Overworld HUD implementation (#15)

constants/gfx_constants.asm

@@ -55,3 +55,8 @@ DEF SPRITE_GFX_LIST_CAPACITY EQU 32 ; see wUsedSprites
 	const ANIM_MON_HOF
 	const ANIM_MON_EGG1
 	const ANIM_MON_EGG2
+
+; LoadHUD indexes (see engine/gfx/hud.asm)
+	const_def 1
+	const HUD_OVERWORLD ; 1
+DEF NUM_HUD_TYPES EQU const_value - 1

constants/hardware_constants.asm

@@ -132,15 +132,15 @@ DEF rLCDC_ENABLE         EQU 7     ; 0=Off, 1=On
 DEF LCDC_DEFAULT         EQU (1 << rLCDC_ENABLE) | (1 << rLCDC_WINDOW_TILEMAP) | (1 << rLCDC_WINDOW_ENABLE) | (1 << rLCDC_SPRITES_ENABLE) | (1 << rLCDC_BG_PRIORITY)
 DEF rSTAT                EQU $ff41 ; LCDC Status (R/W)
 DEF rSTAT_STATUS_FLAGS   EQU  %00000011 ; LCD controller status (Read Only)
-DEF rSTAT_HBLANK_MASK    EQU  %00000000 ; In H-Blank (Read Only)
+DEF rSTAT_HBLANK_MASK    EQU  %00000000 ; In Mode 0: H-Blank (Read Only)
-DEF rSTAT_VBLANK_MASK    EQU  %00000001 ; In V-Blank (Read Only)
+DEF rSTAT_VBLANK_MASK    EQU  %00000001 ; In Mode 1: V-Blank (Read Only)
-DEF rSTAT_OAM_MASK       EQU  %00000010 ; OAM is used by system (Read Only)
+DEF rSTAT_OAM_MASK       EQU  %00000010 ; In Mode 2: OAM is used by system (Read Only)
-DEF rSTAT_LCD_MASK       EQU  %00000011 ; Both OAM and VRAM used by system (Read Only)
+DEF rSTAT_LCD_MASK       EQU  %00000011 ; In Mode 3: Both OAM and VRAM used by system (Read Only)
 DEF rSTAT_BUSY           EQU 1     ; When set, VRAM access is unsafe (Read Only)
 DEF rSTAT_LYC            EQU 2     ; LYC=LY (0=Different, 1=Equal) (Read Only)
-DEF rSTAT_INT_HBLANK     EQU 3     ; Mode 00: H-Blank (Selectable)
+DEF rSTAT_INT_HBLANK     EQU 3     ; Mode 0: H-Blank (Selectable)
-DEF rSTAT_INT_VBLANK     EQU 4     ; Mode 01: V-Blank (Selectable)
+DEF rSTAT_INT_VBLANK     EQU 4     ; Mode 1: V-Blank (Selectable)
-DEF rSTAT_INT_OAM        EQU 5     ; Mode 02: OAM (Selectable)
+DEF rSTAT_INT_OAM        EQU 5     ; Mode 2: OAM (Selectable)
 DEF rSTAT_INT_LYC        EQU 6     ; LYC=LY Coincidence (Selectable)
 DEF rSCY                 EQU $ff42 ; Scroll Y (R/W)
 DEF rSCX                 EQU $ff43 ; Scroll X (R/W)

engine/gfx/dma_transfer.asm

@@ -41,12 +41,12 @@ HDMATransferTilemapAndAttrmap_OverworldEffect::
 	call PadTilemapForHDMATransfer
 	call DelayFrame
 
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .go
-	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUD] >= 0)
+	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUDLY] >= 0)
 .wait_lcd
-;	ldh a, [hWindowHUD]
+;	ldh a, [hWindowHUDLY]
 	ld b, a
 	ldh a, [rLY]
 	sub b
@@ -86,12 +86,12 @@ _HDMATransferTilemapAndAttrmap_OpenAndCloseMenu::
 	call PadTilemapForHDMATransfer
 	call DelayFrame
 
