plib-devel

[Plib-devel] 32 bit integer button limit

[Jim C. <j.c...@zy...>]

Hi,
The problem with only 32 bits in an integer so allowing only 32 buttons 
can be handled in a similiar fashion to the method used in standard 
unix libraries for handling file descriptors. This uses an "fd_set" 
data type which is a "descriptor set" (read button set!!) which can be 
reset,written to, read from and checked using the 
FD_ZERO,FD_SET,FD_ISSET,FD_CLR macros. File descriptors can be up to 
1024 for example so this technique can handle many buttons.(see p396 
etc of Stevens - Advanced Programming in the Unix Environment).
Also one way to build a cockpit may be to cannibalise a standard 
joystick and use the buttons and rotaries accordingly.(This allows 
re-use of existing sware without having to write new "plib" bits to 
handle for example a USB interface such as a Velleman module with 
digital/analogue input and outputs).
cheers
Jim

Re: [Plib-devel] 32 bit integer button limit

[steve <sjb...@ai...>]

Look: the problem with supporting more than 32 buttons is
that only one guy with only one application needs it - the
rest of us can't test the code, we can't maintain the code
we can't verify that it runs under MacOS and five different
flavors of windows and a couple of different Linux drivers
because none of the rest of us have (or are likely to have)
34 button joysticks - nor yet code to use it.

You have to aim projects like this at the 95% line - what
95% of the people need.  The 0.1% of people with 34
button joysticks of whom 0.1% have applications that need
all of those buttons - are just not worth the support grief.

For those very few people running those very few applications,
congratulations - it's OpenSourced - you can make a copy,
stick it into your application code and maintain it yourself.
If there are problems with it - you'll be the one that
answers the mail.

We've had MANY instances of people dumping fancy little
features into our laps then running off and never being
heard from again - it's just not useful to anyone other
than the person that first asked for it - it just adds
to the support load for the remaining few.

Keep it simple.

That's the mantra that got us this library suite in the
first place - and it's what keeps it running with very
little support from very few people.

Re: [Plib-devel] 32 bit integer button limit

[Andy R. <an...@pl...>]

Steve Baker wrote:
 > Look: the problem with supporting more than 32 buttons is
 > that only one guy with only one application needs it

No, this is actually a rather common stick.  It is comparatively
inexpensive.  You can buy them at retail stores pretty much
everywhere.  I have one too.  It's the follow-on product to a
very successful stick (the X-45) that I've recommended to many
FlightGear users over the past several years.

Sorry, but the 32 button limit is a real problem affecting real
people, and one for which you guys need to come up with a
solution.  The bitmask was a poor API choice, and isn't scaling
to common joystick hardware.  You can't brush this one under the
rug via an invocation of KISS, sorry.

Andy