First, MacOS X gamepad code assumes that number of sticks on device is
equivalent to number of X axes. This is not always true: for my gamepad,
there are 1 reported X axis, 1 Y axis and 2 Z axis. Currently, the extra
Z axis gets lost for Allegro :) I think this piece of code needs to be
rewritten not to assume number of sticks in this way.
MaxOS X gamepad code also can't handle d-pad on my gamepad. It has usage
== kHIDUsage_GD_Hatswitch and needs special handling, because its
element represents both axes at once (or maybe it should be mapped to
four buttons?).
I think I can fix those two problems myself, but first I'd like to talk
about a more general thing: I see that Allegro's idea of separate
"sticks" fails on so many platforms it seems to be useless. Time and
time again I get sticks with 3 axes for my gamepad. Mostly, X-axis of my
right sticks gets reported as Z-axis of the left stick. I think this is
a problem with drivers, but it's a problem Allegro can't correct, and it
leads to confusion. I know that would be a backward compatibility
breaking change, but maybe we should consider abandoning the idea of
sticks, and return to a set of independent axes instead, as with SDL?
The current setup gives end-user false sense of security, he might think
that 0th axis of a stick always will be horizontal, and 1st axis will be
vertical, and there can be no 2nd axis on a standard gamepad. But this
is not true :)
As an alternative, we may retain the current setup, but finally give
users controller database, so they might treat sticks and axes reported
by joystick events as "magic", opaque values, from which the REAL
controls might be obtained by querying controller DB (i.e., for my
gamepad, stick 0 axis 3 will map to stick 1 axis 0). This keeps backward
compatibility, but will multiply user confusion. Moving away from sticks
would allow to simplify joystick drivers for all platforms somewhat, and
give us a bit more compatibility with SDL.
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