46 Three.js使用THREE.ExtrudeGeometry拉伸SVG为三维图形
简介
SVG是可缩放矢量图（Scalable Vector Graphics）。它基于XML的标准，用来在网页上创建二维矢量图。该标准是一个所有现代浏览器都支持的开房标准。我们可以使用Three.js的THREE.ExtrudeGeometry来将SVG格式的图形转换成三维图形。
实现方式
- 首先，将库文件引入到页面当中
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/d3-threeD.js">script>- 然后，从
SVG元素中获取到SVG字符串，通过库里面transformSVGPathExposed函数，将字符串转换成THREE.ExtrudeGeometry所需要的THREE.Shape对象。 - 最后，通过转换出来的
THREE.Shape对象创建模型即可。
案例代码
我们将下面的一个SVG图形转换成Three.js格式的三维图形
转换为
案例查看地址：http://www.wjceo.com/blog/threejs/2018-02-12/48.html
以下是全部代码
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
<style type="text/css">
html, body {
margin: 0;
height: 100%;
}
canvas {
display: block;
}
style>
head>
<body onload="draw();">
<div id="batman" style="display:none;">
<svg version="1.0" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="1152px" height="1152px" xml:space="preserve">
<g>
<path id="batman-path" style="fill:rgb(0,0,0);" d="M 261.135 114.535 C 254.906 116.662 247.491 118.825 244.659 119.344 C 229.433 122.131 177.907 142.565 151.973 156.101 C 111.417 177.269 78.9808 203.399 49.2992 238.815 C 41.0479 248.66 26.5057 277.248 21.0148 294.418 C 14.873 313.624 15.3588 357.341 21.9304 376.806 C 29.244 398.469 39.6107 416.935 52.0865 430.524 C 58.2431 437.23 63.3085 443.321 63.3431 444.06 C 63.4748 446.883 102.278 479.707 120.51 492.418 C 131.003 499.734 148.168 509.93 158.654 515.075 C 169.139 520.22 179.431 525.34 181.524 526.454 C 187.725 529.754 187.304 527.547 179.472 515.713 C 164.806 493.553 158.448 464.659 164.322 446.861 C 169.457 431.303 192.013 421.501 214.324 425.132 C 234.042 428.341 252.142 439.186 270.958 459.064 C 286.677 475.67 292.133 482.967 295.31 491.634 C 297.466 497.514 298.948 495.91 304.862 481.293 C 313.673 459.519 329.808 445.735 346.35 445.851 C 367.654 446 399.679 478.239 412.801 512.745 C 414.093 516.144 416.593 522.632 418.355 527.163 C 420.118 531.695 423.604 542.319 426.103 550.773 C 430.848 566.832 432.355 566.851 434.872 550.88 C 436.395 541.215 451.403 502.522 455.655 497.298 C 457.038 495.599 460.63 489.896 463.636 484.625 C 471.696 470.498 492.318 452.688 505.387 448.568 C 514.602 445.663 517.533 445.549 525.51 447.782 C 539.676 451.749 553.43 467.773 560.706 488.788 L 563.242 496.114 L 567.096 490.012 C 577.709 473.208 593.665 453.899 602.47 447.206 C 607.884 443.09 613.378 438.825 614.679 437.729 C 615.98 436.632 622.927 433.259 630.118 430.233 C 655.159 419.693 681.195 423.407 693.273 439.241 C 697.957 445.382 698.932 448.971 699.538 462.294 C 700.174 476.284 699.51 479.864 693.686 493.854 C 690.073 502.533 684.912 512.883 682.217 516.854 C 679.523 520.825 678.172 524.074 679.215 524.074 C 681.932 524.074 718.787 504.481 732.525 495.734 C 760.018 478.228 788.909 452.599 803.9 432.418 C 807.266 427.886 810.569 423.715 811.239 423.149 C 814.498 420.395 828.253 393.099 833.17 379.627 C 838.223 365.782 838.713 361.822 838.741 334.582 C 838.776 300.425 836.431 291.124 820.154 260.873 C 810.649 243.207 807.498 239.005 788.417 218.543 C 751.511 178.968 688.147 142.549 621.582 122.654 C 581.7 110.734 580.388 110.465 580.388 114.195 C 580.388 115.328 581.302 116.255 582.418 116.255 C 584.279 116.255 587.705 122.106 603.399 152.085 C 613.977 172.29 618.077 189.427 618.264 214.21 C 618.42 234.928 617.88 238.368 612.285 252.269 C 604.327 272.04 590.066 286.889 572.829 293.352 C 558.526 298.714 549.193 297.86 535.704 289.955 C 526.777 284.723 512.304 267.644 509.816 259.404 C 509.132 257.138 507.129 251.358 505.366 246.558 C 503.602 241.759 501.646 231.564 501.018 223.902 C 500.39 216.24 498.491 198.402 496.797 184.261 C 495.104 170.121 493.307 152.047 492.803 144.097 C 492.299 136.147 491.292 125.625 490.565 120.715 L 489.242 111.787 L 483.323 118.267 C 480.067 121.832 477.404 125.618 477.404 126.681 C 477.404 127.744 476.603 128.613 475.624 128.613 C 474.645 128.613 471.275 132.321 468.135 136.852 L 462.426 145.091 L 431.038 145.091 L 399.65 145.091 L 386.811 128.494 C 379.749 119.365 373.509 112.36 372.943 112.926 C 372.377 113.491 371.57 118.875 371.15 124.888 C 370.73 130.902 368.94 147.744 367.172 162.315 C 365.405 176.887 363.523 195.424 362.99 203.509 C 360.283 244.622 352.784 266.044 335.323 282.544 C 326.456 290.923 312.488 297.497 303.508 297.518 C 294.864 297.539 278.732 290.063 269.473 281.748 C 246.952 261.521 238.846 229.614 245.481 187.314 C 247.894 171.928 266.562 131.612 275.927 121.56 C 277.987 119.348 279.673 116.786 279.673 115.867 C 279.673 114.947 279.905 113.593 280.188 112.856 C 281.28 110.017 271.977 110.837 261.136 114.536 L 261.135 114.535 "/>
