The Big One Again

Pushing everything I've done, currently doesn't build because the Galarian Birds filesize is too thicc for the section but I need to push this before I go mad

engine/battle/core.asm

@@ -1936,6 +1936,7 @@ DrawPlayerHUDAndHPBar:
 	hlcoord 10, 7
 	call CenterMonName
 	call PlaceString
+	call PrintEXPBar
 	ld hl, wBattleMonSpecies
 	ld de, wLoadedMon
 	ld bc, wBattleMonDVs - wBattleMonSpecies
@@ -7308,3 +7309,187 @@ MeltanIncrement:
 MeltanFullJar:
 	text_far _MeltanFullJar
 	text_end
+
+PrintEXPBar:
+	call CalcEXPBarPixelLength
+	ld a, [hQuotient + 3] ; pixel length
+	ld [wEXPBarPixelLength], a
+	ld b, a
+	ld c, $08
+	ld d, $08
+	coord hl, 17, 11
+.loop
+	ld a, b
+	sub c
+	jr nc, .skip
+	ld c, b
+	jr .loop
+.skip
+	ld b, a
+	ld a, $c0
+	add c
+.loop2
+	ld [hld], a
+	dec d
+	ret z
+	ld a, b
+	and a
+	jr nz, .loop
+	ld a, $c0
+	jr .loop2
+
+CalcEXPBarPixelLength:
+	ld hl, wEXPBarKeepFullFlag
+	bit 0, [hl]
+	jr z, .start
+	res 0, [hl]
+	ld a, $40
+	ld [hQuotient + 3], a
+	ret
+
+.start
+	; get the base exp needed for the current level
+	ld a, [wPlayerBattleStatus3]
+	ld hl, wBattleMonSpecies
+	bit 3, a
+	jr z, .skip
+	ld hl, wPartyMon1
+	call BattleMonPartyAttr
+.skip
+	ld a, [hl]
+	ld [wd0b5], a
+	call GetMonHeader
+	ld a, [wBattleMonLevel]
+	ld d, a
+	ld hl, CalcExperience
+	ld b, BANK(CalcExperience)
+	call Bankswitch
+	ld hl, hMultiplicand
+	ld de, wEXPBarBaseEXP
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hl]
+	ld [de], a
+
+	; get the exp needed to gain a level
+	ld a, [wBattleMonLevel]
+	ld d, a
+	inc d
+	ld hl, CalcExperience
+	ld b, BANK(CalcExperience)
+	call Bankswitch
+
+	; get the address of the active Pokemon's current experience
+	ld hl, wPartyMon1Exp
+	call BattleMonPartyAttr
+
+	; current exp - base exp
+	ld b, h
+	ld c, l
+	ld hl, wEXPBarBaseEXP
+	ld de, wEXPBarCurEXP
+	call SubThreeByteNum
+
+	; exp needed - base exp
+	ld bc, hMultiplicand
+	ld hl, wEXPBarBaseEXP
+	ld de, wEXPBarNeededEXP
+	call SubThreeByteNum
+
+	; make the divisor an 8-bit number
+	ld hl, wEXPBarNeededEXP
+	ld de, wEXPBarCurEXP + 1
+	ld a, [hli]
+	and a
+	jr z, .twoBytes
+	ld a, [hli]
+	ld [hld], a
+	dec hl
+	ld a, [hli]
+	ld [hld], a
+	ld a, [de]
+	inc de
+	ld [de], a
+	dec de
+	dec de
+	ld a, [de]
+	inc de
+	ld [de], a
+	dec de
+	xor a
+	ld [hli], a
+	ld [de], a
+	inc de
+.twoBytes
+	ld a, [hl]
+	and a
+	jr z, .oneByte
+	srl a
+	ld [hli], a
+	ld a, [hl]
+	rr a
+	ld [hld], a
+	ld a, [de]
+	srl a
+	ld [de], a
+	inc de
+	ld a, [de]
+	rr a
+	ld [de], a
+	dec de
+	jr .twoBytes
+.oneByte
+
+	; current exp * (8 tiles * 8 pixels)
+	ld hl, hMultiplicand
+	ld de, wEXPBarCurEXP
+	ld a, [de]
+	inc de
+	ld [hli], a
+	ld a, [de]
+	inc de
+	ld [hli], a
+	ld a, [de]
+	ld [hl], a
+	ld a, $40
+	ld [hMultiplier], a
+	call Multiply
+
+	; product / needed exp = pixel length
+	ld a, [wEXPBarNeededEXP + 2]
+	ld [hDivisor], a
+	ld b, $04
+	jp Divide
+
+; calculates the three byte number starting at [bc]
+; minus the three byte number starting at [hl]
+; and stores it into the three bytes starting at [de]
+; assumes that [hl] is smaller than [bc]
+SubThreeByteNum:
+	call .subByte
+	call .subByte
+.subByte
+	ld a, [bc]
+	inc bc
+	sub [hl]
+	inc hl
+	ld [de], a
+	jr nc, .noCarry
+	dec de
+	ld a, [de]
+	dec a
+	ld [de], a
+	inc de
+.noCarry
+	inc de
+	ret
+
+; return the address of the BattleMon's party struct attribute in hl
+BattleMonPartyAttr:
+	ld a, [wPlayerMonNumber]
+	ld bc, wPartyMon2 - wPartyMon1
+	jp AddNTimes

