input#

This module allows you to read user input from the GBA’s keypad.

Example:

import natu/[video, irq, bios, input]

dispcnt.init()
irq.enable(iiVBlank)

while true:
  VBlankIntrWait()

  # Update key state (call this once per frame.)
  keyPoll()

  # Change backdrop color when the player presses "A".
  if keyIsDown(kiA):
    bgColorMem[0] = rgb5(15, 31, 20)

Types#

type KeyIndex = enum#: Bit positions for keyinput and keycnt. Used with input functions such as keyIsDown.

type KeyState = set[KeyIndex]#

type KeyInput = object#

type KeyIntrOp = enum#

type KeyCnt = object#

Globals#

const allKeys: KeyState = {kiA..kiL}#

var keyCurrState: KeyState#: The set of keys that are currently down on this frame.

var keyPrevState: KeyState#: The set of keys that were down on the previous frame.

Basic Procs#

proc keyPoll()#: Should be called once per frame to update the current key state.

proc keysDown(): KeyState#: Get all the keys which are currently down.

proc keysUp(): KeyState#: Get all the keys which are currently up.

proc keysHit(): KeyState#: Get all the keys which were just pressed on this frame.

proc keysReleased(): KeyState#: Get all the keys which were previously pressed but are no longer pressed.

proc keyIsDown(k: KeyIndex): bool#: True if the given key is currently down.

proc keyIsUp(k: KeyIndex): bool#: True if the given key is currently up.

proc keyWasDown(k: KeyIndex): bool#: True if the given key was previously down.

proc keyWasUp(k: KeyIndex): bool#: True if the given key was previously up.

proc keyHit(k: KeyIndex): bool#: True if the given key was just pressed on this frame.

proc keyReleased(k: KeyIndex): bool#: True if the given key was just released on this frame.

proc anyKeyHit(s: KeyState): bool#: True if any of the given keys were just pressed on this frame.

Repeated Keys#

proc keysRepeated(): KeyState#: Get the keys that just repeated or were newly pressed.

proc keyRepeated(k: KeyIndex): bool#: Check if a key just repeated or was newly pressed.

proc setKeyRepeatMask(mask: KeyState)#: Set which keys will be considered for repeats.

proc setKeyRepeatDelay(delay: uint8)#

Set the initial delay from when a key is first pressed to when it starts repeating.

If keys are already repeating, this will delay them again.

proc setKeyRepeatPeriod(period: uint8)#: Set the interval between repeated keys.

I/O Registers#

let keyinput: KeyInput#

Keypad status register (read only).

This can be used to obtain the current state (up or down) of all the buttons on the GBA. Note that the state is inverted.

It is generally preferable to call keyPoll and use the various input procedures (keyIsDown etc.) rather than reading this directly.

var keycnt: KeyCnt#

Key interrupt control register.

See the irq module for details.

proc state(keyinput: KeyInput): KeyState#: Flip the keyinput register to obtain the set of keys which are currently pressed.