1 files changed, 218 insertions, 0 deletions
diff --git a/Level-cap.md b/Level-cap.md
new file mode 100644
index 0000000..fbe21ff
--- /dev/null
+++ b/Level-cap.md
@@ -0,0 +1,218 @@
+This tutorial guides you through changing the max level.  You will add a new variable, modify level cap logic, and optionally remove gaining exp. once a pokemon is the max level.
+
+**TODO**: 
+Investigate wether one is able to set the level cap by modifying `MAX_LEVEL EQU [0-255]` in `constants/battle_constants.asm`.
+
+## 1. Add Level Cap variable
+First, we want to add a `wLevelCap` variable to `wram.asm` in the root folder.
+In `wram.asm`, go to line 2668, `wBeverlyFightCount:: db ; unused`.
+Since this byte is unused, you can replace it.
+Replace this line with `wLevelCap:: db`.
+This is the value we'll be checking for the level cap
+
+```diff
+; fight counts
+wJackFightCount::    db ; d9f2
+- wBeverlyFightCount:: db ; unused
++ wLevelCap:: db
+wHueyFightCount::    db
+wGavenFightCount::   db
+```
+
+To set the level cap, write this in a script:
+`loadmem wLevelCap, [0-255] ; number from 0 to 255 representing what your level cap should be`
+
+## 2. Replace first level cap check
+
+In `engine/pokemon/experience.asm`, go to line 9: `cp LOW(MAX_LEVEL + 1)`.
+This is what we first need to change.
+Before the `ld a, d` on the line before it, add code to load the new level cap into register `b`.
+
+```diff
+.next_level
+	inc d
++	ld a, [wLevelCap]
++	inc a
++	push bc
++	ld b, a
+	ld a, d
++	cp b
++	pop bc
+	cp LOW(MAX_LEVEL + 1)
+	jr z, .got_level
+	call CalcExpAtLevel
+```
+
+## 3. Replace the rest of the cap checks
+
+There are now five more instances of `MAX_LEVEL` that you'll need to change.
+First, go to the `.no_exp_overflow` label located in `engine/battle/core.asm`.
+Instead of storing the `MAX_LEVEL` value, we load our custom max level.
+
+```diff
+.no_exp_overflow
+	ld a, [wCurPartyMon]
+	ld e, a
+	ld d, 0
+	ld hl, wPartySpecies
+	add hl, de
+	ld a, [hl]
+	ld [wCurSpecies], a
+	call GetBaseData
+	push bc
+-	ld d, MAX_LEVEL
++	push af
++	ld a, [wLevelCap]
++	ld d, a
++	pop af
+	callfar CalcExpAtLevel
+```
+
+Next, `ctrl + f` for the next instance of `MAX_LEVEL`, located in the `.not_max_exp` label. You'll notice that the line before this reads `ld a, [hl]` Before this line, load the level cap into register b. Then, after `ld a, [hl]`, add a comparison and restore the `bc` register.  Here we use the comparison to control the jump.
+
+```diff
+.not_max_exp
+; Check if the mon leveled up
+	xor a ; PARTYMON
+	ld [wMonType], a
+	predef CopyMonToTempMon
+	callfar CalcLevel
+	pop bc
+	ld hl, MON_LEVEL
+	add hl, bc
++	ld a, [wLevelCap]
++	push bc
++	ld b, a
+	ld a, [hl]
++	cp b
++	pop bc
+-	cp MAX_LEVEL
+	jp nc, .next_mon
+```
+
+Third, ctrl + f for the next instance of MAX_LEVEL, located in the `AnimateExpBar` label. You'll notice there's a `ld a, [wBattleMonLevel]` before it. Before this, add
+
+```diff
+AnimateExpBar:
+	push bc
+
+	ld hl, wCurPartyMon
+	ld a, [wCurBattleMon]
+	cp [hl]
+	jp nz, .finish
+
++	ld a, [wLevelCap]
++	push bc
++	ld b, a
+	ld a, [wBattleMonLevel]
++	cp b
++	pop bc
+-	cp MAX_LEVEL
+	jp nc, .finish
+```
+
+Fourth, ctrl + f for the next instance of MAX_LEVEL. Replace `ld d, MAX_LEVEL` with loading the custom max level.
+
+```diff
+	ld [hli], a
+	ld [hl], a
+
+.NoOverflow:
++	push af
++	ld a, [wLevelCap]
++	ld d, a
++	pop af
+	callfar CalcExpAtLevel
+	ldh a, [hProduct + 1]
+	ld b, a
+```
+
+Fifth, ctrl + f for the final instance of MAX_LEVEL. You'll notice before it reads `ld a, e`. Before this, lod the level cap into b, then do the comparison on that.
+
+```diff
+	ld a, e
+	ld d, a
+
+.LoopLevels:
++	ld a, [wLevelCap]
++	push bc
++	ld b, a
+	ld a, e
+-	cp MAX_LEVEL
++	cp b
++	pop bc
+	jr nc, .FinishExpBar
+	cp d
+	jr z, .FinishExpBar
+	inc a
+```
+
+Now you're done with replacing the max level checks with the level cap checks.
+
+## 4. Optional: Remove exp. gain text at max level
+
+You'll notice that the exp. gain text still displays when you reach the level cap.
+To remove this, go to line 7059 in `engine/battle/core.asm`, which should be about the lines of
+
+```diff
+.stat_exp_awarded
+	inc de
+	inc de
+	dec c
+	jr nz, .stat_exp_loop
++	pop bc
++	ld hl, MON_LEVEL
++	add hl, bc
++	ld a, [wLevelCap]
++	push bc
++	ld b, a
++	ld a, [hl]
++	cp b
++	pop bc
++	jp nc, .next_mon
++	push bc
+	xor a
+	ldh [hMultiplicand + 0], a
+	ldh [hMultiplicand + 1], a
+	ld a, [wEnemyMonBaseExp]
+```
+
+Next, go to
+
+```diff
+.EvenlyDivideExpAmongParticipants:
+; count number of battle participants
+	ld a, [wBattleParticipantsNotFainted]
+	ld b, a
+	ld c, PARTY_LENGTH
+	ld d, 0
+.count_loop
++	push bc
++	push de
++	ld a, [wLevelCap]
++	ld b, a
++	ld a, [wPartyCount]
++	cp c
++	jr c, .no_mon
++	ld a, c
++	dec a
++	ld hl, wPartyMon1Level
++	call GetPartyLocation
++	ld a, [hl]
++.no_mon
++	cp b
++	pop de
++	pop bc
++	jr nz, .gains_exp
++	srl b
++	ld a, d
++	jr .no_exp
++.gains_exp
+	xor a
+	srl b
+	adc d
+	ld d, a
++.no_exp
+	dec c
+	jr nz, .count_loop
+```