Curves drawn by randomly placing actors on the canvas, and walking them in a direction determined by the perlin noise function at their location. The continuity of the underlying noise function causes paths to converge together.
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March 11, 2021 12:41
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Perlin Curves I
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| body { | |
| background: rgb(255, 255, 255); | |
| } | |
| </style> | |
| <body> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="/d2fn/raw/8777d620caef32959713/perlin.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500, | |
| noiseScale = 0.003, | |
| actorStepLength = 1, | |
| numActors = 10000, | |
| step = 0, | |
| steps = 150; | |
| var canvas = d3.select("body") | |
| .append("canvas") | |
| .attr({width: width, height: height}); | |
| var context = canvas.node().getContext("2d"); | |
| context.fillStyle = "rgb(0, 0, 0)"; | |
| context.fillRect(-1, -1, width, height); | |
| var actors = []; | |
| for(var i = 0; i < numActors; i++) { | |
| actors.push(actor(width, height, noiseScale, actorStepLength)); | |
| } | |
| var opacity = easeInOut(steps); | |
| d3.timer(function() { | |
| if(++step > steps) { | |
| console.log("done with animation"); | |
| return true; | |
| } | |
| context.lineWidth = 1; | |
| context.globalCompositeOperation = 'lighter'; | |
| context.beginPath(); | |
| for(var i in actors) { | |
| var a = actors[i]; | |
| var ln = a.step(); | |
| var alpha = 0.6*opacity.get(); | |
| context.strokeStyle = "rgba(49, 130, 189, " + alpha + ")"; | |
| context.moveTo(ln.x1, ln.y1); | |
| context.lineTo(ln.x2, ln.y2); | |
| } | |
| context.stroke(); | |
| opacity.step(); | |
| }); | |
| function actor(width, height, noiseScale, stepLength) { | |
| var x = Math.random() * width, | |
| y = Math.random() * height; | |
| var noise = perlin.noise(noiseScale); | |
| return { | |
| // get the last point and the next point | |
| step: function() { | |
| var t = noise(x, y) * Math.PI * 5; | |
| var x1 = x, | |
| y1 = y; | |
| x = x + stepLength * Math.cos(t); | |
| y = y + stepLength * Math.sin(t); | |
| return { | |
| x1: x1, | |
| y1: y1, | |
| x2: x, | |
| y2: y | |
| } | |
| } | |
| } | |
| } | |
| function easeInOut(steps) { | |
| var n = 0; | |
| var val = 0; | |
| return { | |
| step: | |
| function() { | |
| val = 0.5*(1-Math.cos(2 * Math.PI * (n++) / steps)); | |
| }, | |
| get: | |
| function() { | |
| return val; | |
| } | |
| }; | |
| } | |
| </script> |
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