Variable in renderer(_:didAdd:for:) not updating - ios

Question

I am working on a IPhone app that uses CoreML and ARKit simultaneously. The CoreML is supposed to recognize a number and the ARKit should detect a vertical plane (aka wall) and add some planes over that same wall with the content displayed on those planes depending on the recognised number.
So, the CoreML is working 100%. Everytime I "change" the number the topPrediction variable updates automatically ( so far so good ). The thing is that my variable in func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor does not update! What I mean is that the first number recognized by the CoreML is correctly sent to the renderer func and it works like a charm but if I turn the camera to another number it stills assumes that it's the first number! As you may see in the code, I even tried making a func getGabNum() -> Int and then calling it in the renderer func ( var num = getGabNum() ) but I continue getting the warning "Variable 'num' was never mutated; consider changing to 'let' constant" which means that something is not right. So guys, here is my code! Hope you can help me and thank you!
struct Room : Decodable {
let id : Int?
let num : Int?
//Adicionar Schedules
var horario = [Schedule]()
}
struct Schedule : Decodable {
let id : Int?
let hora_ini : Date?
let hora_fim : Date?
let descr : String?
private enum CodingKeys: String, CodingKey {
case id
case hora_ini
case hora_fim
case descr
}
}
class ViewController: UIViewController, ARSCNViewDelegate {
#IBOutlet weak var debugLabel: UILabel!
#IBOutlet weak var debugTextView: UITextView!
#IBOutlet weak var sceneView: ARSCNView!
let dispatchQueueML = DispatchQueue(label: "com.hw.dispatchqueueml") // A Serial Queue
var visionRequests = [VNRequest]()
var room: Room?
var room_array: [[Int]] = [[17, 0], [43, 0], [120,0]]
var teste = 0
var num = -1
override func viewDidLoad() {
super.viewDidLoad()
sceneView.delegate = self
sceneView.showsStatistics = true
let scene = SCNScene()
sceneView.scene = scene
configureLighting()
guard let selectedModel = try? VNCoreMLModel(for: SalasMLv6().model) else {
fatalError("Could not load model.")
}
let classificationRequest = VNCoreMLRequest(model: selectedModel, completionHandler: classificationCompleteHandler)
classificationRequest.imageCropAndScaleOption = VNImageCropAndScaleOption.centerCrop // Crop from centre of images and scale to appropriate size.
visionRequests = [classificationRequest]
loopCoreMLUpdate()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
setUpSceneView()
}
func setUpSceneView()
{
let configuration = ARWorldTrackingConfiguration()
configuration.planeDetection = .vertical
sceneView.session.run(configuration)
sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints]
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
sceneView.session.pause()
}
func configureLighting()
{
sceneView.automaticallyUpdatesLighting = true
sceneView.autoenablesDefaultLighting = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: - ARSCNViewDelegate
func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
DispatchQueue.main.async {
// Do any desired updates to SceneKit here.
}
}
func loopCoreMLUpdate() {
dispatchQueueML.async {
self.updateCoreML()
self.loopCoreMLUpdate()
}
}
func updateCoreML() {
// Get Camera Image as RGB
let pixbuff : CVPixelBuffer? = (sceneView.session.currentFrame?.capturedImage)
if pixbuff == nil { return }
let ciImage = CIImage(cvPixelBuffer: pixbuff!)
// Prepare CoreML/Vision Request
let imageRequestHandler = VNImageRequestHandler(ciImage: ciImage, options: [:])
// Run Vision Image Request
do {
try imageRequestHandler.perform(self.visionRequests)
} catch {
print(error)
}
}
func classificationCompleteHandler(request: VNRequest, error: Error?) {
// Catch Errors
if error != nil {
print("Error: " + (error?.localizedDescription)!)
return
}
guard let observations = request.results else {
print("No results")
return
}
// Get Classifications
let classifications = observations[0...2] // top 3 results
.compactMap({ $0 as? VNClassificationObservation })
.map({ "\($0.identifier) \(String(format:" : %.2f", $0.confidence))" })
.joined(separator: "\n")
// Render Classifications
DispatchQueue.main.async {
// Display Debug Text on screen
self.debugTextView.text = "TOP 3 PROBABILITIES: \n" + classifications
// Display Top Symbol
var symbol = "❌"
var gabNum: Int?
let topPrediction = classifications.components(separatedBy: "\n")[0]
let topPredictionName = topPrediction.components(separatedBy: ":")[0].trimmingCharacters(in: .whitespaces)
// Only display a prediction if confidence is above 90%
let topPredictionScore:Float? = Float(topPrediction.components(separatedBy: ":")[1].trimmingCharacters(in: .whitespaces))
if (topPredictionScore != nil && topPredictionScore! > 0.05) {
if (topPredictionName == "120") {
symbol = "1️⃣2️⃣0️⃣"
gabNum = 120
self.teste = gabNum!
}
if (topPredictionName == "43") {
symbol = "4️⃣3️⃣"
gabNum = 43
self.teste = gabNum!
}
if (topPredictionName == "17") {
symbol = "1️⃣7️⃣"
gabNum = 17
self.teste = gabNum!
}
}
if let gn = gabNum {
// get room from REST
let jsonURL = "someURL\(gn)"
guard let url = URL(string: jsonURL) else {
return
}
URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil{
print("error)")
return
}
do {
self.room = try JSONDecoder().decode(Room.self, from: data!)
}catch{
print(“Decoder Error”)
}
}.resume()
}
self.debugLabel.text = symbol
}
}
// MARK: - HIDE STATUS BAR
override var prefersStatusBarHidden : Bool { return true }
func getGabNum() -> Int {
return self.teste
}
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor)
{
guard room != nil else {
print("room == nil")
return
}
guard let planeAnchor = anchor as? ARPlaneAnchor else {
return
}
num = getGabNum()
if( num == room_array[0][0] && room_array[0][1] == 1 ){
return
}else{
if( num == room_array[1][0] && room_array[1][1] == 1 ){
return
}else{
if( num == room_array[2][0] && room_array[2][1] == 1 ){
return
}else{
var i = 0
for horario in (self.room?.horario)!{
// Planes and Nodes Stuff Right Here
}
switch self.room?.num{
case 17: room_array[0][1] = 1
case 43: room_array[1][1] = 1
case 120:room_array[2][1] = 1
}
}
}
}
}
}