Add support for Metal in macOS images

[Aaron1011]

As described in #1779, Metal is not currently available on Github Actions macOS images.

Having Metal available (even if it's some kind of slow software implementation) would be a huge help for the Ruffle project (https://github.com/ruffle-rs/ruffle). As part of our Github Actions workflow, we render images on Linux and Windows runners, and compare them to expected images checked into the repository. However, we cannot run these image-based tests on macOS runners, resulting in a gap in our test coverage.

This would benefit any project that needs to perform GPU-based rendering on computation on macOS.

[miketimofeev]

@Aaron1011 There is no ETA for now but it's on our radar

[wcandillon]

@miketimofeev thank you for your reply. We are also deeply interested into this feature for https://github.com/shopify/react-native-skia. Are they any workarounds we could use in the meantime? Self-hosted runners?

[Skycoder42]

This is also relevant for flutter projects, as recent flutter based applications cannot run without vulkan support.

See flutter/flutter#118469

[lslzl3000]

@miketimofeev besides metal on Macos, does DX11/12 supported in Windows or Vulkan in Ubuntu runners?
As WebGPU is coming soon, I think Github runners should support those graphic drivers, It is hard to use Github actions to test projects rely on WebGPU rightnow, which basically use dx/vulkan/metal on each os

[Aaron1011]

@lslzl3000 On a Windows runner, you can use the WARP software rasterizer (https://learn.microsoft.com/en-us/windows/win32/direct3darticles/directx-warp). On Ubuntu, you can install mesa-vulkan-drivers to get the 'lavapipe' Vulkan software rasterizer.

[lslzl3000]

Thanks, is there a simple workflow demo to learn how to config a software rasterizer?