menu: SL0P MENU scaffolding with WARP as a submenu

Refactor the flat warp menu into a table-driven top-level SL0P MENU opened by
SELECT. Each entry = a name in SlopMenuText + a routine in SlopMenuHandlers;
handlers return carry set (a warp was started, exit) or clear (back to the
menu). Ships two entries:
  WARP -> WarpSubmenu (the 13-destination town list)
  HEAL -> SlopHealParty (restore party HP + clear status), demoing an action
Shared open/close display handling (hide sprites, single-space flags, wTileMap
push, restore). Add an entry by appending a name+handler and bumping
SLOP_MENU_COUNT. (renamed engine/warp_menu.asm -> engine/slop_menu.asm)

1 files changed, 223 insertions, 0 deletions

diff --git a/engine/slop_menu.asm b/engine/slop_menu.asm
new file mode 100644
index 00000000..56c8e8c5
--- /dev/null
+++ b/engine/slop_menu.asm
@@ -0,0 +1,223 @@
+; SL0P MENU - a top-level menu opened with SELECT in the overworld (hooked in
+; home/overworld.asm). Table-driven so it's easy to grow: each entry has a name
+; in SlopMenuText and a handler in SlopMenuHandlers. A handler returns:
+;     carry SET  -> a map warp was started; exit the menu and let it proceed
+;     carry CLEAR -> return to the SL0P menu (redraw)
+; Handlers may be submenus (WarpSubmenu) or direct actions (SlopHealParty).
+;
+; To add an entry: add a "NAME" line to SlopMenuText, a `dw Handler` to
+; SlopMenuHandlers, and bump SLOP_MENU_COUNT.
+
+DEF SLOP_MENU_COUNT EQU 2
+
+SECTION "Slop Menu", ROMX
+
+SlopMenu::
+; ---- open the menu display (shared by the top menu and every submenu) ----
+	ldh a, [hUILayoutFlags]
+	set BIT_SINGLE_SPACED_LINES, a     ; single-spaced list text
+	set BIT_DOUBLE_SPACED_MENU, a      ; single-spaced cursor
+	ldh [hUILayoutFlags], a
+	ld a, $ff
+	ld [wUpdateSpritesEnabled], a      ; hide the overworld sprites
+	call ClearSprites
+.redraw
+	call ClearScreen
+	hlcoord 5, 1
+	ld de, SlopMenuTitle
+	call PlaceString
+	hlcoord 4, 3
+	lb bc, SLOP_MENU_COUNT + 2, 11
+	call TextBoxBorder
+	hlcoord 6, 4
+	ld de, SlopMenuText
+	call PlaceString
+	call SlopMenuShow
+	xor a
+	ld [wCurrentMenuItem], a
+	ld [wLastMenuItem], a
+	ld [wMenuWatchMovingOutOfBounds], a
+	ld [wMenuJoypadPollCount], a
+	ld a, 5
+	ld [wTopMenuItemX], a
+	ld a, 4
+	ld [wTopMenuItemY], a
+	ld a, PAD_A | PAD_B
+	ld [wMenuWatchedKeys], a
+	ld a, SLOP_MENU_COUNT - 1
+	ld [wMaxMenuItem], a
+	call HandleMenuInput
+	bit B_PAD_B, a
+	jr nz, .close
+; dispatch: call SlopMenuHandlers[wCurrentMenuItem]
+	ld a, [wCurrentMenuItem]
+	add a
+	ld e, a
+	ld d, 0
+	ld hl, SlopMenuHandlers
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld de, .afterHandler
+	push de
+	jp hl                              ; call [hl]; returns to .afterHandler
+.afterHandler
+	jr c, .exitProceed                 ; handler started a warp -> let it run
+	jr .redraw                         ; otherwise back to the SL0P menu
+.exitProceed
+	call SlopMenuRestoreFlags
+	ret
+.close
+	call SlopMenuRestoreFlags
+	ld a, $01
+	ld [wUpdateSpritesEnabled], a
+	call LoadScreenTilesFromBuffer2
+	jp CloseTextDisplay
+
+SlopMenuRestoreFlags:
+	ldh a, [hUILayoutFlags]
+	res BIT_SINGLE_SPACED_LINES, a
+	res BIT_DOUBLE_SPACED_MENU, a
+	ldh [hUILayoutFlags], a
+	ret
+
+; push wTileMap into VRAM and switch on the menu window display (mirrors the
+; tail of DisplayTextIDInit) so a box drawn into wTileMap is actually shown.
