Implement View Map mode [commit 4]: draw arrows OAM and refactor previous commit to support this (#29)

charmap.asm

@@ -187,7 +187,11 @@ DEF BOARD_MENU_BG_FIRST_TILE   EQU "A"
 
 ; Object tile locations (vTiles0)
 DEF SECONDARY_SPRITES_FIRST_TILE      EQU $20
+
 DEF BOARD_MENU_OAM_FIRST_TILE         EQU SECONDARY_SPRITES_FIRST_TILE
 DEF DIE_ROLL_OAM_FIRST_TILE           EQU BOARD_MENU_OAM_FIRST_TILE + 45 ; max(BOARD_MENU_ITEM_SIZE * NUM_BOARD_MENU_ITEMS, DIE_SIZE * 10)
 DEF DIE_NUMBERS_OAM_FIRST_TILE        EQU BOARD_MENU_OAM_FIRST_TILE
+
 DEF BRANCH_ARROWS_OAM_FIRST_TILE      EQU DIE_NUMBERS_OAM_FIRST_TILE + 40 ; DIE_NUMBER_SIZE * 10
+
+DEF VIEW_MAP_MODE_OAM_FIRST_TILE      EQU SECONDARY_SPRITES_FIRST_TILE

constants/wram_constants.asm

@@ -12,6 +12,7 @@ DEF AUTO_INPUT EQU $ff
 	const SECONDARYSPRITES_DIE_ROLL_F         ; 1
 	const SECONDARYSPRITES_SPACES_LEFT_F      ; 2
 	const SECONDARYSPRITES_BRANCH_ARROWS_F    ; 3
+	const SECONDARYSPRITES_VIEW_MAP_MODE_F    ; 4
 
 ; wCurDexMode::
 	const_def

data/sprites/secondary_sprites.asm

@@ -120,3 +120,10 @@ BranchArrowsOAM:
 	dbsprite  7, 10, 4, 0, BRANCH_ARROWS_OAM_FIRST_TILE + 1, PAL_OW_RED ; left
 	dbsprite  9,  8, 4, 0, BRANCH_ARROWS_OAM_FIRST_TILE + 2, PAL_OW_RED ; up
 	dbsprite  9, 12, 4, 0, BRANCH_ARROWS_OAM_FIRST_TILE + 3, PAL_OW_RED ; down
+
+ViewMapModeArrowsOAM:
+; the PAL_ argument is unused (actual palette comes from the player gender)
+	dbsprite 10, 18, 4, 4, VIEW_MAP_MODE_OAM_FIRST_TILE + 3, PAL_OW_RED ; down
+	dbsprite 10,  2, 4, 4, VIEW_MAP_MODE_OAM_FIRST_TILE + 2, PAL_OW_RED ; up
+	dbsprite  1, 10, 4, 0, VIEW_MAP_MODE_OAM_FIRST_TILE + 1, PAL_OW_RED ; left
+	dbsprite 19, 10, 4, 0, VIEW_MAP_MODE_OAM_FIRST_TILE,     PAL_OW_RED ; right

engine/board/menu.asm

@@ -77,6 +77,7 @@ BoardMenuScript::
 	callasm .EnterViewMapMode
 	appearplayermock
 	closetext
+	callasm .ViewMapModeOAM
 	end
 
 .EnterViewMapMode:
@@ -102,6 +103,13 @@ BoardMenuScript::
 	set INVISIBLE_F, [hl]
 	ret
 
+.ViewMapModeOAM:
+; this runs after closetext to prevent graphical glitches with the board menu OAM
+	farcall LoadViewMapModeGFX
+	ld hl, wDisplaySecondarySprites
+	set SECONDARYSPRITES_VIEW_MAP_MODE_F, [hl]
+	ret
+
 .SubmenuCallback:
 ; if submenu has requested a callback through wMenuReturn,
 ; it has also taken care of queuing it into wQueuedScriptBank/wQueuedScriptAddr.

engine/gfx/load_board_gfx.asm

@@ -48,3 +48,13 @@ LoadBranchArrowsGFX::
 
 .BranchArrowsOAMGFX:
 INCBIN "gfx/board/branch_arrows.2bpp"
+
+LoadViewMapModeGFX::
+	ld de, .ViewMapModeArrowsOAMGFX
+	ld hl, vTiles0 + VIEW_MAP_MODE_OAM_FIRST_TILE * LEN_2BPP_TILE
+	lb bc, BANK(.ViewMapModeArrowsOAMGFX), NUM_DIRECTIONS
+	call Get2bppViaHDMA
+	ret
+
+.ViewMapModeArrowsOAMGFX:
+INCBIN "gfx/board/view_map_arrows.2bpp"

engine/overworld/map_objects.asm

@@ -3114,6 +3114,8 @@ InitSecondarySprites:
 	call nz, InitSpacesLeftNumberSprites
 	bit SECONDARYSPRITES_BRANCH_ARROWS_F, a
 	call nz, InitBranchArrowsSprites
+	bit SECONDARYSPRITES_VIEW_MAP_MODE_F, a
+	call nz, InitViewMapModeSprites
 	ret
 
