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小程序中使用three.js

在小程序中使用three.js, 支持基本模型,OrbitControl, GTLFLoader, OBJLoader等。

小程序中使用three.js

目前小程序支持了webgl, 同时项目中有相关3D展示的需求,所以考虑将three.js移植到小程序中。
但是小程序里面没有浏览器相关的运行环境如 window,document等。要想在小程序中使用three.js需要使用相应的移植版本https://github.com/yannliao/three.js实现了一个在 three.js 的基本移植版, 目前测试支持了 包含 BoxBufferGeometry, CircleBufferGeometry, ConeBufferGeometry, CylinderBufferGeometry, DodecahedronBufferGeometry 等基本模型,OrbitControl, GTLFLoader, OBJLoader等。

使用

下载https://github.com/yannliao/three.js项目中build目录下的three.weapp.min.js到小程序相应目录,如:

在index.wxml中加入canvas组件, 其中需要手动绑定相应的事件,用于手势控制。

<view style="height: 100%; width: 100%;" bindtouchstart="documentTouchStart" bindtouchmove="documentTouchMove" bindtouchend="documentTouchEnd" >
    <canvas type="webgl" id="c" style="width: 100%; height:100%;" bindtouchstart="touchStart" bindtouchmove="touchMove" bindtouchend="touchEnd" bindtouchcancel="touchCancel" bindlongtap="longTap" bindtap="tap"></canvas>
</view>

在页面中引用three.js 和相应的Loader:

import * as THREE from '../../libs/three.weapp.min.js'
import { OrbitControls } from '../../jsm/loaders/OrbitControls'

在onLoad中获取canvas对象并注册到THREE.global中,THREE.global.registerCanvas可以传入id, 用于通过THREE.global.document.getElementById找到, 如果不传id默认使用canvas对象中的_canvasID, registerCanvas同时也会将该canvas选为当前使用canvas对象. 同时请在onUnload回调中注销canvas对象. 注意: THREE.global 中最多同时注册 5 个canvas对象, 并可以通过id找到. 注册的canvas对象, 会长驻内存, 如果不及时清理可能造成内存问题. THREE.globalthree.js 的运行环境, 类似于浏览器中的window.

Page({
    data: {
        canvasId: ''
    },
    onLoad: function () {
        wx.createSelectorQuery()
        .select('#c')
        .node()
        .exec((res) => {
            const canvas = THREE.global.registerCanvas(res[0].node)
            this.setData({ canvasId: canvas._canvasId })
            // const canvas = THREE.global.registerCanvas('id_123', res[0].node)
            // canvas代码
        })
    },
    onUnload: function () {
        THREE.global.unregisterCanvas(this.data.canvasId)
        // THREE.global.unregisterCanvas(res[0].node)
        // THREE.global.clearCanvas()
    },

注册相关touch事件. 由于小程序架构原因, 需要手动绑定事件到THREE.global.canvas或者THREE.global.document上. 可以使用THREE.global.touchEventHandlerFactory('canvas', 'touchstart') 生成小程序的事件回调函数,触发默认canvas对象上的touch事件.


{
  touchStart(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchstart')(e)
  },
  touchMove(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchmove')(e)
  },
  touchEnd(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchend')(e)
  },
}

编写three.js代码, 小程序运行环境中没有requestAnimationFrame, 目前可以使用canvas.requestAnimationFrame之后会将requestAnimationFrame注入到THREE.global中.

const camera = new THREE.PerspectiveCamera(70, canvas.width / canvas.height, 1, 1000);
camera.position.z = 500;
const scene = new THREE.Scene();
scene.background = new THREE.Color(0xAAAAAA);
const renderer = new THREE.WebGLRenderer({ antialias: true });

const controls = new OrbitControls(camera, renderer.domElement);
// controls.enableDamping = true;
// controls.dampingFactor = 0.25;
// controls.enableZoom = false;
camera.position.set(200, 200, 500);
controls.update();
const geometry = new THREE.BoxBufferGeometry(200, 200, 200);

const texture = new THREE.TextureLoader().load('./pikachu.png');
const material = new THREE.MeshBasicMaterial({ map: texture });

// const material = new THREE.MeshBasicMaterial({ color: 0x44aa88 });
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);

// renderer.setPixelRatio(wx.getSystemInfoSync().pixelRatio);
// renderer.setSize(canvas.width, canvas.height);

function onWindowResize() {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize(canvas.width, canvas.height);
}
function render() {
    canvas.requestAnimationFrame(render);
    // mesh.rotation.x += 0.005;
    // mesh.rotation.y += 0.01;
    controls.update();
    renderer.render(scene, camera);
}

render()

完整示例:

index.js

import * as THREE from '../../libs/three.weapp.min.js'
import { OrbitControls } from '../../jsm/loaders/OrbitControls'

Page({
  data: {},
  onLoad: function () {
    wx.createSelectorQuery()
      .select('#c')
      .node()
      .exec((res) => {
        const canvas = THREE.global.registerCanvas(res[0].node)
        
        this.setData({ canvasId: canvas._canvasId })

        const camera = new THREE.PerspectiveCamera(70, canvas.width / canvas.height, 1, 1000);
        camera.position.z = 500;
        const scene = new THREE.Scene();
        scene.background = new THREE.Color(0xAAAAAA);
        const renderer = new THREE.WebGLRenderer({ antialias: true });
      
        const controls = new OrbitControls(camera, renderer.domElement);
        // controls.enableDamping = true;
        // controls.dampingFactor = 0.25;
        // controls.enableZoom = false;
        camera.position.set(200, 200, 500);
        controls.update();
        const geometry = new THREE.BoxBufferGeometry(200, 200, 200);
      
        const texture = new THREE.TextureLoader().load('./pikachu.png');
        const material = new THREE.MeshBasicMaterial({ map: texture });
      
