)
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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…

Faster than save/restore HTML5 canvas

  1. const canvas = document.createElement('canvas')
  2. const c = canvas.getContext('2d')
  3.  
  4. canvas.width = innerWidth
  5. canvas.height = innerHeight
  6.  
  7. document.body.append(canvas)
  8.  
  9. c.fillStyle = 'black'
  10. c.fillRect(0, 0, canvas.width, canvas.height)
  11.  
  12. class Shooter {
  13.   constructor() {
  14.     this.x = innerWidth / 2
  15.     this.y = innerHeight / 2
  16.     this.vx = Math.random() * 10 - 5
  17.     this.vy = Math.random() * 10 - 5
  18.     this.color = 'rgba(255, 0, 0, 0.5)'
  19.     this.size = 10
  20.     this.halfSize = this.size / 2
  21.   }
  22.   draw() {
  23.     this.x += this.vx
  24.     this.y += this.vy
  25.  
  26.     if (this.x < 0) {
  27.       this.x = innerWidth
  28.     } else if (this.x > innerWidth) {
  29.       this.x = 0
  30.     }
  31.  
  32.     if (this.y < 0) {
  33.       this.y = innerHeight
  34.     } else if (this.y > innerHeight) {
  35.       this.y = 0
  36.     }
  37.  
  38.     c.fillStyle = this.color
  39.     c.translate(this.x, this.y)
  40.     c.fillRect(-this.halfSize, -this.halfSize, this.size, this.size)
  41.  
  42.     c.setTransform(1, 0, 0, 1, 0, 0)
  43.   }
  44. }
  45.  
  46. const NUM = 1000
  47. const shooters = []
  48. for (let i = 0; i < NUM; i++) {
  49.   shooters.push(new Shooter())
  50. }
  51.  
  52. function loop() {
  53.   c.fillStyle = 'rgba(0, 0, 0, 0.1)'
  54.   c.fillRect(0, 0, innerWidth, innerHeight)
  55.  
  56.   for (let i = 0; i < NUM; i++) {
  57.     shooters[i].draw()
  58.   }
  59.   requestAnimationFrame(loop)
  60. }
  61. loop()

Using setTransform(1, 0, 0, 1, 0, 0) is faster than using save and restore. If you don’t need to save context info like fills, line styles etc… consider this method.

