Merge branch 'master' of https://github.com/pret/pokecrystal

engine/overworld/init_map.asm

@@ -0,0 +1,103 @@
+ReanchorBGMap_NoOAMUpdate:: ; 6454
+	call DelayFrame
+	ld a, [hOAMUpdate]
+	push af
+
+	ld a, $1
+	ld [hOAMUpdate], a
+	ld a, [hBGMapMode]
+	push af
+	xor a
+	ld [hBGMapMode], a
+
+	call .ReanchorBGMap
+
+	pop af
+	ld [hBGMapMode], a
+	pop af
+	ld [hOAMUpdate], a
+	ld hl, wVramState
+	set 6, [hl]
+	ret
+
+.ReanchorBGMap:
+	xor a
+	ld [hLCDCPointer], a
+	ld [hBGMapMode], a
+	ld a, $90
+	ld [hWY], a
+	call OverworldTextModeSwitch
+	ld a, HIGH(vBGMap1)
+	call .LoadBGMapAddrIntoHRAM
+	call _OpenAndCloseMenu_HDMATransferTileMapAndAttrMap
+	farcall LoadOW_BGPal7
+	farcall ApplyPals
+	ld a, $1
+	ld [hCGBPalUpdate], a
+	xor a
+	ld [hBGMapMode], a
+	ld [hWY], a
+	farcall HDMATransfer_FillBGMap0WithBlack ; no need to farcall
+	ld a, HIGH(vBGMap0)
+	call .LoadBGMapAddrIntoHRAM
+	xor a ; LOW(vBGMap0)
+	ld [wBGMapAnchor], a
+	ld a, HIGH(vBGMap0)
+	ld [wBGMapAnchor + 1], a
+	xor a
+	ld [hSCX], a
+	ld [hSCY], a
+	call ApplyBGMapAnchorToObjects
+	ret
+
+.LoadBGMapAddrIntoHRAM: ; 64b9
+	ld [hBGMapAddress + 1], a
+	xor a
+	ld [hBGMapAddress], a
+	ret
+
+LoadFonts_NoOAMUpdate:: ; 64bf
+	ld a, [hOAMUpdate]
+	push af
+	ld a, $1
+	ld [hOAMUpdate], a
+
+	call .LoadGFX
+
+	pop af
+	ld [hOAMUpdate], a
+	ret
+
+.LoadGFX:
+	call LoadFontsExtra
+	ld a, $90
+	ld [hWY], a
+	call SafeUpdateSprites
+	call LoadStandardFont
+	ret
+
+HDMATransfer_FillBGMap0WithBlack: ; 64db
+	ld a, [rSVBK]
+	push af
+	ld a, BANK(wDecompressScratch)
+	ld [rSVBK], a
+
+	ld a, "■"
+	ld hl, wDecompressScratch
+	ld bc, wScratchAttrMap - wDecompressScratch
+	call ByteFill
+	ld a, HIGH(wDecompressScratch)
+	ld [rHDMA1], a
+	ld a, LOW(wDecompressScratch)
+	ld [rHDMA2], a
+	ld a, HIGH(vBGMap0 % $8000)
+	ld [rHDMA3], a
+	ld a, LOW(vBGMap0 % $8000)
+	ld [rHDMA4], a
+	ld a, $3f
+	ld [hDMATransfer], a
+	call DelayFrame
+
+	pop af
+	ld [rSVBK], a
+	ret

