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dithered paths
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| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <body> | |
| <canvas width=800 height=600></canvas> | |
| <script> | |
| let canvas = document.querySelector('canvas'), | |
| ctx = canvas.getContext('2d'), | |
| height = 600, | |
| width = 800, | |
| pChangeDirection = 0.9; | |
| // points of a triangle | |
| let p1 = { | |
| x: 226, | |
| y: 425 | |
| }; | |
| let p2 = { | |
| x: 428, | |
| y: 130 | |
| }; | |
| let p3 = { | |
| x: 623, | |
| y: 425 | |
| } | |
| function drawPath(ctx, points) { | |
| ctx.beginPath(); | |
| ctx.strokeStyle = 'rgba(0, 0, 0, 1)'; | |
| ctx.lineWidth = 1; | |
| ctx.moveTo(points[0].x, points[0].y); | |
| for (let i = 1; i < points.length; i++) { | |
| ctx.lineTo(points[i].x, points[i].y); | |
| } | |
| ctx.stroke(); | |
| } | |
| function getDist(p1, p2) { | |
| return (p2.x - p1.x) * (p2.x - p1.x) + (p2.y - p1.y) * (p2.y - p1.y); | |
| } | |
| function computePath(start, end) { | |
| let count = 0, | |
| path = [], | |
| point = { | |
| x: start.x, | |
| y: start.y | |
| }, | |
| distThresh = 10, | |
| dist = 1000, | |
| angle = 0, | |
| angleResolution = Math.PI / 4, | |
| angleSpread = Math.PI / 4, | |
| speedScale = d3.scaleLinear() | |
| .domain([100, 0]).range([3, 0.01]).clamp(true); | |
| while (dist > distThresh && count < 10000) { | |
| if (Math.random() < pChangeDirection) { | |
| let desiredAngle = Math.atan2(end.y - point.y, end.x - point.x); | |
| angle = d3.randomNormal(desiredAngle, angleSpread)(); | |
| angle = Math.round(angle / angleResolution) * angleResolution; | |
| } | |
| let speed = speedScale(dist); | |
| point.x += Math.cos(angle) * speed; // move in the direction | |
| point.y += Math.sin(angle) * speed; | |
| count += 1; | |
| dist = getDist(point, end); | |
| path.push({ | |
| x: point.x, | |
| y: point.y | |
| }); | |
| } | |
| return path; | |
| } | |
| ctx.globalAlpha = 0.2; | |
| function draw() { | |
| ctx.fillStyle = 'rgba(255, 255, 255, 0.6)'; | |
| ctx.fillRect(0, 0, width, height); | |
| drawPath(ctx, computePath(p1, p2)); | |
| drawPath(ctx, computePath(p2, p3)); | |
| drawPath(ctx, computePath(p3, p1)); | |
| window.requestAnimationFrame(draw); | |
| } | |
| window.requestAnimationFrame(draw); | |
| </script> | |
| </body> |
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