Urquhart Spider Web

Some force-directed points, with the Urquhart graph overlaid. Thanks @enjalot for the idea and time wasted :)

Forked from erlenstar's block: Delaunay Force Mesh II

forked from Fil's block: Urquhart Force Mesh

<!DOCTYPE html>
<meta charset="utf-8">
<style>
  body {
    margin: 0;
    padding: 0;
  }
</style>
<body>
<script src="//d3js.org/d3.v4.js"></script>
<script>

var width = 960,
    height = 500,
    τ = 2 * Math.PI,
    maxLength = 10000,
    maxLength2 = maxLength * maxLength,
    minDistance = 50,
    maxDistance = 70,
    minDistance2 = minDistance * minDistance,
    maxDistance2 = maxDistance * maxDistance;
  
var radius = 300;

var links = urquhart(diagram);
console.log("POLYGONS", polygons)

var force = d3.forceSimulation()
    .nodes(nodes.slice())
    //.force("link", d3.forceLink().id(function(d) { return d.id; }).distance(40).strength(100))
    .force("charge", d3.forceManyBody().strength(function(d,i){
      return i ? -20 : -1000
    }))
    .force("x", d3.forceX())
    .force("y", d3.forceY())
    .force("center", d3.forceCenter(width / 2, height / 2))
    .on("tick", ticked);

var canvas = d3.select("body").append("canvas")
    .attr("width", width)
    .attr("height", height)
    .on("ontouchstart" in document ? "touchmove" : "mousemove", moved);

var context = canvas.node().getContext("2d");
//context.globalCompositeOperation = "screen";
context.lineJoin = "round"

function moved() {
  var p1 = d3.mouse(this);
  nodes[0].fx = p1[0];
  nodes[0].fy = p1[1];
  force.alpha(0.1).restart();
}

function urquhart(diagram){
    var urquhart = d3.map();
    diagram.links()
    .forEach(function(link) {
      var v = d3.extent([link.source.index, link.target.index]);
      urquhart.set(v, link);
    });
    urquhart._remove = [];
    diagram.triangles()
    .forEach(function(t) {

/*
  context.lineWidth = 2;
  context.beginPath();
  for (var i = 0, n = nodes.length; i < n; ++i) {
    var node = nodes[i];
    context.moveTo(node.x, node.y);
    context.arc(node.x, node.y, 2, 0, τ);
  }

context.strokeStyle = "#fff";
  context.stroke();
  context.fillStyle = "#000";
  context.fill();
  */
}
  
function test(x,y) {
  var cx = width/2
  var cy = height/2
  var dx = x - cx
  var dy = y - cy
  var d2 = dx * dx + dy * dy
  var r2 = radius*radius
  if(d2 > r2) {
    x = cx + radius * dx/r2
    y = cy + radius * dy/r2
  }
  return [x,y]
}
function drawCell(cell) {
  if (!cell || !cell[0]) return false;
  var x, y;
  
  x = cell[0][0];
  y = cell[0][1];
  /*
  if(x > width - 5) x = width-5;
  if(x < 5) x = 5;
  if(y > height - 5) y = height - 5;
  if(y < 5) y = 5;
  */
  var p = test(x,y)
  context.moveTo(p[0], p[1]);
  
  for (var j = 1, m = cell.length; j < m; ++j) {
    if(!cell[j]) continue;
    x = cell[j][0];
    y = cell[j][1];
    /*
    if(x > width) x = width-5;
    if(x < 5) x = 5;
    if(y > height - 5) y = height - 5;
    if(y < 5) y = 5;
    */
    p = test(x,y)
    context.lineTo(p[0], p[1]);
  }
  context.closePath();
  return true;
}

</script>

https://d3js.org/d3.v4.js