07875: nes [batmanrj]: Level 1-2, wrong scrolling position

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07875	Graphics	Minor	Always	Feb 14, 2021, 16:04	Sep 30, 2022, 07:25

Tester	ArcadeHistory	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS
Status [?]	Acknowledged			Driver	nintendo/nes.cpp
Version	0.228	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07875: nes [batmanrj]: Level 1-2, wrong scrolling position
Description	At the stage 1-2 of "Batman - Return of the Joker (Euro)", something strange appears. Some lines containg sprites are scrolling with the background but they don't have to scroll. Differents lines of sprites are scrolling depending on what machine your are running the game (see screenshots attached).
Steps To Reproduce	Play the game using "mame64.exe nespal batmanrj" or "mame64.exe dendy batmanrj" until the Level 1-2.
Additional Information	Please note the USA version of the game (batmanrju) on a NTSC system works fine ! It seems only the PAL versions have problems with the 1-2 stages.
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	nes [batmanrj]

Attached Files	original_hardware.jpg (375,407 bytes) Feb 14, 2021, 16:04 Uploaded by ArcadeHistory

No.18466 Tafoid Administrator Feb 14, 2021, 19:59	The cartridge "batmanrj" is in the software list as having partial support. The machine itself (nespal) and all Nintendo home based consoles are already flagged with having graphics issues. Both machine and software issues are known and flagged at source level so by the rules of mametesters, this report isn't needed. While detailed reports can be useful even if things are already known, we'd rather see reports on games or carts that are not already flagged as imperfect or not fully supported. However, given the detail, we will acknowledge it and keep it in the MT system for future reference should it be needed. We need to reevaulate how we handle such instances if for nothing else but to keep all the knowledge available and centralized at software level.
No.18468 ArcadeHistory Tester Feb 16, 2021, 10:08	I think it's useful to have a list of "precise" problems so programmers, when triyng to fix, can take a look at the good example.
No.19692 kmg Senior Tester Jan 17, 2022, 01:46	I've pushed a partial fix for this: https://github.com/mamedev/mame/pull/9166 This makes the issue on nespal much better. Instead of multiple scanlines inappropriately scrolling it's down to one—much like many of the NES driver's other off-by-one scanline problems. As for the Dendy bug, it can't be fixed. It's likely how the hardware behaves (provided you have a NES-Dendy cartridge adapter). These Sunsoft carts don't have scanline counters and the IRQ they use to perform the scrolling splits is tied to the CPU clock. That means Dendy should more-or-less work with the US and JP releases of the same game, however.