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85 Three.js 通过设置morphTargetInfluences属性来创建动画

yongxinz 2023-01-30 阅读 122


简介

​morphTargetInfluences​​​属性是​​mesh​​​对象上面所含有的属性,是专门作用域同等下标下的​​morphTargets​​​顶点的值对当前默认的顶点值的影响权重。
官网的介绍:​​​An array of weights typically from 0-1 that specify how much of the morph is applied. Undefined by default, but reset to a blank array by updateMorphTargets.​​​
​​​morphTargetInfluences​​​的值的取值范围是​​0-1​​​,​​0​​​是默认值,就是没有影响,​​1​​​是最大值,如果别的值全为​​0​​​,就一个值为​​1​​,那么,当前模型的顶点则全部使用的当前模型的顶点值的坐标。

测试案例

 ​​
在案例当中,我们为​​​cube​​​创建了两组二外的顶点,然后可以设置​​morphTargetInfluences​​​的值,来设置影响立方体模型的大小。
- 首先,我们创建两组顶点,和立方体模型:

// 创建显示的立方体
var cubeGeometry = new THREE.BoxGeometry(4, 4, 4);
var cubeMaterial = new THREE.MeshLambertMaterial({morphTargets: true, color: 0x00ffff});

// 创建两个影响立方体的顶点集合
var cubeTarget1 = new THREE.BoxGeometry(2, 10, 2);
var cubeTarget2 = new THREE.BoxGeometry(8, 2, 8);

  • 然后,我们将两组额外的顶点放入到​​morphTargets​​数组当中,提示立方体更新:

// 将两个geometry的顶点放入到立方体的morphTargets里面
cubeGeometry.morphTargets[0] = {name: 't1', vertices: cubeTarget1.vertices};
cubeGeometry.morphTargets[1] = {name: 't2', vertices: cubeTarget2.vertices};
cubeGeometry.computeMorphNormals();

  • 最后,设置好​​gui​​​,并在​​gui​​​里面从新赋值​​morphTargetInfluences​​的值:

gui = {
influence1:0.01,
influence2:0.01,
update : function () {
cube.morphTargetInfluences[0] = gui.influence1;
cube.morphTargetInfluences[1] = gui.influence2;
}
};

datGui.add(gui, 'influence1', 0, 1).onChange(gui.update);
datGui.add(gui, 'influence2', 0, 1).onChange(gui.update);

我们只要修改两个​​morphTargetInfluences​​​的值,便会发现立方体直接会受到影响。也达到了我们案例的目的,查看​​morphTargetInfluences​​对立方体的影响。

案例代码

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style type="text/css">
html, body {
margin: 0;
height: 100%;
}

canvas {
display: block;
}
</style>
</head>

<body onload="draw();">
</body>
<script src="/lib/three.js"></script>
<script src="/lib/js/controls/OrbitControls.js"></script>
<script src="/lib/js/libs/stats.min.js"></script>
<script src="/lib/js/libs/dat.gui.min.js"></script>
<script src="/lib/js/Detector.js"></script>

<script>
var renderer, camera, scene, gui, light, stats, controls, cube;

function initRender() {
renderer = new THREE.WebGLRenderer({antialias: true});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setClearColor(0xeeeeee);
//告诉渲染器需要阴影效果
document.body.appendChild(renderer.domElement);
}

function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.set(0, 40, 50);
}

function initScene() {
scene = new THREE.Scene();
}

//初始化dat.GUI简化试验流程
function initGui() {
//声明一个保存需求修改的相关数据的对象
gui = {
influence1:0.01,
influence2:0.01,
update : function () {
cube.morphTargetInfluences[0] = gui.influence1;
cube.morphTargetInfluences[1] = gui.influence2;
}
};
var datGui = new dat.GUI();
//将设置属性添加到gui当中,gui.add(对象,属性,最小值,最大值)
datGui.add(gui, 'influence1', 0, 1).onChange(gui.update);
datGui.add(gui, 'influence2', 0, 1).onChange(gui.update);
}

function initLight() {
scene.add(new THREE.AmbientLight(0x444444));

light = new THREE.PointLight(0xffffff);
light.position.set(30, 50, 20);

//告诉平行光需要开启阴影投射
light.castShadow = true;

scene.add(light);
}

function initModel() {

//辅助工具
var helper = new THREE.AxesHelper(50);
scene.add(helper);

// 创建显示的立方体
var cubeGeometry = new THREE.BoxGeometry(4, 4, 4);
var cubeMaterial = new THREE.MeshLambertMaterial({morphTargets: true, color: 0x00ffff});

// 创建两个影响立方体的顶点集合
var cubeTarget1 = new THREE.BoxGeometry(2, 10, 2);
var cubeTarget2 = new THREE.BoxGeometry(8, 2, 8);

// 将两个geometry的顶点放入到立方体的morphTargets里面
cubeGeometry.morphTargets[0] = {name: 't1', vertices: cubeTarget1.vertices};
cubeGeometry.morphTargets[1] = {name: 't2', vertices: cubeTarget2.vertices};
cubeGeometry.computeMorphNormals();

cube = new THREE.Mesh(cubeGeometry, cubeMaterial);

// 将立方体添加到顶点当中
scene.add(cube);
}

//初始化性能插件
function initStats() {
stats = new Stats();
document.body.appendChild(stats.dom);
}

function initControls() {

controls = new THREE.OrbitControls(camera, renderer.domElement);

// 如果使用animate方法时,将此函数删除
//controls.addEventListener( 'change', render );
// 使动画循环使用时阻尼或自转 意思是否有惯性
controls.enableDamping = true;
//动态阻尼系数 就是鼠标拖拽旋转灵敏度
//controls.dampingFactor = 0.25;
//是否可以缩放
controls.enableZoom = true;
//是否自动旋转
controls.autoRotate = true;
controls.autoRotateSpeed = 0.5;
//设置相机距离原点的最远距离
controls.minDistance = 1;
//设置相机距离原点的最远距离
controls.maxDistance = 2000;
//是否开启右键拖拽
controls.enablePan = true;
}

function render() {
controls.update();
}

//窗口变动触发的函数
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
}

function animate() {
//更新控制器
render();

//更新性能插件
stats.update();

renderer.render(scene, camera);

requestAnimationFrame(animate);
}

function draw() {
//兼容性判断
if (!Detector.webgl) Detector.addGetWebGLMessage();

initGui();
initRender();
initScene();
initCamera();
initLight();
initModel();
initControls();
initStats();

animate();
window.onresize = onWindowResize;
}


</script>
</html>


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