Share context

[Hromon]

Hi o/
How do I share multiple contexts in one window?

[Perksey]

You can't have multiple contexts in one window. You can share one window's context with another window's context (i.e. so you can have one main window and one invisible background window to allow for multithreading) but multiple contexts in a single window isn't something we can support on every platform, thus it has been excluded from windowing.

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[Hromon]

Ok, how i can share context between windows?

[Perksey]

An example could look like:

// create the first window
var window1 = Window.Create(WindowOptions.Default);

// use initialize to open the window - this is needed so we can share its context
window1.Initialize();

// create window 2 which shares the window's context
var window2opts = WindowOptions.Default;
window2opts.ShareContext = window1.GLContext;
var window2 = Window.Create(window2opts);

// open window 2
window2.Initialize();

You will then need to implement your own game loop so you can run Window 2's render thread on another thread, but keep running the events on the main thread (which is a requirement, you'll break some operating systems otherwise)

For your reference, here is the standard single threaded game loop.

• Initialize creates the window.
• DoEvents must be ran on the main thread. That is, the thread that the program started on. This powers every event but Update and Render.
• DoRender and DoUpdate are the functions you want to run on another thread for Window 2.
• Reset closes the window.
• IsClosing is true when the close button is pressed or you use the Close method on the window.

[Hromon]

Thanks.