Button Constants¶

All input drivers normalize controller buttons to the JP_BUTTON_* constants defined in src/core/buttons.h. These follow the W3C Gamepad API standard ordering, where bit position equals the W3C button index.

Button Reference¶

            ____________________________              __
           / [__L2__]          [__R2__] \               |
          / [__ L1 __]        [__ R1 __] \              | Triggers
       __/________________________________\__         __|
      /                                  _   \          |
     /      /\           __             (B4)  \         |
    /       ||      __  |A1|  __     _       _ \        | Main Pad
   |    <===DP===> |S1|      |S2|  (B3) -|- (B2)|       |
    \       ||      --        --       _       /        |
    /\      \/   /   \        /   \   (B1)   /\       __|
   /  \________ | LS  | ____ | RS  | _______/  \        |
  |         /  \ \___/ /    \ \___/ /  \         |      | Sticks
  |        /    \_____/      \_____/    \        |    __|
  |       /       L3            R3       \       |
   \_____/                                \_____/

Full Button Table¶

Constant	Bit	Value	XInput	Switch	PlayStation	DInput
`JP_BUTTON_B1`	0	0x0001	A	B	Cross	2
`JP_BUTTON_B2`	1	0x0002	B	A	Circle	3
`JP_BUTTON_B3`	2	0x0004	X	Y	Square	1
`JP_BUTTON_B4`	3	0x0008	Y	X	Triangle	4
`JP_BUTTON_L1`	4	0x0010	LB	L	L1	5
`JP_BUTTON_R1`	5	0x0020	RB	R	R1	6
`JP_BUTTON_L2`	6	0x0040	LT	ZL	L2	7
`JP_BUTTON_R2`	7	0x0080	RT	ZR	R2	8
`JP_BUTTON_S1`	8	0x0100	Back	-	Select	9
`JP_BUTTON_S2`	9	0x0200	Start	+	Start	10
`JP_BUTTON_L3`	10	0x0400	LS	LS	L3	11
`JP_BUTTON_R3`	11	0x0800	RS	RS	R3	12
`JP_BUTTON_DU`	12	0x1000	D-Up	D-Up	D-Up	Hat
`JP_BUTTON_DD`	13	0x2000	D-Down	D-Down	D-Down	Hat
`JP_BUTTON_DL`	14	0x4000	D-Left	D-Left	D-Left	Hat
`JP_BUTTON_DR`	15	0x8000	D-Right	D-Right	D-Right	Hat
`JP_BUTTON_A1`	16	0x10000	Guide	Home	PS	13
`JP_BUTTON_A2`	17	0x20000	--	Capture	Touchpad	14
`JP_BUTTON_A3`	18	0x40000	--	--	Mute	--
`JP_BUTTON_A4`	19	0x80000	--	--	--	--
`JP_BUTTON_L4`	20	0x100000	P1	--	--	--
`JP_BUTTON_R4`	21	0x200000	P2	--	--	--

Buttons are active-high: bit = 1 means pressed, 0 means released.

Analog Axis Indices¶

Defined in src/core/input_event.h as analog_axis_index_t:

Index	Constant	Range	Default	Description
0	`ANALOG_LX`	0-255	128	Left stick X (0=left, 255=right)
1	`ANALOG_LY`	0-255	128	Left stick Y (0=up, 255=down)
2	`ANALOG_RX`	0-255	128	Right stick X (0=left, 255=right)
3	`ANALOG_RY`	0-255	128	Right stick Y (0=up, 255=down)
4	`ANALOG_L2`	0-255	0	Left trigger (0=released, 255=fully pressed)
5	`ANALOG_R2`	0-255	0	Right trigger (0=released, 255=fully pressed)
6	`ANALOG_RZ`	0-255	0	RZ axis / twist / spinner

Y-axis convention (HID standard): 0 = stick pushed UP, 128 = centered, 255 = stick pushed DOWN. This matches USB HID and DirectInput. Input drivers for Nintendo controllers (which use inverted Y) must invert before submitting to the router.

Controller Layout Classification¶

The controller_layout_t enum in input_event.h describes the physical button arrangement, mainly relevant for 6-button controllers:

Layout	Physical Arrangement	Examples
`LAYOUT_UNKNOWN`	Unknown / default	--
`LAYOUT_MODERN_4FACE`	Standard 4-face (SNES/PS/Xbox style)	DualSense, Xbox, Pro Controller
`LAYOUT_NINTENDO_4FACE`	Nintendo BAYX face style	SNES controllers
`LAYOUT_NINTENDO_N64`	A/B + C-buttons + Z	N64 controllers
`LAYOUT_GAMECUBE`	AXBY face style	GameCube controllers
`LAYOUT_SEGA_6BUTTON`	Bottom [A][B][C], Top [X][Y][Z]	Genesis/Saturn 6-button pads
`LAYOUT_PCE_6BUTTON`	Bottom [III][II][I], Top [IV][V][VI]	PCEngine Avenue Pad 6
`LAYOUT_ASTROCITY`	Bottom [D][E][F], Top [A][B][C]	Sega Astro City Mini arcade
`LAYOUT_3DO_3BUTTON`	Single row [A][B][C]	3DO controllers

GP2040-CE Canonical Mapping¶

Internally, all 6-button layouts use the GP2040-CE positional mapping:

  Top row:    [B3][B4][R1]
  Bottom row: [B1][B2][R2]

Layout transform functions (e.g., transform_to_pce_layout()) convert between layouts when needed by output drivers.