g>
svg>
div>
body>
<script src="https://johnson2heng.github.io/three.js-demo/lib/three.js">script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/d3-threeD.js">script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/controls/OrbitControls.js">script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/stats.min.js">script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/dat.gui.min.js">script>
<script>
var renderer;
function initRender() {
renderer = new THREE.WebGLRenderer({antialias:true});
//renderer.setClearColor(new THREE.Color(0xEEEEEE, 1.0)); //设置背景颜色
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
}
var camera;
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth/window.innerHeight, 1, 10000);
camera.position.set(0, 0, 1500);
}
var scene;
function initScene() {
scene = new THREE.Scene();
}
var light;
function initLight() {
scene.add(new THREE.AmbientLight(0x404040));
light = new THREE.DirectionalLight(0xffffff);
light.position.set(1,1,1);
scene.add(light);
}
function initModel() {
var shape = new THREE.ShapeGeometry(drawShape());
var material = new THREE.MeshPhongMaterial({color:0xff00ff});
material.side = THREE.DoubleSide;//设置成两面都可见
var mesh = new THREE.Mesh(shape,material);
scene.add(mesh);
/*此方法是创建两种纹理的方法
* var shape = new THREE.ShapeGeometry(drawShape());
var mesh = createMesh(shape);
scene.add(mesh);
* */
}
//生成2d图形
function drawShape() {
var svgString = document.querySelector("#batman-path").getAttribute("d");
var shape = transformSVGPathExposed(svgString);
// 返回shape
return shape;
}
//生成模型
function createMesh(geom) {
//设置当前的模型矩阵沿xy轴偏移，让图片处于显示中心
geom.applyMatrix(new THREE.Matrix4().makeTranslation(-450, -300, 0));
// 创建法向量纹理
var meshMaterial = new THREE.MeshNormalMaterial({
flatShading: THREE.FlatShading,
transparent: true,
opacity: 0.7
});
// 创建一个线框纹理
var wireFrameMat = new THREE.MeshBasicMaterial();
wireFrameMat.wireframe = true;
// 创建模型
var mesh = THREE.SceneUtils.createMultiMaterialObject(geom, [meshMaterial,wireFrameMat]);
//由于图形时反的，让图形翻个个
mesh.rotation.z = Math.PI;
return mesh;
}
//初始化性能插件
var stats;
function initStats() {
stats = new Stats();
document.body.appendChild(stats.dom);
}
//用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
var controls;
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 = false;
//设置相机距离原点的最远距离
controls.minDistance = 20;
//设置相机距离原点的最远距离
controls.maxDistance = 10000;
//是否开启右键拖拽
controls.enablePan = true;
}
//生成gui设置配置项
var gui,shape;
function initGui() {
//声明一个保存需求修改的相关数据的对象
gui = {
amount:2,
bevelThickness:2,
bevelSize:0.5,
bevelEnabled:true,
bevelSegments:3,
curveSegments:12,
steps:1,
asGeom:function () {
// 删除旧的模型
scene.remove(shape);
// 创建一个新的
var options = {
amount: gui.amount,
bevelThickness: gui.bevelThickness,
bevelSize: gui.bevelSize,
bevelSegments: gui.bevelSegments,
bevelEnabled: gui.bevelEnabled,
curveSegments: gui.curveSegments,
steps: gui.steps
};
shape = createMesh(new THREE.ExtrudeGeometry(drawShape(), options));
// 将模型添加到场景当中
scene.add(shape);
}
};
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, 'amount', 0, 200).onChange(gui.asGeom);
datGui.add(gui, 'bevelThickness', 0, 10).onChange(gui.asGeom);
datGui.add(gui, 'bevelSize', 0, 10).onChange(gui.asGeom);
datGui.add(gui, 'bevelSegments', 0, 30).step(1).onChange(gui.asGeom);
datGui.add(gui, 'bevelEnabled').onChange(gui.asGeom);
datGui.add(gui, 'curveSegments', 1, 30).step(1).onChange(gui.asGeom);
datGui.add(gui, 'steps', 1, 5).step(1).onChange(gui.asGeom);
//调用生成一次图形
gui.asGeom();
}
function render() {
renderer.render( scene, camera );
}
//窗口变动触发的函数
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
//更新控制器
controls.update();
render();
//更新性能插件
stats.update();
requestAnimationFrame(animate);
}
function draw() {
initRender();
initScene();
initCamera();
initLight();
//initModel();
initControls();
initStats();
initGui();
animate();
window.onresize = onWindowResize;
}
script>
html>