[Libff-devel] Re: [Libff-kernel] Wingman Force 3D in linux, not only questions.

[Johann D. <joh...@it...>]

Micha=B3 Pytasz wrote:

> Hi,
>=20
> I'm sorry for bothering You, I hope it is the right list. So fat I read=
 most=20
> of it's history, and I guess (almost) all of what is related to logitec=
h=20
> devices.

That's the right place. It's dedicated to all discussions dealing with=20
drivers for force-feedback devices.

>=20
> I have Logitech Wingman Force 3D and I'm interested in getting to know =
how to=20
> use it in own programs, also I think I could help in driver and library=
=20
> development. Earlier I thought I have problems making it work, since on=
ly=20
> "constant force" in fftest was giving a (hardly) noticable effect. Corr=
ect me=20
> if I'm wrong, but is it the only effect implemented for this joystick (=
at=20
> least at the moment) ?

It's the only effect implemented, it will stay that way unless someone=20
else works some more on the driver.

>=20
> I started learning how to communicate with the device, I have c++ class=
=20
> "Joystick" written mostly using HID howto. For now it can only read pos=
ition=20
> from the device (periodicaly, in separate thread), output some informat=
ion=20
> about the device, set gain and autocenter - so it is very far from fini=
shed,=20
> however when it will be closer to the desired result, I think it could =
be=20
> some "beginning" for more universal library.

Yes, great!

> I would be interested in adding (or helping to add) better support for=20
> Logitech Wingman Force 3D (since it is the device I have at the moment)=
.=20
> Do You have any suggestions for beginner (not in programming, but in re=
verse=20
> engineering) on how to find joystick's abilities (and how to connect th=
em to=20
> specific commands)

When I had a working wingman 3d joystick, I used to look at the usb data=20
it sent and received in windows, using a usb packet snooper (I think the=20
name of the soft was snoopy).
I generated effects using some effects designer by immersion (see their=20
developer web pages).

My advice:
1. look at the usb data when nothing happens (no effect played, joystick=20
not moving)
2. look at the data when the joystick moves
3. Identify packets describing the state of the stick. Those are not the=20
packets you are interested in.
4. look at the data when effects are played
5. Identify the packets that were not there in 2 and 1. Those are=20
probably force-feedback packets
6. Change the parameters of the effects, look at the data, guess what=20
bytes encode what parameters

I've already done 1 to 5, I was trying to do 6 for spring/friction=20
effects when my stick stopped working.
The packets for condition effects use the same pipe as packets for=20
constant force, they have a similar structure as well.

You might want to install cygwin so that you get access to grep, sort...=20
they are usefull to sort and filter large anounts of data automatically.

>=20
> Below a little more detailed version of what I can see using ffutils.
>=20

That won't help you reverse engineer anything, unfortunately. You have=20
to look at what happens in windows.

--=20
Johann