What I did for 22/5/2015's #rainbowLinesWeekend :D A canvas animations with lines'n'stuff
A Pen by Matei Copot on CodePen.
Created
November 14, 2019 18:28
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rainbow lines of straightness
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| <canvas id=c></canvas> |
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| var w = c.width = window.innerWidth, | |
| h = c.height = window.innerHeight, | |
| ctx = c.getContext( '2d' ), | |
| minDist = 10, | |
| maxDist = 30, | |
| initialWidth = 10, | |
| maxLines = 100, | |
| initialLines = 4, | |
| speed = 5, | |
| lines = [], | |
| frame = 0, | |
| timeSinceLast = 0, | |
| dirs = [ | |
| // straight x, y velocity | |
| [ 0, 1 ], | |
| [ 1, 0 ], | |
| [ 0, -1 ], | |
| [ -1, 0 ], | |
| // diagonals, 0.7 = sin(PI/4) = cos(PI/4) | |
| [ .7, .7 ], | |
| [ .7, -.7 ], | |
| [ -.7, .7 ], | |
| [ -.7, -.7] | |
| ], | |
| starter = { // starting parent line, just a pseudo line | |
| x: w / 2, | |
| y: h / 2, | |
| vx: 0, | |
| vy: 0, | |
| width: initialWidth | |
| }; | |
| function init() { | |
| lines.length = 0; | |
| for( var i = 0; i < initialLines; ++i ) | |
| lines.push( new Line( starter ) ); | |
| ctx.fillStyle = '#222'; | |
| ctx.fillRect( 0, 0, w, h ); | |
| // if you want a cookie ;) | |
| // ctx.lineCap = 'round'; | |
| } | |
| function getColor( x ) { | |
| return 'hsl( hue, 80%, 50% )'.replace( | |
| 'hue', x / w * 360 + frame | |
| ); | |
| } | |
| function anim() { | |
| window.requestAnimationFrame( anim ); | |
| ++frame; | |
| ctx.shadowBlur = 0; | |
| ctx.fillStyle = 'rgba(0,0,0,.02)'; | |
| ctx.fillRect( 0, 0, w, h ); | |
| ctx.shadowBlur = .5; | |
| for( var i = 0; i < lines.length; ++i ) | |
| if( lines[ i ].step() ) { // if true it's dead | |
| lines.splice( i, 1 ); | |
| --i; | |
| } | |
| // spawn new | |
| ++timeSinceLast | |
| if( lines.length < maxLines && timeSinceLast > 10 && Math.random() < .5 ) { | |
| timeSinceLast = 0; | |
| lines.push( new Line( starter ) ); | |
| // cover the middle; | |
| ctx.fillStyle = ctx.shadowColor = getColor( starter.x ); | |
| ctx.beginPath(); | |
| ctx.arc( starter.x, starter.y, initialWidth, 0, Math.PI * 2 ); | |
| ctx.fill(); | |
| } | |
| } | |
| function Line( parent ) { | |
| this.x = parent.x | 0; | |
| this.y = parent.y | 0; | |
| this.width = parent.width / 1.25; | |
| do { | |
| var dir = dirs[ ( Math.random() * dirs.length ) |0 ]; | |
| this.vx = dir[ 0 ]; | |
| this.vy = dir[ 1 ]; | |
| } while ( | |
| ( this.vx === -parent.vx && this.vy === -parent.vy ) || ( this.vx === parent.vx && this.vy === parent.vy) ); | |
| this.vx *= speed; | |
| this.vy *= speed; | |
| this.dist = ( Math.random() * ( maxDist - minDist ) + minDist ); | |
| } | |
| Line.prototype.step = function() { | |
| var dead = false; | |
| var prevX = this.x, | |
| prevY = this.y; | |
| this.x += this.vx; | |
| this.y += this.vy; | |
| --this.dist; | |
| // kill if out of screen | |
| if( this.x < 0 || this.x > w || this.y < 0 || this.y > h ) | |
| dead = true; | |
| // make children :D | |
| if( this.dist <= 0 && this.width > 1 ) { | |
| // keep yo self, sometimes | |
| this.dist = Math.random() * ( maxDist - minDist ) + minDist; | |
| // add 2 children | |
| if( lines.length < maxLines ) lines.push( new Line( this ) ); | |
| if( lines.length < maxLines && Math.random() < .5 ) lines.push( new Line( this ) ); | |
| // kill the poor thing | |
| if( Math.random() < .2 ) dead = true; | |
| } | |
| ctx.strokeStyle = ctx.shadowColor = getColor( this.x ); | |
| ctx.beginPath(); | |
| ctx.lineWidth = this.width; | |
| ctx.moveTo( this.x, this.y ); | |
| ctx.lineTo( prevX, prevY ); | |
| ctx.stroke(); | |
| if( dead ) return true | |
| } | |
| init(); | |
| anim(); | |
| window.addEventListener( 'resize', function() { | |
| w = c.width = window.innerWidth; | |
| h = c.height = window.innerHeight; | |
| starter.x = w / 2; | |
| starter.y = h / 2; | |
| init(); | |
| } ) |
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| canvas { | |
| position: absolute; | |
| top: 0; | |
| left: 0; | |
| background-color: black; | |
| } |
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