function clickEffect() {

let balls = [];

let longPressed = false;

let longPress;

let multiplier = 0;

let width, height;

let origin;

let normal;

let ctx;

//小球颜色

const colours = ["#F73859", "#14FFEC", "#00E0FF", "#FF99FE", "#FAF15D"];

const canvas = document.createElement("canvas");

document.body.appendChild(canvas);

canvas.setAttribute("style", "width: 100%; height: 100%; top: 0; left: 0; z-index: 99999; position: fixed; pointer-events: none;");

const pointer = document.createElement("span");

pointer.classList.add("pointer");

document.body.appendChild(pointer);



if (canvas.getContext && window.addEventListener) {

ctx = canvas.getContext("2d");

updateSize();

window.addEventListener('resize', updateSize, false);

loop();

window.addEventListener("mousedown", function(e) {

pushBalls(randBetween(5, 10), e.clientX, e.clientY);

document.body.classList.add("is-pressed");

longPress = setTimeout(function() {

document.body.classList.add("is-longpress");

longPressed = true;

}, 500);

}, false);

window.addEventListener("mouseup", function(e) {

clearInterval(longPress);

if (longPressed == true) {

document.body.classList.remove("is-longpress");

pushBalls(randBetween(50 + Math.ceil(multiplier), 100 + Math.ceil(multiplier)), e.clientX, e.clientY);

longPressed = false;

}

document.body.classList.remove("is-pressed");

}, false);

window.addEventListener("mousemove", function(e) {

let x = e.clientX;

let y = e.clientY;

pointer.style.top = y + "px";

pointer.style.left = x + "px";

}, false);

} else {

console.log("canvas or addEventListener is unsupported!");

}





function updateSize() {

canvas.width = window.innerWidth * 2;

canvas.height = window.innerHeight * 2;

canvas.style.width = window.innerWidth + 'px';

canvas.style.height = window.innerHeight + 'px';

ctx.scale(2, 2);

width = (canvas.width = window.innerWidth);

height = (canvas.height = window.innerHeight);

origin = {

x: width / 2,

y: height / 2

};

normal = {

x: width / 2,

y: height / 2

};

}

class Ball {

constructor(x = origin.x, y = origin.y) {

this.x = x;

this.y = y;

this.angle = Math.PI * 2 * Math.random();

if (longPressed == true) {

this.multiplier = randBetween(14 + multiplier, 15 + multiplier);

} else {

this.multiplier = randBetween(6, 12);

}

this.vx = (this.multiplier + Math.random() * 0.5) * Math.cos(this.angle);

this.vy = (this.multiplier + Math.random() * 0.5) * Math.sin(this.angle);

//小球大小

this.r = randBetween(2, 1) + 2 * Math.random();

this.color = colours[Math.floor(Math.random() * colours.length)];

}

update() {

this.x += this.vx - normal.x;

this.y += this.vy - normal.y;

normal.x = -2 / window.innerWidth * Math.sin(this.angle);

normal.y = -2 / window.innerHeight * Math.cos(this.angle);

//消失速度

this.r -= 0.1;

//横向扩大范围

this.vx *= 0.9;

//纵向扩大范围

this.vy *= 0.9;

}

}



function pushBalls(count = 1, x = origin.x, y = origin.y) {

for (let i = 0; i < count; i++) {

balls.push(new Ball(x, y));

}

}



function randBetween(min, max) {

return Math.floor(Math.random() * max) + min;

}



function loop() {

ctx.fillStyle = "rgba(255, 255, 255, 0)";

ctx.clearRect(0, 0, canvas.width, canvas.height);

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

let b = balls[i];

if (b.r < 0) continue;

ctx.fillStyle = b.color;

ctx.beginPath();

ctx.arc(b.x, b.y, b.r, 0, Math.PI * 2, false);

ctx.fill();

b.update();

}

if (longPressed == true) {

multiplier += 0.2;

} else if (!longPressed && multiplier >= 0) {

multiplier -= 0.4;

}

removeBall();

requestAnimationFrame(loop);

}



function removeBall() {

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

let b = balls[i];

if (b.x + b.r < 0 || b.x - b.r > width || b.y + b.r < 0 || b.y - b.r > height || b.r < 0) {

balls.splice(i, 1);

}

}

}

}

clickEffect();