Add Metal as backend option with Vulkan Disabled

[Hibyehello]

Current implementation requires vulkan to be enabled to have the metal backend as an option.

[dvessel]

Thanks, it’s working on my end.

[Pokechu22]

Untested, but looks good to me.

[mbc07]

Also, does Vulkan needs to take precedence on macOS now that we have a native Metal backend?

[Pokechu22]

I'm pretty sure that OpenGL needs to not be the default on macOS still, but I don't know whether it'd be better to have Vulkan or Metal be the default.

[mbc07]

I was talking about making Metal the default on macOS. While MoltenVK is great, it just seems logical to me to default to the native Metal API now that we have a backend for it...

[PEmu2]

I believe the decision in the original Metal PR was to leave Vulkan as default until the Metal backend matures: #10754 (comment)

For what it's worth there's still an unmerged PR of Metal backend fixes in #11028.

[pizuz]

I'm pretty sure that OpenGL needs to not be the default on macOS still

+1

Dolphin requires macOS Mojave or later, which in turn requires a Metal-compatible video adapter.

Yes, there are ways to make an unsupported Mac run later macOS versions (I‘m currently running Monterey via OCLP on my Late 2013 iMac and it works like a charm), but at least the officially supported Macs should run the Metal and Vulkan backends out of the box. Users running patched macOS versions should know what they are doing and switch to OpenGL if their video card doesn't support Metal.

but I don't know whether it'd be better to have Vulkan or Metal be the default.

I‘d leave it at Vulkan for the time being, since the backend has been around for some time to mature. Also #10754 (comment).

[Hibyehello]

I almost considered making metal take precedence, but then I remembered that it was decided to keep vulkan as default for now.