WIP: In-shader vertex loading support

[etang-cw]

MoltenVK counterpart to KhronosGroup/SPIRV-Cross#2204 (Note: Won't pass CI until SPIRV-cross changes are merged)

Now fully supports all parts of Vulkan vertex loading

• No more minVertexInputBindingStrideAlignment
• No more restrictions on alignment of vertex buffer offsets (which there doesn't seem to be a portability flag for, but definitely didn't work before)
• Support (almost) all the vertex formats
• Support larger-than-stride elements
• Fully working divisor 0 support

[goldenx86]

Any chance to push this forward?

[cdavis5e]

Any chance to push this forward?

It's held up on KhronosGroup/SPIRV-Cross#2204, and from what I've read lately, H-K probably thinks that's too invasive (i.e. it doesn't belong in SPIRV-Cross). You'll have to take it up with CW, though.

[FernandoS27]

For us, it's a must have.