01152: saturn: GFX glitch appears on the left bottom corner after you press the P1 start button.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
01152	Graphics	Minor	Always	Feb 12, 2008, 07:18	Jun 19, 2015, 22:35

Tester	etabeta	View Status	Public	Platform
Assigned To		Resolution	Bugs That Aren't Bugs	OS
Status [?]	Resolved			Driver	jaleco/blueprnt.cpp
Version	0.104u3	Fixed in Version		Build
		Fixed in Git Commit		Github Pull Request #

Summary	01152: saturn: GFX glitch appears on the left bottom corner after you press the P1 start button.
Description	GFX glitch appears on the left bottom corner after you press the P1 start button. Also, I noticed a couple of stray red pixels that are present...
Steps To Reproduce
Additional Information
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	saturn

Attached Files	saturn0104u3gre1.png (1,580 bytes) Feb 14, 2008, 18:07
Attached Files	saturn0104u3gre2.png (2,393 bytes) Feb 14, 2008, 18:07

No.01216 nicolasa Developer Jun 7, 2008, 14:38	The glitch happens because the game changes the gfx bank as soon as you press start. The red pixels are in the char data. Could be a bad ROM or just sloppyness by the game designers. This is a low quality game so the problems should be verified on the pcb. There's apparently nothing that can be done until that happens.
No.11776 system11 Senior Tester Jun 19, 2015, 22:33 edited on: Jun 19, 2015, 23:02	Confirming bug - MAME is playing exactly like the original Jaleco board does - red pixels are normal, corruption over the copyright date is normal. As an interesting side note the bootleg/licensed (not sure...) version board still has the red pixels but the corruption doesn't happen, instead it seems to change screen brightness: 1) put coin in (screen is bright at this point) 2) press start 3) screen goes to half brightness, no glitch 4) screen is replaced with gameplay intro, still dimmer 5) Game only returns to title screen brightness after the score entry. I have verified all the ROMs on the bootleg board and they're identical to the Jaleco one so this is an actual hardware difference of some kind despite the boards looking identical in nearly every way. Possible hack to originals to get rid of dimming feature introduced the corruption? I think theres a frame where the screen is blanked between bright and dim. Original seems to run at the same brightness as bootleg dim mode, all the time.

No.01216

nicolasa

Developer

Jun 7, 2008, 14:38

The glitch happens because the game changes the gfx bank as soon as you press start.

The red pixels are in the char data. Could be a bad ROM or just sloppyness by the game designers.

This is a low quality game so the problems should be verified on the pcb. There's apparently nothing that can be done until that happens.

No.11776

system11

Senior Tester

Jun 19, 2015, 22:33

edited on: Jun 19, 2015, 23:02

Confirming bug - MAME is playing exactly like the original Jaleco board does - red pixels are normal, corruption over the copyright date is normal.

As an interesting side note the bootleg/licensed (not sure...) version board still has the red pixels but the corruption doesn't happen, instead it seems to change screen brightness:

1) put coin in (screen is bright at this point)
2) press start
3) screen goes to half brightness, no glitch
4) screen is replaced with gameplay intro, still dimmer
5) Game only returns to title screen brightness after the score entry.

I have verified all the ROMs on the bootleg board and they're identical to the Jaleco one so this is an actual hardware difference of some kind despite the boards looking identical in nearly every way. Possible hack to originals to get rid of dimming feature introduced the corruption? I think theres a frame where the screen is blanked between bright and dim. Original seems to run at the same brightness as bootleg dim mode, all the time.