GraphicsAdapter.Adapters on openGL won`t return secondary monitor

Question

I have been searching for this everywhere and never found the answer.

I am developing a feature to allow the user to select which monitor to run the game.

I have two monitors, primary and secondary. I tried to use "GraphicsAdapter.Adapters" but it always retrieves only 1 monitor (the one I am running the Visual Studio which is the default one).

Is this a bug? How can I retrieve all the monitors available?

Thanks

MONOGAME 3.6 OPENGL (cross platform) Visual Studio 2015 Windows 10 Pro 64bits

Answer 1

If we look at the code for the 3.6 release:

There are three files containing GraphicsAdapter source code. It looks like GraphicsAdapter.Legacy.cs is used if you are using the Windows/OpenGL build of MonoGame.

In this version of the code, the Adapters property performs lazy-initialization of the underlying _adapters array. It has preprocessor blocks to build the array differently based on which platform is being built for. Since you're using Windows, that translates to a call to this line:

_adapters = new ReadOnlyCollection<GraphicsAdapter>(new[] { new GraphicsAdapter() });

The property then simply returns _adapters.

So yes, for OpenGL builds on Windows, GraphicsAdapter.Adapters will only ever return a single item. MonoGame does not appear to implement the functionality necessary to expose multiple-monitor support for OpenGL on Windows, at least not in the fashion you're looking for.