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .go
-	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUD] >= 0)
+	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUDLY] >= 0)
 .wait_lcd
-;	ldh a, [hWindowHUD]
+;	ldh a, [hWindowHUDLY]
 	ld b, a
 	ldh a, [rLY]
 	sub b
@@ -276,12 +276,12 @@ _continue_HDMATransfer:
 	cp d
 	jr nc, .ly_loop
 
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .go
-	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUD] >= 0)
+	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUDLY] >= 0)
 .wait_lcd
-;	ldh a, [hWindowHUD]
+;	ldh a, [hWindowHUDLY]
 	ld b, a
 	ldh a, [rLY]
 	sub b

engine/gfx/hud.asm

@@ -0,0 +1,29 @@
+_LoadHUD::
+	jumptable .Jumptable, wWhichHUD
+
+.Jumptable:
+; entries correspond to HUD_* constants (see constants/gfx_constants.asm)
+	table_width 2, _LoadHUD.Jumptable
+	dw .None
+	dw _LoadOverworldHUDTilemapAndAttrmap
+	assert_table_length NUM_HUD_TYPES + 1
+
+.None:
+	ret
+
+_LoadOverworldHUDTilemapAndAttrmap:
+	call _LoadOverworldHUDAttrmap
+	; fallthrough
+
+_LoadOverworldHUDTilemap:
+	; overworld HUD reads SCREEN_WIDTH tiles from wOverworldHUDTiles
+	ld hl, wOverworldHUDTiles
+	decoord 0, 0, wTilemap
+	ld bc, wOverworldHUDTilesEnd - wOverworldHUDTiles ; SCREEN_WIDTH
+	jp CopyBytes
+
+_LoadOverworldHUDAttrmap:
+	hlcoord 0, 0, wAttrmap
+	ld bc, SCREEN_WIDTH
+	ld a, PAL_BG_TEXT | PRIORITY
+	jp ByteFill

engine/overworld/events.asm

@@ -126,7 +126,9 @@ EnterMap:
 	ld [wPoisonStepCount], a
 .dontresetpoison
 
-	call EnableOverworldWindowHUD
+	call ConstructOverworldHUDTilemap
+	call TransferOverworldHUDToBGMap
+	call EnableOverworldHUD
 
 	xor a ; end map entry
 	ldh [hMapEntryMethod], a

engine/overworld/init_map.asm

@@ -25,17 +25,20 @@ ReanchorBGMap_NoOAMUpdate::
 	xor a
 	ldh [hLCDCPointer], a
 	ldh [hBGMapMode], a
+	; prepare vBGMap1/vBGMap3 to be displayed while vBGMap0/vBGMap2 is reanchored.
+	; draw screen at wTilemap and wAttrmap and then transfer it.
 	ld a, $90
 	ldh [hWY], a
 	call LoadScreenTilemapAndAttrmapPals
+	call LoadWindowHUD
 	ld a, HIGH(vBGMap1)
 	call .LoadBGMapAddrIntoHRAM
 	call HDMATransferTilemapAndAttrmap_OpenAndCloseMenu
 	farcall ApplyPals
 	ld a, TRUE
 	ldh [hCGBPalUpdate], a
-	; display window while BG map is reanchored.
+	; display window using vBGMap1/vBGMap3 while vBGMap0/vBGMap2 is reanchored.
-	; disable LCD interrupt to prevent cropping the window due to hWindowHUD
+	; disable LCD interrupt to prevent cropping the window if window HUD is active
 	; (caller must re-enable when window is hidden again).
 	xor a
 	ldh [rSTAT], a

engine/overworld/load_screen_tilemap.asm

@@ -33,4 +33,5 @@ _LoadScreenTilemap::
 .carry
 	dec b
 	jr nz, .loop
+
 	ret

engine/overworld/scripting.asm

@@ -1165,7 +1165,7 @@ Script_loadtrainer:
 	ret
 
 Script_startbattle:
-	call DisableWindowHUD
+	call DisableOverworldHUD
 	call BufferScreen
 	predef StartBattle
 	ld a, [wBattleResult]

engine/overworld/warp_connection.asm

@@ -1,5 +1,4 @@
 HandleNewMap:
-	call ClearUnusedMapBuffer
 	call ResetMapBufferEventFlags
 	call ResetFlashIfOutOfCave
 	call GetCurrentMapSceneID

engine/phone/phone.asm

@@ -547,7 +547,7 @@ Phone_StartRinging:
 	call PlaySFX
 	call Phone_CallerTextbox
 	call UpdateSprites
-	farcall PhoneRing_CopyTilemapAtOnce
+	call PhoneRing_CopyTilemapAtOnce
 	ret
 
