HTML5的canvas雪花飘落特效

HTML5的canvas雪花飘落特效
一、html代码





雪花飘落








    
    
    
    

二、css代码

@charset "utf-8";
html{height:100%;}
body{
    background:#090b44; /* Old browsers */
    background:-moz-radial-gradient(center, ellipse cover, #090b44 0%, #00001c 100%); /* FF3.6+ */
    background:-webkit-gradient(radial, center center, 0px, center center, 100%, color-stop(0%,#090b44), color-stop(100%,#00001c)); /* Chrome,Safari4+ */
    background:-webkit-radial-gradient(center, ellipse cover, #090b44 0%,#00001c 100%); /* Chrome10+,Safari5.1+ */
    background:-o-radial-gradient(center, ellipse cover, #090b44 0%,#00001c 100%); /* Opera 12+ */
    background:-ms-radial-gradient(center, ellipse cover, #090b44 0%,#00001c 100%); /* IE10+ */
/*  background:radial-gradient(ellipse at center, #090b44 0%,#00001c 100%); *//* W3C */
    background: radial-gradient(ellipse at center, #e1425c 0%,#fc5a75 100%);
    filter:progid:DXImageTransform.Microsoft.gradient( startColorstr='#090b44', endColorstr='#00001c',GradientType=1 ); /* IE6-9 fallback on horizontal gradient */
    padding:0;
    text-align:center;
    font-family:'open sans';
    position:relative;
    margin:0;
    height:100%;
    padding-bottom:50px;
    box-sizing:border-box;
    -webkit-box-sizing:border-box;
    -moz-box-sizing:border-box;
}
a{text-decoration:none;}
canvas{display:block;width:100%;height:100%;top:0;left:0;position:fixed;}
canvas.flare{opacity:0.5;}

三、jquery.let_it_snow.js代码

!function($){
  
  var defaults = {
    speed: 0,
    interaction: true,
    size: 2,
    count: 200,
    opacity: 0,
    color: "#ffffff",
    windPower: 0,
    image: false
    };
    
  
  $.fn.let_it_snow = function(options){
    var settings = $.extend({}, defaults, options),
        el = $(this),
        flakes = [],
        canvas = el.get(0),
        ctx = canvas.getContext("2d"),
        flakeCount = settings.count,
        mX = -100,
        mY = -100;
    
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;
        
    (function() {
        var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame ||
        function(callback) {
            window.setTimeout(callback, 1000 / 60);
        };
        window.requestAnimationFrame = requestAnimationFrame;
    })();
    
    function snow() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);

        for (var i = 0; i < flakeCount; i++) {
            var flake = flakes[i],
                x = mX,
                y = mY,
                minDist = 100,
                x2 = flake.x,
                y2 = flake.y;

            var dist = Math.sqrt((x2 - x) * (x2 - x) + (y2 - y) * (y2 - y)),
                dx = x2 - x,
                dy = y2 - y;

            if (dist < minDist) {
                var force = minDist / (dist * dist),
                    xcomp = (x - x2) / dist,
                    ycomp = (y - y2) / dist,
                    deltaV = force / 2;

                flake.velX -= deltaV * xcomp;
                flake.velY -= deltaV * ycomp;

            } else {
                flake.velX *= .98;
                if (flake.velY <= flake.speed) {
                    flake.velY = flake.speed
                }
                
                switch (settings.windPower) { 
                  case false:
                    flake.velX += Math.cos(flake.step += .05) * flake.stepSize;
                  break;
                  
                  case 0:
                    flake.velX += Math.cos(flake.step += .05) * flake.stepSize;
                  break;
                  
                  default: 
                    flake.velX += 0.01 + (settings.windPower/100);
                }
            }

            var s = settings.color;
            var patt = /^#([\da-fA-F]{2})([\da-fA-F]{2})([\da-fA-F]{2})$/;
            var matches = patt.exec(s);
            var rgb = parseInt(matches[1], 16)+","+parseInt(matches[2], 16)+","+parseInt(matches[3], 16);

