Date:	Wed, 12 Feb 1997 08:38:49 +0000
From:	Bill Currie <billc AT blackmagic DOT tait DOT co DOT nz>
Subject:	Re: Allegro joystick questions
To:	Benjamin D Chambers <chambersb AT juno DOT com>
Cc:	djgpp AT delorie DOT com
Reply-to:	billc AT blackmagic DOT tait DOT co DOT nz
Message-id:	<33018199.16DB@blackmagic.tait.co.nz>
Organization:	Tait Electronics NZ
MIME-version:	1.0
References:	<5dlf2r$sh4 AT organ DOT cs DOT indiana DOT edu>
	<19970210 DOT 173501 DOT 4967 DOT 0 DOT chambersb AT juno DOT com>

Benjamin D Chambers wrote:
> Just out of curiosity, what are the 6 degrees of freedom?  I know 5
> (north/south, east/west, up/down, ana/kata, foreward/backward {the last
> two are time, but people seem to like to think of time as a geometric
> dimension <it is, but that gets _very_ confusing>}), but it's VERY hard
> to real-time more than 3 (at least the way I'm thinking).

6 degrees of freedom comes from the first three you mentiond
(north/south,
east/west), the other three come from ROTATION on those axis (pitch,
yaw,
roll). ie 3 dof with translation along x, y and z and 3 dof with
rotation
around x, y, and z.

I believe you were thinking of dimensions (or actual axis). If you could 
use your five dimensions mentioned above, you would have 10 degrees of 
freedom!

> >And a final question, is it common to get noise from the joystick?  I
> >can
> >leave the joystick in the neutral position, not even touching it, and
> >every now and again the joystick position will jump to non-zero values
> >for
> >one update, and then return to zero.  I'm assuming it's just noise
> >from
> >joystick, but I can't be certain.
> The same thing happens to me (so badly I can't use the joystick with some
> games {even with Allegro}), I wonder what it is?

I believe it's mostly electical noise from the joystick pots (they are
just 
carbon track resistors which are notorious for their noise).  It could
also
be from those nice long antennas running from your pc to the joystick 
picking up the mains (50-60hz depending on where you are).

Bill
-- 
Leave others their otherness.

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