css动画烟花秀__烟花效果

先看效果

CSS烟花秀

这是一个在HTML5页面，实现烟花效果的例子

以下为实现代码

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>烟花</title>
</head>
<style>
  body {
    margin: 0;
    padding: 0;
    overflow: hidden;
  }

  .canvasBox {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
  }

  canvas {
    border: 1px solid;
    background-color: #ccc;
  }
</style>

<body>
<div class="canvasBox">
  <canvas id="canvas"></canvas>
</div>
<audio id="background-music" src="yanhua.mp3"  preload="auto" autoplay loop></audio>
</body>

</html>
<script src="test.js"></script>
<script>
  const canvas = document.getElementById('canvas')
  const canvasWidth = document.documentElement.clientWidth || document.body.clientWidth
  const canvasHeight = document.documentElement.clientHeight || document.body.clientHeight
  const ratio = Math.max(window.devicePixelRatio, 2)
  canvas.width = canvasWidth * ratio
  canvas.height = canvasHeight * ratio
  canvas.style.width = canvasWidth + 'px'
  canvas.style.height = canvasHeight + 'px'
  const ctx = canvas.getContext('2d')
  ctx.scale(ratio, ratio)

  const getRandom = (min, max) => {
    return Math.random() * (max - min) + min
  }

  const drawCircle = ({ opacity = 1, x, y, radius, color }) => {
    ctx.save()
    ctx.globalAlpha = opacity
    ctx.beginPath()
    ctx.arc(x, y, radius, 0, Math.PI * 2)
    ctx.fillStyle = color
    ctx.fill()
    ctx.restore()
  }
  const deleteFromList = (list, target) => {
    const index = list.findIndex(item => {
      return item === target
    })
    list.splice(index, 1)
  }
  // 动画循环
  // 烟花列表
  const fireworkList = []
  const draw = () => {
    // 使用半透明清空画布，形成拖尾效果
    ctx.fillStyle = 'rgba(0,0,0,0.1)'
    ctx.fillRect(0, 0, canvasWidth, canvasHeight)
    ctx.save()

    // 修改坐标系
    ctx.translate(0, canvasHeight)
    ctx.scale(1, -1)

    const list = [...fireworkList]
    list.forEach(firework => {
      firework.update()
      if (firework.isEnd()) {
        deleteFromList(fireworkList, firework)
      }
    })

    ctx.restore()

    requestAnimationFrame(draw)
  }
  draw()

  // 烟花颜色列表
  const createFireworkColor = () => {
    const colorList = [
      '#ff0043',
      '#14fc56',
      '#1e7fff',
      '#e60aff',
      '#ffbf36',
      '#ffffff'
    ]
    return colorList[Math.floor(Math.random() * colorList.length)]
  }

  // 发射烟花
  //canvas.addEventListener('click', () => {
      setInterval(function () {
        const firework = new Firework({
          color: createFireworkColor()
        })
        fireworkList.push(firework)
        firework.launch()
      }, 1000);
  //})

</script>

其中引用的一个test.js文件如下：

// 爆炸碎片类
class ExplosiveDebris {
  constructor(opt) {
    this.firework = opt.firework
    this.x = opt.x
    this.y = opt.y
    this.color = Math.random() > 0.2 ? opt.color : '#fff'
    this.radius = opt.radius || 2
    this.angle = getRandom(0, 2 * Math.PI)
    this.speed = opt.speed || getRandom(0.1, 4)
    this.vx = Math.cos(this.angle) * this.speed
    this.vy = Math.sin(this.angle) * this.speed
    this.g = opt.g || 0.98
    this.time = getRandom(0.5, 1)
    this.startTime = 0
    // 痕迹碎片数量
    this.debrisCount = opt.debrisCount || 3
    // 是否要进行二次爆炸
    this.secondBurst = opt.secondBurst || false
  }

  start() {
    this.startTime = Date.now()
  }

  update() {
    const duration = (Date.now() - this.startTime) / 1000
    const vy = this.vy - this.g * duration
    this.x += this.vx
    this.y += vy
    const progress = duration / this.time
    let opacity = progress > 0.7 ? 1 - 1 * progress : 1
    if (opacity < 0) opacity = 0
    drawCircle({
      x: this.x,
      y: this.y,
      color: this.color,
      radius: this.radius,
      opacity: opacity
    })
    // 添加痕迹碎片
    if (this.debrisCount > 0 && Math.random() > 0.8) {
      this.debrisCount--
      this.firework.addDebris({
        x: this.x + getRandom(-2, 2),
        y: this.y + getRandom(-2, 2),
        color: this.color,
        radius: 0.5,
        g: 0.1
      })
    }
    return {
      x: this.x,
      y: this.y,
      isEnd: progress >= 1
    }
  }
}


