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AboutAll PostsWarningRandom

Fake RNG

  1. let anchors
  2. let idx
  3. let leng = 10
  4. let size = 200
  5. let px = 0
  6. let py = 0
  7.  
  8. function seed() {
  9.   idx = 0
  10.   anchors = (Date.now() + '').split``
  11.     .reverse()
  12.     .map(v => parseFloat(v) / 10)
  13.     .splice(0, leng)
  14. }
  15.  
  16. let last = 0
  17. let zoom = 1
  18. function rand() {
  19.   if (idx > size * size) seed()
  20.  
  21.   px += zoom
  22.   py += ~~(px / size)
  23.  
  24.   if (px >= size) px = 0
  25.   if (py >= size) py = 0
  26.  
  27.   const point = {
  28.     x: anchors[idx % leng],
  29.     y: anchors[(idx + 1) % leng]
  30.   }
  31.   idx++
  32.  
  33.   let dists = []
  34.   for (let i = 0; i < anchors.length; i += 2) {
  35.     let dx = px - anchors[i] * size
  36.     let dy = py - anchors[i + 1] * size
  37.     dists.push(Math.sqrt(dx * dx + dy * dy))
  38.   }
  39.   dists.sort()
  40.   last += (dists[0] / size - last) / 4
  41.   return last
  42. }
  43.  
  44. seed()
  45.  
  46. let d = document
  47. let b = d.body
  48. with (b.appendChild(
  49.   Object.assign(d.createElement`canvas`, { width: 400, height: 400 })
  50. ).getContext`2d`) {
  51.   fillStyle = 'black'
  52.   fillRect(0, 0, 400, 400)
  53.  
  54.   for (let i = 0; i < 200; i++) {
  55.     for (let j = 0; j < 200; j++) {
  56.       const c = rand() * 255
  57.       fillStyle = `rgb(${c}, ${c}, ${c})`
  58.       fillRect(j * 2, i * 2, 1, 2)
  59.     }
  60.   }
  61. }

Another one for genuary “Create your own pseudo-random number generator and visually check the results.”

// canvas // graphics // hacks // math // random // speedcoding

Average Some Curves

  1. const canvas = document.body.appendChild(
  2.   document.createElement('canvas')
  3. );
  4. const c = canvas.getContext('2d');
  5.  
  6. function resize() {
  7.   canvas.width = window.innerWidth;
  8.   canvas.height = window.innerHeight;
  9.   draw();
  10. }
  11.  
  12. function draw() {
  13.   c.clearRect(0, 0, canvas.width, canvas.height);
  14.  
  15.   Math.min(window.innerWidth, window.innerHeight) * 0.0015;
  16.   const iter = 100,
  17.         halfWidth = window.innerWidth / 2,
  18.         halfHeight = window.innerHeight / 2;
  19.   let rad = 50, rad2 = 50, theta = 0, x, y;
  20.   let x2, y2;
  21.   for (let i = 0; i < iter; i++) {
  22.     c.fillStyle = 'blue';
  23.     x = halfWidth + rad * Math.cos(theta);
  24.     y = halfHeight + rad * Math.sin(theta);
  25.     c.fillRect(x, y, 5, 5);
  26.  
  27.     c.fillStyle = 'red';
  28.  
  29.     rad2 = 80 + rad * Math.cos(theta * 3);
  30.     x2 = halfWidth + rad2 * Math.cos(theta);
  31.     y2 = halfHeight + rad2 * Math.sin(theta);
  32.     c.fillRect(x2, y2, 5, 5);
  33.  
  34.     c.fillStyle = 'green';
  35.     c.fillRect((x2 + x) / 2, (y2 + y) / 2, 5, 5);
  36.  
  37.     theta += .1;
  38.   }
  39. }
  40.  
  41. resize();
  42. window.addEventListener('resize', resize);
// canvas // graphics // math // speedcoding

