Configurable button and axis mapping

[Oblomov]

A nice thing to have would be a method to configure the button mapping, to work around limitations in clients that do not support it themselves.

Examples of what this should allow achieving:

• portrait vs landscape D-Pad mapping;
• A/B and 1/2 button swapping (see e.g. tomsik68's patch for Atomic Bomberman support);
• kind of axis for the accelerometer (abs vs tilt, in which case the D-Pad could be used for abs, as proposed in add virtual axes usable with arrow keys #8).

A default configuration should be provided (e.g. the current one), together with a set of default alternatives. It should be possible to combine configuration file (e.g. 'portrait d-pad plus button swapping').

The syntax should be as simple as possible, without being exceedingly verbose. We probably won't need more than a couple of directives:

wii button or axis specification = action specification

for the mappings themselves, and

#include 'other configuration'

Both the Wii button/axis specification and the corresponding action should have clearly readable names; we can base them on the defines, but to improve readability and writeability we might want to allow both _ and as separator for components, and prefixes such as XWII or BTN could be made optional, also allowing key and button as synonyms. So, for example, the swap could be written as:

XWII_KEY_A = BTN_1
XWII_KEY_B = BTN_2
XWII_KEY_ONE = BTN_A
XWII_KEY_TWO = BTN_B

but also

button a = button 1
button a = button 2
button 1 = button a
button 2 = button b

or even

a = 1
b = 2
1 = a
2 = b

[tomsik68]

I might be over-engineering a little bit here, but I got another idea that takes this one step further: What if users could define the virtual joystick themselves?
We could add mappings from axes to buttons or vice versa. Some examples:

• axis 1 max = button 3 (if real axis 1 gets (close) to its maximum value, "press" virtual button 3)
• button 1 = axis 2 min (if button 1 is pressed, set value of virtual axis 2 to its minimum value)
• button 2 = button a
• axis 3 = axis 5

That would make it possible to create virtual axes(like in my previous patch) and also virtual buttons.

[Oblomov]

I don't see why we shouldn't allow it, although I'd be very surprised if the mapping axis -> button ever finds an actual use. Unless of course supporting it would make the code too complex.

I don't particularly like the proposed syntax with max/min though. An axis should probably map to a pair of buttons, and conversely we'd need a pair of buttons to create another axis, plus maybe the keywod none to indicate a dead map.