上一篇：《一起来学three.js构建WebGL应用》第一课
继续来学习 WebGL 的 three.js 库。
今天做些不一样的东西（如 MeshBasicMaterial，MeshLambertMaterial 和 MeshPhongMaterial），尽量使用各种参数（color，opacity，ambient，emissive，specular），讲解如何制作纹理和凹凸映射的使用。
HTML
如果你已经完成了第一课，那这里没什么新的内容。
这是要使用的 HTML 代码：
<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="utf-8" />
<meta name="author" content="Script Tutorials" />
<title>WebGL With Three.js - Lesson 2 | Script Tutorials</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<link href="css/main.css" rel="stylesheet" type="text/css" />
</head>
<body>
<script src="js/three.min.js"></script>
<script src="js/THREEx.WindowResize.js"></script>
<script src="js/OrbitControls.js"></script>
<script src="js/stats.min.js"></script>
<script src="js/script.js"></script>
</body>
</html>
Javascript
主要场景
我们借用以前教程的主体代码
var particleLight;
var lesson2 = {
scene: null,
camera: null,
renderer: null,
container: null,
controls: null,
clock: null,
stats: null,
init: function() { // Initialization
// 创建主场景
this.scene = new THREE.Scene();
var SCREEN_WIDTH = window.innerWidth,
SCREEN_HEIGHT = window.innerHeight;
// 准备照相机
var VIEW_ANGLE = 45, ASPECT = SCREEN_WIDTH / SCREEN_HEIGHT, NEAR = 1, FAR = 5000;
this.camera = new THREE.PerspectiveCamera( VIEW_ANGLE, ASPECT, NEAR, FAR);
this.scene.add(this.camera);
this.camera.position.set(100, 1000, 1000);
this.camera.lookAt(new THREE.Vector3(0,0,0));
// 准备渲染器
this.renderer = new THREE.WebGLRenderer({antialias:true, alpha: false});
this.renderer.setSize(SCREEN_WIDTH, SCREEN_HEIGHT);
this.renderer.setClearColor(0xffffff);
this.renderer.shadowMapEnabled = true;
this.renderer.shadowMapSoft = true;
// 容器
this.container = document.createElement('div');
document.body.appendChild(this.container);
this.container.appendChild(this.renderer.domElement);
// 事件
THREEx.WindowResize(this.renderer, this.camera);
// 轨道控制器 (OrbitControls)
this.controls = new THREE.OrbitControls(this.camera, this.renderer.domElement);
this.controls.target = new THREE.Vector3(0, 0, 0);
// 时钟
this.clock = new THREE.Clock();
// 统计
this.stats = new Stats();
this.stats.domElement.style.position = 'absolute';
this.stats.domElement.style.bottom = '0px';
this.stats.domElement.style.zIndex = 10;
this.container.appendChild( this.stats.domElement );
// 直线光照
var dLight = new THREE.DirectionalLight(0xffffff);
dLight.position.set(1, 300, 1);
dLight.castShadow = true;
// dLight.shadowCameraVisible = true;
dLight.shadowDarkness = 0.2;
dLight.shadowMapWidth = dLight.shadowMapHeight = 1000;
this.scene.add(dLight);
// 特定光照
particleLight = new THREE.Mesh( new THREE.SphereGeometry(10, 10, 10), new THREE.MeshBasicMaterial({ color: 0xffffaa }));
particleLight.position = dLight.position;
this.scene.add(particleLight);
// 背景
var groundGeometry = new THREE.PlaneGeometry(1200, 1200, 1, 1);
ground = new THREE.Mesh(groundGeometry, new THREE.MeshLambertMaterial({
color: 0xFF62B0
}));
ground.position.y = 0;
ground.rotation.x = - Math.PI / 2;
ground.receiveShadow = true;
this.scene.add(ground);
}
};
// 给场景加动画
function animate() {
requestAnimationFrame(animate);
render();
update();
}
// 更新控制器和统计
function update() {
lesson2.controls.update(lesson2.clock.getDelta());
lesson2.stats.update();
// smoothly move the particleLight
var timer = Date.now() * 0.000025;
particleLight.position.x = Math.sin(timer * 5) * 300;
particleLight.position.z = Math.cos(timer * 5) * 300;
}
// 渲染场景
function render() {
if (lesson2.renderer) {
lesson2.renderer.render(lesson2.scene, lesson2.camera);
}
}
// 初始化页面
function initializeLesson() {
lesson2.init();
animate();
}
if (window.addEventListener)
window.addEventListener('load', initializeLesson, false);
else if (window.attachEvent)
window.attachEvent('onload', initializeLesson);
else window.onload = initializeLesson;
颜色
和第一课一样，添加一个函数来生成一个随机的颜色（当然这个随机颜色是从预定义的颜色阵列里随机选择）：
var colors = [
0xFF62B0,
0x9A03FE,
0x62D0FF,
0x48FB0D,
0xDFA800,
0xC27E3A,
0x990099,
0x9669FE,
0x23819C,
0x01F33E,
0xB6BA18,
0xFF800D,
0xB96F6F,
0x4A9586
];
function getRandColor() {
return colors[Math.floor(Math.random() * colors.length)];
}
创建并使用 SphereGeometry 网格来画一个球体：
drawSphere: function(x, z, material) {
var cube = new THREE.Mesh(new THREE.SphereGeometry(70, 70, 20), material);
