OpenGL has never ever been used on PS4, it has always been a custom API. Unless you're talking homebrew stuff.

Vulkan was modeled after Mantle, AMD's own API that was basically what was available on consoles but less specific (ie. supporting more than a few custom GPUs). Direct3D 12 was modeled after consoles and Mantle, just like Vulkan. Same for Metal, that was made available in 2014, same year D3D12 was publicly announced.

https://en.wikipedia.org/wiki/Mantle_(API) https://twitter.com/repi/status/446718535616585730