基于JavaScript实现在线网页烟花效果

目录实现效果关键步骤源码实现效果关键步骤随机颜色varhue=Math.random()*360;varhueVariance=30;functionsetupColors(...

目录

实现效果

关键步骤

随机颜色

var hue = Math.random() * 360;
var hueVariance = 30;

    function setupColors(p){
        p.hue = Math.floor(Math.random() * ((hue + hueVariance) - (hue - hueVariance))) + (hue - hueVariance);
        p.brightness = Math.floor(Math.random() * 21) + 50;
        p.alpha = (Math.floor(Math.random() * 61) + 40) / 100;
    }

随机发射枪口

for (var i = 0; i < count; i++) {
//角度
var angle = 360 / count * i;
//弧度
var radians = angle * Math.PI / 180;

var p = {};

p.x = x;
p.y = y;
p.radians = radians;

//大小
p.size = Math.random()*2+1;

//速度
p.speed = Math.random()*5+.4;

//半径
p.radius = Math.random()*81+50;

p.fx = x + Math.cos(radians) * p.radius;
p.fy = y + Math.sin(radians) * p.radius;

setupColors(p);

particles.push(p);
}

每帧更新调用

//requestAnimationFrame
var lastStamp = 0;
function tick(opt=0) {
if(opt-lastStamp>2000){
lastStamp=opt;
createFireworks(Math.random()*canvas.width,Math.random()*canvas.height);
}

context.globalCompositeOperation = 'destination-out';
context.fillStyle ='rgba(0,0,0,'+10/100+')';
context.fillRect(0,0,canvas.width,canvas.height);
context.globalCompositeOperation = 'lighter';

drawFireworks();

requestAnimationFrame(tick);
}
tick();

源码

 Javascript:
!(function () {
var isDebug = false;
var textCanvas = document.createElement("canvas");
textCanvas.width=1000;
textCanvas.height=300;
if(isDebug){
textCanvas.style.position="absolute";
textCanvas.style.zIndex="9999";
document.body.appendChild(textCanvas);
}
var textctx = textCanvas.getContext("2d");
textctx.fillStyle = "#000000";
textctx.fillRect(0,0,textCanvas.width,textCanvas.height);

var canvas = document.createElement("canvas");
document.body.appendChild(canvas);

canvas.style.position= "fixed";
canvas.style.left = "0";
canvas.style.top = "0";
canvas.style.zIndex = -1;

var context = canvas.getContext("2d");

function resizeCanvas() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

clearCanvas();
}

function clearCanvas() {
context.fillStyle = "#000000";
context.fillRect(0, 0, canvas.width, canvas.height);
}

resizeCanvas();

window.addEventListener("resize", resizeCanvas);


function mouseDownHandler(e) {
var x = e.clientX;
var y = e.clientY;

//发射的文字
createFireworks(x, y,["1024","程序员节日快乐","去死吧 bug!"][Math.floor(Math.random()*3)]);
}
document.addEventListener("mousedown", mouseDownHandler);

var particles = [];

function createFireworks(x, y,text="") {

var hue = Math.random() * 360;
var hueVariance = 30;

function setupColors(p){
p.hue = Math.floor(Math.random() * ((hue + hueVariance) - (hue - hueVariance))) + (hue - hueVariance);
p.brightness = Math.floor(Math.random() * 21) + 50;
p.alpha = (Math.floor(Math.random() * 61) + 40) / 100;
}

if(text!=""){

var gap = 6;
var fontSize = 120;

textctx.font=fontSize+"px _sans";
textctx.fillStyle = "#ffffff";

phpvar textWidth = Math.ceil(textctx.measureText(text).width);
var textHeight = Math.ceil(fontSize*1.2);

textctx.fillText(text,0,fontSize);
var imgData = textctx.getImageData(0,0,textWidth,textHeight);

if(isDebug)context.putImageData(imgData,400,300)

textctx.fillStyle = "#000000";
textctx.fillRect(0,0,textCanvas.width,textCanvas.height);

for (var h = 0; h < textHeight; h+=gap) {
    for(var w = 0; w < textWidth; w+=gap){
            var position = (textWidth * h + w) * 4;
            var r = imgData.data[position], g = imgData.data[position + 1], b = imgData.data[position + 2], a = imgData.data[position + 3];
    
    if(r+g+b==0)continue;

            var p = {};

p.x = x;
p.y = y;

p.fx = x + w - textWidth/2;
p.fy = y + h - textHeight/2;

p.size = Math.floor(Math.random()*2)+1;
p.speed = 1;

setupColors(p);

particles.push(p);
    }
}
}else{
var count = 100;
for (var i = 0; i < count; i++) {
//角度
var angle = 360 / count * i;
//弧度
var radians = angle * Math.PI / 180;

var p = {};

p.x = x;
p.y = y;
p.radians = radians;

//大小
p.size = Math.random()*2+1;

//速度
p.speed = Math.random()*5+.4;

//半径
p.radius = Math.random()*81+50;

p.fx = x + Math.cos(radians) * p.radius;
p.fy = y + Math.sin(radians) * p.radius;

setupColors(p);

particles.push(p);
}
}
}
function drawFireworks() {
clearCanvas();

for (var i = 0; i < particles.length; i++) {
var p = particles[i];

p.x += (p.fx - p.x)/10;
p.y += (p.fy - p.y)/10-(p.alpha-1)*p.speed;

p.alpha -= 0.006;

if (p.alpha<=0) {
particles.splice(i, 1);
continue;
}

context.beginPath();
context.arc(p.x, p.y, p.size, 0, Math.PI * 2, false);
context.closePath();

context.fillStyle = 'hsla('+p.hue+',100%,'+p.brightness+'%,'+p.alpha+')';
context.fill();
}
}

//requestAnimationFrame
var lastStamp = 0;
function tick(opt=0) {
if(opt-lastStamp>2000){
lastStamp=opt;
createFireworks(Math.random()*canvas.width,Math.random()*canvas.height);
}

context.globalCompositeOperation = 'destination-out';
context.fillStyle ='rgba(0,0,0,'+10/100+')';
context.fillRect(0,0,canvas.width,canvas.height);
context.globalCompositeOperation = 'lighter';

drawFireworks();

requestAnimationFrame(tick);
}
tick();
})();

背景音乐自动播放

audio id="bgmusic" src="./bgm.mp3" autoplay="autoplay" loop="loop" style="display: block; width: 3%; height:3%;"></audio>
        <script type="text/javascript">
      function toggleSound() {
                var music = document.getElementById("bgmusic");//获取ID
                    console.log(music);
                    console.log(music.paused);
                if (music.paused) { //判读是否播放
                    music.paused=false;
                    music.play(); //没有就播放
                }
    
            }
            setInterval("toggleSound()",1);
    </script>

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