engine/overworld/landmarks.asm

@@ -0,0 +1,87 @@
+GetLandmarkCoords: ; 0x1ca896
+; Return coordinates (d, e) of landmark e.
+	push hl
+	ld l, e
+	ld h, 0
+	add hl, hl
+	add hl, hl
+	ld de, Landmarks
+	add hl, de
+	ld a, [hli]
+	ld e, a
+	ld d, [hl]
+	pop hl
+	ret
+; 0x1ca8a5
+
+
+GetLandmarkName:: ; 0x1ca8a5
+; Copy the name of landmark e to wStringBuffer1.
+	push hl
+	push de
+	push bc
+
+	ld l, e
+	ld h, 0
+	add hl, hl
+	add hl, hl
+	ld de, Landmarks + 2
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+	ld de, wStringBuffer1
+	ld c, 18
+.copy
+	ld a, [hli]
+	ld [de], a
+	inc de
+	dec c
+	jr nz, .copy
+
+	pop bc
+	pop de
+	pop hl
+	ret
+; 0x1ca8c3
+
+
+INCLUDE "data/maps/landmarks.asm"
+
+
+RegionCheck: ; 0x1caea1
+; Checks if the player is in Kanto or Johto.
+; If in Johto, returns 0 in e.
+; If in Kanto, returns 1 in e.
+	ld a, [wMapGroup]
+	ld b, a
+	ld a, [wMapNumber]
+	ld c, a
+	call GetWorldMapLocation
+	cp FAST_SHIP ; S.S. Aqua
+	jr z, .johto
+	cp SPECIAL_MAP
+	jr nz, .checkagain
+
+; In a special map, get the backup map group / map id
+	ld a, [wBackupMapGroup]
+	ld b, a
+	ld a, [wBackupMapNumber]
+	ld c, a
+	call GetWorldMapLocation
+
+.checkagain
+	cp KANTO_LANDMARK
+	jr c, .johto
+
+; Victory Road area is considered to be Johto.
+	cp VICTORY_ROAD
+	jr c, .kanto
+
+.johto
+	ld e, JOHTO_REGION
+	ret
+.kanto
+	ld e, KANTO_REGION
+	ret

engine/overworld/load_map_part.asm

@@ -0,0 +1,36 @@
+_LoadMapPart:: ; 4d15b
+	ld hl, wSurroundingTiles
+	ld a, [wMetatileStandingY]
+	and a
+	jr z, .top_row
+	ld bc, SURROUNDING_WIDTH * 2
+	add hl, bc
+
+.top_row
+	ld a, [wMetatileStandingX]
+	and a
+	jr z, .left_column
+	inc hl
+	inc hl
+
+.left_column
+	decoord 0, 0
+	ld b, SCREEN_HEIGHT
+.loop
+	ld c, SCREEN_WIDTH
+.loop2
+	ld a, [hli]
+	ld [de], a
+	inc de
+	dec c
+	jr nz, .loop2
+	ld a, l
+	add METATILE_WIDTH
+	ld l, a
+	jr nc, .carry
+	inc h
+
+.carry
+	dec b
+	jr nz, .loop
+	ret

