09090: megadriv, x68000 and others: Some screen modes alter aspect ratio and density of scanlines

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09090	Graphics	Minor	Always	Jan 18, 2025, 19:36	10 days ago

Tester	ICEknight	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10/11 (64-bit)
Status [?]	Direction Needed			Driver	sega/mdconsole.cpp
Version	0.273	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	09090: megadriv, x68000 and others: Some screen modes alter aspect ratio and density of scanlines
Description	Certain PAL games (such as `toejam2` or `sor`) use a higher vertical resolution, filling more screen space as a result. In MAME's Mega Drive emulation all games fill the same screen space regardless of the number of lines they're using, causing the aspect ratio to change. The number of visible scanlines and aspect ratio should stay the same, regardless of the game.
Steps To Reproduce	- Load a PAL game that uses a taller resolution than usual, such as `megadriv/toejam2`. The screen will reach the top and bottom of the display. - Load a PAL game that uses a regular resolution, such as `megadriv/sonic`. It will also reach the top and bottom of the display. This is wrong behavior since the vertical resolution of the emulated display should be the same as before.
Additional Information	Showing the full visible area at all times would fix this, make all PAL games have their proper aspect and also fix issue 7271: https://mametesters.org/view.php?id=7271
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	megadriv, x68000 and others

Attached Files	sonic pal.jpg (310,318 bytes) Jan 18, 2025, 19:41 Uploaded by ICEknight Game window of PAL game with normal vertical resolution
	toejam2 pal.jpg (240,498 bytes) Jan 18, 2025, 19:41 Uploaded by ICEknight Game window of PAL game with extended vertical resolution
	_megadriv sonic.jpg (417,272 bytes) Jan 18, 2025, 19:43 Uploaded by ICEknight MAME's scanline density of PAL game with normal vertical resolution
	_megadriv toejam2.jpg (401,606 bytes) Jan 18, 2025, 19:43 Uploaded by ICEknight MAME's scanline density of PAL game with extended vertical resolution
	sonic.png (5,969 bytes) Jan 18, 2025, 20:59 Uploaded by ICEknight MAME screenshot of PAL game with normal vertical resolution
	toejam2.png (19,688 bytes) Jan 18, 2025, 20:59 Uploaded by ICEknight MAME screenshot of PAL game with extended vertical resolution
	x68000-minic.jpg (436,720 bytes) 11 days ago Uploaded by ICEknight x68000/minic (current emulation)
	x68000-minic real hardware.jpg (54,015 bytes) 11 days ago Uploaded by ICEknight x68000/minic (real hardware)
	x68000-minic real hardware 2.jpg (72,777 bytes) 11 days ago Uploaded by ICEknight x68000/minic (real hardware)

No.23097 ICEknight Tester 11 days ago edited on: 5 days ago	Just adding that these scanline changes extend to other systems as well. For example, `x68000/minic` may look "good" with the vertical stretch but real hardware pictures show it having a more squashed aspect ratio: https://ameblo.jp/koorogiyousyoku/entry-11874019305.html Maybe some of these old monitors are also supposed to auto-adjust their height just like "modern" ones but that's never the case with TV sets. Maybe there should be an "Auto-adjust height" option in the Video menu that the user can disable for TV-connected systems.
No.23102 mahlemiut Developer 10 days ago edited on: 10 days ago	I'm pretty certain x68k games used to display in areas like that, particularly ports of vertical shmups. Star Force is a good example, it is far too wide and just looks weird. Will have to look back and see when this started happening. Update: Looks to have started around 0.233, with 0.232 kinda working but being glitchy when changing resolutions. You can switch between 4 video modes in Star Force by pressing the Help key. In current MAME, for some reason, one of the modes causes the game to run at double speed, but otherwise they all look, more or less, the same (they shouldn't)

No.23097

ICEknight

Tester

11 days ago

edited on: 5 days ago

Just adding that these scanline changes extend to other systems as well.

For example, `x68000/minic` may look "good" with the vertical stretch but real hardware pictures show it having a more squashed aspect ratio: https://ameblo.jp/koorogiyousyoku/entry-11874019305.html

Maybe some of these old monitors are also supposed to auto-adjust their height just like "modern" ones but that's never the case with TV sets. Maybe there should be an "Auto-adjust height" option in the Video menu that the user can disable for TV-connected systems.

No.23102

mahlemiut

Developer

10 days ago

edited on: 10 days ago

I'm pretty certain x68k games used to display in areas like that, particularly ports of vertical shmups. Star Force is a good example, it is far too wide and just looks weird.
Will have to look back and see when this started happening.
Update: Looks to have started around 0.233, with 0.232 kinda working but being glitchy when changing resolutions.
You can switch between 4 video modes in Star Force by pressing the Help key. In current MAME, for some reason, one of the modes causes the game to run at double speed, but otherwise they all look, more or less, the same (they shouldn't)