colorMap.colors.length; i++) {geometry.faces[i].color = colorMap.colors[i]geometry.faces[i].color.offsetHSL(0.1, 0.1, 0)}}
}

3.3 render中更新动画

render() {this.showFrame(this.properties.keyframe.value) // 分步动画刷新if (this.meshAnim) {const delta = this.clock.getDelta() // 获取自上次调用的时间差this.meshAnim.updateAnimation(delta * 1000)this.meshAnim.rotation.y += 0.01}this.renderer.render(this.scene, this.camera)requestAnimationFrame(this.render)
}

4. demo代码

<template><div><div id="container" /><div class="controls-box"><section><el-row><div v-for="(item,key) in properties" :key="key"><div v-if="item&&item.name!=undefined"><el-col :span="8"><span class="vertice-span">{{ item.name }}</span></el-col><el-col :span="13"><el-slider v-model="item.value" :min="item.min" :max="item.max" :step="item.step" :format-tooltip="formatTooltip" /></el-col><el-col :span="3"><span class="vertice-span">{{ item.value }}</span></el-col></div></div></el-row></section></div></div>
</template><script>
// import * as THREE from 'three'
export default {data() {return {properties: {keyframe: {name: 'keyframe',value: 0,min: 0,max: 15,step: 1}},clock: new THREE.Clock(),currentMesh: null,frames: [],camera: null,scene: null,renderer: null,controls: null}},mounted() {this.init()},methods: {formatTooltip(val) {return val},// 初始化init() {this.createScene() // 创建场景this.createModels() // 创建模型this.createLight() // 创建光源this.createCamera() // 创建相机this.createRender() // 创建渲染器this.render() // 渲染},// 创建场景createScene() {this.scene = new THREE.Scene()},// 创建模型createModels() {const THIS = thisconst publicPath = process.env.BASE_URLconst loader = new THREE.JSONLoader()loader.load(`${publicPath}models/horse.js`,(geometry, mat) => {//创建右侧奔跑的马const mat1 = new THREE.MeshLambertMaterial({morphTargets: true,vertexColors: THREE.FaceColors})THIS.morphColorsToFaceColors(geometry) //计算几何体表面颜色geometry.computeVertexNormals() //计算顶点法向量geometry.computeFaceNormals() //计算表面法向量geometry.computeMorphNormals() //计算变形目标法向量// 创建变形动画网格对象并添加到场景THIS.meshAnim = new THREE.MorphAnimMesh(geometry, mat1)THIS.meshAnim.duration = 1000THIS.meshAnim.position.x = 200THIS.meshAnim.position.z = 0this.scene.add(THIS.meshAnim)//创建左侧关键帧-静止的马运动的分步变形目标const mat2 = new THREE.MeshLambertMaterial({color: 0xffffff,vertexColors: THREE.FaceColors})const mesh = new THREE.Mesh(geometry, mat1)mesh.position.x = -100THIS.frames.push(mesh)THIS.currentMesh = mesh// 创建分步网格对象mesh.geometry.morphTargets.forEach(e => {const geom = new THREE.Geometry()geom.vertices = e.vertices // 设置顶点geom.faces = geometry.faces // 设置表面const morpMesh = new THREE.Mesh(geom, mat2)THIS.frames.push(morpMesh)morpMesh.position.x = -100 // 向左平移100})this.showFrame(0) // 显示分步动画0},`${publicPath}models`)},showFrame(e) {this.scene.remove(this.currentMesh)this.scene.add(this.frames[e])this.currentMesh = this.frames[e]},// 取morph颜色设置到几何体面颜色morphColorsToFaceColors(geometry) {if (geometry.morphColors && geometry.morphColors.length) {const colorMap = geometry.morphColors[0]for (let i = 0; i < colorMap.colors.length; i++) {geometry.faces[i].color = colorMap.colors[i]geometry.faces[i].color.offsetHSL(0.1, 0.1, 0)}}},// 创建光源createLight() {// 环境光const ambientLight = new THREE.AmbientLight(0x111111) // 创建环境光this.scene.add(ambientLight) // 将环境光添加到场景const directionLight = new THREE.DirectionalLight(0xffffff)directionLight.position.set(300, 200, 300)directionLight.intensity = 1.5this.scene.add(directionLight)},// 创建相机createCamera() {const element = document.getElementById('container')const width = element.clientWidth // 窗口宽度const height = element.clientHeight // 窗口高度const k = width / height // 窗口宽高比// PerspectiveCamera( fov, aspect, near, far )this.camera = new THREE.PerspectiveCamera(45, k, 0.1, 1000)this.camera.position.set(450, 450, 450) // 设置相机位置this.camera.lookAt(new THREE.Vector3(100, 50, 0)) // 设置相机方向this.scene.add(this.camera)},// 创建渲染器createRender() {const element = document.getElementById('container')this.renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true })this.renderer.setSize(element.clientWidth, element.clientHeight) // 设置渲染区域尺寸this.renderer.setClearColor(0xeeeeee, 1) // 设置背景颜色element.appendChild(this.renderer.domElement)},render() {this.showFrame(this.properties.keyframe.value) // 分步动画刷新if (this.meshAnim) {const delta = this.clock.getDelta() // 获取自上次调用的时间差this.meshAnim.updateAnimation(delta * 1000)this.meshAnim.rotation.y += 0.01}this.renderer.render(this.scene, this.camera)requestAnimationFrame(this.render)}}
}
</script><style>
#container {position: absolute;width: 100%;height: 100%;
}
.controls-box {position: absolute;right: 5px;top: 5px;width: 300px;padding: 10px;background-color: #fff;border: 1px solid #c3c3c3;
}
.vertice-span {line-height: 38px;padding: 0 2px 0 10px;
}
</style>