Hilber curve demonstration in ScalaFiddle

ScalaFiddle.scala

// $FiddleDependency org.scala-js %%% scalajs-dom % 0.9.0
// $FiddleDependency com.lihaoyi %%% scalatags % 0.5.4
import scalatags.JsDom.all._
import org.scalajs.dom
import fiddle.Fiddle, Fiddle.println
import scalajs.js

object ScalaFiddle extends js.JSApp {
  def main() = {
// $FiddleStart
import scala.util.Random

case class Point(x: Int, y: Int)

def hilbert(n: Int, d: Int): Point = {
  var rx = 0
  var ry = 0
  var s = 1
  var t = d
  var p = Point(0, 0)
  while(s < n) {
    rx = 1 & (t/2)
    ry = 1 & (t ^ rx)
    p = rot(s, p, rx, ry)
    p = Point(p.x + s*rx, p.y + s*ry)
    t /= 4
    s *= 2
  }
  p
}

def rot(n: Int, p: Point, rx: Int, ry: Int): Point = {
  var np = p
  if (ry == 0) {
    if (rx == 1) {
      np = Point(n-1 - np.x, n-1 - np.y)
    }

    //Swap x and y
    np = Point(np.y, np.x)
  }
  np
}

def randomColor = 
  s"rgb(${Random.nextInt(240)}, ${Random.nextInt(240)}, ${Random.nextInt(240)})"

val order = 64
val factor = math.min(Fiddle.canvas.height, Fiddle.canvas.width) / order.toDouble
val maxD = order * order
var d = 0
var p = hilbert(order, d)
Fiddle.draw.strokeStyle = randomColor
Fiddle.draw.lineWidth = 2
Fiddle.draw.lineCap = "square"

Fiddle.schedule(10) {
  import Fiddle.draw._
  beginPath
  moveTo(p.x * factor, p.y * factor)
  p = hilbert(order, d)
  lineTo(p.x * factor, p.y * factor)
  stroke
  d += 1
  if(d >= maxD) {
    d = 1
    Fiddle.draw.strokeStyle = randomColor
    p = hilbert(order, 0)
  }
}

// $FiddleEnd
  }
}