canvas星星炫耀

来源：互联网发布：房地产交易数据分渠道编辑：程序博客网时间：2024/04/30 04:20

<!DOCTYPE html>

<html>

<head>

<style>

body {

width: 100%;

margin: 0;

overflow: hidden;

}

canvas{

display:block;

}

</style>

</head>

<body>

var c = document.getElementById('canv');//获取canvas的Id

var $ = c.getContext('2d');/*设置绘制方式*/

var u = 0;

var go = function() {

var sc, g, g1, i, j, p, x, y, z, w, a, cur,

d = new Date() / 1000,

rnd = shift(),

rnd1 = d,

rnd2 = 2.4,

rnd3 = d * 0.2,

rnd1c = Math.cos(rnd1),

rnd1s = Math.sin(rnd1),

rnd2c = Math.cos(rnd2),

rnd2s = Math.sin(rnd2);

c.width = window.innerWidth;

c.height = window.innerHeight;

sc = Math.max(c.width, c.height);

$.translate(c.width * 0.5, c.height * 0.5);//从中心开始绘制

$.scale(sc, sc);//放大最大数值

/*线性渐变*/

g = $.createLinearGradient(-1, -2, 1, 2);

g.addColorStop(0.0, 'hsla(338, 95%, 25%, 1)');

g.addColorStop(0.5, 'hsla(260, 95%, 5%, 1)');

g.addColorStop(1.0, 'hsla(338, 95%, 30%, 1)');

$.fillStyle = g;//颜色

$.fillRect(-0.5, -0.5, 1, 1);

$.globalCompositeOperation = 'lighter';

$.rotate(rnd3 % Math.PI * 2);/*旋转*/

for (i = 0; i < 300; i += 1) {

p = rnd();

x = (p & 0xff) / 128 - 1;

y = (p >>> 8 & 0xff) / 128 - 1;

z = (p >>> 16 & 0xff) / 128 - 1;

w = (p >>> 24 & 0xff) / 256;

z += d * 0.5;

z = (z + 1) % 2 - 1;

a = (z + 1) * 0.5;

if (a < 0.9) {

$.globalAlpha = a / 0.7;

}else {

a -= 0.9;

$.globalAlpha = 1 - a / 0.1;

}

cur = x * rnd1c + y * rnd1s;

y = x * rnd1s - y * rnd1c;

x = cur;

cur = y * rnd2c + z * rnd2s;

z = y * rnd2s - z * rnd2c;

y = cur;

z -= 0.65;

if (z >= 0) {

continue;

}

sc = 0.1 / z;

x *= sc;

y *= sc;

$.save();

g1 = $.createRadialGradient(1, 1, 2, 1, 1, 1);

g1.addColorStop(0.0, 'hsla('+i+', 70%, 40%,.8)');

g1.addColorStop(0.5, 'hsla('+i+', 75%, 50%, 1)');

g1.addColorStop(1.0, 'hsla('+i+', 80%, 60%, .8)');

$.fillStyle = g1;

$.translate(x, y);

$.scale(sc * 0.017, sc * 0.017);

$.beginPath();

$.moveTo(2, 0);

for (j = 0; j < 10; j += 1) {

$.rotate(Math.PI*2 * 0.1);

$.lineTo(j % 2 + 1, 0);

}

$.arc(10, 10, 1, 0, Math.PI * 2);

$.rotate(Math.PI * 2 * 0.1);

$.closePath();

$.fill();

$.restore();

}

};

Marsaglia's Xorshift128 PRG: http://en.wikipedia.org/wiki/Xorshift

var shift = function(x, y, z, w) {

x = x || 123456789;

y = y || 362436069;

z = z || 521288629;

w = w || 88675123;

return function() {

var s = x ^ (x << 11);

x = y;

y = z;

z = w;

w = (w ^ (w >>> 19)) ^ (s ^ (s >>> 8));

return w;

};

}

window.addEventListener('resize', function() {

c.width = window.innerWidth;

c.height = window.innerHeight;

}, false);

window.requestAnimationFrame = window.requestAnimationFrame||

window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame ||

window.msRequestAnimationFrame;

var run = function() {

window.requestAnimationFrame(run);

go();

}

run();

</script>

</body>

</html>

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