How can I get SKEmitterNode to work in SwiftUI?

I'm trying to update the colour of an

SKEmitterNode

within a

UIViewRepresentable

. The hue value is passed in from the state on the parent View, and the emitter colour should update when the hue value in the parent state updates.

It initially displays, and although it updates on the first call to

updateUIView

it does not respond to any subsequent calls, even though the function definitely gets called with the new value of

hue

each time.

Has anyone any idea why the emitter won't update? I'm at the hair-tearing-out stage... I'd be grateful for any help with this.

Here's what I've got. I just can't see what's wrong with this... I'm using the latest XCode GM Seed.

import SwiftUI
import UIKit
import SpriteKit

struct EmitterView: UIViewRepresentable {
  private let view = SKView()

  let scene = SKScene(fileNamed: "myScene")!
  var emitter: SKEmitterNode = SKEmitterNode()
  var hue: Double

  func makeUIView(context: UIViewRepresentableContext) -> SKView {

    // Lets make it manually
    emitter.particleTexture = SKTexture(imageNamed: "spark")
    emitter.particleBirthRate = 80
    emitter.particleLifetime = 2.5
    emitter.particlePositionRange = CGVector(dx: 200, dy: 150)
    emitter.emissionAngle = 90
    emitter.emissionAngleRange = 360
    emitter.particleRotation = CGFloat(Float(arc4random()) / Float(UINT32_MAX))
    emitter.particleRotationSpeed = 0.5
    emitter.particleSpeed = 0
    emitter.particleSpeedRange = 40
    emitter.particleAlpha = 0.8
    emitter.particleAlphaRange = 0.2
    emitter.particleAlphaSpeed = -0.4
    emitter.particleScale = 0.2
    emitter.particleScaleSpeed = 0.45
    emitter.particleColor = SKColor.blue
    emitter.particleColorBlendFactor = 1.0
    emitter.particleColorSequence = nil;

    scene.addChild(emitter)
    view.presentScene(scene)

    return view
  }

  func updateUIView(_ uiView: SKView, context: UIViewRepresentableContext) {
      let color: SKColor = SKColor(
        hue: CGFloat(hue),
        saturation: 1.0,
        brightness: 1.0,
        alpha: 1.0
      )

      print("Hue is now", hue)

      emitter.resetSimulation()
      emitter.particleColor = color
    }
  }

  struct EmitterView_Previews: PreviewProvider {
    static var previews: some View {
    EmitterView(hue: 0.5)
  }
}