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Swrls

  1. const canvas = document.createElement("canvas");
  2. const c = canvas.getContext("2d");
  3.  
  4. canvas.width = innerWidth;
  5. canvas.height = innerHeight;
  6. document.body.append(canvas); 
  7.  
  8. const TWO_PI = 2 * Math.PI;
  9.  
  10. class Dot {
  11.   constructor(id, x, y, theta, parent) {
  12.     this.x = x;
  13.     this.y = y;
  14.     this.t = theta;
  15.     this.vx = Math.cos(this.t) * Math.random() * 2;
  16.     this.vy = Math.sin(this.t) * Math.random() * 2;
  17.     this.life = 30;
  18.     this.col = parent.col;
  19.  
  20.     if (Math.random() < 0.005) this.other = true;
  21.     if (this.other) {
  22.       this.life = 1000;
  23.       this.t = Math.random() * 7;
  24.       this.vx = Math.cos(this.t) * Math.random() * 2;
  25.       this.vy = Math.sin(this.t) * Math.random() * 2;
  26.       this.col = "black";
  27.     }
  28.     this.iter = 0;
  29.     this.parent = parent;
  30.     this.id = id;
  31.     this.alpha = 0.25;
  32.  
  33.     if (Math.random() < 0.3) this.alpha = 0.25;
  34.   }
  35.  
  36.   draw() {
  37.     this.x += this.vx;
  38.     this.y += this.vy;
  39.     this.iter++;
  40.     if (this.iter > this.life) {
  41.       delete this.parent.dots[this.id];
  42.     }
  43.     c.fillStyle = this.col;
  44.     c.globalAlpha = this.alpha;
  45.     if (!this.no) this.alpha -= 0.00125;
  46.     c.fillRect(this.x, this.y, this.parent.size, this.parent.size);
  47.   }
  48. }
  49.  
  50. class Stain {
  51.   constructor(x = innerWidth, y = innerHeight) {
  52.     this.x = x / 2;
  53.     this.y = y / 2;
  54.     this.num = 1;
  55.     this.step = TWO_PI / this.num;
  56.  
  57.     this.size = 1 + Math.random() * Math.random() * 2;
  58.     this.rad = Math.random() * 300;
  59.     this.dots = {};
  60.     this.dotId = 0;
  61.     this.col = Math.random() < 0.8 ? "white" : "black";
  62.     this.to = Math.random() * 7;
  63.     this.S = 20 + Math.random() * 50;
  64.     this.R = 100 + Math.random() * 300;
  65.     this.rr = 50 + Math.random() * 300;
  66.     this.dir = Math.random() < 0.6 ? 1 : Math.random() * 10 - 5;
  67.     this.v = 1;
  68.     this.tt = 0;
  69.     if (Math.random() * 0.25) this.v = Math.random() * 5;
  70.   }
  71.  
  72.   draw() { 
  73.     const circ = this.rad * TWO_PI;
  74.     this.rad -= this.v;
  75.  
  76.     this.step = TWO_PI / circ;
  77.  
  78.     if (this.rad > 0) {
  79.       for (let i = 1; i <= this.R; i += this.S) {
  80.         let t = (i * this.step + this.to) * this.dir;
  81.         let x = this.x + this.rad * Math.cos(t);
  82.         let y = this.y + this.rad * Math.sin(t);
  83.         this.dots[this.dotId] = new Dot(this.dotId, x, y, t, this);
  84.         this.dotId++;
  85.       }
  86.     }
  87.     for (let i in this.dots) {
  88.       if (this.dots[i]) this.dots[i].draw();
  89.     }
  90.   }
  91. }
  92.  
  93. onresize = e => {
  94.   canvas.width = innerWidth;
  95.   canvas.height = innerHeight;
  96.   c.fillStyle = "black";
  97.   c.fillRect(0, 0, innerWidth, innerHeight)
  98. }
  99.  
  100. onresize()
  101.  
  102. let ss = [new Stain()];
  103.  
  104. function loop() {
  105.   if (Math.random() < 0.05) {
  106.     ss.push(
  107.       new Stain(Math.random() * innerWidth * 2, Math.random() * innerHeight * 2)
  108.     );
  109.   }
  110.   ss.forEach((s) => s.draw());
  111.   c.globalAlpha = 0.05;
  112.   c.drawImage(canvas, 0, 3, canvas.width + 0.2, canvas.height - 6);
  113.   c.globalAlpha = 1;
  114.   requestAnimationFrame(loop);
  115. }
  116. loop();

