08079: timelimt: [possible] Corruption of the policeman sprite

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08079	Graphics	Minor	Always	Sep 6, 2021, 10:03	Sep 12, 2021, 00:46

Tester	Wulfaz	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10 (64-bit)
Status [?]	Acknowledged			Driver	thepit/timelimt.cpp
Version	0.235	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	08079: timelimt: [possible] Corruption of the policeman sprite
Description	There is some corruption with the policeman sprite where the lower part and upper part of the sprite interchange. I am not sure if this is an emulation bug or a bug of the original game since this game is extremely rare. Whoever owns a PCB of this game should confirm whether this issue also occurs on the original.
Steps To Reproduce	1. Go to the top of an automatic staircase 2. Duck. 3. While keeping the Duck button pressed, go towards the staircase.
Additional Information
Github Commit

Flags	Possible
Regression Version
Affected Sets / Systems	timelimt

Attached Files	Weird_Policeman.png (305,308 bytes) Sep 6, 2021, 10:03 Uploaded by Wulfaz The sprite bug

No.19232 jkburks Tester Sep 6, 2021, 11:52	I can reproduce this graphic glitch in MAME while holding down and backwards, but technically this is not possible on hardware because Time Limit used a 4-way joystick. You would never be able to press 2 direction switches at once. But the glitch also happens when you shoot while ducking (joystick down + fire button). It briefly flashes the crouched pants graphic above the player. About a month ago a wrote down what little information I have about this game and posted it on reddit: https://www.reddit.com/r/MAME/comments/ou2vkd/time_limit_chuo_co_ltd_1983/ There is only 1 good hardware video of this game, and it was made with the undumped revised release of the game rather than the original ROM version that is in MAME. This original version obviously has gameplay issues. They added the direction arrow to locate the timebomb more easily, removed the curtain edges from the screen.... anything else is speculation. We really need a dump of the revised version to test. In MAME when you shoot while crouched the bullet travels in the last direction you moved (L or R). However, when you shoot while on the ladder the bullet always travels to the left. One of the strategies used when playing the revised edition is to determine the bullet direction you want before mounting the ladder. It is suggested to point the gun in the direction of the nearest doorway for when you exit the ladder. This technique does not work in MAME. It does work on the revised version of the game. It is unknown if this is an emulation issue or just bad programming that was fixed in the revised release.
No.19236 Wulfaz Tester Sep 7, 2021, 08:16	Very interesting. So, since holding two directions was not intended on an original arcade, this is most likely an overlooked bug on the original machine. As an example, in plenty of NES games there is screen corruption at the edges and these were not fixed because the CRT TV's would cover the edges anyway. However, I think evidence will still be required to make sure this is indeed an original bug and not an emulation bug. I look forward for someone to dump the revised version. It seems nicer to play. Finding the time bomb can be a pain in the MAME version.
No.19245 Tafoid Administrator Sep 11, 2021, 22:51	Acknowledging, setting possible (pending actual PCB review). No manuals to check for this one that I've found that would for sure tell us if there was a 8-way with restrictor plate allowing only 4-way movement or not. My gut tells me this is duplicated on actual hardware as well.
No.19246 jkburks Tester Sep 12, 2021, 00:46	Time Limit was a kit game. It was only sold as a PCB with instruction cards (and presumably a manual or DIP sheet & wiring diagram). There is no Time Limit control panel or cabinet, but Game Machine magazine specifically says that the game uses a 4-way lever. I translated these documents for the reddit post I linked above. The thing that seems odd to me is the crouch fire glitch. If you hold down to crouch, when you press the fire button the police man looks like he is trying to stand up, and then the crouched pants graphic appears in the air above him for a brief moment. You will notice that the bullet comes out at the same height as when fired while standing. Without a hardware reference it is difficult to say whether or not this is a btanb, bad programming, or emulation related. Unfortunately the hardware video from the revised game does not show the police man firing his gun from a crouched position. The only time the player ever crouches is by accident when he misses a ladder alignment, or holds down too long when descending a ladder. It appears that the revised game has changed the enemy behavior so that they do not pursue and start shooting immediately upon exiting the door, so there is little need to be ducking bullets...