Vulkan: Avoid using Vulkan by default

[unknownbrackets]

Bugs on Adreno, some issues on Intel and AMD. Let's instead prefer Direct3D 11 or GLES for now.

-[Unknown]

[zminhquanz]

And you can investigate why Vulkan isn't use exactly Multithread ( checked on ProcessHacker) . I think that's reason on Mobile using OpenGL perform faster than Vulkan after implement GL Threading

[unknownbrackets]

It depends on the driver and game. Usually, desktop GL drivers spend a lot more time trying to guess what PPSSPP is trying to do to translate it to actually optimal GPU operations. With Vulkan, this doesn't need to happen. So there's less for it to waste time doing.

Vulkan still often performs better on my Pixel, but no idea if that's because the driver is skipping things it shouldn't be skipping...

-[Unknown]

[hrydgard]

Yeah whether Vulkan will perform better or not depends highly on the drivers. On many of my devices Vulkan generally wins, on some decisively, but definitely not all of them - yet.

OpenGL, or D3D on Windows, is still unfortunately a safer default.