engine/overworld/map_object_action.asm

@@ -0,0 +1,313 @@
+ObjectActionPairPointers: ; 445f
+; entries correspond to OBJECT_ACTION_* constants
+	dw SetFacingStanding,              SetFacingStanding
+	dw SetFacingStandAction,           SetFacingCurrent
+	dw SetFacingStepAction,            SetFacingCurrent
+	dw SetFacingBumpAction,            SetFacingCurrent
+	dw SetFacingCounterclockwiseSpin,  SetFacingCurrent
+	dw SetFacingCounterclockwiseSpin2, SetFacingStanding
+	dw SetFacingFish,                  SetFacingFish
+	dw SetFacingShadow,                SetFacingStanding
+	dw SetFacingEmote,                 SetFacingEmote
+	dw SetFacingBigDollSym,            SetFacingBigDollSym
+	dw SetFacingBounce,                SetFacingFreezeBounce
+	dw SetFacingWeirdTree,             SetFacingCurrent
+	dw SetFacingBigDollAsym,           SetFacingBigDollAsym
+	dw SetFacingBigDoll,               SetFacingBigDoll
+	dw SetFacingBoulderDust,           SetFacingStanding
+	dw SetFacingGrassShake,            SetFacingStanding
+	dw SetFacingSkyfall,               SetFacingCurrent
+; 44a3
+
+SetFacingStanding: ; 44a3
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], STANDING
+	ret
+; 44aa
+
+SetFacingCurrent: ; 44aa
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 44b5
+
+SetFacingStandAction: ; 44b5
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld a, [hl]
+	and 1
+	jr nz, SetFacingStepAction
+	jp SetFacingCurrent
+; 44c1
+
+SetFacingStepAction: ; 44c1
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	inc a
+	and %00001111
+	ld [hl], a
+
+	rrca
+	rrca
+	and %00000011
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 44e4
+
+SetFacingSkyfall: ; 44e4
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	add 2
+	and %00001111
+	ld [hl], a
+
+	rrca
+	rrca
+	and %00000011
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 4508
+
+SetFacingBumpAction: ; 4508
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+
+	ld a, [hl]
+	rrca
+	rrca
+	rrca
+	and %00000011
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 4529
+
+SetFacingCounterclockwiseSpin: ; 4529
+	call CounterclockwiseSpinAction
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld a, [hl]
+	or FACING_STEP_DOWN_0 ; useless
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 4539
+
+SetFacingCounterclockwiseSpin2: ; 4539
+	call CounterclockwiseSpinAction
+	jp SetFacingStanding
+; 453f
+
+CounterclockwiseSpinAction: ; 453f
+; Here, OBJECT_STEP_FRAME consists of two 2-bit components,
+; using only bits 0,1 and 4,5.
+; bits 0,1 is a timer (4 overworld frames)
+; bits 4,5 determines the facing - the direction is counterclockwise.
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	and %11110000
+	ld e, a
+
+	ld a, [hl]
+	inc a
+	and %00001111
+	ld d, a
+	cp 4
+	jr c, .ok
+
+	ld d, 0
+	ld a, e
+	add $10
+	and %00110000
+	ld e, a
+
+.ok
+	ld a, d
+	or e
+	ld [hl], a
+
+	swap e
+	ld d, 0
+	ld hl, .Directions
+	add hl, de
+	ld a, [hl]
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+; 456a
+
+.Directions: ; 456a
+	db OW_DOWN, OW_RIGHT, OW_UP, OW_LEFT
+; 456e
+
+SetFacingFish: ; 456e
+	call GetSpriteDirection
+	rrca
+	rrca
+	add FACING_FISH_DOWN
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 457b
+
+SetFacingShadow: ; 457b
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_SHADOW
+	ret
+; 4582
+
+SetFacingEmote: ; 4582 emote
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_EMOTE
+	ret
+; 4589
+
+SetFacingBigDollSym: ; 4589
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_BIG_DOLL_SYM
+	ret
+; 4590
+
+SetFacingBounce: ; 4590
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	inc a
+	and %00001111
+	ld [hl], a
+	and %00001000
+	jr z, SetFacingFreezeBounce
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_STEP_UP_0
+	ret
+; 45a4
+
+SetFacingFreezeBounce: ; 45a4
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_STEP_DOWN_0
+	ret
+; 45ab
+
+SetFacingWeirdTree: ; 45ab
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	inc a
+	ld [hl], a
+	and %00001100
+	rrca
+	rrca
+	add FACING_WEIRD_TREE_0
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], a
+	ret
+; 45be
+
+SetFacingBigDollAsym: ; 45be
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], FACING_BIG_DOLL_ASYM
+	ret
+; 45c5
+
+SetFacingBigDoll: ; 45c5
+	ld a, [wVariableSprites + SPRITE_BIG_DOLL - SPRITE_VARS]
+	ld d, FACING_BIG_DOLL_SYM ; symmetric
+	cp SPRITE_BIG_SNORLAX
+	jr z, .ok
+	cp SPRITE_BIG_LAPRAS
+	jr z, .ok
+	ld d, FACING_BIG_DOLL_ASYM ; asymmetric
+
+.ok
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	ld [hl], d
+	ret
+; 45da
+
+SetFacingBoulderDust: ; 45da
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+	ld a, [hl]
+
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	and 2
+	ld a, FACING_BOULDER_DUST_1
+	jr z, .ok
+	inc a ; FACING_BOULDER_DUST_2
+.ok
+	ld [hl], a
+	ret
+; 45ed
+
+SetFacingGrassShake: ; 45ed
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+	ld a, [hl]
+	ld hl, OBJECT_FACING_STEP
+	add hl, bc
+	and 4
+	ld a, FACING_GRASS_1
+	jr z, .ok
+	inc a ; FACING_GRASS_2
+
+.ok
+	ld [hl], a
+	ret
+; 4600

