Re: [Playerstage-developers] Client GUI

[brian g. <ge...@ro...>]

On Tue, 28 Oct 2003, Vikram Harinath wrote:

> Reed Hedges wrote:
> 
> > On Monday, October 27, 2003, at 11:02 AM, Vikram Harinath wrote:
> >
> > >
> > > I would like to know what would be the best way to go about doing this?
> >
> > Really, it doesn't matter from the Player perspective, any
> > library/tool/method you choose should work OK with Player; the main
> > thing to watch out for is Player's steady-time running speed.  You may
> > need to switch to using "Request" mode rather than "Push".
> 
> Are you talking about using Player in "Request" mode ?

Yes, he is.  If your GUI (or any client, in general) can't consume data at
Player's default push rate of 10Hz, then you should either: (1) switch to a
pull mode of data delivery (PLAYER_DATAMODE_PULL_NEW) or (2) remain in a
push mode, but lower the data rate.

> > > I tried to do it using QT library but ran into some issues.
> >
> > What were the problems?
> 
> Well, firstly, I get the following when I try to compile my GUI:
> 
> In file included from ../player-1.3/include/player.h:32,
>                  from ../player-1.3/include/playerclient.h:32,
>                  from walkergui.cc:23:
> ../player-1.3/include/playercommon.h:160:1: warning: "ASSERT" redefined
> In file included from /usr/lib/qt-3.1/include/qshared.h:42,
>                  from /usr/lib/qt-3.1/include/qgarray.h:42,
>                  from /usr/lib/qt-3.1/include/qmemarray.h:42,
>                  from /usr/lib/qt-3.1/include/qcstring.h:43,
>                  from /usr/lib/qt-3.1/include/qstring.h:42,
>                  from /usr/lib/qt-3.1/include/qvariant.h:42,
>                  from walkergui.h:4,
>                  from walkergui.cc:2:
> /usr/lib/qt-3.1/include/qglobal.h:959:1: warning: this is the location of the
> previous definition

That's a bug on our part (for #define'ing a macro with such a common name
without first checking for a prior definition), but it's just a warning,
and probably doesn't matter.  Btw, what version of Player are you using?
That definition was removed before we released 1.3.2.  I highly recommend
that you upgrade to 1.3.2.

> Secondly, when I try to run the GUI, the display - which just shows distance
> to an obstacle straight ahead of the walker in numerical form (i.e. looking
> at a particular laser angle) - doesn't update itself even though I have put
> an infinite for loop in [of the same structure as the infinite for loop in
> randomwalk - except its not doing any controlling -just displaying
> information].

That's a tough one.  Mixing event loops (in this case, the GUI update
loop and the Player interaction loop) is a tricky problem, and I don't
know of any general solution to it.

        brian.