        // const material = new THREE.MeshBasicMaterial({ color: 0x44aa88 });
        const mesh = new THREE.Mesh(geometry, material);
        scene.add(mesh);
      
        // renderer.setPixelRatio(wx.getSystemInfoSync().pixelRatio);
        // renderer.setSize(canvas.width, canvas.height);
      
        function onWindowResize() {
          camera.aspect = window.innerWidth / window.innerHeight;
          camera.updateProjectionMatrix();
          renderer.setSize(canvas.width, canvas.height);
        }
        function render() {
          canvas.requestAnimationFrame(render);
          // mesh.rotation.x += 0.005;
          // mesh.rotation.y += 0.01;
          controls.update();
          renderer.render(scene, camera);
        }

        render()

      })
  },
  onUnload: function () {
    THREE.global.unregisterCanvas(this.data.canvasId)
  },
  touchStart(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchstart')(e)
  },
  touchMove(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchmove')(e)
  },
  touchEnd(e) {
    console.log('canvas', e)
    THREE.global.touchEventHandlerFactory('canvas', 'touchend')(e)
  },
  touchCancel(e) {
    // console.log('canvas', e)
  },
  longTap(e) {
    // console.log('canvas', e)
  },
  tap(e) {
    // console.log('canvas', e)
  },
  documentTouchStart(e) {
    // console.log('document',e)
  },
  documentTouchMove(e) {
    // console.log('document',e)
  },
  documentTouchEnd(e) {
    // console.log('document',e)
  },
})

index.wxml

<view style="height: 100%; width: 100%;" bindtouchstart="documentTouchStart" bindtouchmove="documentTouchMove" bindtouchend="documentTouchEnd" >
    <canvas type="webgl" id="c" style="width: 100%; height:100%;" bindtouchstart="touchStart" bindtouchmove="touchMove" bindtouchend="touchEnd" bindtouchcancel="touchCancel" bindlongtap="longTap" bindtap="tap"></canvas>
</view>

其他

全部示例在 https://github.com/yannliao/threejs-example

three.js 库 https://github.com/yannliao/three.js

loader 组件在 threejs-example 中的 jsm 目录中

欢迎提交PR和issue

最后一次编辑于  2019-10-20  
点赞 6
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评论

25 个评论

  • 🌞
    🌞
    2019-12-06

    怎么样让模型消失呢,现在返回上一页面 再进入模型展示的页面 之前的模型 还存在在页面当中

    2019-12-06
    赞同
    回复 4
    • Yann
      Yann
      2019-12-06
      释放回收  threejs对象资源和上下文   具体可以去看示例里面
      2019-12-06
      回复
    • 🌞
      🌞
      2019-12-06回复Yann
      在onHide时注销了它 可是 并没有变化 是需要 其他操作吗
      2019-12-06
      回复
    • Yann
      Yann
      2019-12-06回复🌞
      不是这个    示例里面有介绍
      2019-12-06
      回复
    • Yann
      Yann
      2019-12-06回复🌞
      是 three.js   对象的dispose
      2019-12-06
      回复
  • 。我叫杨小花
    。我叫杨小花
    2019-11-06

    能不能引入wrl格式的文件呀

    2019-11-06
    赞同
    回复 1
    • Yann
      Yann
      2019-12-06
      wrl  是什么?
      2019-12-06
      回复
  • Interesting  soul
    Interesting soul
    2019-10-31

    您好,我通过npm安装THREE后,想使用OrbitControls组件,但是OrbitControls组件需要引入three.weapp.js,因为小程序有2M的大小限制,我想请问下针对这个限制,有没有什么好办法呢?

    2019-10-31
    赞同
    回复 4
    • Interesting  soul
      Interesting soul
      2019-10-31
      还有一个问题就是,我做了一个球体,开发工具上是正常的,到了IOS真机上预览就成了扁的,安卓还没测试~
      2019-10-31
      回复
    • Yann
      Yann
      2019-10-31
      小程序里不需要npm install  直接下载 three.weapp.min.js (压缩过的) 放在相应目录 引用 。  扁的应该是ios 宽度计算有问题, 你用canvas.width/canvas.height 设置aspect看下?
      2019-10-31
      回复
    • Interesting  soul
      Interesting soul
      2019-10-31回复Yann
      您说的aspect是相机的aspect?设置了还是一样啊~
      2019-10-31
      回复
    • Interesting  soul
      Interesting soul
      2019-10-31回复Yann
      好了,没看到,我把render  sesize成了屏幕的宽度...嘿嘿
      2019-10-31
      回复
  • KK
    KK
    2019-10-30


    你好,有个问题请教下。IOS真机可以跑,华为手机跑不了。是啥原因?

    2019-10-30
    赞同
    回复 1
    • Yann
      Yann
      2019-10-30
      你把小程序调试打开 信息打到 vconsole 里面,提个issue呗~
      2019-10-30
      回复

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