engine/overworld/map_objects_2.asm

@@ -0,0 +1,70 @@
+LoadObjectMasks: ; 2454f
+	ld hl, wObjectMasks
+	xor a
+	ld bc, NUM_OBJECTS
+	call ByteFill
+	nop
+	ld bc, wMapObjects
+	ld de, wObjectMasks
+	xor a
+.loop
+	push af
+	push bc
+	push de
+	call GetObjectTimeMask
+	jr c, .next
+	call CheckObjectFlag
+.next
+	pop de
+	ld [de], a
+	inc de
+	pop bc
+	ld hl, OBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	pop af
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop
+	ret
+
+CheckObjectFlag: ; 2457d (9:457d)
+	ld hl, MAPOBJECT_SPRITE
+	add hl, bc
+	ld a, [hl]
+	and a
+	jr z, .masked
+	ld hl, MAPOBJECT_EVENT_FLAG
+	add hl, bc
+	ld a, [hli]
+	ld e, a
+	ld a, [hl]
+	ld d, a
+	cp -1
+	jr nz, .check
+	ld a, e
+	cp -1
+	jr z, .unmasked
+	jr .masked
+.check
+	ld b, CHECK_FLAG
+	call EventFlagAction
+	ld a, c
+	and a
+	jr nz, .masked
+.unmasked
+	xor a
+	ret
+
+.masked
+	ld a, -1
+	scf
+	ret
+
+GetObjectTimeMask: ; 245a7 (9:45a7)
+	call CheckObjectTime
+	ld a, -1
+	ret c
+	xor a
+	ret

