Prefer OpenGL by default on Windows systems

[smoogipoo]

Note that for users that haven't touched the automatic selection, this will now default them to OpenGL. I'm not sure if that's an issue or how to resolve it.

I've been planning to do this for a while now... The D3D buffer management is inefficient and VeldridRenderer.CreateStagingBuffer<>() is a hack to work around it. This breaks on some systems and sometimes creates problems like this (likely). I personally use OpenGL because I notice microstutters and/or inconsistent frame timings on D3D @ 144hz.

I'll probably attempt this again soon, when I get around to implementing SDL_gpu.

[peppy]

I dunno about this..

I'm less worried about performance and more about (lesser) compatibility surrounding things like exclusive fullscreen support.

[smoogipoo]

We already have issues with exclusive fullscreen support on D3D, see:

• osu! no longer running in Exclusive Fullscreen when using newer AMD drivers osu#29647
• Lazer doesn't run in fullscreen exclusive osu#30523
• On Windows, exclusive fullscreen only activates on OpenGL osu#30349

I do not see a future where we resolve any of these issues using Veldrid-D3D, and SDL_gpu is not a priority task right now. As for OpenGL, I would expect most exclusive fullscreen compatibility issues to be isolated to Optimus devices, as osu!stable has used it for the last decade mostly without issue otherwise.

I consider all of the following under the "performance" umbrella:

• "Exclusive" fullscreen support.
• Microstutters
• Frame pacing.

As well, I consider potential breakage as a result of o!f doing shoddy things to be an even bigger issue. It's hard to say whether issues like ppy/osu#31619 are of our own making in the end, regardless of whether the driver should have proper validation to not cause BSODs.

[Susko3]

Those three issues don't seem like big problems for fullscreen on D3D.

• osu! no longer running in Exclusive Fullscreen when using newer AMD drivers osu#29647 (reply in thread)

  all the captures I've made showing practically no difference between Legacy Flip and Independent Flip, then I will just have to get used to it.

  Additionally, the original issue is about OpenGL

• Lazer doesn't run in fullscreen exclusive osu#30523
  This lists OpenGL as things the user tried without success.

• On Windows, exclusive fullscreen only activates on OpenGL osu#30349 (reply in thread)
  This one is legit: one commenter reports that running osu! on a non-primary monitor breaks FSO. OP has two monitors, so it may be related.

The last two discussions also use the volume overlay to show that osu! is not running exclusive, but the visibility of the volume overlay is irrelevant in D3D/FSO. If FSO is working fine, the volume overlay will show, but it will cause a microstutter when it appears and subsequently disappears. That microstutter may be used as a diagnostic to tell if FSO is working.