1 files changed, 151 insertions, 0 deletions
diff --git a/engine/overworld/step_functions.asm b/engine/overworld/step_functions.asm
new file mode 100644
index 00000000..84b09291
--- /dev/null
+++ b/engine/overworld/step_functions.asm
@@ -0,0 +1,151 @@
+ApplyOutOfBattlePoisonDamage:
+	ld a, [wd730]
+	add a
+	jp c, .noBlackOut ; no black out if joypad states are being simulated
+	ld a, [wd492]
+	bit 7, a
+	jp nz, .noBlackOut
+	ld a, [wd72e]
+	bit 6, a
+	jp nz, .noBlackOut
+	ld a, [wPartyCount]
+	and a
+	jp z, .noBlackOut
+	call IncrementDayCareMonExp
+	call Func_c4c7
+	ld a, [wStepCounter]
+	and $3 ; is the counter a multiple of 4?
+	jp nz, .skipPoisonEffectAndSound ; only apply poison damage every fourth step
+	ld [wWhichPokemon], a
+	ld hl, wPartyMon1Status
+	ld de, wPartySpecies
+.applyDamageLoop
+	ld a, [hl]
+	and (1 << PSN)
+	jr z, .nextMon2 ; not poisoned
+	dec hl
+	dec hl
+	ld a, [hld]
+	ld b, a
+	ld a, [hli]
+	or b
+	jr z, .nextMon ; already fainted
+; subtract 1 from HP
+	ld a, [hl]
+	dec a
+	ld [hld], a
+	inc a
+	jr nz, .noBorrow
+; borrow 1 from upper byte of HP
+	dec [hl]
+	inc hl
+	jr .nextMon
+.noBorrow
+	ld a, [hli]
+	or [hl]
+	jr nz, .nextMon ; didn't faint from damage
+; the mon fainted from the damage
+	push hl
+	inc hl
+	inc hl
+	ld [hl], a
+	ld a, [de]
+	ld [wd11e], a
+	push de
+	ld a, [wWhichPokemon]
+	ld hl, wPartyMonNicks
+	call GetPartyMonName
+	xor a
+	ld [wJoyIgnore], a
+	call EnableAutoTextBoxDrawing
+	ld a, $d0
+	ld [hSpriteIndexOrTextID], a
+	call DisplayTextID
+	callab IsThisPartymonStarterPikachu_Party
+	jr nc, .curMonNotPlayerPikachu
+	ld e, $3
+	callab PlayPikachuSoundClip
+	calladb_ModifyPikachuHappiness PIKAHAPPY_PSNFNT
+.curMonNotPlayerPikachu
+	pop de
+	pop hl
+.nextMon
+	inc hl
+	inc hl
+.nextMon2
+	inc de
+	ld a, [de]
+	inc a
+	jr z, .applyDamageLoopDone
+	ld bc, wPartyMon2 - wPartyMon1
+	add hl, bc
+	push hl
+	ld hl, wWhichPokemon
+	inc [hl]
+	pop hl
+	jr .applyDamageLoop
+.applyDamageLoopDone
+	ld hl, wPartyMon1Status
+	ld a, [wPartyCount]
+	ld d, a
+	ld e, 0
+.countPoisonedLoop
+	ld a, [hl]
+	and (1 << PSN)
+	or e
+	ld e, a
+	ld bc, wPartyMon2 - wPartyMon1
+	add hl, bc
+	dec d
+	jr nz, .countPoisonedLoop
+	ld a, e
+	and a ; are any party members poisoned?
+	jr z, .skipPoisonEffectAndSound
+	ld b, $2
+	predef InvertBGPal_4Frames ; change BG white to dark grey for 4 frames
+	ld a, SFX_POISONED
+	call PlaySound
+.skipPoisonEffectAndSound
+	predef AnyPartyAlive
+	ld a, d
+	and a
+	jr nz, .noBlackOut
+	call EnableAutoTextBoxDrawing
+	ld a, $d1
+	ld [hSpriteIndexOrTextID], a
+	call DisplayTextID
+	ld hl, wd72e
+	set 5, [hl]
+	ld a, $ff
+	jr .done
+.noBlackOut
+	xor a
+.done
+	ld [wOutOfBattleBlackout], a
+	ret
+
+Func_c4c7:
+	ld a, [wStepCounter]
+	and a
+	jr nz, .asm_c4de
+	call Random
+	and $1
+	jr z, .asm_c4de
+	calladb_ModifyPikachuHappiness $6
+.asm_c4de
+	ld hl, wPikachuMood
+	ld a, [hl]
+	cp $80
+	jr z, .asm_c4ef
+	jr c, .asm_c4ea
+	dec a
+	dec a
+.asm_c4ea
+	inc a
+	ld [hl], a
+	cp $80
+	ret nz
+.asm_c4ef
+	xor a
+	ld [wd49c], a
+	ret