This article mainly introduces the native JS HTML5 to realize the particle animation effect that flows with the mouse, involving javascript event response, numerical operation and dynamic operation of page element attributes related implementation techniques. Friends in need can refer to it
The example in this article describes the native JS HTML5 implementation of particle animation effects that flow with the mouse. Share it with everyone for your reference, the details are as follows:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset=gbk>
<title>www.jb51.net 粒子效果演示</title>
<meta name="description" content="HTML5/canvas demo, 500 particles to play around with." />
<meta name="keywords" content="html5,canvas,javascript,particles,interactive,velocity,programming,flash" />
<style type="text/css">
html, body {
text-align: center;
margin:0;
padding:0;
background: #000000;
color: #666666;
line-height: 1.25em;
}
#outer {
position: absolute;
top: 50%;
left: 50%;
width: 1px;
height: 1px;
overflow: visible;
}
#canvasContainer {
position: absolute;
width: 1000px;
height: 560px;
top: -280px;
left: -500px;
}
canvas {
border: 1px solid #333333;
}
a {
color: #00CBCB;
text-decoration:none;
font-weight:bold;
}
a:hover {
color:#FFFFFF;
}
#output {
font-family: Arial, Helvetica, sans-serif;
font-size: 0.75em;
margin-top:4px;
}
#footer{
font-size: 0.6em;
font-family: Arial, Helvetica, sans-serif;
position: absolute;
bottombottom:8px;
width:98%;
}
</style>
</head>
<body>
<p id="outer">
<p id="canvasContainer">
<canvas id="mainCanvas" width="1000" height="560"></canvas>
<p id="output"></p>
</p>
</p>
<script type="text/javascript">
//javascript部分
(function(){
var PI_2 = Math.PI * 2;
var canvasW = 1000;
var canvasH = 560;
var numMovers = 600;
var friction = 0.96;
var movers = [];
var canvas;
var ctx;
var canvasp;
var outerp;
var mouseX;
var mouseY;
var mouseVX;
var mouseVY;
var prevMouseX;
var prevMouseY;
var isMouseDown;
function init(){
canvas = document.getElementById("mainCanvas");
if ( canvas.getContext ){
setup();
setInterval( run , 33 );
trace('你们好');
}
else{
trace("Sorry, needs a recent version of Chrome, Firefox, Opera, Safari, or Internet Explorer 9.");
}
}
function setup(){
outerp = document.getElementById("outer");
canvasp = document.getElementById("canvasContainer");
ctx = canvas.getContext("2d");
var i = numMovers;
while ( i-- ){
var m = new Mover();
m.x = canvasW * 0.5;
m.y = canvasH * 0.5;
m.vX = Math.cos(i) * Math.random() * 34;
m.vY = Math.sin(i) * Math.random() * 34;
movers[i] = m;
}
mouseX = prevMouseX = canvasW * 0.5;
mouseY = prevMouseY = canvasH * 0.5;
document.onmousedown = onDocMouseDown;
document.onmouseup = onDocMouseUp;
document.onmousemove = onDocMouseMove;
}
function run(){
ctx.globalCompositeOperation = "source-over";
ctx.fillStyle = "rgba(8,8,12,0.65)";
ctx.fillRect( 0 , 0 , canvasW , canvasH );
ctx.globalCompositeOperation = "lighter";
mouseVX = mouseX - prevMouseX;
mouseVY = mouseY - prevMouseY;
prevMouseX = mouseX;
prevMouseY = mouseY;
var toDist = canvasW * 0.86;
var stirDist = canvasW * 0.125;
var blowDist = canvasW * 0.5;
var Mrnd = Math.random;
var Mabs = Math.abs;
var i = numMovers;
while ( i-- ){
var m = movers[i];
var x = m.x;
var y = m.y;
var vX = m.vX;
var vY = m.vY;
var dX = x - mouseX;
var dY = y - mouseY;
var d = Math.sqrt( dX * dX + dY * dY ) || 0.001;
dX /= d;
dY /= d;
if ( isMouseDown ){
if ( d < blowDist ){
var blowAcc = ( 1 - ( d / blowDist ) ) * 14;
vX += dX * blowAcc + 0.5 - Mrnd();
vY += dY * blowAcc + 0.5 - Mrnd();
}
}
if ( d < toDist ){
var toAcc = ( 1 - ( d / toDist ) ) * canvasW * 0.0014;
vX -= dX * toAcc;
vY -= dY * toAcc;
}
if ( d < stirDist ){
var mAcc = ( 1 - ( d / stirDist ) ) * canvasW * 0.00026;
vX += mouseVX * mAcc;
vY += mouseVY * mAcc;
}
vX *= friction;
vY *= friction;
var avgVX = Mabs( vX );
var avgVY = Mabs( vY );
var avgV = ( avgVX + avgVY ) * 0.5;
if( avgVX < .1 ) vX *= Mrnd() * 3;
if( avgVY < .1 ) vY *= Mrnd() * 3;
var sc = avgV * 0.45;
sc = Math.max( Math.min( sc , 3.5 ) , 0.4 );
var nextX = x + vX;
var nextY = y + vY;
if ( nextX > canvasW ){
nextX = canvasW;
vX *= -1;
}
else if ( nextX < 0 ){
nextX = 0;
vX *= -1;
}
if ( nextY > canvasH ){
nextY = canvasH;
vY *= -1;
}
else if ( nextY < 0 ){
nextY = 0;
vY *= -1;
}
m.vX = vX;
m.vY = vY;
m.x = nextX;
m.y = nextY;
ctx.fillStyle = m.color;
ctx.beginPath();
ctx.arc( nextX , nextY , sc , 0 , PI_2 , true );
ctx.closePath();
ctx.fill();
}
}
function onDocMouseMove( e ){
var ev = e ? e : window.event;
mouseX = ev.clientX - outerp.offsetLeft - canvasp.offsetLeft;
mouseY = ev.clientY - outerp.offsetTop - canvasp.offsetTop;
}
function onDocMouseDown( e ){
isMouseDown = true;
return false;
}
function onDocMouseUp( e ){
isMouseDown = false;
return false;
}
function Mover(){
this.color = "rgb(" + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + "," + Math.floor( Math.random()*255 ) + ")";
this.y = 0;
this.x = 0;
this.vX = 0;
this.vY = 0;
this.size = 1;
}
function rect( context , x , y , w , h ){
context.beginPath();
context.rect( x , y , w , h );
context.closePath();
context.fill();
}
function trace( str ){
document.getElementById("output").innerHTML = str;
}
window.onload = init;
})();
</script>
</body>
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