js跟随彩色气泡 JavaScript实现好看的跟随彩色气泡效果

时间:2021-04-02 空谷丶幽兰人气:0

代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>

<style>
 *{
 margin:0;padding:0;
 }
 body{overflow:hidden;}
 #canvas{
 background-color:black;
 /*width:100%;
 height:100vh;*/
 }
 
</style>

</head>
<body>

<canvas id="canvas" ></canvas> 
 
</body>

<script>
var canvas = document.querySelector('#canvas');
var ctx = canvas.getContext("2d");
var starlist = [];
function init(){
 canvas.width = window.innerWidth;
 canvas.height = window.innerHeight;
}
init();
window.onresize = init;

canvas.addEventListener('mousemove',function(e){
 starlist.push(new Star(e.offsetX,e.offsetY));
 console.log(starlist)
})

function random(min,max){
 return Math.floor((max-min)*Math.random()+ min);
}

function Star(x,y){
 this.x = x;
 this.y = y;
 this.vx = (Math.random()-0.5)*3;
 this.vy = (Math.random()-0.5)*3;
 this.color = 'rgb('+random(0,256)+','+random(0,256)+','+random(0,256)+')';
 this.a = 1;
 console.log(this.color);
 this.draw();
}
Star.prototype={
 draw:function(){
 ctx.beginPath();
 ctx.fillStyle = this.color;
 ctx.globalCompositeOperation='lighter'
 ctx.globalAlpha= this.a;
 ctx.arc(this.x,this.y,30,0,Math.PI*2,false);
 ctx.fill();
 this.updata();
 },
 updata(){
 this.x+=this.vx;
 this.y+=this.vy;
 this.a*=0.98;
 }
}
console.log(new Star(150,200));
function render(){
 ctx.clearRect(0,0,canvas.width,canvas.height)
 
 starlist.forEach((item,i)=>{
 item.draw();
 if(item.a<0.05){
 starlist.splice(i,1);
 }
 })
 
 requestAnimationFrame(render);
}
render(); 

</script>
<div style="text-align:center;">
</div>

</html>

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