StarrySky.js

/* eslint-disable */
import React from 'react'

const StarrySky = () => {
  React.useEffect(() => {
    dark()
  }, [])
  return (
    <div className="relative">
      <canvas id="starry-sky-vixcity" style={{zIndex:1}} className="top-0 fixed pointer-events-none"></canvas>
    </div>
  )
}

export default StarrySky
/**
 * 创建星空雨
 * @param config
 */
function dark() {
  window.requestAnimationFrame =
    window.requestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    window.webkitRequestAnimationFrame ||
    window.msRequestAnimationFrame
  var n,
    e,
    i,
    h,
    t = 0.05,
    s = document.getElementById('starry-sky-vixcity'),
    o = !0,
    a = '180,184,240',
    r = '226,225,142',
    d = '226,225,224',
    c = []
  function f() {
    ;(n = window.innerWidth),
      (e = window.innerHeight),
      (i = 0.216 * n),
      s.setAttribute('width', n),
      s.setAttribute('height', e)
  }
  function u() {
    h.clearRect(0, 0, n, e)
    for (var t = c.length, i = 0; i < t; i++) {
      var s = c[i]
      s.move(), s.fadeIn(), s.fadeOut(), s.draw()
    }
  }
  function y() {
    ;(this.reset = function () {
      ;(this.giant = m(3)),
        (this.comet = !this.giant && !o && m(10)),
        (this.x = l(0, n - 10)),
        (this.y = l(0, e)),
        (this.r = l(1.1, 2.6)),
        (this.dx = l(t, 6 * t) + (this.comet + 1 - 1) * t * l(50, 120) + 2 * t),
        (this.dy = -l(t, 6 * t) - (this.comet + 1 - 1) * t * l(50, 120)),
        (this.fadingOut = null),
        (this.fadingIn = !0),
        (this.opacity = 0),
        (this.opacityTresh = l(0.2, 1 - 0.4 * (this.comet + 1 - 1))),
        (this.do = l(5e-4, 0.002) + 0.001 * (this.comet + 1 - 1))
    }),
      (this.fadeIn = function () {
        this.fadingIn &&
          ((this.fadingIn = !(this.opacity > this.opacityTresh)),
          (this.opacity += this.do))
      }),
      (this.fadeOut = function () {
        this.fadingOut &&
          ((this.fadingOut = !(this.opacity < 0)),
          (this.opacity -= this.do / 2),
          (this.x > n || this.y < 0) && ((this.fadingOut = !1), this.reset()))
      }),
      (this.draw = function () {
        if ((h.beginPath(), this.giant))
          (h.fillStyle = 'rgba(' + a + ',' + this.opacity + ')'),
            h.arc(this.x, this.y, 2, 0, 2 * Math.PI, !1)
        else if (this.comet) {
          ;(h.fillStyle = 'rgba(' + d + ',' + this.opacity + ')'),
            h.arc(this.x, this.y, 1.5, 0, 2 * Math.PI, !1)
          for (var t = 0; t < 30; t++)
            (h.fillStyle =
              'rgba(' +
              d +
              ',' +
              (this.opacity - (this.opacity / 20) * t) +
              ')'),
              h.rect(
                this.x - (this.dx / 4) * t,
                this.y - (this.dy / 4) * t - 2,
                2,
                2
              ),
              h.fill()
        } else
          (h.fillStyle = 'rgba(' + r + ',' + this.opacity + ')'),
            h.rect(this.x, this.y, this.r, this.r)
        h.closePath(), h.fill()
      }),
      (this.move = function () {
        ;(this.x += this.dx),
          (this.y += this.dy),
          !1 === this.fadingOut && this.reset(),
          (this.x > n - n / 4 || this.y < 0) && (this.fadingOut = !0)
      }),
      setTimeout(function () {
        o = !1
      }, 50)
  }
  function m(t) {
    return Math.floor(1e3 * Math.random()) + 1 < 10 * t
  }
  function l(t, i) {
    return Math.random() * (i - t) + t
  }
  f(),
    window.addEventListener('resize', f, !1),
    (function () {
      h = s.getContext('2d')
      for (var t = 0; t < i; t++) (c[t] = new y()), c[t].reset()
      u()
    })(),
    (function t() {
      document.getElementsByTagName('html')[0].className == 'dark' && u(),
        window.requestAnimationFrame(t)
    })()
}