Windows Phone Development On A Mac With MonoGame

This week I have been porting ‘Toss The Floppy Frog’ (my first Android and iOS title with MonoGame) to Windows Phone 8 – and it has been painful. Very painful. So painful that I though I’d write a simple step-by-step guide to the process of porting iOS and Android MonoGame titles to Windows Phone. Hopefully this will ease the pain for others.

Part of the suffering has, no doubt, been due to the fact that I am a complete Windows noob. I have been developing on a Mac since around 1995 and have barely touched a Windows machine since then – I even wrote my own JavaME emulator (running on J2SE) so I could do JavaME development on a Mac! Windows, and all its terminologies and conventions, is very much uncharted territory for me.

The largest chunk of pain has, though, been due to what are in my opinion three key deficiencies in the Windows Phone implementation of MonoGame. These are…

1. The Project Templates Are Broken
The MonoGame project templates provided with the 3.2 install don’t work with Visual Studio 2013 (which is the latest version at the time of writing). I don’t know about previous versions. The basic template doesn’t launch the game correctly and doesn’t get to the ‘cornflower blue’ screen we so long for. No errors are given, it just doesn’t work. This issue caused me around half a day of tearing hair out before I found a post on the MonoGame forum that gave a solution (see the ‘step by step’ guide below). If these templates could be fixed I’m sure it would save a lot of developers a lot of grief and avoid casting MonoGame in an unnecessarily bad light.

2. The Content Pipeline Requirement Sucks
I understand the requirement for a content pipeline, really I do. Optimising your assets for use on different platforms is a great idea, but it should be exactly that – part of the optimisation process, NOT a requirement for getting a basic game up and running. The fact that ‘raw’ image and sound assets can’t be loaded in the Windows Phone implementation of MonoGame but can in the Android and iOS versions kind of makes a mockery of the whole ‘Write once, play anywhere’ mantra. Many developers (myself included) will have games that run perfectly fine without the need for content pipeline optimisations and the requirement to use one is just an unnecessary barrier to ‘getting stuff done’.

3. The Content Pipeline Itself Sucks
I couldn’t get any of the MonoGame content projects to load correctly in Visual Studio 2013 and I was unable to find any information online as to how to get the Monogame content tools to work correctly without these. the MonoGame content tools were completely useless to me. Fortunately someone on the MonoGame forums pointed me to an open-source XNB compiler that I was able to edit (ie hack) to convert all my assets to XNB (see the ‘step by step’ guide). That’s at least a day of pain right there. Frankly, if I hadn’t have been pointed to this tool I probably would have given up (and I hardly ever give up).

Now I have the greatest respect for the MonoGame project and team – they have given and continue to give their time for free to provide an awesome product for the IndieDev community. The criticisms above are given in the hope that these areas of MonoGame will be improved which will lead to more developers adopting the platform and more fun/revenue for all of us. Hopefully they’ll be taken in that spirit.

And, once you’ve got past the pain, there is one gigantic plus to all of this, and that is…

100% code re-use!!

Yes, you read that right. Once I was able to iron out a couple of quirks I was able to get 100% resuse of my game code across Android, iOS and Windows Phone. That’s pretty much the holy grail of cross-platform coding and an extremely big upside! The only platform specific code is in the app-launcher stubs and about three lines in my image loader. Nice.

So, without further ado, on to the step by step guide to porting iOS/Android MonoGame titles to Windows Phone using a Mac…

1. Prepare Your Code For Windows Phone
If, like me, you’re more familiar with a Mac and Xamarin Studio than Windows/Visual Studio it’s easiest to get this out of the way before you even touch Windows. Here are the issues I came across:

System.Collections.Hashtable is not available on Windows Phone.

References to this class can be replaced easily by references to:

System.Collections.Generic.Dictionary<Object><Object>

Note that there is a slight ‘gotcha’ here in that Hashtable will return null when trying to retrieve a value for a key that doesn’t exist whereas Dictionary will throw an exception. Your code may need to be altered to account for this.

System.Collections.ArrayList is not available on Windows Phone.

References to this class can be replaced easily by references to:

System.Collections.Generic.List<Object>

System.Runtime.Remoting package is not available on Windows Phone.

If you use this package you will have to work around this somehow. I was using it for dynamic class instantiation and could quite easily replace it by hard-coded calls to instantiate the relevant classes.

The following MonoGame properties return incorrect values on Windows Phone:

GraphicsDeviceManager.PreferredBackBufferWidth
GraphicsDeviceManager.PreferredBackBufferHeight

GraphicsDevice.DisplayMode.Width
GraphicsDevice.DisplayMode.Hight

If you are using any of these to get display width/height the following alternative seems to work:

GraphicsDevice.Viewport.Bounds.Width
GraphicsDevice.Viewport.Bounds.Height

Texture2D.FromStream() is not implemented in MonoGame for Windows Phone.