 HangUp_Wait20Frames:
@@ -556,7 +556,7 @@ HangUp_Wait20Frames:
 Phone_Wait20Frames:
 	ld c, 20
 	call DelayFrames
-	farcall PhoneRing_CopyTilemapAtOnce
+	call PhoneRing_CopyTilemapAtOnce
 	ret
 
 PhoneRing_CopyTilemapAtOnce:

home.asm

@@ -29,6 +29,7 @@ INCLUDE "home/map.asm"
 INCLUDE "home/farcall.asm"
 INCLUDE "home/predef.asm"
 INCLUDE "home/window.asm"
+INCLUDE "home/hud.asm"
 INCLUDE "home/flag.asm"
 INCLUDE "home/sprite_updates.asm"
 INCLUDE "home/string.asm"

home/hud.asm

@@ -0,0 +1,122 @@
+OVERWORLD_HUD_HEIGHT EQU 8
+
+EnableOverworldHUD::
+	ld a, HUD_OVERWORLD
+	ld [wWhichHUD], a
+	ld a, OVERWORLD_HUD_HEIGHT - 1
+	; fallthrough
+
+EnableWindowHUD:
+	ldh [hWindowHUDLY], a
+	; configure LCD interrupt
+	ldh [rLYC], a
+	; make window hidden this frame to prevent graphical glitches
+	ld a, $90
+	ldh [hWY], a
+	; configure LCD interrupt
+	ld a, 1 << rSTAT_INT_LYC ; LYC=LC
+	ldh [rSTAT], a
+	ret
+
+DisableOverworldHUD::
+	xor a
+	ld [wWhichHUD], a
+	; fallthrough
+
+DisableWindowHUD::
+	xor a
+	ldh [hWindowHUDLY], a
+	; configure LCD interrupt
+	xor a
+	ldh [rLYC], a
+	ld a, 1 << rSTAT_INT_HBLANK ; hblank (default)
+	ldh [rSTAT], a
+	; leave window in default state (hidden with WY=$90)
+	; rLCDC[rLCDC_WINDOW_ENABLE] will be set during next vblank
+	ld a, $90
+	ldh [hWY], a
+	ret
+
+LoadWindowHUD::
+; like LoadHUD, but for HUDs that require a Window overlay
+	ldh a, [hWindowHUDLY]
+	and a
+	ret z
+	; fallthrough
+
+LoadHUD::
+; load the HUD at wWhichHUD to the top of wTilemap and wAttrmap
+	ld a, [wWhichHUD]
+	and a
+	ret z
+	farcall _LoadHUD
+	ret
+
+ConstructOverworldHUDTilemap::
+; draw the overworld HUD's tilemap into wOverworldHUDTiles
+	ld hl, .Tilemap
+	ld de, wOverworldHUDTiles
+	ld bc, .TilemapEnd - .Tilemap ; SCREEN_WIDTH
+	call CopyBytes
+	ret
+
+.Tilemap:
+	db "▶- ▶-   ▶     ▶     "
+.TilemapEnd:
+	assert .TilemapEnd - .Tilemap == wOverworldHUDTilesEnd - wOverworldHUDTiles
+
+TransferOverworldHUDToBGMap::
+; transfer overworld HUD to vBGMap1/vBGMap3 during v/hblank(s)
+; tilemap is read from wOverworldHUDTiles, attrmap is all PAL_BG_TEXT | PRIORITY
+	ldh a, [rVBK]
+	push af
+
+; Tilemap
+	ld a, BANK(vBGMap1)
+	ldh [rVBK], a
+	ld de, vBGMap1
+	ld hl, wOverworldHUDTiles
+
+	ld b, 1 << rSTAT_BUSY ; not in v/hblank
+	ld c, LOW(rSTAT)
+
+rept SCREEN_WIDTH / 2
+; if not in v/hblank, wait until in v/hblank
+.loop\@
+	ldh a, [c]
+	and b
+	jr nz, .loop\@
+; copy
+; we have at least a margin of 16 cycles of Mode2 left
+	ld a, [hli]
+	ld [de], a
+	inc de
+	ld a, [hli]
+	ld [de], a
+	inc de
+endr
+
+; Attrmap
+	ld a, BANK(vBGMap3)
+	ldh [rVBK], a
+	ld hl, vBGMap3
+
+rept SCREEN_WIDTH / 5
+; if not in v/hblank, wait until in v/hblank
+.loop\@
+	ldh a, [c]
+	and b
+	jr nz, .loop\@
+; fill
+; we have at least a margin of 16 cycles of Mode2 left
+	ld a, PAL_BG_TEXT | PRIORITY
+	ld [hli], a
+	ld [hli], a
+	ld [hli], a
+	ld [hli], a
+	ld [hli], a
+endr
+
+	pop af
+	ld [rVBK], a
+	ret

