rgov · December 12, 2017 01:36 · Dec 12, 2017 · Feb 9, 2016 · Oct 30, 2015 · Jun 11, 2015
diff --git a/index.html b/index.html
@@ -50,7 +50,7 @@
       // 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),
+            r = Math.random() * radius + radius,
             x = s[0] + r * Math.cos(a),
             y = s[1] + r * Math.sin(a);
 

diff --git a/.block b/.block
@@ -0,0 +1 @@
+license: gpl-3.0
diff --git a/index.html b/index.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <meta charset="utf-8">
 <body>
-<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
+<script src="//d3js.org/d3.v3.min.js"></script>
 <script>
 
 var width = 960,

diff --git a/index.html b/index.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <meta charset="utf-8">
 <body>
-<script src="http://d3js.org/d3.v3.min.js"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
 <script>
 
 var width = 960,

diff --git a/index.html b/index.html
@@ -9,19 +9,20 @@
 
 var sample = poissonDiscSampler(width, height, 10);
 
-var canvas = d3.select("body").append("canvas")
+var svg = d3.select("body").append("svg")
     .attr("width", width)
     .attr("height", height);
 
-var context = canvas.node().getContext("2d");
-
 d3.timer(function() {
   for (var i = 0; i < 10; ++i) {
     var s = sample();
     if (!s) return true;
-    context.beginPath();
-    context.arc(s[0], s[1], 2, 0, 2 * Math.PI);
-    context.fill();
+    svg.append("circle")
+        .attr("cx", s[0])
+        .attr("cy", s[1])
+        .attr("r", 0)
+      .transition()
+        .attr("r", 2);
   }
 });
 

diff --git a/README.md b/README.md
@@ -1 +1 @@
-Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm.
+Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm. See the [related explanation](/mbostock/dbb02448b0f93e4c82c3).
diff --git a/README.md b/README.md
@@ -0,0 +1 @@
+Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm.
diff --git a/index.html b/index.html
@@ -7,7 +7,7 @@
 var width = 960,
     height = 500;
 
-var sample = poissonDiscSampler(width, height, 5.23);
+var sample = poissonDiscSampler(width, height, 10);
 
 var canvas = d3.select("body").append("canvas")
     .attr("width", width)
@@ -28,10 +28,9 @@
 // Based on https://www.jasondavies.com/poisson-disc/
 function poissonDiscSampler(width, height, radius) {
   var k = 30, // maximum number of samples before rejection
-      diameter = 2 * radius,
-      diameter2 = diameter * diameter,
-      R = 3 * diameter2,
-      cellSize = diameter * Math.SQRT1_2,
+      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),
@@ -50,7 +49,7 @@
       // 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 + diameter2),
+            r = Math.sqrt(Math.random() * R + radius2),
             x = s[0] + r * Math.cos(a),
             y = s[1] + r * Math.sin(a);
 
@@ -79,7 +78,7 @@
           var s,
               dx = s[0] - x,
               dy = s[1] - y;
-          if (dx * dx + dy * dy < diameter2) return false;
+          if (dx * dx + dy * dy < radius2) return false;
         }
       }
     }

diff --git a/index.html b/index.html
@@ -37,38 +37,31 @@
       grid = new Array(gridWidth * gridHeight),
       queue = [],
       queueSize = 0,
-      samples = [];
-
-  sample(Math.random() * width, Math.random() * height);
-
-  // Pick a random existing sample and remove it from the queue.
-  iterate: 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 + diameter2),
-          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)) {
-        sample(x, y);
-        continue iterate;
-      }
-    }
-
-    queue[i] = queue[--queueSize];
-    queue.length = queueSize;
-  }
-
-  samples.reverse();
+      sampleSize = 0;
 
   return function() {
-    return samples.pop();
+    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 + diameter2),
+            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) {
@@ -97,9 +90,10 @@
   function sample(x, y) {
     var s = [x, y];
     queue.push(s);
-    samples.push(s);
     grid[gridWidth * (y / cellSize | 0) + (x / cellSize | 0)] = s;
+    ++sampleSize;
     ++queueSize;
+    return s;
   }
 }
 

