As posted recently, I started to port a few of my games to Windwos 8 using MonoGame. And I’m slowy getting there to submit my first game to the Window 8 Store. However, I had quite some troubles first regarding the adjustment of the viewport when changing the screens resolution. And after reading through several forums, it looks like others have been struggling as well. A few individuals offered alternative forks of MonoGame that have resolved this kind of problem built-in. Others suggested to create a copy and do some manual changes in OpenTK, which is an open source C# wrapper for OpenGL, OpenAL and OpenCL. However, I decided to not use any manually modified version of any of these libraries, because otherwise it will be hard upgrade that dependency at some point.
Anyways, I managed to solve that problem at some point. The following snippet shows the most important bits.
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protected override void Initialize()
{
graphics.IsFullScreen = true;
graphics.PreferredBackBufferHeight = 480;
graphics.PreferredBackBufferWidth = 800;
// …
graphics.ApplyChanges();
ApplicationViewChanged += Game_ApplicationViewChanged;
this.Window.ClientSizeChanged += Window_ClientSizeChanged;
handleScreenViewState();
base.Initialize();
}
void Window_ClientSizeChanged(object sender, EventArgs e)
{
this.GraphicsDevice.Viewport = new Viewport(0, 0, 800, 480);
graphics.PreferredBackBufferHeight = 480;
graphics.PreferredBackBufferWidth = 800;
graphics.ApplyChanges();
}
void Game_ApplicationViewChanged(object sender, ViewStateChangedEventArgs e)
{
handleScreenViewState();
}
The most important part is the ClientSizeChanged callback of the Window class. In particular for Windows 8 Desktop games, also the ApplicationViewChanged callback of the Game class plays an important role here, because this enabled to react on chages of the ViewState, such as when the app entered Snapped Mode. By explicitly setting the back buffer and applying the changes once again in the ClientSizeChanged helps to end up with the same behavior you might be familiar with in XNA. And the screen scales automatically when the viewport or screens aspect ratio changed. For whatever reason, MonoGame performs an unexpected change of the back buffer and the viewport, thus causing the video output to be incorrect. Consquently, manually resetting the preferred back buffer and viewport sizes resolves this problem.