Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07196 Timing Minor Always 20 days ago 18 days ago
Tester bobRetro View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (32-bit)
Status [?] Confirmed Driver snk6502.cpp
Version 0.205 Fixed in Version Build 32-bit
Summary 07196: nibbler: 2-player Slow Down
Description When playing in 2-player mode, the game slows down periodically. This only happens in 2-player mode. In 1-player mode the speed is constant. It happens for both player 1 and player 2.
Steps To Reproduce Insert 2 credits and choose a 2-player game. Immediately go to the right side of the screen then to the top of the screen to the top-right corner and continue to move the snake counter-clockwise around the small square in the top-right corner. You will notice that as the snake comes out of the corner, its speed is diminished. This is not the only place this occurs, but is just mentioned for comparison purposes.

Compare to inserting 1 credit and choosing a 1-player game. Perform the same actions described above and you will notice there is no slowdown.
Additional Information I've been able to reproduce this on both 32-bit and 64-bit builds, on multiple machines and versions as far back as 0.152. I'm not certain, but I think I had a version at one point where this didn't occur, but can't seem to find it.

Sometimes the slowdown is more pronounced than others. The entire game is slowing down and not just the speed of the snake as can be observed by watching the countdown timer when the slowdown is happening (easier to notice when you haven't eaten a dot for a while and the timer is counting down rapidly).
Flags
Regression Version 0.152
Affected Sets / Systems nibbler
Attached Files
 
Relationships
There are no relationship linked to this issue.
Notes
3
User avatar
No.15995
Tafoid
Administrator
20 days ago
edited on: 18 days ago
The issue could be the maincpu speed which was adjusted to match animations and audio correctly using a common divisor to the maincpu xtal crystal (for mame 0.152). I won't consider it a full bug until someone can confirm with an actual PCB either the speed of the maincpu to confirm MAME's setting, or documented proof that it does or does not happen in a real PCB. I've labeled it as possible.
User avatar
No.15996
bobRetro
Tester
20 days ago
I should have mentioned that I have played Nibbler on an original PCB (at the Galloping Ghost Arcade outside of Chicago) and am certain it does not occur. I played in both single and two-player mode and there was no difference in gameplay.
User avatar
No.16009
Tafoid
Administrator
18 days ago
Hopefully we can get some proper speed measurements from someone who can read them and put this one to bed sooner or later.