How to create the rainfall in html5 canvas using javascript

how to make rainfall effect in html5 canvas using javascript - Nibunan

how to create rainfall in html5 canvas using javascript - Nibunan

how to write program to display rainfall effect in html5 canvas using javascript - Nibunan

how to write program to create rainfall animation in html5 canvas using javascript - Nibunan

how to write code to create rainfall effect in html5 canvas using javascript - Nibunan

Html5 canvas is evolving to give the rich graphics on browser without using flash or other plugins. Html5 canvas is being used in many places like games animations and rich user interfaces on web and so on.This airticle explains how to create rainfall effect in html5 canvas using javascript.

Demo

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Source


      <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
      <html xmlns="http://www.w3.org/1999/xhtml">
      <head>
      <title>Creating rainfall effect in html5 canvas - Nibunan</title>
      </head>
      <body style="margin: 0px">
      <canvas width="700" height="450" id="drawing-surface"></canvas>
      <audio style="display:none" id="myAudio" controls="" loop="">
      <source src="rain.wav" />
      </audio>
      <script type="text/javascript">
      var audio = document.getElementById("myAudio");
      var timer = setTimeout(function () { audio.play() }, 2000);
      function Random(range) {
      return Math.floor((Math.random() * range) + 1);
      }
      function RandomFloat(range) {
      return (Math.random() * range) + 1;
      }
      var viewport = new Viewport()
      for (var i = 0; i < 2000; i++) {
      var rain = new RainParticle();
      viewport.addObject(rain);
      }
      viewport.init();
      </script>
      </body>
      </html>
    

Viewport


      function Viewport() {
      var me = this;
      me.objects = [];
      var canvas = document.getElementById("drawing-surface");
      function resizeCanvas() {
      canvas.width = window.innerWidth;
      canvas.height = window.innerHeight;
      }
      resizeCanvas();
      window.onresize = function () {
      resizeCanvas();
      }
      var drawingSurface = document.getElementById("drawing-surface").getContext("2d");
      var image = new Image();
      image.src = "background.png";
      image.onload = function () {
      me.backgroundImage = image;
      me.doPaint = true;
      }
      me.doPaint = true;
      function drawBackgroundImage() {
      if (me.backgroundImage) {
      drawingSurface.drawImage(me.backgroundImage, 0, 0, canvas.width, canvas.height);
      }
      }
      function drawObjects() {
      for (var i = 0; i < me.objects.length; i++) {
      me.objects[i].paint(drawingSurface);
      }
      }
      me.paintInit = function () {
      me.doPaint = true;
      }
      function paint() {
      me.paintInit();
      if (me.doPaint) {
      drawBackgroundImage();
      drawObjects();
      me.doPaint = false;
      }
      }
      var timer;
      me.init = function () {
      timer = setInterval(function () { paint(); }, 1000 / 30);
      };
      me.repaint = function () {
      me.doPaint = true;
      };
      me.addObject = function (obj) {
      me.objects.push(obj);
      }
      }
    

Rain Particle


      function RainParticle() {
      var me = this;
      me.reset = function () {
      me.wind = 2;
      me.speed = RandomFloat(30) + 10;
      me.size = { width: 1 , height: RandomFloat(20) +10};
      me.location = { x: RandomFloat(window.innerWidth), y: -50 };
      };
      me.reset();
      me.move = function () {
      if (me.location.y > window.innerWidth || me.location.x < 0 || me.location.x > window.innerWidth) {
      me.reset();
      }
      me.location.x += me.wind;
      me.location.y += me.speed;
      };
      me.paint = function (context) {
      me.move();
      context.beginPath();
      context.moveTo(me.location.x, me.location.y);
      context.lineTo(me.location.x+2, me.location.y + me.size.height);
      context.strokeStyle = "rgb(198,212,239)";
      context.stroke();
      context.closePath();
      };
      }