You really think Sony is using Nvidia Cg on AMD graphics? And Microsoft HLSL on Unix?
Nvidia Cg parts of PSGL were scrapped when it was adopted for PSSL. Duh no more NV GPU. What was left was made into PSSL with OGL 4.4 support(GLSL), and a heavy emphasis on HLSL/DX11.2 compliance.
PSSL is based on OpenGL ES/GLSL, and modeled after HLSL, With DX11.2 extensions.
PS4 uses a DX wrapper (GMNX)
By your logic PSSL was made with HLSL(On Unix) then modified for OGL 4.4.......isn't that a bit backwards to write a completely new driver based on Direct X for Unix?
Yes PSSL is very similar to HLSL. it was modeled after it using GLSL as a base. It is a hybrid.
Or do you think making new drivers based on GLSL was easier than adopting the AMD OpenGL 4(Linux) drivers and working from there.
That would have been 10x the work.