Detecting a double-tap..

[Downsider]

Trying to make an interface to detect double-taps for any key, as the PSP has a limited control scheme.

Any ideas as far as it could be done?

I was thinking about modifying this struct:

Code: Select all

typedef struct
{
   int      down[2];      // key nums holding it down
   int      state;         // low bit is down state
} kbutton_t;

to have a time value as well, that would be set to like time + .1 when the initial keypress is detected, then if it hasn't expired by the time the second keypress is detected, perform an alternate binding?

Is there a better way? I'm sure you people that have been modding Quake for years could think of a better way.

EDIT: I also have no clue if this is used for button presses or an on-screen-keyboard.

[Downsider]

Got it working

If anybody wants it for one of their PSP projects, swing by me..

[Baker]

I'd like to see the code.

How well does it work if you just single tap?

[avirox]

i can think of an easy way to do this in CSQC, but i am also interested in seeing how you did it in ssqc..

[Downsider]

It's in the engine programming subforum for a reason, Avirox =O

I added the commands binddt and unbinddt and essentially copied over a bunch of the code in key.c with minor alterations to suit the double-tap array of commands assigned to keys. Then I simply had a global variable for the last pressed key and the time it was pressed, compared, and if it was within .3 "time" ago (I have no clue at the scale which Quake does time so I'll refer to it as "time" instead of seconds), I Cbuf_Addtext'd the command that the key was bound to.

For instance, in my game, I want the character to sprint when he double tapped triangle, this is what the config reads as:

Code: Select all

bind "TRIANGLE" "+forward"
binddt "TRIANGLE" "+forward; qcf A_Sprint;"


Works perfectly fine. When you single tap, it just does the normal walk forward.

[Baker]

Possibly another useful related idea, the idea of holding the button down for more than a second or two has an alternate function.

One possible example, alter jump so the jump occurs on key release but if the button is held more than a couple of seconds it is a forward lunge attack that knocks enemies out of the way.

Nice idea downsider on thinking how to reuse existing controls.

[Downsider]

Yeah but that's quite a bit harder to implement.. Now you'd need a function calling every single frame to compare how long since the keydown event.

[avirox]

.. which is why i asked how you were doing it in ssqc, thinking that you may have implemented some extension to read client key inputs. That's how I would do it, sans CSQC, anyways..

[Irritant]

I know it's a different engine, but you could see how this is done in Alien Arena - http://svn.icculus.org/alienarena/

Bulk of it is in p_client.c in Clientthink().

[Jukki]

hello, and sory forreviving this, But how did you do it in code. I need this thing in my engine and my c skills are like how good i speak russian.

[Jukki]

and sory for revivng this againg. Well double tap would help alot atm. Want to share or tell me how to do this. me stupid, veeery stupid