/// Creates A Video Player As An SCNGeometries Diffuse Contents
static func setupVideoOnNode(_ node: SCNNode, fromURL url: URL) {

  //1. Create An SKVideoNode
  var videoPlayerNode: SKVideoNode!

  //2. Create An AVPlayer With Our Video URL
  let videoPlayer = AVPlayer(url: url)

  //3. Initialize The Video Node With Our Video Player
  videoPlayerNode = SKVideoNode(avPlayer: videoPlayer)
  videoPlayerNode.yScale = -1

  //4. Create A SpriteKitScene & Position It
  let spriteKitScene = SKScene(size: CGSize(width: 1024, height: 768))
  spriteKitScene.scaleMode = .aspectFit
  videoPlayerNode.position = CGPoint(x: spriteKitScene.size.width/2,   y: spriteKitScene.size.height/2)
  videoPlayerNode.size = spriteKitScene.size
  spriteKitScene.backgroundColor = .clear

  //5. Alpha transparency
  let effectNode = getAlphaEffectNode(videoPlayerNode: videoPlayerNode)
  spriteKitScene.addChild(effectNode)
  effectNode.addChild(videoPlayerNode)

  //6. Set The Nodes Geoemtry Diffuse Contenets To Our SpriteKit Scene
  node.geometry?.firstMaterial?.diffuse.contents = spriteKitScene

  //7. Play The Video
  videoPlayerNode.play()
  videoPlayer.volume = 0

  //8. Loop Video
  loopVideo(videoPlayer: videoPlayer, node: node)
}


// MARK: - Add Alpha Transparency

static func getAlphaEffectNode(videoPlayerNode: SKVideoNode) -> SKEffectNode {
  // Let's make it transparent, using an SKEffectNode,
  // since a shader cannot be applied to a SKVideoNode directly
  let effectNode = SKEffectNode()
  effectNode.shader = EffectNodeHelper.getAlphaShader()
  return effectNode
}


// MARK: - Loop Video

static func loopVideo(videoPlayer: AVPlayer, node: SCNNode) {
  NotificationCenter.default.addObserver(forName: .AVPlayerItemDidPlayToEndTime,
  object: videoPlayer.currentItem,
  queue: nil) { (_) in
   videoPlayer.seek(to: kCMTimeZero)
   videoPlayer.play()
}