cube.rotation.x = cube.rotation.z = Math.PI * Math.random();
cube.position.x = x;
cube.position.y = 100;
cube.position.z = z;
cube.castShadow = cube.receiveShadow = true;
this.scene.add(cube);
}
材料
如果你已经观看了Demo，很容易就会发现从简单到复杂整个被分成了好几个部分：
- 从左到右开始结束的三个球是最简单的：使用了MeshBasicMaterial，MeshLambertMaterial 和MeshPhongMaterial，且仅使用了
color - 接下来的三个球几乎是相同的，但设置为半透明（透明度为0.5），第二行使用以下属性进行不同的组合：环境（ambient）、发射（emissive）、反射（specular）、光泽（shininess）
- 最后的三排，使用纹理和凹凸组合：
var mlib = {
'1': new THREE.MeshBasicMaterial({ color: getRandColor() }),
'2': new THREE.MeshLambertMaterial({ color: getRandColor() }),
'3': new THREE.MeshPhongMaterial({ color: getRandColor() }),
'4': new THREE.MeshBasicMaterial({ color: getRandColor(), opacity: 0.5, transparent: true }),
'5': new THREE.MeshLambertMaterial({ color: getRandColor(), opacity: 0.5, transparent: true }),
'6': new THREE.MeshPhongMaterial({ color: getRandColor(), opacity: 0.5, transparent: true }),
'7': new THREE.MeshLambertMaterial({ color: 0xff0000, ambient: 0xffffff }),
'8': new THREE.MeshLambertMaterial({ color: 0xff0000, emissive: 0x000088 }),
'9': new THREE.MeshPhongMaterial({ color: 0xff0000, ambient: 0x3ffc33 }),
'10': new THREE.MeshPhongMaterial({ color: 0xff0000, emissive: 0x000088 }),
'11': new THREE.MeshPhongMaterial({ color: 0xff0000, emissive: 0x004000, specular: 0x0022ff }),
'12': new THREE.MeshPhongMaterial({ color: 0xff0000, specular: 0x0022ff, shininess: 3 }),
'13': new THREE.MeshLambertMaterial({ map: texture, color: 0xff0000, ambient: 0x3ffc33 }),
'14': new THREE.MeshLambertMaterial({ map: texture, color: 0xff0000, emissive: 0x000088 }),
'15': new THREE.MeshLambertMaterial({ map: texture, color: 0xff0000, emissive: 0x004000, specular: 0x0022ff }),
'16': new THREE.MeshLambertMaterial({ map: texture, color: 0xff0000, specular: 0x0022ff, shininess: 3 }),
'17': new THREE.MeshPhongMaterial({ map: texture, color: 0xff0000, ambient: 0x3ffc33 }),
'18': new THREE.MeshPhongMaterial({ map: texture, color: 0xff0000, emissive: 0x000088 }),
'19': new THREE.MeshPhongMaterial({ map: texture, color: 0xff0000, emissive: 0x004000, specular: 0x0022ff }),
'20': new THREE.MeshPhongMaterial({ map: texture, color: 0xff0000, specular: 0x0022ff, shininess: 3 }),
'21': new THREE.MeshPhongMaterial({ map: texture, bumpMap: textureBump, color: 0xff0000, ambient: 0x3ffc33 }),
'22': new THREE.MeshPhongMaterial({ map: texture, bumpMap: textureBump, color: 0xff0000, emissive: 0x000088 }),
'23': new THREE.MeshPhongMaterial({ map: texture, bumpMap: textureBump, color: 0xff0000, emissive: 0x004000, specular: 0x0022ff }),
'24': new THREE.MeshPhongMaterial({ map: texture, bumpMap: textureBump, color: 0xff0000, specular: 0x0022ff, shininess: 3 }),
}
把这些材料加入数组方便待会儿的使用。注意这里使用了两个纹理，一是“映射”，其次是“凹凸映射”。代码如下：
var texture = THREE.ImageUtils.loadTexture('texture.png');
texture.repeat.set(10, 10);
texture.wrapS = texture.wrapT = THREE.RepeatWrapping;
texture.anisotropy = 16;
texture.needsUpdate = true;
var textureBump = THREE.ImageUtils.loadTexture('bump.png');
textureBump.repeat.set(10, 10);
textureBump.wrapS = textureBump.wrapT = THREE.RepeatWrapping;
textureBump.anisotropy = 16;
textureBump.needsUpdate = true;
现在只需要把不同位置的球用上不同的材料：
// add spheres with different materials
this.drawSphere(-550, 400, mlib['1']);
this.drawSphere(-350, 400, mlib['2']);
this.drawSphere(-150, 400, mlib['3']);
this.drawSphere( 150, 400, mlib['4']);
this.drawSphere( 350, 400, mlib['5']);
this.drawSphere( 550, 400, mlib['6']);
this.drawSphere(-550, 200, mlib['7']);
this.drawSphere(-350, 200, mlib['8']);
this.drawSphere( -50, 200, mlib['9']);
this.drawSphere( 150, 200, mlib['10']);
this.drawSphere( 350, 200, mlib['11']);
this.drawSphere( 550, 200, mlib['12']);
this.drawSphere(-250, 0, mlib['13']);
this.drawSphere( -90, 0, mlib['14']);
this.drawSphere( 90, 0, mlib['15']);
this.drawSphere( 250, 0, mlib['16']);
this.drawSphere(-250, -200, mlib['17']);
this.drawSphere( -90, -200, mlib['18']);
this.drawSphere( 90, -200, mlib['19']);
this.drawSphere( 250, -200, mlib['20']);
this.drawSphere(-250, -400, mlib['21']);
this.drawSphere( -90, -400, mlib['22']);
this.drawSphere( 90, -400, mlib['23']);
this.drawSphere( 250, -400, mlib['24']);
好啦，今天的教程就到这里。
