[kfprt]

PS4 has a PS specific graphics API.

[mywittyname]

This is probably beneficial, as it provides a clean interface for emulation writers to target.

Part of the intent on getting developers to use these APIs as much as possible is to make forward-porting / "legitimate" emulation of games easier.

[kfprt]

Ideally you could map API calls to Vulkan but it would still be a huge amount of work.

[anthk]

Like Wine with Win32 and DirectX->OpenGL. 5-10% performance loss on translating is nothing, as the PS4 was low-end hardware for its day.