 InitBoardMenuSprites:
@@ -3254,4 +3256,59 @@ InitBranchArrowsSprites:
 	pop af
 	ret
 
+InitViewMapModeSprites:
+	push af
+
+; find the beginning of free space in OAM, and assure there's space for 4 objects
+	ldh a, [hUsedSpriteIndex]
+	cp (NUM_SPRITE_OAM_STRUCTS * SPRITEOAMSTRUCT_LENGTH) - (NUM_DIRECTIONS * SPRITEOAMSTRUCT_LENGTH) + 1
+	jr nc, .oam_full
+
+	ld hl, ViewMapModeArrowsOAM
+	ld de, wTileDown
+	ld c, NUM_DIRECTIONS
+
+.loop
+	ld a, [de]
+	cp $ff
+	jr z, .next1 ; skip this arrow if this direction is not valid
+	gender_to_pal
+	ld b, a
+; draw this arrow and advance hUsedSpriteIndex
+; preserve loop variables d, e, c
+	push de
+	push bc
+	ldh a, [hUsedSpriteIndex]
+	ld e, a
+	ld d, HIGH(wShadowOAM)
+; copy all bytes minus the attributes one.
+; the palette matches the player's color palette.
+	push bc
+	ld bc, SPRITEOAMSTRUCT_LENGTH - 1
+	call CopyBytes
+	pop bc
+	ld a, b ; palette
+	ld [de], a
+	inc de
+	ld a, e
+	ldh [hUsedSpriteIndex], a
+	pop bc
+	pop de
+	jr .next2
+
+.next1
+	inc hl ;
+	inc hl ;
+	inc hl ;
+
+.next2
+	inc hl ; next object in ViewMapModeArrowsOAM
+	inc de
+	dec c
+	jr nz, .loop
+
+.oam_full
+	pop af
+	ret
+
 INCLUDE "data/sprites/secondary_sprites.asm"

engine/overworld/player_movement.asm

@@ -133,80 +133,96 @@ DoPlayerMovement::
 .ViewMapMode:
 ; if View Map mode, ignore regular collisions but account for going off-limits or off-range
 	call .GetAction
-	call .CheckViewMapModeCollision
+	call .ViewMapMode_CheckCollision
 ; perform a normal step (Stand in place if wWalkingDirection is STANDING)
 	ld a, STEP_WALK
 	call .DoStep
 	scf
 	ret
 
-.CheckViewMapModeCollision:
+.ViewMapMode_CheckCollision:
 ; return STANDING into wWalkingDirection if trying to walk
 ; off-limits (unless there is a connected map) or off-range
-	ld a, [wWalkingDirection]
+
+; as wTileDown, wTileUp, wTileLeft, and wTileRight are not used in this mode,
+; they are borrowed in order to signal valid directions to InitSecondarySprites
+	xor a
+	ld hl, wTileDown
+	ld [hli], a
+	ld [hli], a ; wTileUp
+	ld [hli], a ; wTileLeft
+	ld [hl], a ; wTileRight
+
 	ld hl, wYCoord
 	ld de, wMapHeight
 	ld bc, wSouthConnectedMapGroup
-	cp DOWN
+	ld a, DOWN
-	jr z, .next1
+	call .ViewMapMode_CheckDirectionOffLimits
-;	ld hl, wYCoord
+	ld hl, wYCoord
 	ld de, .TopLimit
 	ld bc, wNorthConnectedMapGroup
-	cp UP
+	ld a, UP
-	jr z, .next1
+	call .ViewMapMode_CheckDirectionOffLimits
 	ld hl, wXCoord
 	ld de, wMapWidth
 	ld bc, wEastConnectedMapGroup
-	cp RIGHT
+	ld a, RIGHT
-	jr z, .next1
+	call .ViewMapMode_CheckDirectionOffLimits
-;	ld hl, wXCoord
+	ld hl, wXCoord
 	ld de, .LeftLimit
 	ld bc, wWestConnectedMapGroup
-	cp LEFT
+	ld a, LEFT
-	jr z, .next1
+	call .ViewMapMode_CheckDirectionOffLimits
-	ret ; wWalkingDirection is already STANDING
 
