Skip to content

Instantly share code, notes, and snippets.

@mbostock
Last active February 9, 2016 01:53
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 1 You must be signed in to fork a gist
  • Save mbostock/b22c4c16a6ce605f3c56 to your computer and use it in GitHub Desktop.
Save mbostock/b22c4c16a6ce605f3c56 to your computer and use it in GitHub Desktop.
Poisson-Disc IV
license: gpl-3.0
!function(){function t(t){return function(e,i){e=d3.hsl(e),i=d3.hsl(i);var r=(e.h+120)*a,h=(i.h+120)*a-r,s=e.s,l=i.s-s,o=e.l,u=i.l-o;return isNaN(l)&&(l=0,s=isNaN(s)?i.s:s),isNaN(h)&&(h=0,r=isNaN(r)?i.h:r),function(a){var e=r+h*a,i=Math.pow(o+u*a,t),c=(s+l*a)*i*(1-i);return"#"+n(i+c*(-.14861*Math.cos(e)+1.78277*Math.sin(e)))+n(i+c*(-.29227*Math.cos(e)-.90649*Math.sin(e)))+n(i+c*1.97294*Math.cos(e))}}}function n(t){var n=(t=0>=t?0:t>=1?255:0|255*t).toString(16);return 16>t?"0"+n:n}var a=Math.PI/180;d3.scale.cubehelix=function(){return d3.scale.linear().range([d3.hsl(300,.5,0),d3.hsl(-240,.5,1)]).interpolate(d3.interpolateCubehelix)},d3.interpolateCubehelix=t(1),d3.interpolateCubehelix.gamma=t}();
<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="cubehelix.min.js"></script>
<script>
var width = 960,
height = 500;
var sample = poissonDiscSampler(width, height, 5.68),
samples = [],
s;
while (s = sample()) samples.push(s);
var voronoi = d3.geom.voronoi()
.clipExtent([[0, 0], [width, height]]); // TODO overdraw
var color = d3.scale.cubehelix()
.domain([0, 200])
.range([d3.hsl(96, .6, 1), d3.hsl(276, .6, 0)])
.clamp(true);
d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.selectAll("path")
.data(voronoi(samples))
.enter().append("path")
.style("fill", function(d) { return color(d3.geom.polygon(d).area()); })
.attr("d", function(d) { return "M" + d.join("L") + "Z"; });
// Based on https://www.jasondavies.com/poisson-disc/
function poissonDiscSampler(width, height, radius) {
var k = 30, // maximum number of samples before rejection
radius2 = radius * radius,
R = 3 * radius2,
cellSize = radius * Math.SQRT1_2,
gridWidth = Math.ceil(width / cellSize),
gridHeight = Math.ceil(height / cellSize),
grid = new Array(gridWidth * gridHeight),
queue = [],
queueSize = 0,
sampleSize = 0;
return function() {
if (!sampleSize) return sample(Math.random() * width, Math.random() * height);
// Pick a random existing sample and remove it from the queue.
while (queueSize) {
var i = Math.random() * queueSize | 0,
s = queue[i];
// Make a new candidate between [radius, 2 * radius] from the existing sample.
for (var j = 0; j < k; ++j) {
var a = 2 * Math.PI * Math.random(),
r = Math.sqrt(Math.random() * R + radius2),
x = s[0] + r * Math.cos(a),
y = s[1] + r * Math.sin(a);
// Reject candidates that are outside the allowed extent,
// or closer than 2 * radius to any existing sample.
if (0 <= x && x < width && 0 <= y && y < height && far(x, y)) return sample(x, y);
}
queue[i] = queue[--queueSize];
queue.length = queueSize;
}
};
function far(x, y) {
var i = x / cellSize | 0,
j = y / cellSize | 0,
i0 = Math.max(i - 2, 0),
j0 = Math.max(j - 2, 0),
i1 = Math.min(i + 3, gridWidth),
j1 = Math.min(j + 3, gridHeight);
for (j = j0; j < j1; ++j) {
var o = j * gridWidth;
for (i = i0; i < i1; ++i) {
if (s = grid[o + i]) {
var s,
dx = s[0] - x,
dy = s[1] - y;
if (dx * dx + dy * dy < radius2) return false;
}
}
}
return true;
}
function sample(x, y) {
var s = [x, y];
queue.push(s);
grid[gridWidth * (y / cellSize | 0) + (x / cellSize | 0)] = s;
++sampleSize;
++queueSize;
return s;
}
}
</script>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment