Artistic Sierpinski Triangle (Playing with Scala.JS)

SierpinskiTriangle.scala

import org.scalajs.dom
 
final case class Pt(x: Double, y: Double)

@JSExport
object SierpinskiTriangle {
  val corners = Seq(
    Pt(canvas.width/2, 0),
    Pt(0, canvas.height),
    Pt(canvas.width, canvas.height)
  )
  
  var p = corners(0)
  val (w, h) = (canvas.height.toDouble, canvas.height.toDouble)
  
  @JSExport
  def main(args: Array[String]): Unit = {
    dom.setInterval(() => for(_ <- 0 until 10){
      val c = corners(util.Random.nextInt(3))
      val s = util.Random.nextInt(5)
      
      p = Pt((p.x + c.x) / 2, (p.y + c.y) / 2)
      val m = (p.y / h)
      val r = 255 - (p.x / w * m * 255).toInt
      val g = 255 - ((w-p.x) / w * m * 255).toInt
      val b = 255 - ((h - p.y) / h * 255).toInt
      
      renderer.fillStyle = s"rgba($r, $g, $b, 0.02)"

      renderer.beginPath()
      renderer.arc(p.x, p.y, s, 0, Math.PI*2, true) 
      renderer.closePath()
      renderer.fill()
    }, 5)
  }
}