// Weighted Voronoi Stippling

// https://thecodingtrain.com/challenges/181-image-stippling

​

let seedPoints = [];

let velocities = [];

​

let delaunay;

​

function setup() {

  createCanvas(500, 300);

  for (let i = 0; i < 200; i++) {

    seedPoints[i] = createVector(random(width), random(height));

    velocities[i] = p5.Vector.random2D().setMag(random(0.25, 1));

  }

}

​

function draw() {

  background(255);

​

  delaunay = calculateDelaunay(seedPoints);

  voronoi = delaunay.voronoi([0, 0, width, height]);

​

  for (let i = 0; i < seedPoints.length; i++) {

    let p = seedPoints[i];

    let v = velocities[i];

    stroke(0);

    strokeWeight(4);

    point(p.x, p.y);

    p.add(v);

    if (p.x > width || p.x < 0) {

      v.x *= -1;

    }

    if (p.y > height || p.y < 0) {

      v.y *= -1;

    }

  }

​

  noFill();

  strokeWeight(1);

  let { points, triangles } = delaunay;

  // for (let i = 0; i < triangles.length; i += 3) {

  //   let a = 2 * delaunay.triangles[i];

  //   let b = 2 * delaunay.triangles[i + 1];

  //   let c = 2 * delaunay.triangles[i + 2];

  //   triangle(

  //     points[a],

  //     points[a + 1],

  //     points[b],

  //     points[b + 1],

  //     points[c],

  //     points[c + 1]

  //   );

  // }

​

  let polygons = voronoi.cellPolygons();

  let cells = Array.from(polygons);

​

  for (let poly of cells) {

    stroke(0);

    strokeWeight(1);

    noFill();

    beginShape();

    for (let i = 0; i < poly.length; i++) {

      vertex(poly[i][0], poly[i][1]);

    }

    endShape();

  }

}

​

function calculateDelaunay(points) {

  let pointsArray = [];

  for (let v of points) {

    pointsArray.push(v.x, v.y);

  }

  return new d3.Delaunay(pointsArray);

}

​