// 爆炸器类
class Explosive {
  constructor(opt) {
    this.firework = opt.firework
    this.x = opt.x
    this.y = opt.y
    this.color = opt.color
    // 爆炸碎片列表
    this.debrisList = []
    // 爆炸碎片数量
    this.debrisNum = opt.debrisNum || getRandom(10, 2000)
    // 是否要二次爆炸
    this.secondBurst = opt.secondBurst || this.debrisNum <= 100
    //是否是第一次爆炸
    this.isFirstBurst = true
  }

  start(debrisNum, opt = {}) {
    const num = debrisNum || this.debrisNum
    opt.x = opt.x || this.x
    opt.y = opt.y || this.y
    opt.secondBurst = this.secondBurst && this.isFirstBurst
    for (let i = 0; i < num; i++) {
      const explosiveDebris = new ExplosiveDebris({
        firework: this.firework,
        color: this.color,
        ...opt
      })
      explosiveDebris.start()
      this.debrisList.push(explosiveDebris)
    }
    this.isFirstBurst = false
  }

  update() {
    const list = [...this.debrisList]
    list.forEach(debris => {
      const res = debris.update()
      if (res.isEnd) {
        deleteFromList(this.debrisList, debris)
        // 二次爆炸
        if (debris.secondBurst) {
          this.start(5, {
            x: res.x,
            y: res.y,
            speed: 1
          })
        }
      }
    })
    return {
      isEnd: list.length <= 0
    }
  }
}

// 痕迹碎片类
class Debris {
  constructor(opt = {}) {
    // 颜色
    this.color = opt.color || '#fff'
    // 透明度
    this.opacity = getRandom(0.1, 0.5)
    // 半径
    this.radius = opt.radius || 1
    // 存在时间
    this.time = getRandom(0.5, 1)
    // 重力，px/s2
    this.g = opt.g || 0.98
    // 位置
    this.x = opt.x
    this.y = opt.y
    // 创建的时间
    this.startTime = 0
  }

  start() {
    this.startTime = Date.now()
  }

  update() {
    const duration = (Date.now() - this.startTime) / 1000
    this.y -= this.g * duration
    drawCircle({
      opacity: this.opacity,
      x: this.x,
      y: this.y,
      radius: this.radius,
      color: this.color
    })
    return {
      x: this.x,
      y: this.y,
      isEnd: duration > this.time
    }
  }
}


// 发射器类
class Launcher {
  constructor(opt = {}) {
    // 烟花实例
    this.firework = opt.firework
    // 颜色
    this.color = opt.color
    // 初始位置
    this.x = opt.x || canvasWidth * getRandom(0.2, 0.8)
    this.y = opt.y || 0
    // 目标位置
    this.ty = canvasHeight * getRandom(0.6, 0.8)
    // 半径
    this.radius = opt.radius || getRandom(2, 5)
    // 发射的持续时间
    this.duration = opt.duration || getRandom(2000, 3500)
    // 发射时的时间
    this.startTime = 0
  }

  start() {
    this.startTime = Date.now()
  }

  easeOutCubic(t, b, c, d) {
    return c * ((t = t / d - 1) * t * t + 1) + b
  }

  update() {
    const x = this.x
    let y = this.easeOutCubic(
      Date.now() - this.startTime,
      this.y,
      this.ty - this.y,
      this.duration
    )
    y = Math.min(y, this.ty)
    // 透明度变小
    let opacity = 1 - 1 * (y / this.ty)
    if (opacity < 0) opacity = 0
    this.draw(x, y, opacity)
    // 添加痕迹碎片
    if (Math.random() > 0.7 && opacity >= 0.1) {
      this.firework.addDebris({
        x: x + getRandom(-2, 2), // x坐标添加一段随机量
        y
      })
    }
    return {
      x,
      y,
      isEnd: y >= this.ty //返回true代表发射结束
    }
  }
  draw(x, y, opacity) {
    // 外圆，烟花的颜色
    drawCircle({
      opacity: opacity,
      x: x,
      y: y,
      radius: this.radius,
      color: this.color
    })
    // 内圆，白色
    drawCircle({
      opacity: opacity,
      x: x,
      y: y,
      radius: this.radius / 2,
      color: '#fff'
    })
  }
}

// 烟花类
class Firework {
  constructor(opt = {}) {
    // 颜色
    this.color = opt.color || tinycolor.random().toHexString()
    // 发射器
    this.launcher = null
    // 爆炸器
    this.explosive = null
    // 烟花状态：waiting（等待发射）、launching（发射中）、bursting（爆炸中）、end（烟花结束）
    this.status = 'waiting'
    // 痕迹碎片列表
    this.debrisList = []
  }

  // 发射
  launch() {
    this.launcher = new Launcher({
      firework: this,
      color: this.color
    })
    this.launcher.start()
    this.status = 'launching'
  }

  // 爆炸
  burst({ x, y }) {
    this.explosive = new Explosive({
      firework: this,
      x,
      y,
      color: this.color
    })
    this.explosive.start()
  }

  // 更新
  update() {
    if (this.status === 'launching') {
      const res = this.launcher.update()
      if (res.isEnd) {
        this.status = 'bursting'
        this.burst(res)
      }
    } else if (this.status === 'bursting') {
      const res = this.explosive.update()
      if (res.isEnd) {
        this.status = 'end'
      }
    }
    // 更新痕迹碎片
    this.updateDebris()
  }

  // 添加痕迹碎片
  addDebris(opt = {}) {
    const debris = new Debris({
      ...opt,
      color: opt.color || this.color
    })
    debris.start()
    this.debrisList.push(debris)
  }

  // 更新痕迹碎片
  updateDebris() {
    const list = [...this.debrisList]
    list.forEach(debris => {
      const res = debris.update()
      if (res.isEnd) {
        deleteFromList(this.debrisList, debris)
      }
    })
  }

  isEnd() {
    return this.status === 'end'
  }
}