path: root/home/joypad.asm

Joypad::
; Replaced by UpdateJoypad, called from VBlank instead of the useless
; joypad interrupt.

; This is a placeholder in case the interrupt is somehow enabled.
	reti

ClearJoypad::
	xor a
; Pressed this frame (delta)
	ldh [hJoyPressed], a
; Currently pressed
	ldh [hJoyDown], a
	ret

UpdateJoypad::
; This is called automatically every frame in VBlank.
; Read the joypad register and translate it to something more
; workable for use in-game. There are 8 buttons, so we can use
; one byte to contain all player input.

; Updates:

; hJoypadReleased: released this frame (delta)
; hJoypadPressed: pressed this frame (delta)
; hJoypadDown: currently pressed
; hJoypadSum: pressed so far

; Any of these three bits can be used to disable input.
	ld a, [wJoypadDisable]
	and (1 << JOYPAD_DISABLE_MON_FAINT_F) | (1 << JOYPAD_DISABLE_SGB_TRANSFER_F) | (1 << 4)
	ret nz

; If we're saving, input is disabled.
	ld a, [wGameLogicPaused]
	and a
	ret nz

; We can only get four inputs at a time.
; We take d-pad first for no particular reason.
	ld a, R_DPAD
	ldh [rJOYP], a
; Read twice to give the request time to take.
	ldh a, [rJOYP]
	ldh a, [rJOYP]

; The Joypad register output is in the lo nybble (inversed).
; We make the hi nybble of our new container d-pad input.
	cpl
	and $f
	swap a

; We'll keep this in b for now.
	ld b, a

; Buttons make 8 total inputs (A, B, Select, Start).
; We can fit this into one byte.
	ld a, R_BUTTONS
	ldh [rJOYP], a
; Wait for input to stabilize.
rept 6
	ldh a, [rJOYP]
endr
; Buttons take the lo nybble.
	cpl
	and $f
	or b
	ld b, a

; Reset the joypad register since we're done with it.
	ld a, $30
	ldh [rJOYP], a

; To get the delta we xor the last frame's input with the new one.
	ldh a, [hJoypadDown] ; last frame
	ld e, a
	xor b
	ld d, a
; Released this frame:
	and e
	ldh [hJoypadReleased], a
; Pressed this frame:
	ld a, d
	and b
	ldh [hJoypadPressed], a

; Add any new presses to the list of collective presses:
	ld c, a
	ldh a, [hJoypadSum]
	or c
	ldh [hJoypadSum], a

; Currently pressed:
	ld a, b
	ldh [hJoypadDown], a

; Now that we have the input, we can do stuff with it.

; For example, soft reset:
	and A_BUTTON | B_BUTTON | SELECT | START
	cp  A_BUTTON | B_BUTTON | SELECT | START
	jp z, Reset

	ret

GetJoypad::
; Update mirror joypad input from hJoypadDown (real input)

; hJoyReleased: released this frame (delta)
; hJoyPressed: pressed this frame (delta)
; hJoyDown: currently pressed

; bit 0 A
;     1 B
;     2 SELECT
;     3 START
;     4 RIGHT
;     5 LEFT
;     6 UP
;     7 DOWN

	push af
	push hl
	push de
	push bc

; The player input can be automated using an input stream.
; See more below.
	ld a, [wInputType]
	cp AUTO_INPUT
	jr z, .auto

; To get deltas, take this and last frame's input.
	ldh a, [hJoypadDown] ; real input
	ld b, a
	ldh a, [hJoyDown] ; last frame mirror
	ld e, a

; Released this frame:
	xor b
	ld d, a
	and e
	ldh [hJoyReleased], a

; Pressed this frame:
	ld a, d
	and b
	ldh [hJoyPressed], a

; It looks like the collective presses got commented out here.
	ld c, a

; Currently pressed:
	ld a, b
	ldh [hJoyDown], a ; frame input

.quit
	pop bc
	pop de
	pop hl
	pop af
	ret

.auto
; Use a predetermined input stream (used in the catching tutorial).

; Stream format: [input][duration]
; A value of $ff will immediately end the stream.

; Read from the input stream.
	ldh a, [hROMBank]
	push af
	ld a, [wAutoInputBank]
	rst Bankswitch

	ld hl, wAutoInputAddress
	ld a, [hli]
	ld h, [hl]
	ld l, a

; We only update when the input duration has expired.
	ld a, [wAutoInputLength]
	and a
	jr z, .updateauto

; Until then, don't change anything.
	dec a
	ld [wAutoInputLength], a
	pop af
	rst Bankswitch
	jr .quit

.updateauto
; An input of $ff will end the stream.
	ld a, [hli]
	cp -1
	jr z, .stopauto
	ld b, a

; A duration of $ff will end the stream indefinitely.
	ld a, [hli]
	ld [wAutoInputLength], a
	cp -1
	jr nz, .next

; The current input is overwritten.
	dec hl
	dec hl
	ld b, NO_INPUT
	jr .finishauto

.next
; On to the next input...
	ld a, l
	ld [wAutoInputAddress], a
	ld a, h
	ld [wAutoInputAddress + 1], a
	jr .finishauto

.stopauto
	call StopAutoInput
	ld b, NO_INPUT

.finishauto
	pop af
	rst Bankswitch
	ld a, b
	ldh [hJoyPressed], a ; pressed
	ldh [hJoyDown], a ; input
	jr .quit

StartAutoInput::
; Start reading automated input stream at a:hl.