Raphaël Easing Equations

  1. var ef = R.easing_formulas = {
  2.     linear: function (n) {
  3.         return n;
  4.     },
  5.     "<": function (n) {
  6.         return pow(n, 1.7);
  7.     },
  8.     ">": function (n) {
  9.         return pow(n, .48);
  10.     },
  11.     "<>": function (n) {
  12.         var q = .48 - n / 1.04,
  13.             Q = math.sqrt(.1734 + q * q),
  14.             x = Q - q,
  15.             X = pow(abs(x), 1 / 3) * (x < 0 ? -1 : 1),
  16.             y = -Q - q,
  17.             Y = pow(abs(y), 1 / 3) * (y < 0 ? -1 : 1),
  18.             t = X + Y + .5;
  19.         return (1 - t) * 3 * t * t + t * t * t;
  20.     },
  21.     backIn: function (n) {
  22.         var s = 1.70158;
  23.         return n * n * ((s + 1) * n - s);
  24.     },
  25.     backOut: function (n) {
  26.         n = n - 1;
  27.         var s = 1.70158;
  28.         return n * n * ((s + 1) * n + s) + 1;
  29.     },
  30.     elastic: function (n) {
  31.         if (n == !!n) {
  32.             return n;
  33.         }
  34.         return pow(2, -10 * n) * math.sin((n - .075) * (2 * PI) / .3) + 1;
  35.     },
  36.     bounce: function (n) {
  37.         var s = 7.5625,
  38.             p = 2.75,
  39.             l;
  40.         if (n < (1 / p)) {
  41.             l = s * n * n;
  42.         } else {
  43.             if (n < (2 / p)) {
  44.                 n -= (1.5 / p);
  45.                 l = s * n * n + .75;
  46.             } else {
  47.                 if (n < (2.5 / p)) {
  48.                     n -= (2.25 / p);
  49.                     l = s * n * n + .9375;
  50.                 } else {
  51.                     n -= (2.625 / p);
  52.                     l = s * n * n + .984375;
  53.                 }
  54.             }
  55.         }
  56.         return l;
  57.     }
  58. };
  59. ef.easeIn = ef["ease-in"] = ef["<"];
  60. ef.easeOut = ef["ease-out"] = ef[">"];
  61. ef.easeInOut = ef["ease-in-out"] = ef["<>"];
  62. ef["back-in"] = ef.backIn;
  63. ef["back-out"] = ef.backOut;

Another fun chunk of code directly from the Raphaël source. Makes me think of the Penner easing equations.

// animation // javascript // math

HSL to RGB JavaScript

  1. const hsl2rgb = (h, s, l, o) => {
  2.   if (h > 1 || s > 1 || l > 1) {
  3.       h /= 360;
  4.       s /= 100;
  5.       l /= 100;
  6.   }
  7.   h *= 360;
  8.  
  9.   let R, G, B, X, C;
  10.  
  11.   h = (h % 360) / 60;
  12.   C = 2 * s * (l < .5 ? l : 1 - l);
  13.   X = C * (1 - Math.abs(h % 2 - 1));
  14.   R = G = B = l - C / 2;
  15.  
  16.   h = ~~h;
  17.   R += [C, X, 0, 0, X, C][h];
  18.   G += [X, C, C, X, 0, 0][h];
  19.   B += [0, 0, X, C, C, X][h];
  20.   return `rgba(${~~(R * 255)}, ${~~(G * 255)}, ${~~(B * 255)}, ${o})`;
  21. };
  22.  
  23. console.log(hsl2rgb(122, 50, 50, .5));

Taken from the Raphaël source… Always fun to browse – I’ve learned lots of great stuff from it 😀

// color // javascript // math

Polar Forking Tweak

  1. const FOUR_PI = 6 * Math.PI;
  2. const { cos, sin } = Math;
  3.  
  4. const canvas = document.body.appendChild(
  5.   document.createElement('canvas')
  6. );
  7. const c = canvas.getContext('2d');
  8.  
  9. function resize() {
  10.   canvas.width = window.innerWidth;
  11.   canvas.height = window.innerHeight;
  12. }
  13.  
  14. let inc = 0;
  15. function draw() { 
  16.   c.fillStyle = 'rgba(0, 0, 0, .3)'
  17.   c.fillRect(0, 0, canvas.width, canvas.height)
  18.   c.fillStyle = 'white';
  19.  
  20.   const halfWidth = window.innerWidth / 2;
  21.   const halfHeight = window.innerHeight / 2;
  22.   let theta = 0,
  23.     a = 20 * Math.min(window.innerWidth, window.innerHeight) * 0.005,
  24.     x,
  25.     y;
  26.  
  27.   c.save();
  28.   c.translate(halfWidth, halfHeight)
  29.  
  30.   let b = 5 * cos(inc);
  31.   inc += .02;
  32.  
  33.   for (let i = 0; theta < FOUR_PI; i++) {
  34.     let rad = a * (b + 10 * sin(theta / 3));
  35.     // randomly speed-coded and tweaked... leaving as is :D
  36.     x = rad * cos(theta + b / 10) * cos(b / 10 +theta * 2) * cos(theta * 2);
  37.     y = rad * sin(theta * 2) * cos(theta + b / 3) * cos(theta * 2);
  38.     c.fillRect(x,y, 2, 2);
  39.     theta += 0.04;
  40.   }
  41.   c.restore();
  42.  
  43.   requestAnimationFrame(draw)
  44. }
  45.  
  46. resize();
  47. addEventListener('resize', resize);
  48.  
  49. draw();

Just randomly futzing with sin/cos…

// animation // canvas // curves // graphics // hacks // humor // math
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