Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|01852||Graphics||Minor||Always||May 31, 2008, 20:50||Sep 3, 2021, 17:14|
|Tester||Fujix||View Status||Public||Platform||MAME (Self-compiled)|
|Version||0.125u3||Fixed in Version||Build||C2D|
|Fixed in Git Commit||Github Pull Request #|
|Summary||01852: fantzone, fantzone1: Graphical glitch of the background at the beginning of the game.|
The background briefly gets corrupted when I start a game and get ready to play.
This is a long existing "one-frame" issue but clearly a bug and never seen on the real arcade.
|Steps To Reproduce|
|Flags||Verified with Original|
|Affected Sets / Systems||fantzone, fantzone1|
fanta.gif (165,717 bytes) May 31, 2008, 20:53
Dec 8, 2012, 22:29
|looks fixed in 147u2|
Dec 13, 2012, 23:45
|Still happens here, tested with 0.147u3. You really can see if it you SHIFT+P (pause by frame) your way to it.|
Dec 18, 2012, 15:56
What's happening is the MSBs of the scroll registers are being overwritten mid-frame when the round starts by a routine which clears the text RAM (the scroll registers occupy the last few words of the RAM). The correct scroll values are restored during the following VBLANK.
Adding VIDEO_UPDATE_AFTER_VBLANK will hide the glitch.
Sep 3, 2021, 15:27
|It is just this single-frame glitch? Then VIDEO_UPDATE_AFTER_VBLANK (or an other hacky workaround) is not worth it.|
Sep 3, 2021, 17:14
|yeah, as I previously speculated I think maybe the hardware latches these scroll values at some point, but doing that was shot down when I suggested it.|