How to fix IUnityGraphicsMetal error when I run Xcode project - ios

Question

I work to integrate an amazing AR model from Unity into Swift 4.
I finally did that using Unity 2018 (version 2018.2.4) and Swift 4.1 (Xcode 9.4.1) but when I run the project on my device (iPhone 7 Plus) is crushing and the error is coming from the path MyProjectName/Unity/Classes/Unity/IUnityGraphicsMetal.h
The error is: Thread 1: EXC_BAD_ACCESS (code=1, address=0x8).
I exported the project from Unity selecting Graphics API as Metal and also as OpenGLES3, none of this helped me.
Also in XCode -> Edit Scheme -> Run -> Options Tab -> Metal API Validation -> I set this one to Disabled, and I still get the same error.
I also update ARKit Plugin (in Unity) to the latest version (1.5) hoping that will fix the problem with UnityGraphicsMetal but apparently not.
Can anyone help me please to fix this error or to guide me to the wright way ?
Here I have 3 screenshots with the errors which maybe can help you more.
Thank you if you are reading this !
EDIT:
Here is the source code for my ViewController which is managing the bridge between Swift and Unity:
import UIKit
class ViewController: UIViewController {
#IBOutlet var rotateSwitch: UISwitch!
override func viewDidLoad() {
super.viewDidLoad()
if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
appDelegate.startUnity()
NotificationCenter.default.addObserver(self, selector: #selector(handleUnityReady), name: NSNotification.Name("UnityReady"), object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(handleUnityToggleRotation(_:)), name: NSNotification.Name("UnityToggleRotation"), object: nil)
}
}
#objc func handleUnityReady() {
showUnitySubView()
}
#objc func handleUnityToggleRotation(_ n: NSNotification) {
if let isOn = n.userInfo?["isOn"] as? NSNumber {
rotateSwitch.isOn = isOn.boolValue
}
}
#IBAction func handleSwitchValueChanged(sender: UISwitch) {
UnityPostMessage("NATIVE_BRIDGE", "PlayHologram", sender.isOn ? "start" : "stop")
}
func showUnitySubView() {
if let unityView = UnityGetGLView() {
// insert subview at index 0 ensures unity view is behind current UI view
view?.insertSubview(unityView, at: 0)
unityView.translatesAutoresizingMaskIntoConstraints = false
let views = ["view": unityView]
let w = NSLayoutConstraint.constraints(withVisualFormat: "|-0-[view]-0-|", options: [], metrics: nil, views: views)
let h = NSLayoutConstraint.constraints(withVisualFormat: "V:|-75-[view]-0-|", options: [], metrics: nil, views: views)
view.addConstraints(w + h)
}
}
}
Here is the AppDelegate file:
import UIKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var application: UIApplication?
#objc var currentUnityController: UnityAppController!
var isUnityRunning = false
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
self.application = application
unity_init(CommandLine.argc, CommandLine.unsafeArgv)
currentUnityController = UnityAppController()
currentUnityController.application(application, didFinishLaunchingWithOptions: launchOptions)
// first call to startUnity will do some init stuff, so just call it here and directly stop it again
startUnity()
stopUnity()
return true
}
func applicationWillResignActive(_ application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
if isUnityRunning {
currentUnityController.applicationWillResignActive(application)
}
}
func applicationDidEnterBackground(_ application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
if isUnityRunning {
currentUnityController.applicationDidEnterBackground(application)
}
}
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
if isUnityRunning {
currentUnityController.applicationWillEnterForeground(application)
}
}
func applicationDidBecomeActive(_ application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
if isUnityRunning {
currentUnityController.applicationDidBecomeActive(application)
}
}
func applicationWillTerminate(_ application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
if isUnityRunning {
currentUnityController.applicationWillTerminate(application)
}
}
func startUnity() {
if !isUnityRunning {
isUnityRunning = true
currentUnityController.applicationDidBecomeActive(application!)
}
}
func stopUnity() {
if isUnityRunning {
currentUnityController.applicationWillResignActive(application!)
isUnityRunning = false
}
}
}

Answer 1

This seems to be a tricky problem, here's a few things which may help, please try them:
In the Unity Editor -> Project Settings -> Player, there is also a checkbox option called "Metal API Validation", you said that you only set the Xcode option to disabled, perhaps this one needs to be disabled as well. Or a combination of on/off for the two.
Instead of selecting Metal and OpenGLES3, try ticking the checkbox "Auto Graphics API". In one of my projects, I left it on manual with Metal selected, but it wouldn't render at all on iOS, fixed it by turning on automatic.
In Color Gamut, have both sRGB and P3 Wide-colour selected. The iPhone 7 and newer all have displays rated for P3 wide-colour.
Hope this helps!