> Geometry shaders are an older, cruder method to generate geometry. Like tessellation, the M1 lacks geometry shader hardware so we emulate with compute.
Is this potentially a part of why Apple doesn't want to support Vulkan themselves? Because they don't want to implement common Vulkan features in hardware, which leads to less than ideal performance?
(I realize performance is still relatively fast in practice, which is awesome!)
Yes, it's a big reason.
I tried to port the yuzu switch emulator to macos a few years ago, and you end up having to write compute shaders that emulate the geometry shaders to make that work.
Even fairly modern games like Mario Odyssey use geometry shaders.
Needless to say, I was not enough of a wizard to make this happen!
If you’re using geometry shaders, you’re almost always going to get better performance with compute shaders and indirect draws or mesh shaders.
A lot of hardware vendors will handle them in software which tanks performance. Metal decided to do away with them rather than carry the baggage of something that all vendors agree is bad.
It takes up valuable die space for very little benefit.