git.r.bdr.sh - rbdr/r.bdr.sh/blob - js/animation.js

   1 (function () {
   2
   3   var canvas = document.querySelector('canvas'),
   4       r = Math.random,
   5       pi = Math.PI,
   6       cos = Math.cos,
   7       sin = Math.sin,
   8       context = canvas.getContext('2d'),
   9       fps = 30,
  10       lastFrame = 0,
  11       speed = 1,
  12       size = 5 + rand(10),
  13       clear = !!(r() > 0.5),
  14       changeColor = !!(r() > 0.5),
  15       items = Array(rand(10) + 6).fill(null).map(() => ({
  16         x: rand(64),
  17         y: rand(64),
  18         angle: r() * 2 * pi,
  19         color: Array(3).fill(rand(256))
  20       })),
  21       shapes = [square, circle, heart, chaos, lineChaos],
  22       positions = [identity, spin(5), spin(15)],
  23       draw = shapes[rand(shapes.length)],
  24       position = positions[rand(positions.length)];
  25
  26   function rand (x) {
  27     return Math.floor(r() * x);
  28   }
  29
  30   function square(item) {
  31
  32     var p = position(item);
  33     context.fillRect(p.x, p.y, size, size);
  34   }
  35
  36   function circle(item) {
  37
  38     var p = position(item);
  39     context.beginPath();
  40     context.arc(p.x, p.y, size / 2, 0, 2 * pi);
  41     context.fill();
  42   }
  43
  44   function chaos(item) {
  45
  46     var p = position(item);
  47     context.beginPath();
  48     context.moveTo(p.x, p.y);
  49     context.lineTo(p.x * 10 * cos(item.angle), p.y * 10 * sin(item.angle));
  50     context.lineTo(rand(64), rand(64));
  51     context.fill();
  52   }
  53
  54   function lineChaos(item) {
  55
  56     var p = position(item);
  57     context.beginPath();
  58     context.lineWidth = 5;
  59     context.strokeStyle = `rgb(${item.color.join(',')})`;
  60     context.moveTo(p.x, p.y);
  61     context.lineTo(p.x * 10 * cos(item.angle), p.y * 10 * sin(item.angle));
  62     context.stroke();
  63   }
  64
  65   function square(item) {
  66
  67     var p = position(item);
  68     context.fillRect(p.x, p.y, size, size);
  69   }
  70
  71   function heart(item) {
  72
  73     var p = position(item);
  74     context.fillRect(p.x, p.y, size, size);
  75
  76     context.beginPath();
  77     context.arc(p.x + size / 2, p.y, size / 2, 0, 2 * pi, false);
  78     context.fill();
  79     context.closePath();
  80
  81     context.beginPath();
  82     context.arc(p.x + size, p.y + size / 2, size / 2, 0, 2 * pi, false);
  83     context.fill();
  84     context.closePath();
  85   }
  86
  87   function identity(position) {
  88
  89     return position;
  90   }
  91
  92   function spin(radius) {
  93     return function (position) {
  94
  95       return {
  96         x: position.x + radius * cos(lastFrame),
  97         y: position.y + radius * sin(lastFrame)
  98       }
  99     }
 100   }
 101
 102   function move(item) {
 103
 104     item.x = item.x + speed * cos(item.angle);
 105     item.y = item.y + speed * sin(item.angle);
 106
 107     if (item.x < 0 || item.x > 64) {
 108       item.angle = Math.atan2(sin(item.angle), -cos(item.angle))
 109     }
 110
 111     if (item.y < 0 || item.y > 64) {
 112       item.angle = Math.atan2(-sin(item.angle), cos(item.angle))
 113     }
 114   }
 115
 116   function updateColor(item) {
 117
 118     item.color = item.color.map((c) => {
 119       c = c + 5;
 120       return c > 255 ? 0 : c;
 121     })
 122   }
 123
 124   function frame(time) {
 125
 126     window.requestAnimationFrame(frame);
 127
 128     var delta = time - lastFrame;
 129
 130     if (delta > 1000 / fps) {
 131       clear && context.clearRect(0, 0, 64, 64);
 132       for (var item of items) {
 133         context.fillStyle = `rgb(${item.color.join(',')})`;
 134         draw(item);
 135         changeColor && updateColor(item);
 136         move(item);
 137       }
 138
 139       lastFrame = time;
 140     }
 141   }
 142
 143   frame();
 144 }
 145 )();