FBW-based Screen Clear Issue

[tadanokojin]

Games Tested:

• Evil Dead: Fist Full of Boomstick (dump)
• Tom And Jerry: War of The Whiskers (dump)
• Narc (dump)
• State of Emergency 2 (dump)
• Singstar (dump)

Games Not Tested (but potentially have the same issue):

• State of Emergency
• Brave: The Search for Spirit Dancer
• The Powerpuff Girls: Relish Rampage

Example of the Issue:

Cause:
Caused by a screen clear where the game attempts to clear a 32-bit GS texture by setting the frame buffer width to 1 and then drawing a 64x2048 quad with flat shading in order to clear the buffer to a specific color (often a pink color).

Basically because of how GS memory works, it is possible on the GS to write to the framebuffer with FBW of 1 and then starting writing again with a larger FBW value. However since the cache does not emulate this behavior, what results is a larger line on the left hand of the screen.

Here is an example of the incoming vertices:

VERTEX COORDS (XYZ)
	v0: 0.0000, 0.0000, 0
	v1: 64.0000, 2048.0000, 0

VERTEX COLOR (RGBA)
	v0: 000, 000, 000, 000
	v1: 239, 061, 239, 061

Here is an example FRAME register setting for the clear:

FRAME
	FBP (*32):0x2e00
	FBW:1
	PSM:0x0
	FBMSK:0x0

Here is an example of the FRAME register setting for a latter draw:

FRAME
	FBP (*32):0x2e00
	FBW:10
	PSM:0xa
	FBMSK:0x0

Previously, Superman Returns was the only game known to have this issue.

[iMineLink]

I'm positive with the FBW conversion in the texture cache to tackle this issue, given also the fact that the clear is a solid rectangle draw, thus the conversion might be extremely optimized in this case.

[seta-san]

it's possible Zone of Enders: second runner suffers from this too

[tadanokojin]

provide a gs dump so I can confirm

[seta-san]

provide a gs dump so I can confirm

gsdx_20201210133535.gs.zip

[coornio]

Here's a more modern dump from 1.7.2427. The shadows are now in the correct place, though the issue is still present. Here's a new picture too:

gs_20220309233833.gs.zip