Make display, surface and context creation safe

[notgull]

• Tested on all platforms changed
• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• Created or updated an example program if it would help users understand this functionality

Uses rust-windowing/raw-window-handle#116 to make display, surface and context creation safe.

I want to get a good idea of what this kind of API would look like. I want to test out the new safe window handles before they're released onto the world.

[notgull]

Hmm, looks like this model kind of breaks glutin-winit. Right now, an &EventLoopWindowTarget is used to provide the display handle for creating the Display. However, since the reference to the ELWT will disappear for event handling, this can't be used as a persistent handle for the display.

A solution would be to use an &Window or an Rc<Window> instead, but the Display initialization generally happens before the Window is created. Maybe we could add a type to winit similar to EventLoopWindowTarget that doesn't disappear during event handling?

[notgull]

Rebased around rust-windowing/raw-window-handle#125, aka raw-window-handle v0.6

[notgull]

Rebased on the newest master

[notgull]

The main caveat is that the OwnedDisplayHandle change wasn't accepted into winit, so the DisplayBuilder function is now unsafe.

[emilk]

Any chance for a glutin release with raw-window-handle 0.6? 🙏

[kchibisov]

I'm not sure how soon, since I don't have time to review the glutin stuff now. it's not like you can't use it at all if you have only raw-window-handle 0.6, since you can convert 0.6 to 0.5 and e.g. winit provides all 3 of them at the same time, so you can pick 0.5 for glutin and 0.6 for other winit stuff.

But it'll be review/merge within a month...

[emilk]

Ah, winit supports all three of them at the same time, I didn't realize that (thought I had to pick one). Then I can probably figure something out. Thanks for the pointer!

EDIT: actually, juggling several rwh-versions is a nightmare.
EDIT2: ok, I think I have figured it out :)

[MarijnS95]

@emilk what makes you juggle multiple versions, instead of locking winit to 0.5 and using that in glutin?

[emilk]

eframe has to support both glutin (locked at 0.5) and wgpu (locked at 0.6).

[MarijnS95]

Right, that is indeed a painful situation.

[notgull]

Don't really feel like rebasing this and it's unlikely to be reviewed, so I'll abandon this in favor of #1670

[kchibisov]

It'll be though, but there's a big chance that I write parts myself. Like I'd like to use safe handles myself, it's just winit is lacking and I said it to you before. Forcing everyone to just start Arc everything sounds a bit wasteful.