Monogame layer background is not transparent in Xamarin Android

Android
1

Is there any sample code to place 3d model on top of camera in Xamarin Android?

I have try this by using FrameLayout following this guidance

http://www.infinitespace-studios.co.uk/general/getting-started-on-argumented-reality-using-xamarin-android-and-monogame/

but the 3d model background of monogame is not transparent?

Any idea?

2

have you tryed color.transparent. Even you are clearing the screen in monogamies’.

Hard to help without any code to look at.

3

Here is my code. For testing I just use an image at background instead of camera feed. Any idea?

This is Android activity:

 [Activity(Label = "Game1"
        , MainLauncher = true
        , Icon = "@drawable/icon"
        , AlwaysRetainTaskState = true
        , LaunchMode = Android.Content.PM.LaunchMode.SingleInstance
        , ScreenOrientation = ScreenOrientation.SensorLandscape
        , ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.Keyboard | ConfigChanges.KeyboardHidden | ConfigChanges.ScreenSize)]
    public class Activity1 : Microsoft.Xna.Framework.AndroidGameActivity
    {
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            this.SetContentView(TestFBX.Resource.Layout.layout1);
            var gameWindowLayout = FindViewById<RelativeLayout>(TestFBX.Resource.Id.gameWindow);
            var game1 = new Game1();
            gameWindowLayout.AddView(game1.Services.GetService<View>());
            game1.Run(GameRunBehavior.Asynchronous);
        }
    }

Here is layout1.axml:

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">     
     
<!--This is my background image in Android-->
      <ImageView
          android:id="@+id/flag"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"            
          android:src="@drawable/stars" />

<!-- This is where Monogame layer will appear over above background image -->
      <RelativeLayout
            android:id="@+id/gameWindow"
            android:layout_width="800dp"
            android:layout_height="800dp"
            android:layout_alignParentTop="true"
            android:layout_marginTop="20dp"        
            android:background="#00ffffff"> 
      </RelativeLayout>

    </RelativeLayout>

Here is Game1.cs, just use default code with clear background transparent:

public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            graphics.IsFullScreen = true;
            graphics.PreferredBackBufferWidth = 800;
            graphics.PreferredBackBufferHeight = 480;
            graphics.SupportedOrientations = DisplayOrientation.LandscapeLeft | DisplayOrientation.LandscapeRight;
        }

        Matrix projection;

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            base.Initialize();
        }
        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// game-specific content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
           
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                Exit();

            // TODO: Add your update logic here            

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.Transparent);
         
            base.Draw(gameTime);
        }
    }
4

And if I use following code to change the Game surface format to Rgba8888:

var game1View = game1.Services.GetService<View>();
game1View.JavaCast<OpenTK.Platform.Android.AndroidGameView>().SurfaceFormat = Android.Graphics.Format.Rgba8888;

It will throw exception:

System.InvalidCastException: Unable to convert instance of type 'Microsoft.Xna.Framework.MonoGameAndroidGameView' to type 'OpenTK.Platform.Android.AndroidGameView'.

I am using Monogame 3.5

5

Ok it works now.

It turns out that I have to reference to OpenTK-1.0 dll instead of OpenTK.

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\MonoAndroid\v7.0\OpenTK-1.0.dll