Mesh/Task Shader Queries Land For RADV With RDNA2, RDNA3 Support On The Way

[skeevy420]

It was NVidia's idea, and MS ran with it. That happens all the time - most of the stuff in DirectX is coming from the 3 hardware vendors, originally, and MS is figuring out what they like and want to promote.

Exactly. And it's just as likely to happen with AMD as it is with NVIDIA. Let's not forget that DX12 and Vulkan are forks of AMD Mantle. It has to piss off NVIDIA that practically everything modern is based on AMD's work.

This situation is kind of like that GNOME/Mutter/Wayland/EEE point of view I've been having lately where depending on one's view it's some nefarious hostile takeover of the open source world or it's just proposing and implementing new advancements to open standards with a dash of trying different things to see what works. AMD makes an API, NVIDIA extends it, AMD picks that extension up...isn't that how all this is supposed to work?

[Alpha_Lyrae]

Weren’t mesh shaders pushed hard by Microsoft for DX12 Ultimate?

There were two competing fast-path geometry shader types: mesh shaders from Nvidia and primitive shaders from AMD. They're functionally similar, but because MS chose mesh shaders, RDNA1 was immediately put on the backfoot, as it could not support mesh shaders after silicon had already taped-out; trying to make RDNA1 support mesh shaders results in undesirable effects, as the hardware implementation is not there. This also happened to Nvidia when MS chose AMD's async compute, so it's give and take.

RDNA1 supports only primitive shaders, and the largest use case will probably be in the PS5 via 1st party exclusives, which is mostly RDNA1 with RT (RA units accelerating traversal plus ray/triangle intersects in conjunction with geometry engines and TMUs doing rayboxing).

[Eirikr1848]

There were two competing fast-path geometry shader types: mesh shaders from Nvidia and primitive shaders from AMD. They're functionally similar, but because MS chose mesh shaders, RDNA1 was immediately put on the backfoot, as it could not support mesh shaders after silicon had already taped-out; trying to make RDNA1 support mesh shaders results in undesirable effects, as the hardware implementation is not there. This also happened to Nvidia when MS chose AMD's async compute, so it's give and take.

RDNA1 supports only primitive shaders, and the largest use case will probably be in the PS5 via 1st party exclusives, which is mostly RDNA1 with RT (RA units accelerating traversal plus ray/triangle intersects in conjunction with geometry engines and TMUs doing rayboxing).

Got it, thank you. My understanding based on Reddit was that Vega, RDNA1 primitive shaders are seen by DX12 as mesh shaders, and that functionally they can be the same under Linux as well.

I'm not entirely sure what it's supposed to mean: that the primitives are essentially programmable as mesh shaders if someone builds them out to be?