實現(xiàn)一個小而簡單的煙霧效果葵袭。
引入一個 smoke.js 的插件,就可以開始玩煙霧了依痊。
最后面有插件的源代碼
Smoke.js的使用文檔
smokemachine（ctx曲秉，[r顷霹，g，b]）
//[r跳夭，g涂圆，b] - （可選）我們想要的煙的顏色
party.start（）//開始動畫们镜！
party.stop（）//停止動畫
party.addsmoke（X币叹，Y，numberofparticles）
x模狭，y - 應(yīng)在畫布中創(chuàng)建煙霧的坐標 , 數(shù)量多 - 更多的煙霧
party.step（毫秒）//重新點燃煙霧
畫煙霧
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<style type="text/css">
//給canvas弄上一些效果
html, body {
position: absolute;
margin: 0;
width: 100%;
}
#hi{
position: absolute;
top: 40%;
width: 100%;
text-align: center;
}
#hi a {
color: #fff;
font-size: 80px;
text-decoration: none;
font-family: Lobster;
}
</style>
<body>
<canvas id="canvas"></canvas>
</body>
//根據(jù)自己的文件路徑引入插件
<script src="js/smoke.js"></script>
<script type="text/javascript">
var canvas = document.getElementById('canvas')
var ctx = canvas.getContext('2d')
//設(shè)置畫布寬高
canvas.width = innerWidth;
canvas.height = innerHeight;
var party = smokemachine(ctx, [54, 16.8, 18.2])
party.start() //開始動畫
onmousemove = function (e) {
var x = e.clientX;
var y = e.clientY;
var n = .5;
var t = Math.floor(Math.random() * 200) + 3800;
party.addsmoke(x, y, n, t)
}
setInterval(function(){
party.addsmoke(innerWidth/2, innerHeight, 1)
}, 100)
</script>
</html>
Somke.js 的源代碼
var smokemachine = function (context, color){
color = color || [24, 46.8, 48.2]
var polyfillAnimFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame ||
window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
var lastframe;
var currentparticles = []
var pendingparticles = []
var buffer = document.createElement('canvas'),
bctx = buffer.getContext('2d')
buffer.width = 20
buffer.height = 20
var opacities = [0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,3,5,5,7,4,4,1,1,0,1,0,0,0,0,0,1,0,0,17,27,41,52,56,34,23,15,11,4,9,5,1,0,0,0,0,0,0,1,45,63,57,45,78,66,52,41,34,37,23,20,0,1,0,0,0,0,1,43,62,66,64,67,115,112,114,56,58,47,33,18,12,10,0,0,0,0,39,50,63,76,87,107,105,112,128,104,69,64,29,18,21,15,0,0,0,7,42,52,85,91,103,126,153,128,124,82,57,52,52,24,1,0,0,0,2,17,41,67,84,100,122,136,159,127,78,69,60,50,47,25,7,1,0,0,0,34,33,66,82,113,138,149,168,175,82,142,133,70,62,41,25,6,0,0,0,18,39,55,113,111,137,141,139,141,128,102,130,90,96,65,37,0,0,0,2,15,27,71,104,129,129,158,140,154,146,150,131,92,100,67,26,3,0,0,0,0,46,73,104,124,145,135,122,107,120,122,101,98,96,35,38,7,2,0,0,0,50,58,91,124,127,139,118,121,177,156,88,90,88,28,43,3,0,0,0,0,30,62,68,91,83,117,89,139,139,99,105,77,32,1,1,0,0,0,0,0,16,21,8,45,101,125,118,87,110,86,64,39,0,0,0,0,0,0,0,0,0,1,28,79,79,117,122,88,84,54,46,11,0,0,0,0,0,0,0,0,0,1,0,6,55,61,68,71,30,16,0,0,0,0,0,0,0,0,0,0,0,0,0,0,14,23,25,20,12,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,12,9,8,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,2,2,0,0,0,0,0,0,0,0]
var data = bctx.createImageData(20,20)
var d = data.data
for(var i=0;i<d.length;i+=4){
d[i]=color[0]
d[i+1]=color[1]
d[i+2]=color[2]
d[i+3]=opacities[i / 4]
}
bctx.putImageData(data,0,0)
var imagewidth = 20 * 5
var imageheight = 20 * 5
function particle(x,y,l){
this.x = x
this.y = y
this.age = 0
this.vx = (Math.random()*8-4)/100
this.startvy = -(Math.random()*30+10)/100
this.vy = this.startvy
this.scale = Math.random()*.5
this.lifetime = Math.random()*l+l/2
this.finalscale = 5+this.scale+Math.random()
this.update = function(deltatime){
this.x+=this.vx*deltatime
this.y+=this.vy*deltatime
var frac = Math.pow((this.age)/this.lifetime,.5)
this.vy = (1-frac)*this.startvy
this.age+=deltatime
this.scale=frac*this.finalscale
}
this.draw = function(){
context.globalAlpha = (1-Math.abs(1-2*(this.age)/this.lifetime))/8
var off = this.scale*imagewidth/2
var xmin = this.x-off
var xmax = xmin+this.scale*imageheight
var ymin = this.y-off
var ymax = ymin+this.scale*imageheight
context.drawImage(buffer, xmin, ymin, xmax-xmin, ymax-ymin)
}
}
function addparticles(x,y,n,lifetime){
lifetime = lifetime || 4000
n = n || 10
if(n < 1) return Math.random() <= n && pendingparticles.push(new particle(x,y,lifetime));
for (var i = 0; i < n; i++) {
pendingparticles.push(new particle(x,y,lifetime))
};
}
function updateanddrawparticles(deltatime){
context.clearRect(0, 0, context.canvas.width, context.canvas.height);
deltatime = deltatime || 16
var newparticles = []
currentparticles = currentparticles.concat(pendingparticles)
pendingparticles = []
currentparticles.forEach(function(p){
p.update(deltatime)
if (p.age<p.lifetime){
p.draw()
newparticles.push(p)
}
})
currentparticles = newparticles
}
function frame(time){
if(running){
var deltat = time-lastframe
lastframe = time;
updateanddrawparticles(deltat)
polyfillAnimFrame(frame)
}
}
var running = false
function start(){
running = true
polyfillAnimFrame(function(time){
lastframe = time
polyfillAnimFrame(frame)
})
}
function stop(){
running = false
}
return {
start:start,
stop:stop,
step: updateanddrawparticles,
addsmoke: addparticles
}
}
弄完之后就可以在網(wǎng)頁上颈抚，隨著鼠標的移動，煙霧就生成了.
