DirectInput7 & problem with simultaneously pressed keys

[Coach]

Somehow it will not register Up on arrow keypad when Left and Right is already pressed. Combinations like Left, Right & Down or Left & Up or Up alone works well.

Has anyone else encountered this?

(I have tried with another keyboard but the problem remains.)

[PeterM]

I think this is more of a keyboard thing than a DirectInput thing. As far as I know, most keyboards have problems with particular combinations of simultaneous key presses.

Maybe the problem goes away for USB keyboards, but I've never used one.

[Nikster]

I just tried the DirectInput keyboard sample that comes with the DX9 sample browser, seems that has problems with up/left/right being pressed at the same time, this is the only combo that seems to have problems, I'm sure I've seen this query before on either here, dexterity or gamedev and it was down to keyboards :/

EDIT: left/down/up suffers too..

[Matthew]

Keyboard ghosting is a hardware problem. This is the clearest explanation I've seen: http://www.dribin.org/dave/keyboard/html/ghosting.html

[Hiro_Antagonist]

The old game Star Control (and StarCon2) used the keyboard, and ran into this problem. There was left/right/thrust/fire1/fire2, and 2 players could play on the same keyboard. This meant it was possible for players to want to press up to 8 keys at once.

Unfortunately, the limit is well below that, and the limit is different depending on different combinations of keys.

StarCon shipped with a seperate .exe that let you press keys on your keyboard to see which it could recognize in combinations with which others. You could then set your keyboard settings to use whatever combinations you found best.

My main point here is that this has been a problem for keyboard games since the old DOS days.

-Hiro_Antagonist

[tolik]

Offtopic: Today I've plugged Apple one-button mouse (as the only mouse device) into Win2k box and it all ended up with crashing several DirectInput games. Official DX9 mouse sample wasn't detecting this mouse too. Heh.
When any other USB mouse was connected besides Apple one, both of them were working.

Just to be sure it's a keyboard problem, map up/down/left/right to distant keys over the keyboard to avoid ghosting - like A/HOME/ARROW/NUMPAD and then use both hands to see if it's a code or ghosting problem ;-)

[Coach]

Dammit! There goes my sophisticated and intuitive control method...

Thanks a lot for your input guys.