	ld [wAutoInputBank], a
	ld a, l
	ld [wAutoInputAddress], a
	ld a, h
	ld [wAutoInputAddress + 1], a
; Start reading the stream immediately.
	xor a
	ld [wAutoInputLength], a
; Reset input mirrors.
	xor a
	ldh [hJoyPressed], a ; pressed this frame
	ldh [hJoyReleased], a ; released this frame
	ldh [hJoyDown], a ; currently pressed

	ld a, AUTO_INPUT
	ld [wInputType], a
	ret

StopAutoInput::
; Clear variables related to automated input.
	xor a
	ld [wAutoInputBank], a
	ld [wAutoInputAddress], a
	ld [wAutoInputAddress + 1], a
	ld [wAutoInputLength], a
; Back to normal input.
	ld [wInputType], a
	ret

JoyTitleScreenInput:: ; unreferenced
.loop
	call DelayFrame

	push bc
	call JoyTextDelay
	pop bc

; Save data can be deleted by pressing Up + B + Select.
	ldh a, [hJoyDown]
	cp D_UP | SELECT | B_BUTTON
	jr z, .keycombo

; Press Start or A to start the game.
	ldh a, [hJoyLast]
	and START | A_BUTTON
	jr nz, .keycombo

	dec c
	jr nz, .loop

	and a
	ret

.keycombo
	scf
	ret

JoyWaitAorB::
.loop
	call DelayFrame
	call GetJoypad
	ldh a, [hJoyPressed]
	and A_BUTTON | B_BUTTON
	ret nz
	call UpdateTimeAndPals
	jr .loop

WaitButton::
	ldh a, [hOAMUpdate]
	push af
	ld a, 1
	ldh [hOAMUpdate], a
	call WaitBGMap
	call JoyWaitAorB
	pop af
	ldh [hOAMUpdate], a
	ret

JoyTextDelay::
	call GetJoypad
	ldh a, [hInMenu]
	and a
	ldh a, [hJoyPressed]
	jr z, .ok
	ldh a, [hJoyDown]
.ok
	ldh [hJoyLast], a
	ldh a, [hJoyPressed]
	and a
	jr z, .checkframedelay
	ld a, 15
	ld [wTextDelayFrames], a
	ret

.checkframedelay
	ld a, [wTextDelayFrames]
	and a
	jr z, .restartframedelay
	xor a
	ldh [hJoyLast], a
	ret

.restartframedelay
	ld a, 5
	ld [wTextDelayFrames], a
	ret

WaitPressAorB_BlinkCursor::
; Show a blinking cursor in the lower right-hand
; corner of a textbox and wait until A or B is
; pressed.
;
; NOTE: The cursor has to be shown before calling
; this function or no cursor will be shown at all.
	ldh a, [hMapObjectIndex]
	push af
	ldh a, [hObjectStructIndex]
	push af
	xor a
	ldh [hMapObjectIndex], a
	ld a, 6
	ldh [hObjectStructIndex], a

.loop
	push hl
	hlcoord 18, 17
	call BlinkCursor
	pop hl

	call JoyTextDelay
	ldh a, [hJoyLast]
	and A_BUTTON | B_BUTTON
	jr z, .loop

	pop af
	ldh [hObjectStructIndex], a
	pop af
	ldh [hMapObjectIndex], a
	ret

SimpleWaitPressAorB::
.loop
	call JoyTextDelay
	ldh a, [hJoyLast]
	and A_BUTTON | B_BUTTON
	jr z, .loop
	ret

PromptButton::
; Show a blinking cursor in the lower right-hand
; corner of a textbox and wait until A or B is
; pressed, afterwards, play a sound.
	ld a, [wLinkMode]
	and a
	jr nz, .link
	call .wait_input
	push de
	ld de, SFX_READ_TEXT_2
	call PlaySFX
	pop de
	ret

.link
	ld c, 65
	jp DelayFrames

.wait_input
	ldh a, [hOAMUpdate]
	push af
	ld a, $1
	ldh [hOAMUpdate], a
	ld a, [wInputType]
	or a
	jr z, .input_wait_loop
	farcall _DudeAutoInput_A

.input_wait_loop
	call .blink_cursor
	call JoyTextDelay
	ldh a, [hJoyPressed]
	and A_BUTTON | B_BUTTON
	jr nz, .received_input
	call UpdateTimeAndPals
	ld a, $1
	ldh [hBGMapMode], a
	call DelayFrame
	jr .input_wait_loop

.received_input
	pop af
	ldh [hOAMUpdate], a
	ret

.blink_cursor
	ldh a, [hVBlankCounter]
	and %00010000 ; bit 4, a
	jr z, .cursor_off
	ld a, "▼"
	jr .load_cursor_state

.cursor_off
	ld a, "─"

.load_cursor_state
	ldcoord_a 18, 17
	ret

BlinkCursor::
	push bc
	ld a, [hl]
	ld b, a
	ld a, "▼"
	cp b
	pop bc
	jr nz, .place_arrow
	ldh a, [hMapObjectIndex]
	dec a
	ldh [hMapObjectIndex], a
	ret nz
	ldh a, [hObjectStructIndex]
	dec a
	ldh [hObjectStructIndex], a
	ret nz
	ld a, "─"
	ld [hl], a
	ld a, -1
	ldh [hMapObjectIndex], a
	ld a, 6
	ldh [hObjectStructIndex], a
	ret

.place_arrow
	ldh a, [hMapObjectIndex]
	and a
	ret z
	dec a
	ldh [hMapObjectIndex], a
	ret nz
	dec a
	ldh [hMapObjectIndex], a
	ldh a, [hObjectStructIndex]
	dec a
	ldh [hObjectStructIndex], a
	ret nz
	ld a, 6
	ldh [hObjectStructIndex], a
	ld a, "▼"
	ld [hl], a
	ret