engine/overworld/map_setup.asm

@@ -0,0 +1,260 @@
+RunMapSetupScript:: ; 15363
+	ld a, [hMapEntryMethod]
+	and $f
+	dec a
+	ld c, a
+	ld b, 0
+	ld hl, MapSetupScripts
+	add hl, bc
+	add hl, bc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	call ReadMapSetupScript
+	ret
+; 15377
+
+INCLUDE "data/maps/setup_scripts.asm"
+
+ReadMapSetupScript: ; 1541d
+.loop
+	ld a, [hli]
+	cp -1
+	ret z
+
+	push hl
+
+	ld c, a
+	ld b, 0
+	ld hl, MapSetupCommands
+	add hl, bc
+	add hl, bc
+	add hl, bc
+
+	; bank
+	ld b, [hl]
+	inc hl
+
+	; address
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+	; Bit 7 of the bank indicates a parameter.
+	; This is left unused.
+	bit 7, b
+	jr z, .go
+
+	pop de
+	ld a, [de]
+	ld c, a
+	inc de
+	push de
+
+.go
+	ld a, b
+	and $7f
+	rst FarCall
+
+	pop hl
+	jr .loop
+; 15440
+
+MapSetupCommands: ; 15440
+; entries correspond to command indexes in constants/map_setup_constants.asm
+	dba EnableLCD ; 00
+	dba DisableLCD ; 01
+	dba MapSetup_Sound_Off ; 02
+	dba PlayMapMusic ; 03
+	dba RestartMapMusic ; 04
+	dba FadeToMapMusic ; 05
+	dba RotatePalettesRightMapAndMusic ; 06
+	dba EnterMapMusic ; 07
+	dba ForceMapMusic ; 08
+	dba FadeInMusic ; 09
+	dba LoadBlockData ; 0a (callback 1)
+	dba LoadNeighboringBlockData ; 0b
+	dba SaveScreen ; 0c
+	dba BufferScreen ; 0d
+	dba LoadGraphics ; 0e
+	dba LoadTileset ; 0f
+	dba LoadMapTimeOfDay ; 10
+	dba LoadMapPalettes ; 11
+	dba LoadWildMonData ; 12
+	dba RefreshMapSprites ; 13
+	dba HandleNewMap ; 14
+	dba InitCommandQueue ; 15
+	dba LoadObjectsRunCallback_02 ; 16
+	dba LoadSpawnPoint ; 17
+	dba EnterMapConnection ; 18
+	dba LoadWarpData ; 19
+	dba LoadMapAttributes ; 1a
+	dba LoadMapAttributes_SkipPeople ; 1b
+	dba ClearBGPalettes ; 1c
+	dba FadeOutPalettes ; 1d
+	dba FadeInPalettes ; 1e
+	dba GetCoordOfUpperLeftCorner ; 1f
+	dba RestoreFacingAfterWarp ; 20
+	dba SpawnInFacingDown ; 21
+	dba SpawnPlayer ; 22
+	dba RefreshPlayerCoords ; 23
+	dba DelayClearingOldSprites ; 24
+	dba DelayLoadingNewSprites ; 25
+	dba UpdateRoamMons ; 26
+	dba JumpRoamMons ; 27
+	dba FadeOldMapMusic ; 28
+	dba ActivateMapAnims ; 29
+	dba SuspendMapAnims ; 2a
+	dba RetainOldPalettes ; 2b
+	dba DontScrollText ; 2c
+	dba ReturnFromMapSetupScript ; 2d
+; 154ca
+
+
+DontScrollText: ; 154ca
+	xor a
+	ld [wDisableTextAcceleration], a
+	ret
+; 154cf
+
+ActivateMapAnims: ; 154cf
+	ld a, $1
+	ld [hMapAnims], a
+	ret
+; 154d3
+
+SuspendMapAnims: ; 154d3
+	xor a
+	ld [hMapAnims], a
+	ret
+; 154d7
+
+LoadObjectsRunCallback_02: ; 154d7
+	ld a, MAPCALLBACK_OBJECTS
+	call RunMapCallback
+	farcall LoadObjectMasks
+	farcall InitializeVisibleSprites
+	ret
+; 154ea (5:54ea)
+
+; unused
+	ret
+; 154eb
+
+DelayClearingOldSprites: ; 154eb
+	ld hl, wPlayerSpriteSetupFlags
+	set PLAYERSPRITESETUP_RESET_ACTION_F, [hl]
+	ret
+; 154f1
+
+DelayLoadingNewSprites: ; 154f1
+	ld hl, wPlayerSpriteSetupFlags
+	set PLAYERSPRITESETUP_SKIP_RELOAD_GFX_F, [hl]
+	ret
+
+CheckReplaceKrisSprite: ; 154f7
+	nop
+	call .CheckBiking
+	jr c, .ok
+	call .CheckSurfing
+	jr c, .ok
+	call .CheckSurfing2
+	jr c, .ok
+	ret
+
+.ok
+	call ReplaceKrisSprite
+	ret
+
+.CheckBiking: ; 1550c (5:550c)
+	and a
+	ld hl, wBikeFlags
+	bit BIKEFLAGS_ALWAYS_ON_BIKE_F, [hl]
+	ret z
+	ld a, PLAYER_BIKE
+	ld [wPlayerState], a
+	scf
+	ret
+
+.CheckSurfing2: ; 1551a (5:551a)
+	ld a, [wPlayerState]
+	cp PLAYER_NORMAL
+	jr z, .nope
+	cp PLAYER_SKATE
+	jr z, .nope
+	cp PLAYER_SURF
+	jr z, .surfing
+	cp PLAYER_SURF_PIKA
+	jr z, .surfing
+	call GetMapEnvironment
+	cp INDOOR
+	jr z, .checkbiking
+	cp ENVIRONMENT_5
+	jr z, .checkbiking
+	cp DUNGEON
+	jr z, .checkbiking
+	jr .nope
+.checkbiking
+	ld a, [wPlayerState]
+	cp PLAYER_BIKE
+	jr nz, .nope
+.surfing
+	ld a, PLAYER_NORMAL
+	ld [wPlayerState], a
+	scf
+	ret
+
+.nope
+	and a
+	ret
+
+.CheckSurfing: ; 1554e (5:554e)
+	call CheckOnWater
+	jr nz, .ret_nc
+	ld a, [wPlayerState]
+	cp PLAYER_SURF
+	jr z, ._surfing
+	cp PLAYER_SURF_PIKA
+	jr z, ._surfing
+	ld a, PLAYER_SURF
+	ld [wPlayerState], a
+._surfing
+	scf
+	ret
+.ret_nc
+	and a
+	ret
+; 15567
+
+FadeOldMapMusic: ; 15567
+	ld a, 6
+	call SkipMusic
+	ret
+; 1556d
+
+RetainOldPalettes: ; 1556d
+	farcall _UpdateTimePals
+	ret
+
+RotatePalettesRightMapAndMusic: ; 15574
+	ld e, 0
+	ld a, [wMusicFadeID]
+	ld d, 0
+	ld a, [wMusicFadeID + 1]
+	ld a, $4
+	ld [wMusicFade], a
+	call RotateThreePalettesRight
+	ret
+; 15587
+
+ForceMapMusic: ; 15587
+	ld a, [wPlayerState]
+	cp PLAYER_BIKE
+	jr nz, .notbiking
+	call VolumeOff
+	ld a, $88
+	ld [wMusicFade], a
+.notbiking
+	call TryRestartMapMusic
+	ret
+; 1559a

