rsx: Treat blend colour as BGRA

[CookiePLMonster]

HARDWARE TESTS PENDING: @kd-11 mentioned he'll test it relatively soon.

This PR corrects decoding of SET_BLEND_COLOR RSX commands. Previously colour would be interpreted as RGBA, whereas it appears like it should have been treated as BGRA.

It's assumed this feature is not used by many games, and even the ones using it do not use it consistently.

Afftected games:

• Gran Turismo HD Concept - fixes blue tail lights in some vehicles. Oddly enough, most cars looked just fine (and they still do), which hints blend color is not used to achieve red material color often.
• Gran Turismo 5 - possibly affected. Untested, but screenshots from current RPCS3 builds show the same bug as in GTHD.

The most prominent example in GTHD is Infiniti G35, clearly showing what was wrong. Notice that the center brake light is correctly coloured in both cases!

Best reference from real PS3 I could find:
https://youtu.be/FAMPvAZ3VPc?t=1418

When testing for regressions, look for obvious miscolorations - red things becoming blue and blue things becoming red.

[mavethee]

The same issue was in GTA IV with cellphone.
But the thing that was blue supposed to be green. I need test that PR tomorrow ;)

[CookiePLMonster]

That sadly sounds unrelated - or maybe the fix is not full. When you test, provide screenshots!

[elad335]

No need for hw test, it matches cellGcm interface.

[elad335]

Though atleast reorder the methods, they are supposed to be ordered in incrementing bits order.

[CookiePLMonster]

No need for hw test, it matches cellGcm interface.

What about a 16-bit variation of this command? Currently the first chunk of the command carries RG, while the other carries BA. Is this valid or should also be switched, akin to a 8-bit version?

Though atleast reorder the methods, they are supposed to be ordered in incrementing bits order.

Will do!

[elad335]

16 bits variation of them is fine.

[CookiePLMonster]

Force pushed the requested change.