08778: dcjp [Langrisser Millennium]: priority conflict between borders of menu window and leftest or rightest character in the line

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08778	Graphics	Minor	Always	Oct 8, 2023, 03:26	Feb 10, 2024, 04:00

Tester	VasiliyFamiliya	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10/11 (64-bit)
Status [?]	Acknowledged			Driver	sega/dccons.cpp
Version	0.259	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	08778: dcjp [Langrisser Millennium]: priority conflict between borders of menu window and leftest or rightest character in the line
Description	Surprisingly, MAME Dreamcast driver has a common bug with Flycast - priority conflict between borders of menu window and leftest or rightest character in the line. Below you can find a few screenshots, taken with 2 different emulators.
Steps To Reproduce	In the case of Flycast, it's enough to just load the game, but MAME still hasn't VMU emulation, so only thing you can do is to skip all beginning cutscenes.
Additional Information	Flycast uses per-pixel sorting and native depth interpolation. For some reason, even full framebuffer emulation can't fix this bug. In MAME, the chosen bios is v1.004, screen connection type is S-Video, bilinear filtering is enabled. Here is the reference video (cfr. 10:00 minute mark -AS):
Github Commit

Flags
Regression Version
Affected Sets / Systems	dcjp [Langrisser Millennium]

Attached Files	mame0.png (219,340 bytes) Oct 8, 2023, 03:28 Uploaded by VasiliyFamiliya
	mame1.png (229,778 bytes) Oct 8, 2023, 03:28 Uploaded by VasiliyFamiliya
	flycast0.png (667,957 bytes) Oct 8, 2023, 03:29 Uploaded by VasiliyFamiliya
	flycast1.png (817,631 bytes) Oct 8, 2023, 03:29 Uploaded by VasiliyFamiliya
	flycast2.png (825,105 bytes) Oct 8, 2023, 03:30 Uploaded by VasiliyFamiliya

No.21795 Fujix Administrator Oct 10, 2023, 08:27	Can you make your report decent?
No.21798 Robbbert Senior Tester Oct 11, 2023, 13:21	There seems to be issues with this report. 1. You can only compare with real hardware. Comparisons with other emulators is not valid because they might be wrong too. 2. "Langrisser Millennium" is not in the software list. 3. The system "dcjp" is listed as NOT WORKING. Or have I missed something?
No.21937 Kale Developer Feb 1, 2024, 19:43 edited on: Feb 1, 2024, 19:48	Tracked here upstream in Flycast: https://github.com/flyinghead/flycast/issues/1201 he changed number of things: 4444 textures color extension (which may be not true but a hack to avoid issue) more accurate SH4 FMAC command emulation, which does single rounding, so x86 single precision MUL + ADD produce less accurate result Alpha-test changes in shaders and code, they finally found it should be performed very last, and something depth related [...] It seems to use a punch-through polygon too, which MAME renderer don't do iirc Acknowledging this bug, we need a number of things first (cfr. https://github.com/mamedev/mame/projects/2 plus the fact that it's not in the SW list ) before even attempting a fix here.