diff --git a/index.html b/index.html
@@ -30,7 +30,7 @@
   var k = 30, // maximum number of samples before rejection
       diameter = 2 * radius,
       diameter2 = diameter * diameter,
-      k = 3 * diameter2,
+      R = 3 * diameter2,
       cellSize = diameter * Math.SQRT1_2,
       gridWidth = Math.ceil(width / cellSize),
       gridHeight = Math.ceil(height / cellSize),
@@ -49,7 +49,7 @@
     // 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() * k + diameter2),
+          r = Math.sqrt(Math.random() * R + diameter2),
           x = s[0] + r * Math.cos(a),
           y = s[1] + r * Math.sin(a);
 

diff --git a/index.html b/index.html
@@ -7,7 +7,7 @@
 var width = 960,
     height = 500;
 
-var sample = poissonDiscSampler(width, height, 5.66);
+var sample = poissonDiscSampler(width, height, 5.23);
 
 var canvas = d3.select("body").append("canvas")
     .attr("width", width)

diff --git a/index.html b/index.html
@@ -30,6 +30,7 @@
   var k = 30, // maximum number of samples before rejection
       diameter = 2 * radius,
       diameter2 = diameter * diameter,
+      k = 3 * diameter2,
       cellSize = diameter * Math.SQRT1_2,
       gridWidth = Math.ceil(width / cellSize),
       gridHeight = Math.ceil(height / cellSize),
@@ -41,23 +42,27 @@
   sample(Math.random() * width, Math.random() * height);
 
   // Pick a random existing sample and remove it from the queue.
-  while (queueSize) {
+  iterate: while (queueSize) {
     var i = Math.random() * queueSize | 0,
         s = queue[i];
-    queue[i] = queue[--queueSize];
-    queue.pop();
 
     // 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 = diameter * 1 + Math.random(),
+          r = Math.sqrt(Math.random() * k + diameter2),
           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)) sample(x, y);
+      if (0 <= x && x < width && 0 <= y && y < height && far(x, y)) {
+        sample(x, y);
+        continue iterate;
+      }
     }
+
+    queue[i] = queue[--queueSize];
+    queue.length = queueSize;
   }
 
   samples.reverse();

diff --git a/thumbnail.png b/thumbnail.png
diff --git a/index.html b/index.html
@@ -0,0 +1,101 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<body>
+<script src="http://d3js.org/d3.v3.min.js"></script>
+<script>
+
+var width = 960,
+    height = 500;
+
+var sample = poissonDiscSampler(width, height, 5.66);
+
+var canvas = d3.select("body").append("canvas")
+    .attr("width", width)
+    .attr("height", height);
+
+var context = canvas.node().getContext("2d");
+
+d3.timer(function() {
+  for (var i = 0; i < 10; ++i) {
+    var s = sample();
+    if (!s) return true;
+    context.beginPath();
+    context.arc(s[0], s[1], 2, 0, 2 * Math.PI);
+    context.fill();
+  }
+});
+
+// Based on https://www.jasondavies.com/poisson-disc/
+function poissonDiscSampler(width, height, radius) {
+  var k = 30, // maximum number of samples before rejection
+      diameter = 2 * radius,
+      diameter2 = diameter * diameter,
+      cellSize = diameter * Math.SQRT1_2,
+      gridWidth = Math.ceil(width / cellSize),
+      gridHeight = Math.ceil(height / cellSize),
+      grid = new Array(gridWidth * gridHeight),
+      queue = [],
+      queueSize = 0,
+      samples = [];
+
+  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];
+    queue[i] = queue[--queueSize];
+    queue.pop();
+
+    // 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 = diameter * 1 + Math.random(),
+          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)) sample(x, y);
+    }
+  }
+
+  samples.reverse();
+
+  return function() {
+    return samples.pop();
+  };
+
+  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 < diameter2) return false;
+        }
+      }
+    }
+
+    return true;
+  }
+
+  function sample(x, y) {
+    var s = [x, y];
+    queue.push(s);
+    samples.push(s);
+    grid[gridWidth * (y / cellSize | 0) + (x / cellSize | 0)] = s;
+    ++queueSize;
+  }
+}
+
+</script>
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm.
		Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm. See the [related explanation](/mbostock/dbb02448b0f93e4c82c3).
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Based on [Jason Davies’ implementation](https://www.jasondavies.com/poisson-disc/) of Bridson’s algorithm.