Canvas Path2D

  1. const canvas = document.body.appendChild(
  2.   document.createElement('canvas')
  3. )
  4. const c = canvas.getContext('2d')
  5.  
  6. canvas.width = innerWidth
  7. canvas.height = innerHeight
  8.  
  9. c.translate(10, 10)
  10. const path = new Path2D('M 154.75 61.5 Q 169.75 63.8 184.8 69.35 173.15 68.3 161.7 69.4 173.1 73.85 184.8 75.95 173.1 77.15 161.65 75.95 173.05 80.45 184.8 82.55 173 83.75 160.05 82.35 173 87.05 184.8 89.15 172.95 90.35 161.65 89.1 172.9 93.65 184.8 95.75 172.8 96.9 161.65 95.7 172.8 100.2 184.8 102.35 172.75 103.5 163.7 102.7 172.7 106.8 184.8 110.3 172.7 110.1 161.65 108.85 172.6 113.35 184.8 118.85 171.05 116.05 158.35 114.65 167.3 126.9 174 141.45 166.5 132.45 157.65 125.1 162.55 136.3 169.35 146.1 160.2 138.65 152.95 129.7 157.85 141 164.7 150.75 155.5 143.25 147.3 133.15 153.15 145.6 160 155.45 150.75 147.9 143.65 139 148.45 150.2 155.35 160.1 146.05 152.4 139 143.65 143.7 154.75 150.7 164.75 141.3 157.05 135.5 150.05 139 159.35 145.05 170.4 136.65 161.7 129.7 152.95 134.25 163.9 139 176.45 131.3 164.75 123.3 154.8 121 169.8 115.45 184.8 116.5 173.15 115.4 161.7 110.95 173.1 108.85 184.8 107.65 173.1 108.85 161.65 104.35 173.05 102.25 184.8 101.05 173 102.45 160.05 97.75 173 95.65 184.8 94.45 172.95 95.7 161.65 91.15 172.9 89.05 184.8 87.9 172.8 89.1 161.65 84.6 172.8 82.45 184.8 81.3 172.75 82.1 163.7 78 172.7 74.5 184.8 74.7 172.7 75.95 161.65 71.45 172.6 65.95 184.8 68.75 171.05 70.15 158.4 57.9 167.35 43.35 174.05 52.35 166.55 59.7 157.7 48.5 162.6 38.7 169.4 46.15 160.25 55.1 153 43.8 157.9 34.05 164.75 41.55 155.55 51.65 147.35 39.2 153.2 29.35 160.05 36.9 150.8 45.8 143.7 34.6 148.5 24.7 155.4 32.4 146.1 41.15 139.05 30.05 143.75 20.05 150.75 27.75 141.35 34.75 135.55 25.45 139.05 14.4 145.1 23.1 136.7 31.85 129.75 20.9 134.3 8.35 139.05 20.05 131.3 30.05 123.3 15.05 121 0 115.45 11.65 116.5 23.1 115.4 11.7 110.95 0 108.85 11.7 107.65 23.15 108.85 11.75 104.35 0 102.25 11.8 101.05 24.75 102.45 11.8 97.75 0 95.65 11.85 94.45 23.15 95.7 11.9 91.15 0 89.05 12 87.9 23.15 89.1 12 84.6 0 82.45 12.05 81.3 21.1 82.1 12.1 78 0 74.5 12.1 74.7 23.15 75.95 12.2 71.45 0 65.95 13.75 68.75 26.45 70.15 17.45 57.9 10.75 43.35 18.25 52.35 27.1 59.7 22.2 48.5 15.4 38.7 24.55 46.15 31.8 55.1 26.9 43.8 20.05 34.05 29.25 41.55 37.45 51.65 31.6 39.2 24.75 29.35 34 36.9 41.1 45.8 36.3 34.6 29.4 24.7 38.7 32.4 45.75 41.15 41.05 30.05 34.05 20.05 43.45 27.75 49.25 34.75 45.75 25.45 39.7 14.4 48.1 23.1 55.05 31.85 50.5 20.9 45.75 8.35 53.5 20.05 61.5 30.05 63.8 15.05 69.35 0 68.3 11.65 69.4 23.1 73.85 11.7 75.95 0 77.15 11.7 75.95 23.15 80.45 11.75 82.55 0 83.75 11.8 82.35 24.75 87.05 11.8 89.15 0 90.35 11.85 89.1 23.15 93.65 11.9 95.75 0 96.9 12 95.7 23.15 100.2 12 102.35 0 103.5 12.05 102.7 21.1 106.8 12.1 110.3 0 110.1 12.1 108.85 23.15 113.35 12.2 118.85 0 116.05 13.75 114.65 26.45 126.9 17.45 141.45 10.75 132.45 18.25 125.1 27.1 136.3 22.2 146.1 15.4 138.65 24.55 129.7 31.8 141 26.9 150.75 20.05 143.25 29.25 133.15 37.45 145.6 31.6 155.45 24.75 147.9 34 139 41.1 150.2 36.3 160.1 29.4 152.4 38.7 143.65 45.75 154.75 41.05 164.75 34.05 157.05 43.45 150.05 49.25 159.35 45.75 170.4 39.7 161.7 48.1 152.95 55.05 163.9 50.5 176.45 45.75 164.75 53.5 154.75 61.5 140.2 73.15 129.35 85.4 146 97.85 158.35 114.65 M 61.5 30.05 Q 73.15 44.6 85.4 55.45 97.8 38.8 114.65 26.45 M 30.05 123.3 Q 44.6 111.65 55.45 99.45 38.8 87 26.45 70.15 M 123.3 154.8 Q 111.65 140.25 99.4 129.4 86.95 146.05 70.15 158.4');
  11.  
  12. c.stroke(path);

