Dithering in Colour(obrhubr.org)

    var img
    var pixel
    var threshold
    var error = [0, 0, 0]
    var a0

    function preload() {
      img = loadImage("https://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Albrecht_D%C3%BCrer_-_Hare%2C_1502_-_Google_Art_Project.jpg/1920px-Albrecht_D%C3%BCrer_-_Hare%2C_1502_-_Google_Art_Project.jpg")
    }

    function setup() {
      // I'm just using a low discrepancy sequence for a quasirandom
      // dither and diffusing the error to the right, because it's
      // trivial to implement
      a0 = 1/sqrt(5)
      pixelDensity(2)
      createCanvas(400, 400);
      image(img, 0, 0, 400, 400)
      loadPixels()
      pixel = 0
      threshold = 0
    }

    function draw() {
      if (pixel > 400*400*16) {
        return
      }
      for (var i = 0; i < 2000; i++) {
        threshold = (threshold + a0)%1
        for(var j=0; j< 3; j++) {
          var c = pixels[pixel + j]
          pixels[pixel + j] = c + error[j] > threshold * 255 ? 255 : 0
          error[j] += c - pixels[pixel + j]
        }
        pixel += 4
      }
      updatePixels()
    }