+SlopMenuShow:
+	ld b, HIGH(vBGMap1)
+	call CopyScreenTileBufferToVRAM
+	xor a
+	ldh [hWY], a
+	call LoadFontTilePatterns
+	ld a, $01
+	ldh [hAutoBGTransferEnabled], a
+	ret
+
+SlopMenuTitle:
+	db "SL0P MENU@"
+SlopMenuText:
+	db   "WARP"
+	next "HEAL@"
+SlopMenuHandlers:
+	dw WarpSubmenu
+	dw SlopHealParty
+
+
+; ---------------------------------------------------------------------------
+; WARP submenu: a town list. On A, start a fly-warp to the chosen map (no
+; BIT_USED_FLY, so no bird) and return carry set. On B, return carry clear.
+; The display was already set up by SlopMenu.
+; ---------------------------------------------------------------------------
+DEF WARP_COUNT EQU 13
+
+WarpSubmenu:
+	call ClearScreen
+	hlcoord 4, 0
+	ld de, WarpTitleText1
+	call PlaceString
+	hlcoord 5, 1
+	ld de, WarpTitleText2
+	call PlaceString
+	hlcoord 3, 2
+	lb bc, 13, 11
+	call TextBoxBorder
+	hlcoord 5, 3
+	ld de, WarpMenuText
+	call PlaceString
+	call SlopMenuShow
+	xor a
+	ld [wCurrentMenuItem], a
+	ld [wLastMenuItem], a
+	ld [wMenuWatchMovingOutOfBounds], a
+	ld [wMenuJoypadPollCount], a
+	ld a, 4
+	ld [wTopMenuItemX], a
+	ld a, 3
+	ld [wTopMenuItemY], a
+	ld a, PAD_A | PAD_B
+	ld [wMenuWatchedKeys], a
+	ld a, WARP_COUNT - 1
+	ld [wMaxMenuItem], a
+	call HandleMenuInput
+	bit B_PAD_B, a
+	jr nz, .cancel
+	ld a, [wCurrentMenuItem]
+	ld e, a
+	ld d, 0
+	ld hl, WarpMapTable
+	add hl, de
+	ld a, [hl]
+	ld [wDestinationMap], a
+	ld hl, wStatusFlags6
+	set BIT_FLY_WARP, [hl]
+	scf                                ; carry set = warp started
+	ret
+.cancel
+	and a                              ; carry clear = back to SL0P menu
+	ret
+
+WarpTitleText1:
+	db "SECRET SL0P@"
+WarpTitleText2:
+	db "WARP MENU@"
+WarpMenuText:
+	db   "PALLET"
+	next "VIRIDIAN"
+	next "PEWTER"
+	next "CERULEAN"
+	next "LAVENDER"
+	next "VERMILION"
+	next "CELADON"
+	next "FUCHSIA"
+	next "CINNABAR"
+	next "INDIGO"
+	next "SAFFRON"
+	next "ROUTE 4"
+	next "ROUTE 10@"
+WarpMapTable:
+	db PALLET_TOWN, VIRIDIAN_CITY, PEWTER_CITY, CERULEAN_CITY, LAVENDER_TOWN
+	db VERMILION_CITY, CELADON_CITY, FUCHSIA_CITY, CINNABAR_ISLAND, INDIGO_PLATEAU
+	db SAFFRON_CITY, ROUTE_4, ROUTE_10
+
+
+; ---------------------------------------------------------------------------
+; HEAL action: restore every party member to full HP and clear status.
+; Returns carry clear (back to the SL0P menu).
+; ---------------------------------------------------------------------------
+; party_struct offsets: curHP +$01 (BE), status +$04, maxHP +$22 (BE), size $2C
+SlopHealParty:
+	ld a, [wPartyCount]
+	and a
+	jr z, .done
+	ld c, a
+	ld hl, wPartyMon1
+.loop
+	push hl                            ; save mon base
+	ld de, $04
+	add hl, de
+	xor a
+	ld [hl], a                         ; status = 0
+	pop hl
+	push hl
+	ld de, $22
+	add hl, de                         ; -> maxHP
+	ld a, [hli]
+	ld b, a                            ; maxHP hi
+	ld e, [hl]                         ; maxHP lo
+	ld d, b
+	pop hl                             ; mon base
+	push hl
+	inc hl                             ; -> curHP hi
+	ld a, d
+	ld [hli], a
+	ld a, e
+	ld [hl], a                         ; curHP = maxHP
+	pop hl                             ; mon base
+	ld de, $2C
+	add hl, de                         ; next mon
+	dec c
+	jr nz, .loop
+.done
+	and a                              ; carry clear = back to SL0P menu
+	ret