AFAIK Apple support fallback to compute shader based implementations of both raytracing and mesh shading on older GPUs. It’ll be slower, but for something like amplification shaders the win would be worth it
I actually researched this a bit right when it came out.... I can't find my source now, but Vision Pro has its own SOC with an M2 CPU with a "2.5" GPU (between M2 and M3 families, like M2 with some goodies). Oddly, Vision isn't discussed in the handy Metal Feature Set Table [1].
The GPU Family Apple7 was the first with Mesh Shader support, but as you noted it might be software fallbacks down there.
I did just check with my Vision Pro and I get MTLGPUFamily [2] up to apple8, which does correspond to other M2 devices. I probed a max amplification count of 8.
No it’s a standard M2. You can probe all the values that are exposed to software and it’ll line up. People have done tear downs and the SoC is the same size as a regular M2, which wouldn’t be possible otherwise.
The GPU Family Apple7 was the first with Mesh Shader support, but as you noted it might be software fallbacks down there.
I did just check with my Vision Pro and I get MTLGPUFamily [2] up to apple8, which does correspond to other M2 devices. I probed a max amplification count of 8.
[1] https://developer.apple.com/metal/Metal-Feature-Set-Tables.p...
[2] https://developer.apple.com/documentation/metal/mtlgpufamily