前言
Three.js 是一款运行在浏览器中的 3D 引擎，你可以用它创建各种三维场景，包括了摄影机、光影、材质等各种对象。
一个典型的 Three.js 程序至少要包括渲染器（Renderer）、场景（Scene）、照相机（Camera），以及你在场景中创建的物体。
Three.js相关文档：http://docs.thingjs.com/
一、Three.js的使用
安装第三方包：npm i --save threejs-miniprogram
1.球体的绘制
<view style="display:inline-block;">
<button size="mini" type="primary" class="btn" bindtap="play">走</button>
<button size="mini" type="primary" class="btn" bindtap="play">跳</button>
<button size="mini" type="primary" class="btn" bindtap="play">坐</button>
<button size="mini" type="primary" class="btn" bindtap="play">站</button>
</view>
<canvas
type="webgl"
style="width: 100%; height: 450px;"
bindtouchstart="touchStart"
bindtouchmove="touchMove"
bindtouchend="touchEnd"
></canvas>
import { createScopedThreejs } from 'threejs-miniprogram'
const { renderSphere } = require('../../../lib/test-cases/sphere')
const app = getApp()
Page({
data: {},
onLoad: function () {
wx.createSelectorQuery()
.select('#webgl')
.node()
.exec((res) => {
const canvas = res[0].node
this.canvas = canvas
const THREE = createScopedThreejs(canvas)
renderSphere(canvas, THREE)//球
})
},
play(e){
let action = e.currentTarget.dataset.action
this.fadeToAction(action)
},
touchStart(e) {
this.canvas.dispatchTouchEvent({...e, type:'touchstart'})
},
touchMove(e) {
this.canvas.dispatchTouchEvent({...e, type:'touchmove'})
},
touchEnd(e) {
this.canvas.dispatchTouchEvent({...e, type:'touchend'})
}
})
二、球体相关js文件
export function renderSphere(canvas, THREE) {
var container, stats;
var camera, scene, renderer;
var pointLight;
var objects = [], materials = [];
init();
animate();
function init() {
camera = new THREE.PerspectiveCamera(45, canvas.width / canvas.height, 1, 2000);
camera.position.set(0, 200, 800);
scene = new THREE.Scene();
// Grid
var helper = new THREE.GridHelper(1000, 40, 0x303030, 0x303030);
helper.position.y = - 75;
scene.add(helper);
// Materials
// var texture = new THREE.Texture(generateTexture());
// texture.needsUpdate = true;
// materials.push(new THREE.MeshLambertMaterial({ map: texture, transparent: true }));
materials.push(new THREE.MeshLambertMaterial({ color: 0xdddddd }));
materials.push(new THREE.MeshPhongMaterial({ color: 0xdddddd, specular: 0x009900, shininess: 30, flatShading: true }));
materials.push(new THREE.MeshNormalMaterial());
materials.push(new THREE.MeshBasicMaterial({ color: 0xffaa00, transparent: true, blending: THREE.AdditiveBlending }));
materials.push(new THREE.MeshLambertMaterial({ color: 0xdddddd }));
materials.push(new THREE.MeshBasicMaterial({ color: 0xffaa00, wireframe: true }));
// materials.push(new THREE.MeshPhongMaterial({ color: 0xdddddd, specular: 0x009900, shininess: 30, map: texture, transparent: true }));
materials.push(new THREE.MeshBasicMaterial({ color: 0xffaa00, transparent: true, blending: THREE.AdditiveBlending }));
materials.push(new THREE.MeshNormalMaterial({ flatShading: true }));
materials.push(new THREE.MeshBasicMaterial({ color: 0xffaa00, wireframe: true }));
materials.push(new THREE.MeshDepthMaterial());
materials.push(new THREE.MeshLambertMaterial({ color: 0x666666, emissive: 0xff0000 }));
materials.push(new THREE.MeshPhongMaterial({ color: 0x000000, specular: 0x666666, emissive: 0xff0000, shininess: 10, opacity: 0.9, transparent: true }));
materials.push(new THREE.MeshPhongMaterial({ color: 0x000000, specular: 0x666666, emissive: 0xff0000, shininess: 10, opacity: 0.9, transparent: true }));
// materials.push(new THREE.MeshBasicMaterial({ map: texture, transparent: true }));
// Spheres geometry
var geometry = new THREE.SphereBufferGeometry(70, 32, 16);
for (var i = 0, l = materials.length; i < l; i++) {
addMesh(geometry, materials[i]);
}
// Lights
scene.add(new THREE.AmbientLight(0x111111));
var directionalLight = new THREE.DirectionalLight(0xffffff, 0.125);
directionalLight.position.x = Math.random() - 0.5;
directionalLight.position.y = Math.random() - 0.5;
directionalLight.position.z = Math.random() - 0.5;
directionalLight.position.normalize();
scene.add(directionalLight);
pointLight = new THREE.PointLight(0xffffff, 1);
scene.add(pointLight);
pointLight.add(new THREE.Mesh(new THREE.SphereBufferGeometry(4, 8, 8), new THREE.MeshBasicMaterial({ color: 0xffffff })));
//
renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
renderer.setPixelRatio(wx.getSystemInfoSync().pixelRatio);
renderer.setSize(canvas.width ,canvas.height);
}
function addMesh(geometry, material) {
var mesh = new THREE.Mesh(geometry, material);
mesh.position.x = (objects.length % 4) * 200 - 400;
mesh.position.z = Math.floor(objects.length / 4) * 200 - 200;
mesh.rotation.x = Math.random() * 200 - 100;
mesh.rotation.y = Math.random() * 200 - 100;
mesh.rotation.z = Math.random() * 200 - 100;
objects.push(mesh);
scene.add(mesh);
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
}
function generateTexture() {
canvas.width = 256;
canvas.height = 256;
var context = canvas.getContext('2d');
var image = context.getImageData(0, 0, 256, 256);
var x = 0, y = 0;
for (var i = 0, j = 0, l = image.data.length; i < l; i += 4, j++) {
x = j % 256;
y = x == 0 ? y + 1 : y;
image.data[i] = 255;
image.data[i + 1] = 255;
image.data[i + 2] = 255;
image.data[i + 3] = Math.floor(x ^ y);
}
context.putImageData(image, 0, 0);
return canvas;
}
//
function animate() {
render();
canvas.requestAnimationFrame(animate);
}
function render() {
var timer = 0.0005 * Date.now();
camera.position.x = Math.cos(timer) * 1000;
camera.position.z = Math.sin(timer) * 1000;
camera.lookAt(scene.position);
for (var i = 0, l = objects.length; i < l; i++) {
var object = objects[i];
object.rotation.x += 0.01;
object.rotation.y += 0.005;
}
// materials[materials.length - 2].emissive.setHSL(0.54, 1, 0.35 * (0.5 + 0.5 * Math.sin(35 * timer)));
// materials[materials.length - 3].emissive.setHSL(0.04, 1, 0.35 * (0.5 + 0.5 * Math.cos(35 * timer)));
pointLight.position.x = Math.sin(timer * 7) * 300;
pointLight.position.y = Math.cos(timer * 5) * 400;
pointLight.position.z = Math.cos(timer * 3) * 300;
renderer.render(scene, camera);
}
}
三、效果图
四、总结
three.js画一个图形主要经历如下八个步骤：
- 1.创建透视相机
- 2.创建场景
- 3.创建光源
- 4.构造辅助网格
- 5.创建加载器，加载模型文件
- 6.创建渲染器，渲染场景
- 7.创建控制器
- 8.循环渲染场景