Speed coding for some recent youtube shorts…

Golfed Codepen – 3D Spiral Thing

  1. // sort of golfed version of https://www.instagram.com/p/C1uv6Kqv19T/
  2. // by @mewtru
  3. b = document.body
  4. a = Object.assign
  5. a(b.style, { background:'#000', color:'#fff'})
  6. w = 'snippet.zone snippet.zone'.toUpperCase().split``
  7. F = (n, O = 0, C, S, o, t) => { 
  8.   b.innerHTML += `<div id=${n} style='position:absolute;left:50%;top:50%;translate:-50% -50%;width:100% text-align:center;white-space:nowrap'></div>`
  9.   w.map(l => this[n].innerHTML += `<span style='display:inline-block;margin-right:5px;font-size:28px'>${l}</span>`)
  10.   t = O
  11.   setInterval(_ => {
  12.     t += .005
  13.     ;[...this[n].children].map((e, i) => { 
  14.       T = t + i / 2.7
  15.       a(e.style, {
  16.         translate: `0 ${Math.sin(T) * 100}px`,
  17.         scale: Math.cos(T) * .5 + .5})
  18.     }, 16)
  19.   })
  20. }
  21. F('Z') 
  22. F('X', 3)

“Very cool” pen by Lucas Fernando that comes from @mewtru
I decided to do a speed-coded semi-golfed version… can definitely be way more golfed 😀

Parametric Equation for Rectangle

  1. // from http://math.stackexchange.com/questions/69099/equation-of-a-rectangle
  2. const rect = (px, py, rx, ry, t) => ({
  3.   x: px + rx + rx * (Math.abs(Math.cos(t)) * Math.cos(t) + Math.abs(Math.sin(t)) * Math.sin(t)),
  4.   y: py + ry + ry * (Math.abs(Math.cos(t)) * Math.cos(t) - Math.abs(Math.sin(t)) * Math.sin(t))
  5. })
  6.  
  7. const SIZE = 200
  8.  
  9. const c = document.body.appendChild(
  10.   Object.assign(document.createElement`canvas`,
  11.     { width: SIZE, height: SIZE }
  12.   )).getContext`2d`
  13.  
  14. c.fillStyle = 'black'
  15. c.fillRect(0, 0, SIZE, SIZE)
  16.  
  17. let t = 0
  18. setInterval(() => {
  19.   const { x, y } = rect(20, 20, 60, 70, t)
  20.   c.fillStyle = 'rgba(255, 0, 0, .1)'
  21.   c.fillRect(x, y, 10, 10)
  22.   t += .05
  23. }, 16)

Wanted to know how to do this for something back in 2015. Great math stackexchange answer here: http://math.stackexchange.com/questions/69099/equation-of-a-rectangle

Could be optimized but leaving as is to match:

x = p(|cos t|cos t + |sin t| sin t)
y = p(|cos t|cos t - |sin t| sin t)

One small change here is to add the width and height to the offset so that it draws from the upper left hand corner instead of the center…

