// Weighted Voronoi Stippling

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

​

let points = [];

let grid = [];

let seed_count = 500;

let centroids, weights, counts;

let delaunay, voronoi;

​

let eric, felix;

let current_image;

​

function preload() {

  eric = loadImage("eric_clapton.jpeg");

  felix = loadImage("felix.jpeg");

}

​

function loadThePixels(img) {

  img.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 = img.pixels[index + 0];

      let g = img.pixels[index + 1];

      let b = img.pixels[index + 2];

      let bright = (r + g + b) / 3;

      let weight = 1 - bright / 255;

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

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

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

      weights[delaunayIndex] += weight;

      counts[delaunayIndex]++;

    }

  }

}

​

function gridPoints() {

  let x_max = round(sqrt(width / height * seed_count));

  let y_max = round(seed_count / x_max);

  seed_count = x_max * y_max;

  for(let i = 0, y = 0; y < y_max; y++) {

    for(let x = 0; x < x_max; x++, i++) {

      let px = map(x, 0, x_max, 0, width);

      let py = map(y, 0, y_max, 0, height);

      grid[i] = createVector(px, py);

    }

  }

}

​

​

function setup() {

  current_image = felix;

  createCanvas(current_image.width, current_image.height);

  gridPoints();

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

    let x = grid[i].x;

    let y = grid[i].y;

    let col = current_image.get(x, y);

    if(brightness(col) < 100) {

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

    }

/*    

    let col = current_image.get(x, y);

      if (random(100) > brightness(col)) {

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

    } else {

      i--;

    }

*/    

  }

}

​

function draw() {

  background(255);

  delaunay = d3.Delaunay.from(points.map(p=>[p.x, p.y]));

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

​

  let polygons = voronoi.cellPolygons();

  let cells = Array.from(polygons);

​

  centroids = new Array(cells.length);

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

  counts = new Array(cells.length).fill(0);

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

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

    centroids[i] = createVector(0, 0);

  }

​

  if(frameCount < 500) {

    loadThePixels(current_image);

  } else if(frameCount < 1000) {

    current_image = eric;

    loadThePixels(eric);

  } else {

    noLoop();

    print("done");

  }

  let maxWeight = 0;

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

    if (weights[i] > 0) {

      centroids[i].div(weights[i]);

      avgWeights[i] = weights[i] / (counts[i] || 1);

      if (avgWeights[i] > maxWeight) {

        maxWeight = avgWeights[i];

      }

    } else {

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

    }

  }

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

    points[i].lerp(centroids[i], 0.1);

  }

/*

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

    let poly = cells[i];

    let centroid = centroids[i];

    let col =current_image.get(centroid.x, centroid.y)

    stroke(0);

    strokeWeight(0.5);

    // fill(col);

    noFill();

    beginShape();

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

      vertex(poly[i][0], poly[i][1]);

    }

    endShape();

  }

*/  

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

    let v = points[i];

    let col = current_image.get(v.x, v.y);

    let sw = map(avgWeights[i], 0, maxWeight, 0, 3, true);

    stroke(0);

    strokeWeight(sw);

    point(v.x, v.y);

  }

}

​

​