Reasoning for COPY_BYTES_PER_ROW_ALIGNMENT

[Upliner]

What is the reason for such big hardcoded row alignment? Vulkan doesn't have such limitation. Which backends require such a big alignment? In this case can we somehow make row alignment a per-device limitation? Or such alignment is mentioned somewhere in WebGPU standard? I can't find any mention of it.

[grovesNL]

This is a D3D12 limitation (see gpuweb/gpuweb#69 for more context). There's a newer capability UnrestrictedBufferTextureCopyPitchSupported that removes the alignment restrictions for hardware that don't require it.