Re: [Plib-devel] Saitek X52 joystick with 34 buttons

[Trammell H. <hud...@sw...>]

On Wed, May 04, 2005 at 04:12:55PM -0700, Steve Baker wrote:
> Trammell Hudson wrote:
> >I've recently started using a Saitek X52 joystick with my Linux box and
> >have run into problems with plib's JS module limitation in the number
> >of supported buttons.  It only supports up to 32 buttons due to the
> >MAX_BUTTONS definition and the fact that it uses an int to store the
> >button state, but the X52 has 34 buttons (and 12 axes). 
> 
> That's practically a keyboard!

I'm not sure I could touch type on it -- I have enough trouble
remembering which button is "lower the flaps" and which one will
irrevocably initiate the autodestruct sequence.

> [...]
> I personally find it very hard to believe that there are any
> applications out there that would actually use that many - so
> for now, I'm not inclined to change the interface to support
> more buttons.

Flight simulators have an insatiable desire for more buttons and axes.
In this case, I have a subset of these mapped, depending on the flight
model that I am debugging:

Flaps up/down
Gear up/down
Speed brakes up/down
Arrestor hook up/down
Forward view
POV
"Check 6"
Autopilot mode
Autopilot heading bug left/right
Drouge chute
Ejector seat
Left brake
Right brake
Timer start/stop/reset
Elevator trim up/down/reset
Rudder trim left/right/reset
Vector sweep forward/aft
Thrust vector up/down
Weapon select
Pause
Engine start
Flight model load/save/reset

> If there is a bug to fix in *limiting* the number of buttons
> to 32 - then we should fix that.

plib doesn't seem to have a problem, but other applications do.  xplane,
for instance, maps 32 -> 0 and 33 -> 1 on Linux.  On OS X, it doesn't
see any button higher than 16 (I think -- not all of them work and I
haven't done any serious debugging on it).

> >Changing tmp_buttons to a uint64_t, updating the arguments to
> >jsJoystick::rawRead and jsJoystick::read fixed that for me.
> 
> But it would break other applications.  We absolutely cannot do that.

Exactly, which I why I cautioned against on making the change too soon,
since there is probably a better way to represent button state rather
than a single integral type bitmask.  It worked for me on my system,
but I was recompiling plib, SimGear and FlightGear from source, so there
was no problem with binary compatibility.

Trammell