From 0986626f38ce64adaa9a19991124d60082a094f1 Mon Sep 17 00:00:00 2001
From: Justin Scofield <justin.scofield@outlook.com>
Date: Mon, 30 May 2022 23:12:35 -0400
Subject: [PATCH] Book of Mudora reveals secrets hack

---
 Book/book.asm           | 10 ++++++++++
 Book/reveal_secrets.asm | 44 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 Book/book.asm
 create mode 100644 Book/reveal_secrets.asm

diff --git a/Book/book.asm b/Book/book.asm
new file mode 100644
index 0000000..4177623
--- /dev/null
+++ b/Book/book.asm
@@ -0,0 +1,10 @@
+;===========================================================
+; Book of Secrets
+;
+;
+;===========================================================
+
+namespace Book
+{
+  incsrc "reveal_secrets.asm"
+}  ; namespace Book
\ No newline at end of file
diff --git a/Book/reveal_secrets.asm b/Book/reveal_secrets.asm
new file mode 100644
index 0000000..7c6686f
--- /dev/null
+++ b/Book/reveal_secrets.asm
@@ -0,0 +1,44 @@
+;this is for making BG2 disappear when pressing X+R and having the book of mudora (modified parallel worlds x button secret), i use bank 0x3C for the whole code
+;WRITTEN: 	by XaserLE
+;THANKS TO: -MathOnNapkins' Zelda Doc's
+;			-wiiqwertyuiop for his Zelda Disassembly
+
+; Layer Flags: xxxsabcd (i count BG from 1 to 4 - MathOnNapkins RAM-Map counts from 0 to 3)
+; s - Sprite layer enabled 
+; a - BG4 enabled
+; b - BG3 enabled
+; c - BG2 enabled
+; d - (BG1 disabled) --> only works properly if the room uses the feature "BG2 on Top"
+
+header
+lorom
+
+
+ORG $0288FD			; go to the code that branches behind the dungeon map load if player didn't press X
+BRA $1C				; make it always branch, so map isn't loaded anymore
+
+ORG $068365			; go to an originally JSL that is executed every frame
+JSL $3CA600			; overwrite it (originally JSL $099F91)
+
+ORG $3CA600			; go to expanded space to write our routine (keep EveryFrame.asm in mind for the right adresses)
+LDA $1B				; load data that tells us whether we are in a building or not
+AND #$01			; are we in a building?
+BEQ END_XBUTTONSECRET				; if not, don't use the x-button-secret
+	;BG2 disable on pressing R
+	LDA $7EF34D			; load book of mudora slot
+	CMP #$01			; do we have the moon pearl?
+	BNE $0F				; if not, go to enable BG2
+	LDA $F2				; load unfiltered joypad 1 register (AXLR|????)
+	AND #$50 			; delete all bits except those for X and R
+	SEC 				; set carry for the following subtraction
+	SBC #$50			; X+R button pressed? (if yes, zero flag is set)
+	BNE $06				; if not, go to enable BG2
+		LDA $1C				; load layer flags
+		AND #$FD			; disable BG2 (0xFD = 11111101)
+		BRA $04				; go to store layer flags
+	LDA $1C				; load layer flags
+	ORA #$02			; enable BG2 (0x02 = 00000010)
+	STA $1C				; store layer flags
+END_XBUTTONSECRET:
+JSL $099F91			; at least execute original code
+RTL
\ No newline at end of file