Re: [Plib-users] Input Library

[Steve B. <sjb...@ai...>]

Ryujin Doraegon wrote:
> 
> Hello, i'm looking for a library that help me manage user input from a keyboard
> or joystick but with some special features.

Well, PLIB has a joystick library that makes reading the current position
quite easy - but to decide which "move" was made via some complex sequence
of joystick actions is beyond what we do.

I seriously doubt you'll find a package that'll have those features
directly - but it wouldn't be to hard to write.

You'd have to decide exactly which parts of the joystick range constitute "down"
(the joystick axes go from -1 to +1 - so "down" could mean "any Y value less
than -0.5"...say).

You could split the ranges of the joystick into (say) 8 regions with a neutral
region in the middle:

  int where_is_the_stick ( float x, float y )
  {
    if ( y > 0.5 )
    {
       if ( x < -0.5 ) return TOP_LEFT  ;
       if ( x >  0.5 ) return TOP_RIGHT ;
       return TOP_CENTER ;
    }

    if ( y < -0.5 )
    {
       if ( x < -0.5 ) return BOTTOM_LEFT  ;
       if ( x >  0.5 ) return BOTTOM_RIGHT ;
       return BOTTOM_CENTER ;
    }

    if ( x < -0.5 ) return LEFT  ;
    if ( x >  0.5 ) return RIGHT ;
    return NEUTRAL ; 
  }

...call that routine every frame to catagorize the position.
Every time the joystick CHANGES position compared to last frame,
store that in an array that holds (say) the last 20 places the
joystick visited.

Now, whenever you add an entry into that array, you can compare
the last few locations the joystick was at against a table of
"moves" that your game needs to recognise.

So, "Hit forwards twice" would be when you've seen NEUTRAL/TOP/NEUTRAL/TOP/NEUTRAL
and "Moved in a semicircle" would be BOTTOM/BOTTOM-LEFT/LEFT/TOP-LEFT/TOP or
something. You'll probably need to recognise several combinations of functions
for each move because he may start his semicircle at BOTTOM-LEFT instead of
BOTTOM - and you probably don't want the moves to have to be TOO exact.

> im using OpenGL and the GLUT Library, it seems that GLUT doesn't support this
> features.

I don't think any library does - you have to write it yourself.

> Another thing is that i don want the keyboard autorepeat feature,
> when i press a key i want it pressed until i release it.

You can turn off autorepeat in GLUT. Just call glutIgnoreKeyRepeat().

-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjb...@ai... (home)  http://www.woodsoup.org/~sbaker
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