<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>HTML5 Canvas鼠标移动圆点粒子跟随动画特效</title>
<style>
body,
html{
margin: 0;
padding: 0;
border: 0;
font-family: 'Nunito', sans-serif;
}
body{background:#000;}
canvas{
margin: 0;
padding: 0;
display: block; /* ˉ\_(ツ)_/ˉ */
touch-action: none;
}
h1{
position: absolute;
top: 50%;
left: 0;
margin: auto;
width: 100%;
text-align: center;
color:#fff;
}
</style>
</head>
<body>
<h1>
别害羞, 把鼠标挪过来!
</h1>
<canvas></canvas>
<script>
var canvas = document.querySelector('canvas');
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
c = canvas.getContext('2d');
window.addEventListener('resize', function(){
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
initCanvas();
})
var mouse = {
x: undefined,
y: undefined
}
window.addEventListener('mousemove',
function (event) {
mouse.x = event.x;
mouse.y = event.y;
drawCircles();
}
)
window.addEventListener("touchmove",
function (event) {
let touch = event.touches[0];
mouse.x = touch.clientX;
mouse.y = touch.clientY;
drawCircles();
}
)
function Circle(x, y, radius, vx, vy, rgb, opacity, birth, life){
this.x = x;
this.y = y;
this.radius = radius;
this.minRadius = radius;
this.vx = vx;
this.vy = vy;
this.birth = birth;
this.life = life;
this.opacity = opacity;
this.draw = function() {
c.beginPath();
c.arc(this.x, this.y, this.radius, Math.PI * 2, false);
c.fillStyle = 'rgba(' + rgb +','+ this.opacity +')';
c.fill();
}
this.update = function(){
if (this.x + this.radius > innerWidth || this.x - this.radius < 0) {
this.vx = -this.vx;
}
if (this.y + this.radius > innerHeight || this.y - this.radius < 0) {
this.vy = -this.vy;
}
this.x += this.vx;
this.y += this.vy;
this.opacity = 1- (((frame - this.birth) * 1) / this.life);
if (frame > this.birth + this.life){
for (let i = 0; i < circleArray.length; i++){
if (this.birth == circleArray[i].birth && this.life == circleArray[i].life){
circleArray.splice(i, 1);
break;
}
}
} else{
this.draw();
}
}
}
var circleArray = [];
function initCanvas() {
circleArray = [];
}
var colorArray = [
'355,85,80',
'9,80,100',
'343,81,45'
]
function drawCircles(){
for (let i = 0; i < 6; i++) {
let radius = Math.floor(Math.random() * 4) + 2;
let vx = (Math.random() * 2) - 1;
let vy = (Math.random() * 2) - 1;
let spawnFrame = frame;
let rgb = colorArray[Math.floor(Math.random() * colorArray.length)];
let life = 100;
circleArray.push(new Circle(mouse.x, mouse.y, radius, vx, vy, rgb, 1, spawnFrame, life));
}
}
var frame = 0;
function animate() {
requestAnimationFrame(animate);
frame += 1;
c.clearRect(0, 0, innerWidth, innerHeight);
for (let i = 0; i < circleArray.length; i++ ){
circleArray[i].update();
}
}
initCanvas();
animate();
// This is just for demo purposes :
for (let i = 1; i < 110; i++) {
(function (index) {
setTimeout(function () {
mouse.x = 100 + i * 10;
mouse.y = 100;
drawCircles();
}, i * 10);
})(i);
}
</script>
</body>
</html>
