Bizarre problem running JJ1 on DOSBox. HELP!

[MG_EyE_04]

When I run any version of JJ1, including HH95, on Dosbox, there is a really strange issue with the CTRL & ALT key configurations. But it only happens with the right alt key.

I'm on Windows 10.

Whenever I press ALT, Jazz jumps, but the weapon select also happens at the same time. So DOSBox is registering the CTRL key alongside the ALT key, every time I press RIGHT ALT.

I tried the key configuration in the main menu. Every time I push ALT, it comes up as CTRL. This doesn't happen with LEFT ALT.

Tried the DOSBox keymapper, nothing is off there.
Tried different versions of DOSBox, same problem.
Tried uninstalling & reinstalling Jazz, same problem.
Tried online emulations of Jazz running DOSBox, same problem.

This ONLY happens in JJ. No other game has this problem.

Is this a common problem? How do I fix it?

HELP!

[Torkell]

In Windows, the right Alt key (sometimes labelled "Alt Gr") behaves as if you're pressing both Ctrl and Alt. It's to do with support for extended characters on some keyboard layouts, particularly non-English ones - you get the characters by pressing AltGr and the key (for example AltGr+4 gives € on a UK layout). https://en.wikipedia.org/wiki/AltGr_key has some more details.

Unfortunately I don't know how to fix this. It's not a JJ1 problem - it'll be a Dosbox setting if anything.

[MG_EyE_04]

Thank you for that info.

Seems like a potential headache trying to fix. I just switched the weapon select key to shift. Not perfect but one heck of a lot less annoying.

[Simon]

You've done excellent debugging, in particular with the online emulation. The Dosbox mapper file should be OK.

It might depend on Windows's keyboard layout, as Torkell explains. On Windows's German layout, most programs interpret (AltGr = right Alt) as (Ctrl + left Alt). I don't remember if that happens at scancode level, or merely during key chords. AltGr, or Ctrl + left Alt, input symbols from a third layer. The US doesn't use AltGr to access symbols from a third key layer; it has only the normal layer and the shift layer.

Idea 1: Toggle the Windows keyboard layout to US before you play.

Idea 2: In the JJ1 main menu, remap jump/fire to left-hand letters. Use the numbers to select weapon. That's faster anyway than cycling weapons, you don't have to look at the panel anymore.

Idea 3: Because JJ1 hardcodes some keys (weapons, turtle mode, load, save, pause, ingame menu), remap everything in the Dosbox mapper for 100 % convenience. The downside is that you probably want a mapper file for each game in Dosbox, thus have to move them around between games.

I use a nonstandard keyboard layout and had to remap heavily in the Dosbox mapper anyway. In JJ1, 12345 are weapons, D is jump, F is fire, and JKL; are directions.

-- Simon