WIP: Metal backend

[SamoZ256]

This PR implements a Metal backend for macOS. It should bring better performance compared to Vulkan, as well as fix some issues that wouldn't be possible with Vulkan due to MoltenVK limitations. I haven't tested many games, but those that I tried worked pretty well.

TODO:

• sRGB
• fix low resolution
• proper present
• fix black textures in sm3dw
• buffer copies in a vertex shader
• pipeline cache with binary archives
• geometry shaders
• GamePad screen in a separate window
• fix texture readback
• output shader
• ImGui
• Intel Macs support
• proper surface copy
• extend the shader hash
• triangle fans
• 1D shadow sampler emulation
• instancing with mesh shaders
• occlusion queries
• async shader compilation
• load pipeline binaries at startup
• async pipeline compilation
• accurate occlusion queries
• fix CI
• synchronize resource access manually
• binary archives

Screenshots:

New Super Mario Bros U

Captain Toad Treasure Tracker

Super Mario 3D World

Mario Kart 8

The Legend of Zelda: Breath of the Wild

Super Mario Maker

[Exzap]

Very impressive work so far! I did not expect anyone to take on adding a whole new renderer. From past experience when working on the OpenGL and Vulkan renderer I learned that the hardest problems come up at the end in regards to performance optimizations, weird API limitations which require workarounds or specifically for Metal: lack of geometry shaders. If the Metal backend gets past those problems into a fully functional state that is on par with the Vulkan renderer then we can talk about getting this merged and discuss any long term support plans. A proper full code review would also be necessary of course.

Looking forward to seeing this progress!

[Spritzerland]

this is some good work, thank you for it Samo

[SamoZ256]

Metal 3 based? Metal 2 don't have the requirements for emulating geometry shaders.

The concern would be that adding a third renderer would eventually lead to code rot, with fixes hitting the 2 windows/linux compatible api's and not the macos one.

I don't think I use any Metal 3 functionality. Regarding geometry shaders, they could be emulated with compute shaders, though I would much rather use mesh shaders and give up on Metal 2 compatibility.

[SamoZ256]

log.txt

thanks for the hard work. Unfortunately, Mario Kart doesn't start the second time

Hi! This could probably (temporarily) be solved by clearing the shader cache. Also, make sure you are on the latest testing release.

[SamoZ256]

For anyone wanting to report game status/issues, please use this guide: https://github.com/SamoZ256/cemu-metal-game-compatibility.