            
            flake.y += flake.velY;
            flake.x += flake.velX;

            if (flake.y >= canvas.height || flake.y <= 0) {
                reset(flake);
            }


            if (flake.x >= canvas.width || flake.x <= 0) {
                reset(flake);
            }
            if (settings.image == false) {
              ctx.fillStyle = "rgba(" + rgb + "," + flake.opacity + ")"
              ctx.beginPath();
              ctx.arc(flake.x, flake.y, flake.size, 0, Math.PI * 2);
              ctx.fill();
            } else {
              
              ctx.drawImage($("img#lis_flake").get(0), flake.x, flake.y, flake.size * 2, flake.size * 2);
            }
            
        }
        requestAnimationFrame(snow);
    };
    
    
    function reset(flake) {
        
        if (settings.windPower == false || settings.windPower == 0) {
          flake.x = Math.floor(Math.random() * canvas.width);
          flake.y = 0;
        } else {
          if (settings.windPower > 0) {
            var xarray = Array(Math.floor(Math.random() * canvas.width), 0);
            var yarray = Array(0, Math.floor(Math.random() * canvas.height))
            var allarray = Array(xarray, yarray)
            
            var selected_array = allarray[Math.floor(Math.random()*allarray.length)];
            
             flake.x = selected_array[0];
             flake.y = selected_array[1];
          } else {
            var xarray = Array(Math.floor(Math.random() * canvas.width),0);
            var yarray = Array(canvas.width, Math.floor(Math.random() * canvas.height))
            var allarray = Array(xarray, yarray)
            
            var selected_array = allarray[Math.floor(Math.random()*allarray.length)];
            
             flake.x = selected_array[0];
             flake.y = selected_array[1];
          }
        }
        
        flake.size = (Math.random() * 3) + settings.size;
        flake.speed = (Math.random() * 1) + settings.speed;
        flake.velY = flake.speed;
        flake.velX = 0;
        flake.opacity = (Math.random() * 0.5) + settings.opacity;
    }
     function init() {
      for (var i = 0; i < flakeCount; i++) {
          var x = Math.floor(Math.random() * canvas.width),
              y = Math.floor(Math.random() * canvas.height),
              size = (Math.random() * 3)  + settings.size,
              speed = (Math.random() * 1) + settings.speed,
              opacity = (Math.random() * 0.5) + settings.opacity;
      
          flakes.push({
              speed: speed,
              velY: speed,
              velX: 0,
              x: x,
              y: y,
              size: size,
              stepSize: (Math.random()) / 30,
              step: 0,
              angle: 180,
              opacity: opacity
          });
      }
      
      snow();
    }
    
    if (settings.image != false) {
      $("").prependTo("body")
    }
    
    init();
    
    $(window).resize(function() {
      if(this.resizeTO) clearTimeout(this.resizeTO);
      this.resizeTO = setTimeout(function() {
        el2 = el.clone();
        el2.insertAfter(el);
        el.remove();
        
        el2.let_it_snow(settings);
      }, 200);
    });
    
    if (settings.interaction == true) {
      canvas.addEventListener("mousemove", function(e) {
          mX = e.clientX,
          mY = e.clientY
      });
    }
  }
}(window.jQuery);


四、jqone.js


$(document).ready(function(){
//闪光
    $("canvas.flare").let_it_snow({
        windPower: 0,
        speed: 0,
        color: "#392F52",
        size:120,
        opacity: 0.00000001,
        count: 40,
        interaction: false
    });
//雪花
    $("canvas.snow").let_it_snow({
        windPower: 3,
        speed: 1,
        count: 250,
        size: 0
    });
//小碎片
    $("canvas.flake").let_it_snow({
        windPower: -3,
        speed: 1,
        count: 20,
        size: 10,
        image: "images/white-snowflake.png"
    });

});

你可能感兴趣的:(HTML5的canvas雪花飘落特效)