home/lcd.asm

@@ -4,7 +4,7 @@ LCD::
 	push af
 
 ; hLCDCPointer is used in battle transition, battle anims, and movies (crystal intro, credits, etc.)
-; uses rSTAT_INT_HBLANK and doesn't overlap with hWindowHUD.
+; uses rSTAT_INT_HBLANK and doesn't overlap with hWindowHUDLY.
 	ldh a, [hLCDCPointer]
 	and a
 	jr z, .next
@@ -23,8 +23,8 @@ LCD::
 	pop bc
 
 .next
-; hWindowHUD uses rSTAT_INT_LYC
+; hWindowHUDLY uses rSTAT_INT_LYC
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .done
 

home/map.asm

@@ -1,12 +1,5 @@
 ; Functions dealing with rendering and interacting with maps.
 
-ClearUnusedMapBuffer::
-	ld hl, wUnusedMapBuffer
-	ld bc, wUnusedMapBufferEnd - wUnusedMapBuffer
-	ld a, 0
-	call ByteFill
-	ret
-
 CheckScenes::
 ; Checks wCurMapSceneScriptPointer.  If it's empty, returns -1 in a.  Otherwise, returns the active scene ID in a.
 	push hl
@@ -146,7 +139,6 @@ LoadMetatiles::
 	ld e, l
 	ld d, h
 	; Set hl to the address of the current metatile data ([wTilesetBlocksAddress] + (a) tiles).
-; BUG: LoadMetatiles wraps around past 128 blocks (see docs/bugs_and_glitches.md)
 	ld l, a
 	ld h, 0
 	add hl, hl

home/tilemap.asm

@@ -49,20 +49,15 @@ CopyTilemapAtOnce::
 	xor a
 	ldh [hMapAnims], a
 
-; .wait
-; 	ldh a, [rLY]
-; 	cp $80 - 1
-; 	jr c, .wait
-
 	call DelayFrame
 
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .go
 
-	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUD] >= 0)
+	; wait until LCD interrupt has ocurred this frame ([rLY] - [hWindowHUDLY] >= 0)
 .wait_lcd
-;	ldh a, [hWindowHUD]
+;	ldh a, [hWindowHUDLY]
 	ld b, a
 	ldh a, [rLY]
 	sub b
@@ -78,11 +73,6 @@ CopyTilemapAtOnce::
 	ldh [rVBK], a
 	hlcoord 0, 0
 	call .CopyBGMapViaStack
-
-; .wait2
-; 	ldh a, [rLY]
-; 	cp $80 - 1
-; 	jr c, .wait2
 	ei
 
 	pop af

home/vblank.asm

@@ -65,12 +65,12 @@ VBlank0::
 	ldh a, [hROMBank]
 	ldh [hROMBankBackup], a
 
-	; enable window back in case LCD interrupt disabled it mid-frame due to hWindowHUD
+	; enable window back in case LCD interrupt disabled it mid-frame due to hWindowHUDLY
 	ldh a, [rLCDC]
 	set rLCDC_WINDOW_ENABLE, a
 	ldh [rLCDC], a
 
