Mixed content in Xamarin.Forms

[Therzok]

Testing around a bit, an app using XF and CocosSharp as simple as below, fails on iOS:

    public class App : Application
    {
        public App ()
        {
            // The root page of your application
            MainPage = new ContentPage {
                Content = new StackLayout {
                    VerticalOptions = LayoutOptions.Start, // This line is the culprit.
                    Children = {
                        new Label {
                            XAlign = TextAlignment.Center,
                            Text = "Welcome to Xamarin Forms!"
                        },
                        new CocosSharpView {
                            HorizontalOptions = LayoutOptions.FillAndExpand,
                            VerticalOptions = LayoutOptions.FillAndExpand,
                            DesignResolution = new Size (1024, 768),
                            ViewCreated = LoadGame,
                        },
                    }
                }
            };
        }

        static void LoadGame (object sender, EventArgs e)
        {
            var gameView = sender as CCGameView;

            if (gameView != null) {

                // Set world dimensions
                gameView.DesignResolution = new CCSizeI (1024, 768);

                gameView.ContentManager.SearchPaths = new List<string> { "Fonts", "Sounds", "Images" };

                CCScene gameScene = new CCScene (gameView);
                gameScene.AddLayer (new MainLayer ());
                gameView.RunWithScene (gameScene);
            }
        }

System.InvalidOperationException: Error with EAGLContext.RenderBufferStorage!
  at at OpenTK.Platform.iPhoneOS.iPhoneOSGameView.CreateFrameBuffer () in <filename unknown>:line 0
  at at CocosSharp.CCGameView.CreateFrameBuffer () in <filename unknown>:line 0
  at at CocosSharp.CCGameView.LayoutSubviews () in <filename unknown>:line 0
  at at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at at UIKit.UIApplication.Main (System.String[] args, IntPtr principal, IntPtr delegate) in /Users/builder/data/lanes/2356/9ce9e8b9/source/maccore/src/UIKit/UIApplication.cs:line 77
  at at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) in /Users/builder/data/lanes/2356/9ce9e8b9/source/maccore/src/UIKit/UIApplication.cs:line 61
  at at TestCCS.iOS.Application.Main (System.String[] args) in /Users/therzok/Personal/TestCCS/iOS/Main.cs:line 17

[rtabbara]

@Therzok Can you try setting an explicit HeightRequest for the CocosSharpView to see if that helps?

As a test, I tried replacing CocosSharpView with the Xam.Forms OpenGLView using the same layout options, and while no exception was thrown, nothing was displayed either.

I think the issue is that a StackLayout implicitly has no height when setting VerticalOptions = LayoutOptions.Start --- those dimensions are dictated by its children. For a Label control, the height dimensions are driven by the native label dimensions. But for a CocosSharpView and more generally, a OpenGLView, we require the opposite situation. That is, we need the CocosSharpView dimensions to be set before we can create the native frame buffer.