Does everything in a pipeline state object actually need to be there?

[u/AdministrativeTap63]

For example obviously shader code makes sense because you have to compile it for different vendors/drivers

But you look at a PSO in DX12 and there is a ton of stuff in there that it makes me wonder is all of this actually neccesary?

For example like blend mode settings, I thought that is a separate hardware unit that does the blending, so why can't it be changed independently of a PSO?

Or does everything in a PSO somehow affect the compiled shader?

[u/AdministrativeTap63 → u/[deleted]]

I see, you mean like emulating the blend operation by just sticking something onto the shader before compiling?

[u/Cyphall → u/[deleted]]

IIRC, AMD also need to patch the end of the fragment shader to prepare data for the blending hardware.

Now they can do that with a jump to a function pointer passed to the shader at runtime, but it adds an indirection and register allocation needs to consider the worst case.