A number of controllers on the market have digital DPads that emulate analog axes.  There currently does not exist a method to bind "half" an axis to a button.

Two possibilities exist to fix this.  The first one is a bit of a hack, but it changes no ABI.  You would define a DPad thusly:

dpup:a4,dpdown:a4,dpleft:a3,dpright:a3

Presently, if you do this, movement on a3 (either direction) presses both dpleft and dpright, and likewise for a4 and dpup/dpdown.  The code can be modified to check the special case of a DPad button and assume negative axis values trigger left/up and positive trigger down/right.  This maintains ABI compatibility with 2.0.0 and 2.0.1.


Option #2 introduces new syntax for the mapping string.  This would be an addition, but currently just about all of the GameController mapping structure and functions are exposed to the outside, even if nobody is (or should be) using them.  The mapping would look like:

dpup:a4-,dpdown:a4+,dpleft:a3-,dpright:a3+

The forward and reverse mapping structures would have to change accordingly.  On the other hand, it offers the chance to implement "a0/" as a way to invert an axis or something.  :)


If we were dealing with a not-yet-released 2.0.0, I'd say do the latter.  Because we're post-release, I think we kind of have to do the former for ABI reasons.