-; check if walking off-limits
+; now check in which directions the player would be walking off-range
+	ld hl, wViewMapModeRange
+	ld de, wViewMapModeDisplacementY
+	ld bc, wTileDown
+	ld a, [de]
+	cp [hl]
+	jr nz, .next1
+	ld a, $ff
+	ld [bc], a
 .next1
-	ld a, [bc] ; connected map group
+	inc bc ; wTileUp
-	inc a
+	ld a, [de]
-	jr nz, .next2 ; it's ok if there's any connected map in this direction
-	ld a, [de] ; map dimension size (in metatiles), or 0 if moving up/left
-	add a
-	and a
-	jr z, .ok
-	dec a ; if e.g. size is 0x10, limit is at coord=0x1f
-.ok
-	cp [hl] ; player coord (in half-metatiles)
-	jr z, .already_in_limit
-
-.next2
-; not walking off-limits; check if walking off-range
-	ld hl, wViewMapModeDisplacementY
-	ld a, [wWalkingDirection]
-	cp DOWN
-	jr z, .next3
-	cp UP
-	jr z, .next3
-	ld hl, wViewMapModeDisplacementX
-.next3
-	ld c, [hl]
-	cp DOWN
-	jr z, .next4
-	cp RIGHT
-	jr z, .next4
-; if UP or LEFT, the displacement to check is negative
-	ld a, c
 	xor $ff
 	inc a
-	ld c, a
+	cp [hl]
+	jr nz, .next2
+	ld a, $ff
+	ld [bc], a
+.next2
+	ld de, wViewMapModeDisplacementX
+	inc bc ; wTileLeft
+	ld a, [de]
+	xor $ff
+	inc a
+	cp [hl]
+	jr nz, .next3
+	ld a, $ff
+	ld [bc], a
+.next3
+	inc bc ; wTileRight
+	ld a, [de]
+	cp [hl]
+	jr nz, .next4
+	ld a, $ff
+	ld [bc], a
 .next4
-	ld a, [wViewMapModeRange]
-	cp c
-	ret nz
-	; fallthrough
 
-.already_in_limit
+; finally return STANDING into wWalkingDirection in the current direction at
+; wWalkingDirection has had its corresponding wTile* address set to $ff.
+	ld a, [wWalkingDirection]
+	cp STANDING
+	ret z
+	ld hl, wTileDown
+	ld c, a
+	ld b, 0
+	add hl, bc
+	ld a, [hl]
+	inc a ; cp $ff
+	ret nz
 	ld a, STANDING
 	ld [wWalkingDirection], a
 	ret
@@ -215,6 +231,36 @@ DoPlayerMovement::
 .LeftLimit:
 	db 0
 
+; check if player would be walking off-limits in this direction
+.ViewMapMode_CheckDirectionOffLimits:
+	push af
+
+	ld a, [bc] ; connected map group
+	inc a
+	jr nz, .valid ; it's ok if there's any connected map in this direction
+
+	ld a, [de] ; map dimension size (in metatiles), or 0 if moving up/left
+	add a
+	and a
+	jr z, .ok
+	dec a ; if e.g. size is 0x10, limit is at coord=0x1f
+.ok
+	cp [hl] ; player coord (in half-metatiles)
+	jr nz, .valid
+
+; not valid: set wTile* to $ff
+	pop af
+	ld hl, wTileDown
+	ld c, a
+	ld b, 0
+	add hl, bc
+	ld [hl], $ff
+	ret
+
+.valid
+	pop af
+	ret
+
 .CheckTile:
 ; Tiles such as waterfalls and warps move the player
 ; in a given direction, overriding input.

engine/overworld/scripting.asm

@@ -1277,6 +1277,8 @@ Script_reloadmapafterviewmapmode:
 	ld [wDefaultSpawnpoint], a
 	ld a, BOARDEVENT_REDISPLAY_MENU
 	ldh [hCurBoardEvent], a
+	ld hl, wDisplaySecondarySprites
+	res SECONDARYSPRITES_VIEW_MAP_MODE_F, [hl]
 	ld a, MAPSTATUS_ENTER
 	call LoadMapStatus
 	ld hl, wPlayerFlags

home/map.asm

@@ -1515,6 +1515,12 @@ SaveScreen_LoadConnection::
 	ret
 
 GetMovementPermissions::
+; permissions are ignored in View Map mode
+; collisions are handled differently in View Map mode
+	ld a, [hCurBoardEvent]
+	cp BOARDEVENT_VIEW_MAP_MODE
+	ret z
+
 	xor a
 	ld [wTilePermissions], a
 	call .LeftRight

ram/wram.asm

@@ -171,6 +171,9 @@ wTileDown::  db
 wTileUp::    db
 wTileLeft::  db
 wTileRight:: db
+	assert wTileUp - wTileDown == UP
+	assert wTileLeft - wTileDown == LEFT
+	assert wTileRight - wTileDown == RIGHT
 
 wTilePermissions::
 ; set if tile behavior prevents