Two Circles Explode

  1. const { random, min, sqrt, cos, sin, PI } = Math
  2. let TWO_PI = PI * 2
  3. let minSize
  4.  
  5. document.body.style.margin = 0
  6. document.body.style.background = 'black'
  7. const canvas = document.body.appendChild(
  8.   document.createElement('canvas')
  9. )
  10. const c = canvas.getContext('2d')
  11.  
  12. addEventListener('resize', resize)
  13. resize()
  14.  
  15. function resize() {
  16.   canvas.width = innerWidth
  17.   canvas.height = innerHeight
  18.   minSize = min(innerWidth, innerHeight)
  19.   clear()
  20. }
  21.  
  22. function clear() {
  23.   c.fillStyle = 'rgba(0, 0, 0, .15)'
  24.   c.fillRect(0, 0, innerWidth, innerHeight)
  25. }
  26.  
  27. let dots = []
  28. function dot({x, y, vx, vy, rad, grav = .15}) {
  29.   let sx = x
  30.   let sy = y
  31.   let svx = vx
  32.   let svy = vy
  33.   let intersected
  34.   let partsNum = 20
  35.   let parts = []
  36.   let delay = random() * 5
  37.   let time = 0
  38.  
  39.   dots.push(() => y > innerHeight)
  40.  
  41.   return {
  42.     step() {
  43.       time++
  44.       if (time < delay) return
  45.       if (intersected) {
  46.         for (let i = 0; i < partsNum; i++) {
  47.           parts[i].step()
  48.         }
  49.         return
  50.       }
  51.       x += vx
  52.       y += vy
  53.       vy += grav;
  54.       c.beginPath()
  55.       c.arc(x, y, rad(), 0, 7)
  56.       c.fill()
  57.     },
  58.     reset() {
  59.       x = sx;
  60.       y = sy;
  61.       vx = svx;
  62.       vy = svy;
  63.       intersected = false
  64.     },
  65.     hit() {
  66.       if (!intersected) {
  67.         partsNum = rad() / 3
  68.         for (let i = 0; i < partsNum; i++) {
  69.           let t = random() * TWO_PI
  70.           let r = 5 + random() * 5
  71.           let size = random() * 10
  72.  
  73.           parts.push(
  74.             dot({
  75.               x, y,
  76.               vx: r * cos(t),
  77.               vy: r * sin(t),
  78.               rad: () => size
  79.             })
  80.           )
  81.         }
  82.       }
  83.       intersected = true
  84.     },
  85.     get x() {
  86.       return x
  87.     },
  88.     get y() {
  89.       return y
  90.     }
  91.   }
  92. }
  93.  
  94. const bigRad = () => minSize * .14;
  95.  
  96. let leftDot
  97. let rightDot
  98.  
  99. function start() {
  100.  
  101.   rightDot = dot({
  102.     x: innerWidth, 
  103.     y: innerHeight / 2, 
  104.     vx: -innerWidth * .005, 
  105.     vy: -6, rad: bigRad
  106.   })
  107.  
  108.   leftDot = dot({
  109.     x: 0, 
  110.     y: innerHeight / 2, 
  111.     vx: innerWidth * .005, 
  112.     vy: -6, rad: bigRad
  113.   })
  114. }
  115. start()
  116.  
  117. function collide(a, b) {
  118.   const dx = a.x - b.x
  119.   const dy = a.y - b.y
  120.   const dist = sqrt(dx**2 + dy**2)
  121.   return dist <= bigRad() * 1.8
  122. }
  123.  
  124. function loop() {
  125.   let inc = 2
  126.  
  127.   clear()
  128.   c.fillStyle = 'white'
  129.   if (collide(leftDot, rightDot)) {
  130.  
  131.     leftDot.hit()
  132.     rightDot.hit()
  133.   }
  134.  
  135.   leftDot.step()
  136.   rightDot.step()
  137.  
  138.   dots.forEach(done => {
  139.     if (done()) inc++;
  140.   }) 
  141.  
  142.   if (dots.length > 2 && inc == dots.length)  {
  143.     dots = []
  144.     start()
  145.   }
  146.  
  147.   requestAnimationFrame(loop)
  148. }
  149. loop()

Two circles intersect and explode repeatedly… works at any browser size…

CoffeeScript Ikeda Map

  1. canvas = document.querySelector "canvas"
  2. c = canvas.getContext "2d"
  3. locX = 120
  4. locY = 400
  5. xn1 = xn = yn1 = yn = tn = 0
  6. u = .7
  7. steps = 10
  8. iterations = 200
  9. scale = 180
  10.  
  11. c.fillStyle = "black"
  12. c.fillRect 0, 0, canvas.width, canvas.height
  13. c.fillStyle = "rgba(255,255,255,0.2)"
  14.  
  15. run = setInterval ->
  16.   clearInterval run if u > 1
  17.   i = 0
  18.  
  19.   while i < steps
  20.     u += 0.00015
  21.     j = 0
  22.  
  23.     while j < iterations
  24.       xn = xn1
  25.       yn = yn1
  26.       tn = 0.4 - (6 / (1 + xn * xn + yn * yn))
  27.       xn1 = 1 + u * (xn * Math.cos(tn) - yn * Math.sin tn)
  28.       yn1 = u * (xn * Math.sin(tn) + yn * Math.cos tn)
  29.       c.fillRect locX + xn1 * scale, locY + yn1 * scale, 1, 1
  30.       j++
  31.     i++
  32. , 30

I do quite miss CoffeeScript sometimes… here is an old codepen of the Ikeda Map:

See the Pen Ikeda Map by Zevan Rosser (@ZevanRosser) on CodePen.

snippet.zone ~ 2021-24 /// {s/z}