前面几篇介绍的都是基于二维的平面几何体。今天开始介绍基于三维的几何体，譬如像 BoxGeometry 方块。这是一种非常简单的三维几何体，你只要指定宽度、高度及深度就可以创建出一个方块。下面给出了常用的几个属性：
| 属性 | 描述 |
|---|---|
| width | 必选。此属性定义方块的宽度。即方块沿 x 轴方向的长度 |
| height | 必选。此属性定义方块的高度。即方块沿 y 轴方向的长度 |
| depth | 必选。此属性定义方块的深度。即方块沿 z 轴方向的长度 |
| widthSegments | 可选。此属性定义方块沿 x 轴方向，将面分成的段数。默认值是 1 |
| heightSegments | 可选。此属性定义方块沿 y 轴方向，将面分成的段数。默认值是 1 |
| depthSegments | 可选。此属性定义方块沿 z 轴方向，将面分成的段数。默认值是 1 |
<!DOCTYPE html>
<html>
<head>
<title>示例 05.04 - BoxGeometry</title>
<script src="../build/three.js"></script>
<script src="../build/js/controls/OrbitControls.js"></script>
<script src="../build/js/libs/stats.min.js"></script>
<script src="../build/js/libs/dat.gui.min.js"></script>
<script src="../jquery/jquery-3.2.1.min.js"></script>
<style>
body {
/* 设置 margin 为 0，并且 overflow 为 hidden，来完成页面样式 */
margin: 0;
overflow: hidden;
}
/* 统计对象的样式 */
#Stats-output {
position: absolute;
left: 0px;
top: 0px;
}
</style>
</head>
<body>
<!-- 用于 WebGL 输出的 Div -->
<div id="webgl-output"></div>
<!-- 用于统计 FPS 输出的 Div -->
<div id="stats-output"></div>
<!-- 运行 Three.js 示例的 Javascript 代码 -->
<script type="text/javascript">
var scene;
var camera;
var render;
var webglRender;
//var canvasRender;
var controls;
var stats;
var guiParams;
var ground;
var box;
//var sphere;
//var plane;
var meshMaterial;
var ambientLight;
var spotLight;
//var cameraHelper;
$(function() {
stats = initStats();
scene = new THREE.Scene();
webglRender = new THREE.WebGLRenderer( {antialias: true, alpha: true} ); // antialias 抗锯齿
webglRender.setSize(window.innerWidth, window.innerHeight);
webglRender.setClearColor(0xeeeeee, 1.0);
webglRender.shadowMap.enabled = true; // 允许阴影投射
render = webglRender;
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 30, 1000); // 2147483647
camera.position.set(-45.5, 68.2, 90.9);
var target = new THREE.Vector3(10, 0 , 0);
controls = new THREE.OrbitControls(camera, render.domElement);
controls.target = target;
camera.lookAt(target);
$('#webgl-output')[0].appendChild(render.domElement);
window.addEventListener('resize', onWindowResize, false);
ambientLight = new THREE.AmbientLight(0x0c0c0c);
scene.add(ambientLight);
spotLight = new THREE.SpotLight(0xffffff);
spotLight.position.set(0, 30, 60);
spotLight.shadow.mapSize.width = 5120; // 必须是 2的幂，默认值为 512
spotLight.shadow.mapSize.height = 5120; // 必须是 2的幂，默认值为 512
spotLight.castShadow = true;
scene.add(spotLight);
//cameraHelper = new THREE.CameraHelper(spotLight.shadow.camera);
//scene.add(cameraHelper);
// 加入一个地面
var groundGeometry = new THREE.PlaneGeometry(100, 100, 4, 4);
var groundMaterial = new THREE.MeshLambertMaterial({color: 0x777777});
ground = new THREE.Mesh(groundGeometry, groundMaterial);
ground.rotation.set(-0.5 * Math.PI, 0, 0); // 沿着 X轴旋转-90°
ground.receiveShadow = true;
scene.add(ground);
// 材质
meshMaterial = [
new THREE.MeshNormalMaterial({side: THREE.DoubleSide}),
new THREE.MeshBasicMaterial({wireframe: true})
];
/** 用来保存那些需要修改的变量 */
guiParams = new function() {
this.rotationSpeed = 0.02;
this.width = 26;
this.height = 26;
this.depth = 10;
this.widthSegments = 5;
this.heightSegments = 5;
this.depthSegments = 5;
}
/** 定义 dat.GUI 对象，并绑定 guiParams 的几个属性 */
var gui = new dat.GUI();
gui.add(guiParams, 'width', 1, 50, 1).onChange(function(e){updateMesh()});
gui.add(guiParams, 'height', 1, 50, 1).onChange(function(e){updateMesh()});
gui.add(guiParams, 'depth', 1, 50, 1).onChange(function(e){updateMesh()});
gui.add(guiParams, 'widthSegments', 1, 10, 1).onChange(function(e){updateMesh()});
gui.add(guiParams, 'heightSegments', 1, 10, 1).onChange(function(e){updateMesh()});
gui.add(guiParams, 'depthSegments', 1, 10, 1).onChange(function(e){updateMesh()});
updateMesh();
renderScene();
});
/** 渲染场景 */
function renderScene() {
stats.update();
rotateMesh(); // 旋转物体
requestAnimationFrame(renderScene);
render.render(scene, camera);
}
/** 初始化 stats 统计对象 */
function initStats() {
stats = new Stats();
stats.setMode(0); // 0 为监测 FPS；1 为监测渲染时间
$('#stats-output').append(stats.domElement);
return stats;
}
/** 当浏览器窗口大小变化时触发 */
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render.setSize(window.innerWidth, window.innerHeight);
}
/** 旋转物体 */
var step = 0;
function rotateMesh() {
step += guiParams.rotationSpeed;
scene.traverse(function(mesh) {
if ((mesh instanceof THREE.Mesh || mesh instanceof THREE.Line) && mesh != ground) {
//mesh.rotation.x = step;
mesh.rotation.y = step;
//mesh.rotation.z = step;
}
});
}
function updateMesh() {
scene.remove(box);
// 定义 box
var boxGeometry = new THREE.BoxGeometry(guiParams.width, guiParams.height, guiParams.depth, guiParams.widthSegments, guiParams.heightSegments, guiParams.depthSegments);
box = new THREE.SceneUtils.createMultiMaterialObject(boxGeometry, meshMaterial);
box.children[1].castShadow = true;
box.position.set(0, guiParams.height / 2 + 3, 0);
scene.add(box);
}
</script>
</body>
</html>未完待续···