-	ld a, [hWindowHUD]
+	ld a, [hWindowHUDLY]
 	and a
 	jr z, .next
 
@@ -117,8 +117,8 @@ VBlank0::
 	xor a
 	ld [wVBlankOccurred], a
 
-	; if hWindowHUD is active, enable interrupts so the LCD interrupt can trigger
+	; if hWindowHUDLY is active, enable interrupts so the LCD interrupt can trigger
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	jr z, .next2
 
@@ -163,17 +163,17 @@ VBlank0::
 	ldh a, [hROMBankBackup]
 	rst Bankswitch
 
-	; if hWindowHUD is not active, we're done
+	; if hWindowHUDLY is not active, we're done
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	ret z
 
-	; interrupts must be enabled in the cycle that rLY becomes [hWindowHUD] to prevent flickering
+	; interrupts must be enabled in the cycle that rLY becomes [hWindowHUDLY] to prevent flickering
-	; wait until [hWindowHUD] - [rLY] is NOT between 0 and 2 before disabling interrupts
+	; wait until [hWindowHUDLY] - [rLY] is NOT between 0 and 2 before disabling interrupts
 .wait_loop
 	ldh a, [rLY]
 	ld b, a
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	sub b
 	cp 2 + 1
 	jr c, .wait_loop

home/window.asm

@@ -110,7 +110,7 @@ SafeUpdateSprites::
 HideWindow_EnableLCDInt::
 	ld a, $90
 	ldh [hWY], a
-	ldh a, [hWindowHUD]
+	ldh a, [hWindowHUDLY]
 	and a
 	ld a, 1 << rSTAT_INT_HBLANK
 	jr z, .ok
@@ -118,35 +118,3 @@ HideWindow_EnableLCDInt::
 .ok
 	ldh [rSTAT], a
 	ret
-
-OVERWORLD_HUD_HEIGHT EQU 8
-
-EnableOverworldWindowHUD::
-	ld a, OVERWORLD_HUD_HEIGHT - 1
-	; fallthrough
-
-EnableWindowHUD:
-	ldh [hWindowHUD], a
-	; configure LCD interrupt
-	ldh [rLYC], a
-	; make window hidden this frame to prevent graphical glitches
-	ld a, $90
-	ldh [hWY], a
-	; configure LCD interrupt
-	ld a, 1 << rSTAT_INT_LYC ; LYC=LC
-	ldh [rSTAT], a
-	ret
-
-DisableWindowHUD::
-	xor a
-	ldh [hWindowHUD], a
-	; configure LCD interrupt
-	xor a
-	ldh [rLYC], a
-	ld a, 1 << rSTAT_INT_HBLANK ; hblank (default)
-	ldh [rSTAT], a
-	; leave window in default state (hidden with WY=$90)
-	; rLCDC[rLCDC_WINDOW_ENABLE] will be set during next vblank
-	ld a, $90
-	ldh [hWY], a
-	ret

layout.link

@@ -249,7 +249,7 @@ WRAM0
 	"Sprites"
 	"Tilemap"
 	"Miscellaneous"
-	"Unused Map Buffer"
+	"Overworld HUD"
 	align 8
 	"Overworld Map"
 	align 4

main.asm

@@ -189,6 +189,7 @@ INCLUDE "engine/menus/empty_sram.asm"
 INCLUDE "engine/events/checksave.asm"
 INCLUDE "data/maps/scenes.asm"
 INCLUDE "engine/overworld/load_screen_tilemap.asm"
+INCLUDE "engine/gfx/hud.asm"
 
 
 SECTION "bank13_2", ROMX

ram/hram.asm

@@ -148,7 +148,7 @@ if DEF(_DEBUG)
 hDebugRoomMenuPage:: db
 endc
 
-hWindowHUD::
+hWindowHUDLY::
 ; Window HUD is enabled when non-0.
 ; Its value indicates the last scanline that the window spans from the top.
 	db