Bummer. If you are using this (as I was) you will have to work around it. I caught the System.NotImplemented exception and loaded the relevant asset(s) using the content manager instead. I really hope this gets implemented soon as it’s an important function.

Assets are loaded without the file suffix.

On Android/iOS you will probably be using something this:

Content.Load(“myimage.png”)

to load assets which will have to change to:

Content.Load(“myimage”)

on Windows Phone. Ideally write code that catches the exception and tries the alternative method if the first attempt fails.

2. Install Some Kind Of Virtual Machine
You probably want either VMWare Fusion or Parallels. I used Fusion which seems OK though it took quite a bit of farting around to get the ‘shared folder’ feature (which allows you to access files on your ‘host’ mac from the ‘guest’ PC) to work.

3. Set Up The Virtual Machine And Install Windows
Set up an x64 virtual machine and install a 64bit version of Windows otherwise the Windows Phone emulators won’t work. I’m still running a 32bit version of Windows which means I have been unable to launch the emulators so far – I’ve been using an actual device for testing. I believe it must also be the ‘pro’ version of Windows in order for the emulators to work.

4. Install Visual Studio 2013 Twice(!)
From here. You want both the ‘Windows’ version (for Windows Phone) and the ‘Windows Desktop’ version (for the content pipeline stuff). Fortunately both will reside happily side-by-side (unlike my children).

5. Install MonoGame 3.2
From here. May well have been updated since this was written.

6. Install XNA
You will need this for the content pipeline stuff. Follow the instructions and use the PowerShell script kindly provided here.

7. Install Windows Media Player
If it’s not there already – some versions of Windows install it by default, some don’t. You’ll need it for audio processing in the content pipeline and it can be downloaded from here.

8. Set Up A New MonoGame Solution
Launch Visual Studio for Windows and choose the ‘MonoGame Windows Phone’ project template uncder ‘Visual C#’ templates. If it’s not there you need to check MonoGame has installed properly. Call the project something sensible (e.g. the name of your app) and save it anywhere.

9. Update The MonoGame Packages
This is necessary to fix the broken MonoGame template issue and must be done with a solution open in Visual Studio. Launch the NuGet console under Tools->NuGet Package Manager->Package Manager Console and type in the following:

PM: Install-Package MonoGame

This will update the template. It asks if you want to overwrite a few files – click ‘yes’ to each one but ‘no’ to ‘Game1.cs’ as this file will have been altered to reference your app’s namespace.

10. Check For ‘Cornflower Blue’
Now you have done this you should be able to build/run the project and get our old friend the ‘cornflower blue’ screen on your chosen emulator or device. Well done! It took me about a day to get to this point!

11. Import Your Source Code
Having wasted a lot of time trying to get Visual Studio to reference files on my Mac I came to the conclusion that this is impossible. Unlike Xamarin Studio, Visual Studio won’t let you import files as links – they have to reside within the project directory, so the simple-but-far-from-ideal solution is to copy the files from your Mac to the host PC and import. Note that you can ‘copy’ directories from within Windows Explorer and ‘paste’ into Visual Studio which I found the easiest way to import a lot of files at once.

12. Compile Your Source
Hopefully if you followed the suggestions in step one your source just compiles at this point. If not you will have to fix any errors, unfortunately I can’t tell you what these might be as I covered everything I came across in step 1!

13. Convert Your Content To XNB
This should be possible just by using the MonoGame tools but I never succeeded. I had to download an open-source XNB compiler tool from here, open in Visual Studio Desktop, then compile and run to convert my files. It works OK, but the tool only appears to allow you to add one file at a time. Thankfully it was fairly easy for me to modify the code to allow all files in a directory to be added and I’ve included my edited source here. The tool successfully converted PNG, JPG and WAV files for me. If you get an error regarding a missing .dll whilst trying to covert audio you probably need to install Windows Media Player as described in step 7. Whilst MP3 files seem to convert OK I haven’t managed to get them playing correctly yet but I will update this post if and when I do.

14. Import Your XNB Files Into Visual Studio
These go in the ‘Content’ directory exactly as you’d have them organised for iOS or Android. Once imported select the files and under ‘properties’ set ‘build action’ to ‘content’ and ‘copy to output directory’ to ‘copy always’.

15. Change The Template Code To Start Your Game
In Visual Studio find the GamePage.xaml file. Click the little disclosure triangle next to it to reveal GamePage.xaml.cs. Edit this file to replace references to the Game1 with references to your Game class.

16. Run Your App
Congratulations, assuming you followed the tips in stage 1 about loading assets your app should now run on device or emulator. It took me almost three days to get to this point!

I hope this guide is of help to someone – any suggestions for improvement just let me know!

Toss The Floppy Frog – Feels Like My Life’s Work


cornflower
Not Since Yves Klein Has A Blue Square Seemed This Exciting

floppy
At Last – Frog Tossing On Windows
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