彩虹雨源码
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>彩虹雨</title>
<style>
canvas{
position:absolute;
top:0;
left:0;
background-color:black;
}</style>
</head>
<body>
<canvas id=c></canvas>
<script>
//initial
var w = c.width = window.innerWidth,
h = c.height = window.innerHeight,
ctx = c.getContext('2d'),
//parameters
total = (w/8)|0,
accelleration = .05,
lineAlpha = .02,
range = 25,
//afterinitial calculations
size = w/total,
occupation = w/total,
repaintColor = 'rgba(0, 0, 0, .04)'
colors = [],
dots = [],
dotsVel = [];
//setting the colors' hue
//and y level for all dots
var portion = 360/total;
for(var i = 0; i < total; ++i){
colors[i] = portion * i;
dots[i] = h;
dotsVel[i] = 10;
}
function anim(){
window.requestAnimationFrame(anim);
ctx.fillStyle = repaintColor;
ctx.fillRect(0, 0, w, h);
for(var i = 0; i < total; ++i){
var currentY = dots[i] - 1;
dots[i] += dotsVel[i] += accelleration;
for(var j = i+1; j < i+range && j < total; ++j){
if(Math.abs(dots[i] - dots[j]) <= range*size){
ctx.strokeStyle = 'hsla(hue, 80%, 50%, alp)'.replace('hue', (colors[i] + colors[j] + 360)/2 - 180).replace('alp', lineAlpha);
ctx.beginPath();
ctx.moveTo(i * occupation, dots[i]);
ctx.lineTo(j * occupation, dots[j]);
ctx.stroke();
}
}
if(dots[i] > h && Math.random() < .01){
dots[i] = dotsVel[i] = 0;
}
}
}
anim();</script>
</body>
</html>
