How does GroovyMAME display and rotate vertical games on 15 kHz monitors?

[sofakng]

How does GroovyMAME display and rotate vertical games on 15 kHz monitors?

For example, a lot of SHMUPs are 240x320.  You can't simply rotate it because 320p is too high for 15 kHz.

Does GroovyMAME automatically use 480i or how is this handled?

[dmckean]

Yes, by default GroovyMame will convert resolutions outside your monitor's scan range to 480i. There's a downscale option too but both are ugly though. There's no real good solution to this and is why most of us have separate horizontal and vertical setups.

[Zebidee]

Groovymame will automatically rotate the screen according to your specifications in VMMaker.

Check the "edit settings" tab and you'll see a monitor rotation pictogram displaying how you want you monitor. If you choose "rotate to the right". You'll see two full looking 3:4 CRT screens, with one rotated. Do it this way you get the UI/menu in horizontal but vertical games are rotated to the right and in proper resolution.

EDIT: You must also check the "export settings to mame.ini" box on the 4th tab, otherwise VMMaker doesn't update mame settings for you.