threejs使用canvas更新纹理代码实例
作者:gis分享者
在使用three.js开发的过程中,我们常常使用canvas来作为纹理贴图,下面这篇文章主要介绍了如何基于Three.js在三维场景中使用Canvas更新纹理,通过实现思路和代码样例,帮助读者掌握这一技能,需要的朋友可以参考下
一、前言
本文详细介绍如何基于threejs在三维场景中使用canvas更新纹理,亲测可用。希望能帮助到您。一起学习,加油!加油!
1.1 Texture 贴图
创建一个纹理贴图,将其应用到一个表面,或者作为反射/折射贴图。
构造函数:Texture( image, mapping, wrapS, wrapT, magFilter, minFilter, format, type, anisotropy, encoding )
常用属性:
方法:
二、使用canvas更新纹理
1. 实现思路
- 1、初始化renderer渲染器
- 2、初始化Scene三维场景scene,创建THREE.CubeTextureLoader立方体纹理加载器cubeTextureLoader,加载cubeTextureLoader的六个方位的图片获取纹理对象cubeTexture,scene背景background设置为cubeTexture。
- 3、创建id为‘surface’的canvas页面元素火焰然后动画,并执行。具体实现参考下面代码样例。
- 4、初始化camera相机,定义相机位置 camera.position.set
- 5、初始化THREE.AmbientLight环境光源,scene场景加入环境光源,初始化THREE.DirectionalLight平行光源,设置平行光源位置,设置平行光源投影,scene添加平行光源。
- 6、加载几何模型:创建THREE.AxesHelper坐标辅助工具helper,scene场景中加入helper。创建THREE.BoxGeometry立方体几何体geometry,创建THREE.MeshBasicMaterial基础材质material,material设置map贴图(为步骤3canvas元素)、水平和垂直贴图包裹,传入geometry和material创建THREE.Mesh网格对象,scene中加入创建的网格对象。
- 7、加入controls控制,加入stats监控器,监控帧数信息。
2. 代码样例
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>learn60(使用CANVAS更新纹理)</title> <script src="lib/threejs/127/three.js-master/build/three.js"></script> <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script> <script src="lib/threejs/127/three.js-master/examples/js/controls/OrbitControls.js"></script> <script src="lib/threejs/127/three.js-master/examples/js/libs/stats.min.js"></script> <script src="lib/threejs/127/three.js-master/examples/js/libs/dat.gui.min.js"></script> <script src="lib/js/Detector.js"></script> </head> <style type="text/css"> html, body { margin: 0; height: 100%; } canvas { display: block; } #surface { position: fixed; left: 0; bottom: 0; } </style> <body onload="draw()"> <canvas id="surface"></canvas> </body> <script> var renderer, camera, scene, gui, light, stats, controls //引入一个canvas动画 function initCanvas() { $(document).ready(function () { // Set canvas drawing surface var space = document.getElementById("surface") var surface = space.getContext("2d") surface.scale(1, 1) // Set Particles var particles = [] var particle_count = 150 for (var i = 0; i < particle_count; i++) { particles.push(new particle()) } var time = 0 // Set wrapper and canvas items size var canvasWidth = 480 var canvasHeight = 480 $(".wrapper").css({width: canvasWidth, height: canvasHeight}) $("#surface").css({width: canvasWidth, height: canvasHeight}) // shim layer with setTimeout fallback from Paul Irish window.requestAnimFrame = (function () { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function (callback) { window.setTimeout(callback, 6000 / 60) } })() function particle() { this.speed = {x: -1 + Math.random() * 2, y: -5 + Math.random() * 5} canvasWidth = (document.getElementById("surface").width) canvasHeight = (document.getElementById("surface").height) this.location = {x: canvasWidth / 2, y: (canvasHeight / 2) + 35} this.radius = .5 + Math.random() * 1 this.life = 10 + Math.random() * 10 this.death = this.life this.r = 255 this.g = Math.round(Math.random() * 155) this.b = 0 } function ParticleAnimation() { surface.globalCompositeOperation = "source-over" surface.fillStyle = "black" surface.fillRect(0, 0, canvasWidth, canvasHeight) surface.globalCompositeOperation = "lighter" for (var i = 0; i < particles.length; i++) { var p = particles[i] surface.beginPath() p.opacity = Math.round(p.death / p.life * 100) / 100 var gradient = surface.createRadialGradient(p.location.x, p.location.y, 0, p.location.x, p.location.y, p.radius) gradient.addColorStop(0, "rgba(" + p.r + ", " + p.g + ", " + p.b + ", " + p.opacity + ")") gradient.addColorStop(0.5, "rgba(" + p.r + ", " + p.g + ", " + p.b + ", " + p.opacity + ")") gradient.addColorStop(1, "rgba(" + p.r + ", " + p.g + ", " + p.b + ", 0)") surface.fillStyle = gradient surface.arc(p.location.x, p.location.y, p.radius, Math.PI * 2, false) surface.fill() p.death-- p.radius++ p.location.x += (p.speed.x) p.location.y += (p.speed.y) //regenerate particles if (p.death < 0 || p.radius < 0) { //a brand new particle replacing the dead one particles[i] = new particle() } } requestAnimFrame(ParticleAnimation) } ParticleAnimation() }) } var initRender = () => { renderer = new THREE.WebGLRenderer({antialias: true}) renderer.setClearColor(0xeeeeee) renderer.setSize(window.innerWidth, window.innerHeight) renderer.shadowMap.enabled = true renderer.setPixelRatio(window.devicePixelRatio) document.body.appendChild(renderer.domElement) } var initCamera = () => { camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000) camera.position.set(0, 0, 15) } var initScene = () => { var cubeTextureLoader = new THREE.CubeTextureLoader() cubeTextureLoader.setPath('data/texture/skybox/space/') var cubeTexture = cubeTextureLoader.load([ 'right.jpg', 'left.jpg', 'top.jpg', 'bottom.jpg', 'front.jpg', 'back.jpg' ]) scene = new THREE.Scene() scene.background = cubeTexture } var initLight = () => { scene.add(new THREE.AmbientLight(0x444444)) light = new THREE.DirectionalLight(0xffffff) light.position.set(0, 20, 20) light.castShadow = true scene.add(light) } var initModel = () => { var helper = new THREE.AxesHelper(50) scene.add(helper) var geometry = new THREE.BoxBufferGeometry(5, 5, 5) var canvas = $('#surface')[0] var texture = new THREE.Texture(canvas) material = new THREE.MeshBasicMaterial({map: texture}) scene.add(new THREE.Mesh(geometry, material)) } var initStats = () => { stats = new Stats() document.body.appendChild(stats.dom) } var initControls = () => { controls = new THREE.OrbitControls(camera, renderer.domElement) controls.enableDamping = true } var render = () => { material.map.needsUpdate = true renderer.render(scene, camera) } var onWindowResize = () => { camera.aspect = window.innerWidth / window.innerHeight camera.updateProjectionMatrix() renderer.setSize(window.innerWidth, window.innerHeight) } var animate = () => { render() stats.update() controls.update() requestAnimationFrame(animate) } var draw = () => { if(!Detector.webgl)Detector.addGetWebGLMessage() initCanvas() initRender() initScene() initCamera() initLight() initModel() initStats() initControls() animate() window.onresize = onWindowResize } </script> </html>
效果如下:
总结
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