[PD-dev] making a libusb object (expanding on [hid] toolkit)

[Mathieu Bouchard]

On Fri, 20 Jan 2006, Christian Klippel wrote:

> yea, good idea, but impossible to do. you can be sure that whatever
> interface you take, it will send its data in a different way.

I'm sure that Ben is talking about having a common interface for things 
that objects have in common, and not for the things that they don't have 
in common. Just because the commonality can't be total doesn't mean it 
can't exist at all.

> each unit has different resolutions, different amounts of i/o, and for
> that reason, a different protocol.

The commonality between objects may be increased by specifying that 
classes in particular should have a query interface in order to 
figure out how many sensors there are, how they are labeled if they 
are labeled, and what is the type and possible values of each sensor.

> this is neccesarry because of the differencies in the devices. it is
> even possible that you take two different joysticks, and both pack their
> messages in completely different ways: one could put all info in just
> one report-descriptor, the other may use serveral of them, or even one
> for each axis/button.

Does this happen in practice? Do you have an actual situation where three 
joystick models do exactly that?

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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada