How to combine Unity and Native OpenGL in iOS (Sparrow)?

Ok, i kinda got it myself. Originally i started the native app in its own window, then (later in the app life) started the appController by initializing it and calling "didFinishLaunching..". This creates a second window with the unity stuff and one can easily switch between native and unity. But OpenGL seems not really happy with this solution.

Here is what i did:

• Now there is only the unity-window (My own AppDelegate directly calls AppControllers launching method) where i put my native stuff on top by letting the UnityGLViewController present my native ViewController modally. Additionally i call applicationWillResignActive and applicationDidEnterBackground before i "switch" to the native stuff. Therefore Unity stopps drawing and is not interfering with my Native OpenGL.

• After starting the app (in "Unitymode") i save the GLContext to a member variable (via [EAGLContext currentContext]). Before switching back to Unity i "restore" the context by [EAGLContext setCurrentContext:unityContext]; (where unityContext is the member-variable). Then i call applicationWillEnterForeground and applicationDidBecomeActive and dismiss the modal view controller.

This way everything works perfectly fine. I dont even need GL.invalidateState. Both the Unity and the Sparrow-View are only paused (or stopped for Sparrow) when they are not visible so they not disturb each other.

I dont know if its possible to do it with seperate windows (so one can start the unity-player in the background and dont have to wait on startup), but it works this way.

UPDATED VERSION FOR UNITY 4.3

Here is some edited Version as i am doing it for Unity 4.3 at the moment: I have a lot of native iOS stuff and therefor didnt derive from UnityAppController but use my own AppDelegate which i use in main.mm My own AppDelegate creates an instance of the UnityAppController and handles the switch between Unity and Native Code. Therefore i had to change some Unitycode: In UnityAppController i changed GetAppController() to return the UnityAppController stored within my own AppDelegate

I think the startup progress changed with Unity 4.2 because it was no longer possible to just switch to native after applicationDidFinishLaunching... so i added a Callback at the end of OnUnityReady() withing iPhone_View.mm. In my own applicationDidFinishLaunching... i do as follows: -create my own view hierachy but no own window. -create the UnityAppController and call didFinischLaunching on it - use the window returned by UnityGetMainWindow() but not setting the rootViewController yet - wait till the callback in OnUnityReady() is called, then set the rootViewController to my own viewhierachy (after sending WillResignActive and DidEnterBackground to the UnityAppController)

It is necessary that no OpenGL stuff is executed during the startup until unity is done. Otherwise the context and framebuffers etc. got messed up.

regarding the context: its no longer necessary to save the context yourself cause unity already does that. i just make sure to set it when switching back to unity (before calling willEnterForeground but after setting the rootViewcontroller back to unityAppController:

 [EAGLContext setCurrentContext:[DisplayManager Instance].mainDisplay->surface.context];

Hope this helps markus