engine/overworld/player_step.asm

@@ -0,0 +1,270 @@
+_HandlePlayerStep:: ; d497 (3:5497)
+	ld a, [wPlayerStepFlags]
+	and a
+	ret z
+	bit 7, a ; starting step
+	jr nz, .update_overworld_map
+	bit 6, a ; finishing step
+	jr nz, .update_player_coords
+	bit 5, a ; ongoing step
+	jr nz, .finish
+	ret
+
+.update_overworld_map
+	ld a, 4
+	ld [wHandlePlayerStep], a
+	call UpdateOverworldMap
+	jr .finish
+
+.update_player_coords
+	call UpdatePlayerCoords
+	jr .finish
+
+.finish
+	call HandlePlayerStep
+	ld a, [wPlayerStepVectorX]
+	ld d, a
+	ld a, [wPlayerStepVectorY]
+	ld e, a
+	ld a, [wPlayerBGMapOffsetX]
+	sub d
+	ld [wPlayerBGMapOffsetX], a
+	ld a, [wPlayerBGMapOffsetY]
+	sub e
+	ld [wPlayerBGMapOffsetY], a
+	ret
+
+ScrollScreen:: ; d4d2 (3:54d2)
+	ld a, [wPlayerStepVectorX]
+	ld d, a
+	ld a, [wPlayerStepVectorY]
+	ld e, a
+	ld a, [hSCX]
+	add d
+	ld [hSCX], a
+	ld a, [hSCY]
+	add e
+	ld [hSCY], a
+	ret
+
+HandlePlayerStep: ; d4e5 (3:54e5)
+	ld hl, wHandlePlayerStep
+	ld a, [hl]
+	and a
+	ret z
+	dec [hl]
+	ld a, [hl]
+	ld hl, .Jumptable
+	rst JumpTable
+	ret
+
+.Jumptable: ; d4f2 (3:54f2)
+	dw GetMovementPermissions
+	dw BufferScreen
+	dw .mobile
+	dw .fail2
+; The rest are never used.  Ever.
+	dw .fail1
+	dw .fail1
+	dw .fail1
+	dw .fail1
+	dw .fail1
+	dw .fail1
+	dw .fail1
+
+.fail1 ; d508 (3:5508)
+	ret
+
+.mobile ; d509 (3:5509)
+	farcall StubbedTrainerRankings_StepCount
+	ret
+
+.fail2 ; d510 (3:5510)
+	ret
+
+UpdatePlayerCoords: ; d511 (3:5511)
+	ld a, [wPlayerStepDirection]
+	and a
+	jr nz, .check_step_down
+	ld hl, wYCoord
+	inc [hl]
+	ret
+
+.check_step_down
+	cp UP
+	jr nz, .check_step_left
+	ld hl, wYCoord
+	dec [hl]
+	ret
+
+.check_step_left
+	cp LEFT
+	jr nz, .check_step_right
+	ld hl, wXCoord
+	dec [hl]
+	ret
+
+.check_step_right
+	cp RIGHT
+	ret nz
+	ld hl, wXCoord
+	inc [hl]
+	ret
+
+UpdateOverworldMap: ; d536 (3:5536)
+	ld a, [wPlayerStepDirection]
+	and a
+	jr z, .step_down
+	cp UP
+	jr z, .step_up
+	cp LEFT
+	jr z, .step_left
+	cp RIGHT
+	jr z, .step_right
+	ret
+
+.step_down
+	call .ScrollOverworldMapDown
+	call LoadMapPart
+	call ScrollMapUp
+	ret
+
+.step_up
+	call .ScrollOverworldMapUp
+	call LoadMapPart
+	call ScrollMapDown
+	ret
+
+.step_left
+	call .ScrollOverworldMapLeft
+	call LoadMapPart
+	call ScrollMapRight
+	ret
+
+.step_right
+	call .ScrollOverworldMapRight
+	call LoadMapPart
+	call ScrollMapLeft
+	ret
+
