激光绘制爱心代码

王术煜 2024-08-13 157次阅读

<!DOCTYPE html>

<head>

<title>激光汇聚成爱心</title>

<style>

canvas {

position: absolute;

left: 0;

top: 0;

width: 100%;

height: 100%;

background-color: rgba(0, 0, 0, 0.2);

}

</style>

</head>

<body>

window.requestAnimationFrame =

window.__requestAnimationFrame ||

window.requestAnimationFrame ||

window.webkitRequestAnimationFrame ||

window.mozRequestAnimationFrame ||

window.oRequestAnimationFrame ||

window.msRequestAnimationFrame ||

(function () {

return function (callback, element) {

var lastTime = element.__lastTime;

if (lastTime === undefined) {

lastTime = 0;

}

var currTime = Date.now();

var timeToCall = Math.max(1, 33 - (currTime - lastTime));

window.setTimeout(callback, timeToCall);

element.__lastTime = currTime + timeToCall;

};

})();

window.isDevice =

(

navigator.userAgent ||

navigator.vendor ||

window.opera

).toLowerCase()

);

var loaded = false;

var init = function () {

if (loaded) return;

loaded = true;

var mobile = window.isDevice;

var koef = mobile ? 1.5 : 1;

var canvas = document.getElementById('heart');

var ctx = canvas.getContext('2d');

var width = (canvas.width = koef * innerWidth);

var height = (canvas.height = koef * innerHeight);

var rand = Math.random;

ctx.fillStyle = 'rgba(0,0,0,1)';

ctx.fillRect(0, 0, width, height);

var heartPosition = function (rad) {

return [

Math.pow(Math.sin(rad), 3),

15 * Math.cos(rad) -

5 * Math.cos(2 * rad) -

2 * Math.cos(3 * rad) -

Math.cos(4 * rad)

];

};

var scaleAndTranslate = function (pos, sx, sy, dx, dy) {

return [dx + pos[0] * sx, dy + pos[1] * sy];

};

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

width = canvas.width = koef * innerWidth;

height = canvas.height = koef * innerHeight;

ctx.fillStyle = 'rgba(0,0,0,1)';

ctx.fillRect(0, 0, width, height);

});

var traceCount = 50;

var pointsOrigin = [];

var i;

var dr = 0.1;

for (i = 0; i < Math.PI * 2; i += dr)

pointsOrigin.push(

scaleAndTranslate(heartPosition(i), 105, 6.5, 0, 0)

); // 修改比例参数

for (i = 0; i < Math.PI * 2; i += dr)

pointsOrigin.push(scaleAndTranslate(heartPosition(i), 75, 4.5, 0, 0)); // 修改比例参数

for (i = 0; i < Math.PI * 2; i += dr)

pointsOrigin.push(scaleAndTranslate(heartPosition(i), 45, 2.5, 0, 0)); // 修改比例参数

var heartPointsCount = pointsOrigin.length;

var targetPoints = [];

var pulse = function (kx, ky) {

for (i = 0; i < pointsOrigin.length; i++) {

targetPoints[i] = [];

targetPoints[i][0] = kx * pointsOrigin[i][0] + width / 2;

targetPoints[i][1] = ky * pointsOrigin[i][1] + height / 2;

}

};

var e = [];

for (i = 0; i < heartPointsCount; i++) {

var x = rand() * width;

var y = rand() * height;

e[i] = {

vx: 0,

vy: 0,

R: 2,

speed: rand() + 5,

q: ~~(rand() * heartPointsCount),

D: 2 * (i % 2) - 1,

force: 0.2 * rand() + 0.7,

'hsla(0,' +

~~(40 * rand() + 60) +

'%,' +

~~(60 * rand() + 20) +

'%,.3)',

trace: [],

};

for (var k = 0; k < traceCount; k++) e[i].trace[k] = { x: x, y: y };

}

var config = {

traceK: 0.4,

timeDelta: 0.01,

};

var time = 0;

var loop = function () {

var n = -Math.cos(time);

pulse((1 + n) * 0.5, (1 + n) * 0.5);

time +=

(Math.sin(time) < 0 ? 9 : n > 0.8 ? 0.2 : 1) * config.timeDelta;

ctx.fillStyle = 'rgba(0,0,0,.1)';

ctx.fillRect(0, 0, width, height);

for (i = e.length; i--; ) {

var u = e[i];

var q = targetPoints[u.q];

var dx = u.trace[0].x - q[0];

var dy = u.trace[0].y - q[1];

var length = Math.sqrt(dx * dx + dy * dy);

if (10 > length) {

if (0.95 < rand()) {

u.q = ~~(rand() * heartPointsCount);

} else {

if (0.99 < rand()) {

u.D *= -1;

}