Gamepad input support

[christianparpart]

trafficstars

@asmuth suggested gamepad support for allowing basic TUI movements (up/left/down/right, ESC, CR, ...). I think however it can be extended to a general purpose VT gamepad sequence extension.

Rough spec

Functions

• feature detection DECRQM <mode_num>
• enable mode SM ? <mode_num>
• disable mode RM ? <mode_num>
• report number of joysticks currently plugged in
• report buttons/cursors for a single joystick

Event reporting

• Joystick attached / removed
• Buttons: L1, L2, L..., R1, R2, R..., A, B, X, Y
• Cursor: Up, Right, Down, Left
• Special buttons: S1, S2, S3, S4
• plus an arbitrary number of 2 360-degree buttons with N (>=2) varying speeds/intensities and button-press ability.
• touch area coordinates (Steam Deck / steam controller having that?)

This could be reported via a yet to be determined new CSI sequence. (or DCS because it's physical device? :-) )