​

let delaunay;

let voronoi;

let picture;

​

function preload() {

  picture = loadImage("dog.png"); 

}

​

function setup() {

  createCanvas(412, 366);

  //noLoop();

  /*

  for(let i = 0; i < 100; i++) {

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

  }

  */

  for (let i = 0; i < 10000; i++) {

    let x = random(width);

    let y = random(height);

    let col = picture.get(x, y);

//    if(brightness(col) < 80) {

//      seedPoints.push(createVector(x, y));

//    }

    if(random(80) > brightness(col)) {

      seedPoints.push(createVector(x, y));

    } else {

      i--;

    }

  }

  delaunay = calculateDelaunay(seedPoints);

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

}

​

function draw() {

  if(frameCount > 200) {

    noLoop();

    print("done");

  }

  background(255);

​

  strokeWeight(2);

  stroke(0);

  for (let v of seedPoints) {

    point(v.x, v.y);

  }

  strokeWeight(1);

  noFill();

/*  

  let {points, triangles} = delaunay;

  for (let i = 0; i < delaunay.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();

  }

*/

  /*

  let centroids = [];

  for(let poly of cells) {

    let area = 0;

    let centroid = createVector(0, 0);

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

      let v0 = poly[i];

      let v1 = poly[(i+1) % poly.length];

      let crossVal = v0[0] * v1[1] - v1[0] * v0[1];

      area += crossVal;

      centroid.x += (v0[0] + v1[0]) * crossVal;

      centroid.y += (v0[1] + v1[1]) * crossVal;

    }

    area /= 2;

    centroid.div(6 * area);

    centroids.push(centroid);

  }

  */

  let centroids = new Array(cells.length);

  let weights = new Array(cells.length).fill(0);

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

    centroids[i] = createVector(0,0);

  }

  picture.loadPixels();

  let delaunayIndex = 0;

  for(let i = 0; i < width; i++) {

    for(let j = 0; j < height; j++) {

      let index = (i + j * width) * 4;

      let r = picture.pixels[index + 0];

      let g = picture.pixels[index + 1];

      let b = picture.pixels[index + 2];

      let val = (r+g+b) / 3;

      let weight = 1 - val / 255;

      delaunayIndex = delaunay.find(i,j, delaunayIndex);

      centroids[delaunayIndex].x += i * weight;

      centroids[delaunayIndex].y += j * weight;

      weights[delaunayIndex] += weight;

    }

  }

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

    if(weights[i] > 0) {

      centroids[i].div(weights[i]);

    } else {

      centroids[i] = seedPoints[i].copy();

    }

  }

  /*

  for(let poly of cells) {

    let centroid = createVector(0, 0);

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

      centroid.x += poly[i][0];

      centroid.y += poly[i][1];

    }

    centroid.div(poly.length);

    // stroke(255, 0, 0);

    // strokeWeight(4);

    // point(centroid.x, centroid.y);

    centroids.push(centroid);

  }

  */

​

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

    seedPoints[i].lerp(centroids[i], 1);

  }

  delaunay = calculateDelaunay(seedPoints);

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

}

​

function calculateDelaunay(points) {

  let pointsArray = [];

  for(let v of points) {

    pointsArray.push(v.x, v.y);

  }

  return new d3.Delaunay(pointsArray);

}

​

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