ref: 14a2ea835edc0fdd52b04ecd010a0c123471e0c6
dir: /docs/menu.md/
# Everything you've ever wanted to know about menus* **\* but were afraid to ask** ## Contents - [ScrollingMenu](#scrollingmenu) - [\_2DMenu](#_2dmenu) - [DoNthMenu/SetUpMenu](#donthmenusetupmenu) - [VerticalMenu](#verticalmenu) - [Misc/Generic](#miscgeneric) ## `ScrollingMenu` This is the only menu that does scrolling. It doesn't draw any `TextBox` around the menu. Structure: ```asm .MenuHeader: db MENU_BACKUP_TILES ; flags menu_coords 2, 4, SCREEN_WIDTH - 1, 13 dw .MenuData db 1 ; default option .MenuData: db 0 ; flags db 5, 0 ; rows, columns db 1 ; horizontal spacing dba Items dba Function1 dba Function2 dba Function3 ``` `wMenuDataFlags`: ``` 7: Select is functional 6: Start is functional 5: Call Function3 4: Show arrows on the right-hand side 3: D-Left is functional 2: D-Right is functional 1: Call Function3 only if [wSwitchItem] is 0 0: Call Function1 to display the cancel entry ``` If the columns entry in `MenuData` of a scrolling menu is 0, `Function2` isn't called either. It doesn't affect the position of the arrows. Call state for functions in `MenuData` of `ScrollingMenu`: ``` All of them: [wMenuSelection] = Current item. -1 is the CANCEL item. [wMenuSelectionQuantity] = Quantity of the current item. Function1: Called to display a menu entry. de = Cursor position in TileMap Function2: Called to display the quantity of a menu entry. de = Cursor position in TileMap + columns Function3: Called to display anything else, whenever the cursor is moved. ``` There is no register of importance that should be preserved in any of these functions. The `; horizontal spacing` item in each `MenuData` is a misnomer. It changes how the `Items` struct looks. If it's 1: ``` db entries not including cancel db entry1 db entry2 db -1 ; cancel ... ``` If it's 2: ``` db entries not including cancel db entry1, quantity1 db entry2, quantity2 db -1 ; cancel ... ``` In case it's 1, `[wMenuSelectionQuantity]` will simply contain the next entry. ## `_2DMenu` This, like is implied by the name, is a 2-dimensional menu, where you can move your cursor in all 4 directions. It's only used for the battle menus as well as Earl's academy. Structure: ```asm .MenuHeader: db MENU_BACKUP_TILES ; flags db 12, 08 ; start coords db 17, 19 ; end coords dw .MenuData db 1 ; default option .MenuData: db STATICMENU_CURSOR ; flags dn 2, 2 ; rows, columns db 6 ; spacing dba Strings dba Function ``` `wMenuDataFlags`: ``` 7: Leave one tile of spacing between the left textbox border and the text, enabling the cursor. 6: Don't leave one tile of spacing between the top textbox border and the text 5: Set bits 4 and 5 in w2DMenuFlags1 (Wrap around horizontally and vertically) 4: Unused 3: Unused 2: Unused 1: Select is functional 0: Disable B button ``` The bank for the `Strings` is generated when you call `_2DMenu`, and as such it doesn't really matter what bank you specify there (unless you callba `_2DMenu_` directly, of course). `; spacing` is not a misnomer here, it's used to define how much space there is between columns. `Function` is called after printing all the strings. `hl` will be pointed at the row below the last in the menu in `TileMap`. We don't know of its purpose, since it's never actually used anywhere. Only the bank number is always set to the same bank as the menu, but not used otherwise, since the address is 0. ## `DoNthMenu`/`SetUpMenu` These are like the regular `VerticalMenu`, except they allow for creating slightly more "dynamic" menus, where the options aren't predefined, much like the `ScrollingMenu`. Structure: ``` .MenuHeader: db MENU_BACKUP_TILES ; flags menu_coords 0, 0, 10, 7 dw .MenuData db 1 ; default option .MenuData: db STATICMENU_CURSOR | STATICMENU_DISABLE_B ; flags db 0 ; items dw Items dw DisplayFunction dw StringPointers ``` `wMenuDataFlags`: ``` 7: Unused 6: Unused 5: Set bit 5 in w2DMenuFlags1 (Wrap around vertically) 4: Unused 3: Start is functional 2: D-left and D-right are functional 1: Unused 0: Unused ``` The `; items` entry should be left empty, as it's autogenerated with the `Items` array in `GetMenuIndexSet`. The bottom coord (`07` in the example) is autogenerated regardless of what you specify when building the MenuBox in `AutomaticGetMenuBottomCoord`, which also calculates the `bc` passed to MenuBox, which is useless because it's calculated again by MenuBox in `GetMenuBoxDims`. `[wWhichIndexSet]` decides which menu is used through `GetMenuIndexSet`. You can define multiple menus at the Items pointer as such: ``` Items: db entries not including cancel db entry1, entry2, entry3 db -1 ; cancel db entries not including cancel for 2nd menu db entry1, entry2, entry3, entry4 db -1 ; cancel ``` This is actively used in `MainMenu`. `StringPointers` isn't handled by `DoNthMenu` internally. It's handled by different `DisplayFunction`s. A custom one could choose to completely ignore it. `StringPointers` struct handled through `PlaceNthMenuStrings` as `DisplayFunction` and `MenuJumptable`: ```asm StringPointers: dw FunctionToCall, PointerToString ; index 1 dw FunctionToCall, PointerToString ; index 2 ... ``` `StringPointers` struct handled through `PlaceMenuStrings`: ```asm StringPointers: db "STRING1@" db "STRING2@" ... ``` Call state for `DisplayFunction`: ``` [wMenuSelection] = Current item. -1 is the CANCEL item. de = Cursor position in TileMap ``` ## `VerticalMenu` This is the simplest menu. Like, the most boring. Nothing special. Just normal. …nooooooormal… Structure: ```asm .MenuHeader: db MENU_SPRITE_ANIMS | MENU_BACKUP_TILES ; flags menu_coords 12, 12, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1 dw .MenuData db 1 ; default option .MenuData: db STATICMENU_CURSOR ; flags db 2 ; # items db "GIVE@" db "TAKE@" ``` `wMenuDataFlags`: ``` 7: Leave one tile of spacing between the left textbox border and the text 6: Don't leave one tile of spacing between the top textbox border and the text 5: Set bit 5 in w2DMenuFlags1 (Wrap around vertically) 4: Place menubox "title". See notes. 3: Unused 2: Unused 1: Select is functional 0: Disable B button ``` If bit 4 is set, a string at the end of the items array will be put at an offset from the start coord of the menu box. This string is defined like this: ```asm db 2 ; # items db "GIVE@" db "TAKE@" db 2 ; x offset db "TEST@" ``` This is used in the menu for selecting the character's name. ## Misc/Generic `MenuHeader` flags (`wMenuFlags`): ``` 7: Save a backup of the tiles 6: Save a backup of the tiles 5: Unused 4: Set bit 6 in w2DMenuFlags1 (Enable sprite animations) 3: Disable click sound 2: Unused 1: Unused 0: Call RestoreTileBackup when exiting the menu. This bit depends on whether bit 6 or 7 are set. ``` `w2DMenuFlags1`: ``` 7: Disable checking of wMenuJoypadFilter 6: Enable sprite animations 5: Wrap around vertically 4: Wrap around horizontally 3: Set bit 7 in w2DMenuFlags2 and exit the loop if bit 5 is disabled and we tried to go too far down 2: Set bit 7 in w2DMenuFlags2 and exit the loop if bit 5 is disabled and we tried to go too far up 1: Set bit 7 in w2DMenuFlags2 and exit the loop if bit 4 is disabled and we tried to go too far left 0: Set bit 7 in w2DMenuFlags2 and exit the loop if bit 4 is disabled and we tried to go too far right ``` `w2DMenuFlags2`: ``` 7: ????? 6: ????? 5: ????? 4: ????? 3: ????? 2: ????? 1: ????? 0: ????? ```