Refactor book code, close namespaces, housekeeping

Items/book_of_secrets.asm

@@ -1,10 +1,57 @@
-;===========================================================
-; Book of Secrets
+; =============================================================================
+; Book of Secrets (Reveal Secrets with Book of Mudora)
+; Makes BG2 Disappear when pressing X+R
+; Based on the Parallel Worlds feature
 ;
+; Bank 0x3C used for whole code
+; 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"
 ;
-;===========================================================
+; Written by XaserLE
+; Edited by scawful
+; =============================================================================
 
-namespace Book
-{
-  incsrc "reveal_secrets.asm"
-}  ; namespace Book
+; =============================================================================
+; code that branches behind the dungeon map load if player didn't press X
+org $0288FD			  
+BRA $1C				    ; make it always branch, so map isn't loaded anymore
+
+; =============================================================================
+; long subroutine that is executed every frame
+org $068365			  
+JSL $3CA600			  ; overwrite it (originally JSL $099F91)
+
+; =============================================================================
+; go to expanded space to write our routine 
+; (keep EveryFrame.asm in mind for the right adresses)
+org $3CA600			  
+LDA $1B				    ; load data that tells us whether we are in a building or not
+AND #$01			    ; are we in a building?
+BEQ END				    ; if not, don't use the x-button-secret
+
+  ; ----------
+  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:
+JSL $099F91			  ; at least execute original code
+RTL
+
+; =============================================================================