Use SVG style paths in canvas…

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…

ES5 Canvas Thing

  1. var canvas = document.body.appendChild(
  2.   document.createElement('canvas')
  3. ),
  4. c = canvas.getContext("2d"),
  5. size = canvas.width,
  6. quarterSize = size / 4,
  7. eightSize = size / 8,
  8. halfSize = size / 2,
  9. TWO_PI = Math.PI * 2,
  10. bombNum = 3,
  11. bombs = [],
  12. wanderers = {}, 
  13. wandererIndex = 0,
  14. particles = {},
  15. particleIndex = 0;
  16.  
  17. canvas.width = canvas.height = 300
  18.  
  19. c.fillStyle = "rgb(100,100,100)";
  20. c.fillRect(0,0,size,size);
  21.  
  22. function Particle(x, y){
  23.   this.x = x;
  24.   this.y = y;
  25.   var rad = 3 + Math.random() * 6;
  26.   var theta = Math.random() * TWO_PI;
  27.   this.vx = rad * Math.cos(theta);
  28.   this.vy = rad * Math.sin(theta);
  29.   this.alpha = 1;
  30.   particleIndex++;
  31.   this.index = particleIndex;
  32.   particles[this.index] = this;
  33. }
  34. Particle.prototype.draw = function(){
  35.   this.x += this.vx;
  36.   this.y += this.vy;
  37.   this.vx *= 0.9;
  38.   this.vy *= 0.9;
  39.   this.alpha -= 0.05;
  40.  
  41.   if (this.alpha <= 0){
  42.     this.alpha = 0;
  43.     delete particles[this.index];
  44.  
  45.   }
  46.  
  47.   c.fillStyle = "rgba(255,255,255,"+this.alpha+")";
  48.   c.beginPath();
  49.   c.arc(this.x, this.y, 1, 0, TWO_PI, false);
  50.   c.fill();
  51. };
  52.  
  53. function Bomb(){
  54.   this.x = quarterSize + Math.random() * halfSize;
  55.   this.y = quarterSize + Math.random() * halfSize;
  56.   this.radius = 15 + Math.random() * 20;
  57. }
  58. Bomb.prototype.draw = function(){
  59.   c.fillStyle = "#e64c25";
  60.   c.beginPath();
  61.   c.arc(this.x, this.y, this.radius, 0, TWO_PI, false);
  62.   c.fill();
  63. };
  64.  
  65. function Wanderer(x, y){
  66.   this.x = x;
  67.   this.y = y;
  68.   this.vx = Math.random() * 4 - 2;
  69.   this.vy = Math.random() * 4 - 2;
  70.   particleIndex++;
  71.   this.index = particleIndex;
  72.   particles[this.index] = this;
  73. }
  74. Wanderer.prototype.die = function(){
  75.   for (var j = 0; j < 4; j++){
  76.     new Particle(this.x, this.y);
  77.   }
  78.  
  79.   delete particles[this.index];
  80. };
  81. Wanderer.prototype.draw = function(){
  82.   this.x += this.vx;
  83.   this.y += this.vy;
  84.  
  85.   if (Math.random() < 0.1){
  86.     this.vx = Math.random() * 4 - 2;
  87.     this.vy = Math.random() * 4 - 2;
  88.   }
  89.  
  90.   if (this.x < 0) this.x = size;
  91.   if (this.x > size) this.x = 0;
  92.   if (this.y < 0) this.y = size;
  93.   if (this.y > size) this.y = 0;
  94.  
  95.   c.fillStyle = "white";
  96.   c.beginPath();
  97.   c.arc(this.x, this.y, 2, 0, TWO_PI, false);
  98.   c.closePath();
  99.   c.fill();
  100.  
  101.   for (var i = 0; i < bombNum; i++){
  102.     var bomb = bombs[i];
  103.     var dx = this.x - bomb.x;
  104.     var dy = this.y - bomb.y;
  105.     if (Math.sqrt(dx * dx + dy * dy) < bomb.radius){
  106.       this.die();
  107.     }
  108.   }
  109. };
  110.  
  111. for (var i = 0; i < bombNum; i++){
  112.   bombs[i] = new Bomb();
  113. }
  114.  
  115. new Wanderer(eightSize, eightSize); 
  116.  
  117. setInterval(function(){
  118.   c.fillStyle = "rgba(100,100,100, 0.2)";
  119.   c.fillRect(0,0,size,size);
  120.   c.strokeStyle = "white";
  121.   c.beginPath();
  122.   c.arc(eightSize, eightSize, 5, 0, TWO_PI, false);
  123.   c.stroke();
  124.  
  125.   if (Math.random() < 0.02){
  126.     new Wanderer(eightSize, eightSize); 
  127.   }
  128.  
  129.   for (var i = 0; i < bombNum; i++){
  130.     bombs[i].draw();
  131.   }
  132.  
  133.   for (var i in wanderers){
  134.     wanderers[i].draw(); 
  135.   }
  136.  
  137.   for (var i in particles){
  138.     particles[i].draw();
  139.   }
  140. }, 16);

An old es5 speedcoded thing…

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