在自己的 ViewController 中嵌入 Unity

Question

Using Unity 2019.3.0f3 and its Unity as a library feature I'm trying to embed a Unity project inside my iOS application.

Unity officially only supports full screen rendering. Nevertheless I'm looking for a way around that restriction.
In previous versions of Unity i successfully used swift-unity to do the integration. Within this approach it is easy to just get the View where Unity is rendering to (using UnityGetGLView() ). I had no problems regarding stability or resources.

Using the new library approach, every time I try to access the UnityView , unity forces it's complete Window as keyWindow .

I tried accessing the UnityView in my own ViewController using

if let unityView = UnityFramework.getInstance()?.appController()?.rootViewController.view {
    // insert subview at index 0 ensures unity view is behind current UI view
    view?.insertSubview(unityView, at: 0)
}

But that immediately activates the complete unity-window and hides my parenting UITabBarController .

Trying to make the UnityFramework.getInstance()?.appController()?.rootViewController a child of my UITabBarController failed with the same result.

Furthermore it is not possible to add a child ViewController . Only adding subviews seems possible.

Does anybody know where that window-behaviour is located or how i can access the UnityView (or the RootViewController) and use it freely?

Answer 1

I found a solution to the problem based on this approach from the unity forum . Using this approach I'm able to use the UnityViewController as a child in my own TabBarController .

The approach is working for Unity 2019.3.0f3, but I'm not sure if it will work in future versions. It feels like Unity tries to actively prevent such use. Then again I found hints in comments in the library-code that would suggest that a modified ViewController-Hierarchy was at least contemplated eg in UnityAppController+ViewHandling.h . But the instructions are unclear and methods with the hinted names don't exist.

---

Solution

1. Create UnityEmbeddedSwift.swift

The official example App provided by Unity is a real mess. I ended up using the UnityEmbeddedSwift.swift from the linked forum post with additions for pausing. This class encapsulates all Unity-related functionality in one clean class.

//
//  UnityEmbeddedSwift.swift
//  Native
//
//  Created by NSWell on 2019/12/19.
//  Copyright © 2019 WEACW. All rights reserved.
//

//
//  Created by Simon Tysland on 19/08/2019.
//  Copyright © 2019 Simon Tysland. All rights reserved.
//

import Foundation
import UnityFramework

class UnityEmbeddedSwift: UIResponder, UIApplicationDelegate, UnityFrameworkListener {

    private struct UnityMessage {
        let objectName : String?
        let methodName : String?
        let messageBody : String?
    }

    private static var instance : UnityEmbeddedSwift!
    private var ufw : UnityFramework!
    private static var hostMainWindow : UIWindow! // Window to return to when exiting Unity window
    private static var launchOpts : [UIApplication.LaunchOptionsKey: Any]?

    private static var cachedMessages = [UnityMessage]()

    // MARK: - Static functions (that can be called from other scripts)

    static func getUnityRootViewController() -> UIViewController! {
        return instance.ufw.appController()?.rootViewController
    }

    static func getUnityView() -> UIView! {
        return instance.ufw.appController()?.rootViewController?.view
    }

    static func setHostMainWindow(_ hostMainWindow : UIWindow?) {
        UnityEmbeddedSwift.hostMainWindow = hostMainWindow
        let value = UIInterfaceOrientation.landscapeLeft.rawValue
        UIDevice.current.setValue(value, forKey: "orientation")
    }

    static func setLaunchinOptions(_ launchingOptions :  [UIApplication.LaunchOptionsKey: Any]?) {
        UnityEmbeddedSwift.launchOpts = launchingOptions
    }

    static func showUnity() {
        if(UnityEmbeddedSwift.instance == nil || UnityEmbeddedSwift.instance.unityIsInitialized() == false) {
            UnityEmbeddedSwift().initUnityWindow()
        }
        else {
            UnityEmbeddedSwift.instance.showUnityWindow()
        }
    }

    static func hideUnity() {
        UnityEmbeddedSwift.instance?.hideUnityWindow()
    }

    static func pauseUnity() {
        UnityEmbeddedSwift.instance?.pauseUnityWindow()
    }

    static func unpauseUnity() {
        UnityEmbeddedSwift.instance?.unpauseUnityWindow()
    }

    static func unloadUnity() {
        UnityEmbeddedSwift.instance?.unloadUnityWindow()
    }

    static func sendUnityMessage(_ objectName : String, methodName : String, message : String) {
        let msg : UnityMessage = UnityMessage(objectName: objectName, methodName: methodName, messageBody: message)

        // Send the message right away if Unity is initialized, else cache it
        if(UnityEmbeddedSwift.instance != nil && UnityEmbeddedSwift.instance.unityIsInitialized()) {
            UnityEmbeddedSwift.instance.ufw.sendMessageToGO(withName: msg.objectName, functionName: msg.methodName, message: msg.messageBody)
        }
        else {
            UnityEmbeddedSwift.cachedMessages.append(msg)
        }
    }

    // MARK - Callback from UnityFrameworkListener

    func unityDidUnload(_ notification: Notification!) {
        ufw.unregisterFrameworkListener(self)
        ufw = nil
        UnityEmbeddedSwift.hostMainWindow?.makeKeyAndVisible()
    }

