Use percentage

[rbdr/r.bdr.sh] / js / animation.js

(function () {

  var K = document.querySelector('canvas'),
      { random: R, PI, cos: C, sin: S, floor, atan2: A } = Math,
      id = p => p,
      spn = rad => p => ({
          x: p.x + rad * C(l),
          y: p.y + rad * S(l)
      }),
      X = K.getContext('2d'),
      f = 24,
      l = 0,
      s = 1,
      z = 5 + r(10),
      k = R() > 0.5,
      c = R() > 0.5,
      I = Array(r(10) + 6).fill().map(() => ({
        x: r(64),
        y: r(64),
        a: R() * 2 * PI,
        c: r(100)
      })),
      H = [sqr, crc, hrt, chs, lch],
      P = [id, spn(5), spn(15)],
      draw = H[r(H.length)],
      pos = P[r(P.length)]

  function r(x) {
    return floor(R() * x)
  }

  function sqr(i) {

    var {x, y} = pos(i)
    X.fillRect(x, y, z, z)
  }

  function crc(i) {

    var {x, y} = pos(i)
    X.beginPath()
    X.arc(x, y, z / 2, 0, 2 * PI)
    X.fill()
  }

  function chs(i) {

    var {x, y} = pos(i)
    X.beginPath()
    X.moveTo(x, y)
    X.lineTo(x * 10 * C(i.a), y * 10 * S(i.a))
    X.lineTo(r(64), r(64))
    X.fill()
  }

  function lch(i) {

    var {x, y} = pos(i)
    X.beginPath()
    X.lineWidth = 5
    X.strokeStyle = `hsl(0,0%,${i.c}%)`
    X.moveTo(x, y)
    X.lineTo(x * 10 * C(i.a), y * 10 * S(i.a))
    X.stroke()
  }

  function hrt(i) {

    var {x, y} = pos(i)
    X.fillRect(x, y, z, z)

    X.beginPath()
    X.arc(x + z / 2, y, z / 2, 0, 2 * PI, false)
    X.fill()
    X.closePath()

    X.beginPath()
    X.arc(x + z, y + z / 2, z / 2, 0, 2 * PI, false)
    X.fill()
    X.closePath()
  }

  function mov(i) {

    i.x = i.x + s * C(i.a)
    i.y = i.y + s * S(i.a)

    if (i.x < 0 || i.x > 64) {
      i.a = A(S(i.a), -C(i.a))
    }
    if (i.y < 0 || i.y > 64) {
      i.a = A(-S(i.a), C(i.a))
    }
  }

  function ucl(i) {
    i.c = (i.c + 2) % 101
  }

  function frm(t) {

    requestAnimationFrame(frm)

    var dt = t - l

    if (dt > 1000 / f) {
      k && X.clearRect(0, 0, 64, 64)
      for (var i of I) {
        X.fillStyle = `hsl(0,0%,${i.c}%)`
        draw(i)
        c && ucl(i)
        mov(i)
      }

      l = t
    }
  }

  frm()
}
)()