D3D9 Fixed Function: To-Do

[K0bin]

Optimize FF configurations beforehand on the CPU:

• Analyze FF VS configurations for texture stages that are configured identically
• Analyze FF FS configuration for false-positive hazards (see #5285)

After we get to use more spec constants:

• Optimize all 8 texture stages of FF FS shaders using spec constants (#5285)
• Optimize argument 0 of FF FS shaders using spec constants
• Optimize FF VS using spec constants

After the new shader compiler has landed (because the old shader compiler shares code with the FF shader generator):

• Remove old FF shader generator

[doitsujin]

Analyze FF VS configurations for texture stages that are configured identically

I'd honestly rather not and just keep things simple. This is the kind of thing that's just going to create hundreds of additional edge cases that will result in subtle breakage for no real reason at all.

If we do throw spec constants at FFVS then we need to make sure that UE2 doesn't suffer from PSO explosion.