    // MARK: - Private functions (called within the class)

    private func unityIsInitialized() -> Bool {
        return ufw != nil && (ufw.appController() != nil)
    }

    private func initUnityWindow() {
        if unityIsInitialized() {
            showUnityWindow()
            return
        }

        ufw = UnityFrameworkLoad()!
        ufw.setDataBundleId("com.unity3d.framework")
        ufw.register(self)
//        NSClassFromString("FrameworkLibAPI")?.registerAPIforNativeCalls(self)

        ufw.runEmbedded(withArgc: CommandLine.argc, argv: CommandLine.unsafeArgv, appLaunchOpts: UnityEmbeddedSwift.launchOpts)

        sendUnityMessageToGameObject()

        UnityEmbeddedSwift.instance = self
    }

    private func showUnityWindow() {
        if unityIsInitialized() {
            ufw.showUnityWindow()
            sendUnityMessageToGameObject()
        }
    }

    private func hideUnityWindow() {
        if(UnityEmbeddedSwift.hostMainWindow == nil) {
            print("WARNING: hostMainWindow is nil! Cannot switch from Unity window to previous window")
        }
        else {
            UnityEmbeddedSwift.hostMainWindow?.makeKeyAndVisible()
        }
    }

    private func pauseUnityWindow() {
        ufw.pause(true)
    }

    private func unpauseUnityWindow() {
        ufw.pause(false)
    }

    private func unloadUnityWindow() {
        if unityIsInitialized() {
            UnityEmbeddedSwift.cachedMessages.removeAll()
            ufw.unloadApplication()
        }
    }

    private func sendUnityMessageToGameObject() {
        if (UnityEmbeddedSwift.cachedMessages.count >= 0 && unityIsInitialized())
        {
            for msg in UnityEmbeddedSwift.cachedMessages {
                ufw.sendMessageToGO(withName: msg.objectName, functionName: msg.methodName, message: msg.messageBody)
            }

            UnityEmbeddedSwift.cachedMessages.removeAll()
        }
    }

    private func UnityFrameworkLoad() -> UnityFramework? {
        let bundlePath: String = Bundle.main.bundlePath + "/Frameworks/UnityFramework.framework"

        let bundle = Bundle(path: bundlePath )
        if bundle?.isLoaded == false {
            bundle?.load()
        }

        let ufw = bundle?.principalClass?.getInstance()
        if ufw?.appController() == nil {
            // unity is not initialized
            //            ufw?.executeHeader = &mh_execute_header

            let machineHeader = UnsafeMutablePointer<MachHeader>.allocate(capacity: 1)
            machineHeader.pointee = _mh_execute_header

            ufw!.setExecuteHeader(machineHeader)
        }
        return ufw
    }
}

2. Modify AppDelegate.swift

Sets window and launch options needed by UnityEmbeddedSwift

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        UnityEmbeddedSwift.setHostMainWindow(window)
        UnityEmbeddedSwift.setLaunchinOptions(launchOptions)

        return true
    }

3. Create RootTabBarController.swift

This class sets up the hierarchy.
It is important to use the UnityRootViewController right after calling UnityEmbeddedSwift.showUnity() .
The Tab-Switching is not nice, but if it is missing Unity will pause (or freeze?) during loading. The timing seems to depend on the Unity-Projects loading time. It can be faster for small projects and needs more time for larger projects.

import UIKit

class RootTabBarController: UITabBarController, UITabBarControllerDelegate {

    var unityNC: UINavigationController?
    var nativeNC: UINavigationController?

    override func viewDidLoad() {
        super.viewDidLoad()

        delegate = self

        // start unity and immediatly set as rootViewController
        // this loophole makes it possible to run unity in the same window
        UnityEmbeddedSwift.showUnity()
        let unityViewController = UnityEmbeddedSwift.getUnityRootViewController()!
        unityViewController.navigationItem.title = "Unity"

        unityNC = UINavigationController.init(rootViewController: unityViewController)
        unityNC?.tabBarItem.title = "Unity"

        let nativeViewController = UIViewController.init()
        nativeViewController.view.backgroundColor = UIColor.darkGray
        nativeViewController.navigationItem.title = "Native"

        nativeNC = UINavigationController.init(rootViewController: nativeViewController)
        nativeNC?.tabBarItem.title = "Native"

        viewControllers = [unityNC!, nativeNC!]

        // select other tab and reselect first tab to unfreeze unity-loading
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2, execute: {
            self.selectedIndex = 1

            DispatchQueue.main.asyncAfter(deadline: .now() + 0.01, execute: {
                self.selectedIndex = 0
            })
        })
    }

    // MARK: - UITabBarControllerDelegate

    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
        // pause unity if unity-tab is not selected
        if viewController != unityNC {
            UnityEmbeddedSwift.pauseUnity()
        } else {
            UnityEmbeddedSwift.unpauseUnity()
        }
    }
}

4. Modify Main.storyboard

Modify the storyboard to start with the RootTabBarController .

Answer 2

For anyone who is still interested in preventing the freezing, I am building on top of aalmigthy's answer :

You do not need to add a TabBar controller and switch between the tabs. All you need to do is:

• Add the Unity view as a subview
• Send the subview to back

Here's the modified ViewController class (no need for a tab bar):

import UIKit

class HybridViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        UnityEmbeddedSwift.showUnity()
        
        let uView = UnityEmbeddedSwift.getUnityView()
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1, execute: {
            self.view.addSubview(uView!)
            
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1, execute: {
                self.view.sendSubviewToBack(uView!)
            })
        })
    }
}