shorten random function

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

(function () {

  var K = document.querySelector('canvas'),
      { random: R, PI, cos, sin, floor, atan2 } = Math,
      ctx = K.getContext('2d'),
      fps = 24,
      lst = 0,
      spd = 1,
      siz = 5 + r(10),
      clr = R() > 0.5,
      ccl = R() > 0.5,
      I = Array(r(10) + 6).fill(null).map(() => ({
        x: r(64),
        y: r(64),
        a: R() * 2 * PI,
        c: Array(3).fill(r(256))
      })),
      SHP = [sqr, crc, hrt, chs, lch],
      POS = [id, spn(5), spn(15)],
      draw = SHP[r(SHP.length)],
      pos = POS[r(POS.length)];

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

  function sqr(i) {

    var p = pos(i);
    ctx.fillRect(p.x, p.y, siz, siz);
  }

  function crc(i) {

    var p = pos(i);
    ctx.beginPath();
    ctx.arc(p.x, p.y, siz / 2, 0, 2 * PI);
    ctx.fill();
  }

  function chs(i) {

    var p = pos(i);
    ctx.beginPath();
    ctx.moveTo(p.x, p.y);
    ctx.lineTo(p.x * 10 * cos(i.a), p.y * 10 * sin(i.a));
    ctx.lineTo(r(64), r(64));
    ctx.fill();
  }

  function lch(i) {

    var p = pos(i);
    ctx.beginPath();
    ctx.lineWidth = 5;
    ctx.strokeStyle = `rgb(${i.c.join(',')})`;
    ctx.moveTo(p.x, p.y);
    ctx.lineTo(p.x * 10 * cos(i.a), p.y * 10 * sin(i.a));
    ctx.stroke();
  }

  function hrt(i) {

    var p = pos(i);
    ctx.fillRect(p.x, p.y, siz, siz);

    ctx.beginPath();
    ctx.arc(p.x + siz / 2, p.y, siz / 2, 0, 2 * PI, false);
    ctx.fill();
    ctx.closePath();

    ctx.beginPath();
    ctx.arc(p.x + siz, p.y + siz / 2, siz / 2, 0, 2 * PI, false);
    ctx.fill();
    ctx.closePath();
  }

  function id(p) {

    return p;
  }

  function spn(rad) {
    return function (p) {

      return {
        x: p.x + rad * cos(lst),
        y: p.y + rad * sin(lst)
      }
    }
  }

  function mov(i) {

    i.x = i.x + spd * cos(i.a);
    i.y = i.y + spd * sin(i.a);

    if (i.x < 0 || i.x > 64) {
      i.a = atan2(sin(i.a), -cos(i.a))
    }

    if (i.y < 0 || i.y > 64) {
      i.a = atan2(-sin(i.a), cos(i.a))
    }
  }

  function ucl(i) {

    i.c = i.c.map((c) => {
      c = c + 5;
      return c > 255 ? 0 : c;
    })
  }

  function frm(t) {

    window.requestAnimationFrame(frm);

    var dt = t - lst;

    if (dt > 1000 / fps) {
      clr && ctx.clearRect(0, 0, 64, 64);
      for (var i of I) {
        ctx.fillStyle = `rgb(${i.c.join(',')})`;
        draw(i);
        ccl && ucl(i);
        mov(i);
      }

      lst = t;
    }
  }

  frm();
}
)();