Re: [Plib-devel] joystick jungle

[Bert D. <dri...@pl...>]

On Wed, 9 Mar 2005, Bram Stolk wrote:

> I'm struggling with the lack of joystick/gamepad/wheel standardization.
> There does not seem to be a manner by which I can get to
> know more about an axis for a linux joystick.
>
> Maybe this kind of stuff is in directx, but I want this
> kind of info on joystick axes:

I doubt DirectX fares better. I have four different USB joysticks geared 
more or less to flight simulation, plus a pedal set, and unless the app 
comes with a database of joysticks there is little logic to default 
assignments.

> - Is axis part of a 2DOF joystick?
> - Is axis an accelerator pedal?
> - Is axis a brake padel?
> - Is axis combined brake/accel?
> - If axis is up/down joystick, is up positive or negative?
> - Is the axis analog?
>  (Strangely enough, digital pads are treated as axes, not buttons)

I'm not sure how many plib apps support those hat switches; I think 
there is something to be said to introduce a seperate "hat" abstraction, 
along with axis and button.

> I assume no API exists for getting this info.
> And if this is the case, I think a 'joystick database' indexed
> by the USB device name would be a valuable asset for many projects.
>
> Does anyone on this list know whether such a db exists?
> And if not, I think I want to start one. I dont care if at first
> it will only contain a handful of the 1000s of current gamepads.
>
> The alternative is probably to burden the user by configuring
> his joystick which seems ugly to me.

Many Windows games come with extensive databases for joystick to 
application matching, and I rarely use the defaults for long. I have
copies of Microsoft Flight Simulator (of different vintages), I have 
X-Plane, I use FlightGear. Then, to make matters worse, I have MS 
TrainSim, Trainz and BVE, but no trainsim specific devices, so I control 
brake line pressure with the Cessna-styled "Mixture" control of a CH 
Yoke.

The three flightsims and four joysticks make for twelve combinations. 
There is no guessing which button will extend the flaps, or reduce 
them, not with an identical joystick across games, and not with an 
identical game across joysticks. The default aileron/elevator control on 
a Logitech Rumblepad is usually the left joystick, which really is a bad 
choice for righthanded folks. Etcetera, etcetera: my list of gripes is 
endless. Oh, and that's without changing airplane types in the sim, e.g. 
going from a plane with one brake to a type that support differential 
braking.

The practical upshot is this: the first thing I do when I get a new sim 
(or must re-install one) is to remove all assignments, then reassign 
them (the ones I need, that is).

I think the hard part is not in having to assign them, but in user 
interface design. I can recommend anyone interested in this to look at 
X-Plane 8.x (http://www.x-plane.com/, available for Windows, MacOS 9 or 
X, and some recent Linux versions). Download the demo and try to assign 
joystick axes and buttons. The screen looks daunting and unfriendly, but 
it isn't until you justapose MSFS's screen that you'll appreciate how 
well X-Plane's is done.

The ideal Joystick configuration GUI
  - knows different layouts for analogue inputs: X-Y, Y-only, X-only, 
slider, 270 degree knob (this needs a database)
  - can present all axes as simple representations of the above choices
  - can store profiles per app, per joystick
  - can default a profile to an existing one
  - can map all available axes to terms relevant to the app, so the user
    can answer the question "what does this button do?"

X-Plane's weakness is in dealing with hats (represented as eight 
unrelated buttons). I have not yet checked how well it can deal with 
different joysticks (in other words, if it stores profiles per Joystick 
or not).

And actually, FlightGears's fgjs ain't bad, except that it can be a 
challenge to get all button assignments right in one go, as eventually 
the "ANY" button will come up for assignment :-)

Other good ideas can be had from Logitech's Windoze drivers (which are 
not my favorite drivers, but they come with good representations to 
visualize button and axis assignments).

So if anyone has any time to burn, I would recommend improving the GUI 
to do assignment (possibly as an advanced plib widget, accepting a list 
of possible actions and preexisting assignments, and returning user 
assignments and/or maintaining profiles). The key functionality missing 
from most GUI's is the basic "what does this button do" thing. But even 
just a simple GUI version of fgjs that allows for going back and fixing 
mistakes would be an improvement. It should not be rocket science to 
write such a joystick profile manager to be application independent 
(but I'm the first to admit it will be a lot of work to get the GUI 
just right).

Anyway, before embarking on the idea of a joystick database I'd suggest 
having a critical look at existing attempts to do precisely that on 
Windows (e.g., Logitech's profile manager, which covers dozens of 
joysticks and hundreds of games and can make a 2GHz machine feel like 
a 486/33).

Cheers,

 				-- Bert

-- 
Bert Driehuis -- dri...@pl... -- +31-20-3116119
If the only tool you've got is an axe, every problem looks like fun!