Vulkan's Portability Extension Coming Along, MoltenVK Now Boasts EXTX_portability_subset

It has yet to appear in a Vulkan specification update, but the MoltenVK implementation that supports the Vulkan API on iOS/macOS by mapping it to Apple's Metal drivers now supports the VK_EXTX_portability_subset functionality.

VK_EXTX_portability_subset is the experimental feature designed as part of the Vulkan Portability initiative. This allows for Vulkan implementations like MoltenVK to mark features as unsupported that otherwise are required by the Vulkan specification. The VK_EXTX_portability_subset extension can also be used to define properties/limits on what it can allow.

Basically it allows for a slightly slimmer Vulkan implementation than what would be allowed in a strict sense but is good enough for most games/applications. The effort around Vulkan Portability has been happening via a separate Git repository.

With today's MoltenVK update there is support now for the portability subset extension as well as other iOS/macOS support improvements.