ref: 9ac0fc631b313af94ee4fcc9f261e72550884a5f
dir: /engine/joypad.asm/
JoypadInt: ; 92e ; Replaced by Joypad, called from VBlank instead of the useless ; joypad interrupt. ; This is a placeholder in case the interrupt is somehow enabled. reti ; 92f ClearJoypadPublic: ; 92f xor a ; Pressed this frame (delta) ld [hJoyPressed], a ; Currently pressed ld [hJoyDown], a ret ; 935 Joypad: ; 935 ; 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, [$cfbe] and %11010000 ret nz ; If we're saving, input is disabled. ld a, [$c2cd] and a ret nz ; We can only get four inputs at a time. ; We take d-pad first for no particular reason. ld a, D_PAD ld [rJOYP], a ; Read twice to give the request time to take. ld a, [rJOYP] ld 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, BUTTONS ld [rJOYP], a ; Wait for input to stabilize. ld a, [rJOYP] ld a, [rJOYP] ld a, [rJOYP] ld a, [rJOYP] ld a, [rJOYP] ld a, [rJOYP] ; 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 ld [rJOYP], a ; To get the delta we xor the last frame's input with the new one. ld a, [hJoypadDown] ; last frame ld e, a xor b ld d, a ; Released this frame: and e ld [hJoypadReleased], a ; Pressed this frame: ld a, d and b ld [hJoypadPressed], a ; Add any new presses to the list of collective presses: ld c, a ld a, [hJoypadSum] or c ld [hJoypadSum], a ; Currently pressed: ld a, b ld [hJoypadDown], a ; Now that we have the input, we can do stuff with it. ; For example, soft reset: and BUTTON_A | BUTTON_B | SELECT | START cp BUTTON_A | BUTTON_B | SELECT | START jp z, Reset ret ; 984 GetJoypadPublic: ; 984 ; 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, [InputType] cp a, AUTO_INPUT jr z, .auto ; To get deltas, take this and last frame's input. ld a, [hJoypadDown] ; real input ld b, a ld a, [hJoyDown] ; last frame mirror ld e, a ; Released this frame: xor b ld d, a and e ld [hJoyReleased], a ; Pressed this frame: ld a, d and b ld [hJoyPressed], a ; It looks like the collective presses got commented out here. ld c, a ; Currently pressed: ld a, b ld [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. ld a, [hROMBank] push af ld a, [AutoInputBank] rst Bankswitch ld hl, AutoInputAddress ld a, [hli] ld h, [hl] ld l, a ; We only update when the input duration has expired. ld a, [AutoInputLength] and a jr z, .updateauto ; Until then, don't change anything. dec a ld [AutoInputLength], a pop af rst Bankswitch jr .quit .updateauto ; An input of $ff will end the stream. ld a, [hli] cp a, $ff jr z, .stopauto ld b, a ; A duration of $ff will end the stream indefinitely. ld a, [hli] ld [AutoInputLength], a cp a, $ff 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 [AutoInputAddress], a ld a, h ld [AutoInputAddress+1], a jr .finishauto .stopauto call StopAutoInput ld b, NO_INPUT .finishauto pop af rst Bankswitch ld a, b ld [hJoyPressed], a ; pressed ld [hJoyDown], a ; input jr .quit ; 9ee StartAutoInput: ; 9ee ; Start reading automated input stream at a:hl. ld [AutoInputBank], a ld a, l ld [AutoInputAddress], a ld a, h ld [AutoInputAddress+1], a ; Start reading the stream immediately. xor a ld [AutoInputLength], a ; Reset input mirrors. xor a ld [hJoyPressed], a ; pressed this frame ld [hJoyReleased], a ; released this frame ld [hJoyDown], a ; currently pressed ld a, AUTO_INPUT ld [InputType], a ret ; a0a StopAutoInput: ; a0a ; Clear variables related to automated input. xor a ld [AutoInputBank], a ld [AutoInputAddress], a ld [AutoInputAddress+1], a ld [AutoInputLength], a ; Back to normal input. ld [InputType], a ret ; a1b