Useful patches

This page describes code patches which can be applied to the disassembly to make various useful changes.

Both games

Remove Beginning Locks

When you begin a game, you cannot open the menu, and music does not play properly. This state doesn't get lifted until you view the intro cutscenes.

You probably don't want this. There is a simple way to disable this. Simply navigate to constants/common/version.s and add the following line at the bottom:

.redefine HACK_DISABLE_INTRO_LOCKS 1

This will activate some code added to the hack-base branch which disables the intro events. If you'd like to learn how this works, read on.

How it works

A single flag named "GLOBALFLAG_INTRO_DONE" is responsible for these events. The uses of this flag can be easily found by running git grep GLOBALFLAG_INTRO_DONE in the oracles-disasm folder:

$ git grep GLOBALFLAG_INTRO_DONE
code/ages/roomSpecificTileChanges.s:    ld a,GLOBALFLAG_INTRO_DONE
code/bank1.s:   ld a, GLOBALFLAG_INTRO_DONE
code/bank2.s:   ld a,(wGlobalFlags+GLOBALFLAG_INTRO_DONE/8)
code/bank2.s:   bit GLOBALFLAG_INTRO_DONE&7,a
code/seasons/roomGfxChanges.s:  ld a,GLOBALFLAG_INTRO_DONE
constants/globalFlags.s:        GLOBALFLAG_INTRO_DONE                   db ; $0a: Once set, start/select are usable
[...etc...]

It is used a number of times, but we're going to focus on its occurrences in bank1.s and bank2.s.

See the following code in code/bank1.s:

checkPlayRoomMusic:
; HACK-BASE: This define allows music to play before finishing the intro
.ifndef HACK_DISABLE_INTRO_LOCKS
	ld a, GLOBALFLAG_INTRO_DONE
	call checkGlobalFlag
	ret z
.endif

We can see that these 3 lines of code, which are responsible for disabling the music before completing the intro, are wrapped around .ifndef HACK_DISABLE_INTRO_LOCKS. .ifndef stands for "if not defined", meaning the code will only exist if HACK_DISABLE_INTRO_LOCKS is never defined. Because we defined it in version.s, the code becomes disabled.

Moving on, we can find the following code in code/bank2.s:

; HACK-BASE: This define allows opening the inventory without finishing the intro
.ifndef HACK_DISABLE_INTRO_LOCKS
	ld a,(wKeysJustPressed)
	and BTN_START | BTN_SELECT
	jr z,+

	; Return if you haven't seen the opening cutscene yet
	ld a,(wGlobalFlags+GLOBALFLAG_INTRO_DONE/8)
	bit GLOBALFLAG_INTRO_DONE&7,a
	ld a, SND_ERROR
	jp z,playSound
+
.endif

Similarly, this code does not allow you to open the inventory unless you've cleared the intro. Having HACK_DISABLE_INTRO_LOCKS defined disables the code in question.