Use JavaScript and canvas for snow-animated effects

Last Update:2015-07-14 Source: Internet

Author: User

Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

The snow animation effect is implemented using canvas canvas in HTML5, which involves knowledge and computation of curve motion in physics.

Index.html

<! DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <meta content="width=device-width,initial-scale=1.0,maximum-scale=1.0, User-scalable=no " name=" Viewport ">    <meta content="yes" name="Apple-mobile-web-app-capable" >    <meta content="Black" name=" Apple-mobile-web-app-status-bar-style ">    <meta content="Telephone=no" name="Format-detection">     <meta content="Email=no" name="Format-detection">     <title>Snow</title>    <link rel="stylesheet" href="Css/main.css"> </head><body>    <canvas id="Canvas"></Canvas>    <script src="Js/snow.js"></script>    <script>window.addeventlistener (' load ',  function(){this. Snow = new
       Snow ();        //Initialize the Snow object and start the Snow animation snow.init (). Start ();    });             </script></body></html>

Main.css

HTML,Body{ width: % ; height: % ; Overflow: hidden ; margin: 0  ; padding: 0  ; background-color: #000  ; font-family: Microsoft Black, Chinese fine black, blackbody ;}

Snow.js

( function(exports, undefined){' use strict ';varDocument = Exports.document; function Snow(){         This. colors = [' #fff ']; This. balls = []; This. winddirection =-1; This. Ballradius =3; This. Ballsperframe =2; This. TimeInterval = +; This. Winddirectionchangedinterval = the; This. Accumulativetime =0;return  This;    }; Exports.    Snow = snow; Snow.prototype = {init: function(args){             for(varPinchargs) { This[P] = args[p]; } This. Canvas = This. Canvas | | Document.queryselector (' #canvas '); This. Context = This. Context | | This. Canvas.getcontext (' 2d '); This. Canvaswidth = This. canvaswidth | | Document.body.offsetWidth | | Document.body.clientWidth; This. Canvasheight = This. canvasheight | | Document.body.offsetHeight | | Document.body.clientHeight; This. Canvas.width = This. canvaswidth; This. Canvas.height = This. canvasheight;return  This; }, Start: function(){             This. Timer = This. Timer | | SetTimeout ( This. Frame.bind ( This), This. timeinterval);return  This; }, Frame: function(){             This. accumulativetime + = This. timeinterval; ( This. Accumulativetime% This. winddirectionchangedinterval < This. TimeInterval) && ( This. winddirection *=-1); This. Render.call ( This); This. Update.call ( This); This. Timer =NULL; This. Timer = SetTimeout ( This. Frame.bind ( This), This. timeinterval); }, UPDATE: function(){             This. Addballs.call ( This); This. Updateballs.call ( This); }, Updateballs: function(){            varBalls = This. Balls, Len = balls.length, i =0, cnt =0; for(; i<len;i++) {balls[i].x + = BALLS[I].VX * This. winddirection;                Balls[i].y + = Balls[i].vy;                Balls[i].vy + = BALLS[I].G * BALLS[I].T; balls[i].t + = This. timeinterval;if(Balls[i].y- This. Ballradius < This. canvasheight) {balls[cnt++] = balls[i]; }            } while(len>cnt)                {Balls.pop ();            len--; }}, Addballs: function(){            varBall, i =0, Len = This. ballsperframe, _this = This; for(; i<len;i++) {ball = {x:Math. POW (-1,Math. Ceil (Math. Random () * +)) *Math. Floor (Math. Random () * _this.canvaswidth *1.5), Y:Math. Floor (Math. Random () * This. Ballradius) *-1G:0.00005, VX:1+Math. Floor (Math. Random () *2), VY:2+Math. Floor (Math. Random () *5), T:0, Color: _this.colors[Math. Floor (Math. Random () * _this.colors.length)]} This. Balls.push (ball); }}, Render: function(){            varCXT = This. Context, I =0, Len = This. balls.length; Cxt.clearrect (0,0, This. Canvaswidth, This. canvasheight); for(; i<len;i++) {Cxt.fillstyle = This. Balls[i].color;                Cxt.beginpath (); Cxt.arc ( This. balls[i].x, This. BALLS[I].Y, This. Ballradius,0,2*Math. Pitrue);                Cxt.closepath ();            Cxt.fill (); }}, pause: function(){Cleartimeout ( This. timer); This. Timer =NULL; }, Resume: function(){             This. Start.call ( This); }, clear: function(){Cleartimeout ( This. timer); This. Timer =NULL; This. Context.clearrect (0,0, This. Canvaswidth, This. canvasheight); }}) (window);

Use JavaScript and canvas for snow-animated effects

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

Sales Support

1 on 1 presale consultation

Chat Contact Sales
After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

Open a Ticket
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

Learn More

Use JavaScript and canvas for snow-animated effects

Contact Us

A Free Trial That Lets You Build Big!

Sales Support

After-Sales Support