Poisson-Disc Voronoi

Playing with varying the radius of the poisson disc as it generates

Based on Jason Davies’ implementation of Bridson’s algorithm. See the related explanation.

forked from mbostock's block: Poisson-Disc

<!DOCTYPE html>
<meta charset="utf-8">
<style>
  body: {
    position:fixed;
    top:0; bottom: 0;
    left: 0; right: 0;
  }
  canvas {
    width: 100%;
    height: 100%;
    position:absolute;
    top:0;
    left: 0;
  }
  path {
    fill: #fff;
    stroke: #de4459;
  }
  path:nth-child(2n+1) {
    
    fill: #de4459;
  }
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
  
  <canvas></canvas>
<script>

var bbox = d3.select("body").node().getBoundingClientRect();
var width = bbox.width,
    height = bbox.height;

var r = 8;
var sample = poissonDiscSampler(width, height, r);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var grid;
var points = [[width/2, height/2]];

// Based on https://www.jasondavies.com/poisson-disc/
function poissonDiscSampler(width, height, radius) {
  var k = 30; // maximum number of samples before rejection
  var radius2 = radius * radius;
  var R = 3 * radius2
  var cellSize = radius * Math.SQRT1_2
  var gridWidth = Math.ceil(width / cellSize)
  var gridHeight = Math.ceil(height / cellSize)
  grid = new Array(gridWidth * gridHeight)
  var queue = []
  var queueSize = 0
  var sampleSize = 0

return function(newRadius) {
    radius2 = newRadius * newRadius;
  	R = 3 * radius2
  	cellSize = radius * Math.SQRT1_2;
    
    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(),
            rad = Math.sqrt(Math.random() * R + radius2),
            x = s[0] + rad * Math.cos(a) * Math.random(),
            y = s[1] + rad * Math.sin(a) * Math.random();

// 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)) {
          points.push([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>

https://d3js.org/d3.v3.min.js