engine/battle/effects.asm

@@ -804,7 +804,6 @@ ThrashPetalDanceEffect:
 	inc a
 	ld [de], a ; set thrash/petal dance counter to 2 or 3 at random
 	ldh a, [hWhoseTurn]
-	add SHRINKING_SQUARE_ANIM
 	jp PlayBattleAnimation2
 
 SwitchAndTeleportEffect:

engine/battle/experience.asm

@@ -167,6 +167,7 @@ GainExperience:
     xor a ; PLAYER_PARTY_DATA
     ld [wMonDataLocation], a
 	call LoadMonData
+	call AnimateEXPBar
 	pop hl
 	ld bc, wPartyMon1Level - wPartyMon1Exp
 	add hl, bc
@@ -177,6 +178,7 @@ GainExperience:
 	ld [wTempLevel], a
 	cp d
 	jp z, .nextMon ; if level didn't change, go to next mon
+	call KeepEXPBarFull
 	ld a, [wCurEnemyLVL]
 	push af
 	push hl
@@ -399,3 +401,71 @@ GrewLevelText:
 	text_far _GrewLevelText
 	sound_level_up
 	text_end
+
+AnimateEXPBarAgain:
+	call IsCurrentMonBattleMon
+	ret nz
+	xor a
+	ld [wEXPBarPixelLength], a
+	coord hl, 17, 11
+	ld a, $c0
+	ld c, $08
+.loop
+	ld [hld], a
+	dec c
+	jr nz, .loop
+AnimateEXPBar:
+	call IsCurrentMonBattleMon
+	ret nz
+	ld a, SFX_HEAL_HP
+	call PlaySoundWaitForCurrent
+	ld hl, CalcEXPBarPixelLength
+	ld b, BANK(CalcEXPBarPixelLength)
+	call Bankswitch
+	ld hl, wEXPBarPixelLength
+	ld a, [hl]
+	ld b, a
+	ld a, [hQuotient + 3]
+	ld [hl], a
+	sub b
+	jr z, .done
+	ld b, a
+	ld c, $08
+	coord hl, 17, 11
+.loop1
+	ld a, [hl]
+	cp $c8
+	jr nz, .loop2
+	dec hl
+	dec c
+	jr z, .done
+	jr .loop1
+.loop2
+	inc a
+	ld [hl], a
+	call DelayFrame
+	dec b
+	jr z, .done
+	jr .loop1
+.done
+	ld bc, $08
+	coord hl, 10, 11
+	ld de, wTileMapBackup + 10 + 11 * 20
+	call CopyData
+	ld c, $20
+	jp DelayFrames
+
+KeepEXPBarFull:
+	call IsCurrentMonBattleMon
+	ret nz
+	ld a, [wEXPBarKeepFullFlag]
+	set 0, a
+	ld [wEXPBarKeepFullFlag], a
+	ret
+
+IsCurrentMonBattleMon:
+	ld a, [wPlayerMonNumber]
+	ld b, a
+	ld a, [wWhichPokemon]
+	cp b
+	ret