+.ScrollOverworldMapDown: ; d571 (3:5571)
+	ld a, [wBGMapAnchor]
+	add 2 * BG_MAP_WIDTH
+	ld [wBGMapAnchor], a
+	jr nc, .not_overflowed
+	ld a, [wBGMapAnchor + 1]
+	inc a
+	and %11
+	or HIGH(vBGMap0)
+	ld [wBGMapAnchor + 1], a
+.not_overflowed
+	ld hl, wMetatileStandingY
+	inc [hl]
+	ld a, [hl]
+	cp 2 ; was 1
+	jr nz, .done_down
+	ld [hl], 0
+	call .Add6ToOverworldMapAnchor
+.done_down
+	ret
+
+.Add6ToOverworldMapAnchor: ; d595 (3:5595)
+	ld hl, wOverworldMapAnchor
+	ld a, [wMapWidth]
+	add 6
+	add [hl]
+	ld [hli], a
+	ret nc
+	inc [hl]
+	ret
+
+.ScrollOverworldMapUp: ; d5a2 (3:55a2)
+	ld a, [wBGMapAnchor]
+	sub 2 * BG_MAP_WIDTH
+	ld [wBGMapAnchor], a
+	jr nc, .not_underflowed
+	ld a, [wBGMapAnchor + 1]
+	dec a
+	and %11
+	or HIGH(vBGMap0)
+	ld [wBGMapAnchor + 1], a
+.not_underflowed
+	ld hl, wMetatileStandingY
+	dec [hl]
+	ld a, [hl]
+	cp -1 ; was 0
+	jr nz, .done_up
+	ld [hl], $1
+	call .Sub6FromOverworldMapAnchor
+.done_up
+	ret
+
+.Sub6FromOverworldMapAnchor: ; d5c6 (3:55c6)
+	ld hl, wOverworldMapAnchor
+	ld a, [wMapWidth]
+	add 6
+	ld b, a
+	ld a, [hl]
+	sub b
+	ld [hli], a
+	ret nc
+	dec [hl]
+	ret
+
+.ScrollOverworldMapLeft: ; d5d5 (3:55d5)
+	ld a, [wBGMapAnchor]
+	ld e, a
+	and $e0
+	ld d, a
+	ld a, e
+	sub $2
+	and $1f
+	or d
+	ld [wBGMapAnchor], a
+	ld hl, wMetatileStandingX
+	dec [hl]
+	ld a, [hl]
+	cp -1
+	jr nz, .done_left
+	ld [hl], 1
+	call .DecrementwOverworldMapAnchor
+.done_left
+	ret
+
+.DecrementwOverworldMapAnchor: ; d5f4 (3:55f4)
+	ld hl, wOverworldMapAnchor
+	ld a, [hl]
+	sub 1
+	ld [hli], a
+	ret nc
+	dec [hl]
+	ret
+
+.ScrollOverworldMapRight: ; d5fe (3:55fe)
+	ld a, [wBGMapAnchor]
+	ld e, a
+	and $e0
+	ld d, a
+	ld a, e
+	add $2
+	and $1f
+	or d
+	ld [wBGMapAnchor], a
+	ld hl, wMetatileStandingX
+	inc [hl]
+	ld a, [hl]
+	cp 2
+	jr nz, .done_right
+	ld [hl], 0
+	call .IncrementwOverworldMapAnchor
+.done_right
+	ret
+
+.IncrementwOverworldMapAnchor: ; d61d (3:561d)
+	ld hl, wOverworldMapAnchor
+	ld a, [hl]
+	add 1
+	ld [hli], a
+	ret nc
+	inc [hl]
+	ret

engine/overworld/select_menu.asm

@@ -0,0 +1,191 @@
+SelectMenu:: ; 13327
+
+	call CheckRegisteredItem
+	jr c, .NotRegistered
+	jp UseRegisteredItem
+
+.NotRegistered:
+	call OpenText
+	ld b, BANK(ItemMayBeRegisteredText)
+	ld hl, ItemMayBeRegisteredText
+	call MapTextbox
+	call WaitButton
+	jp CloseText
+; 13340
+
+
+ItemMayBeRegisteredText: ; 13340
+	text_jump UnknownText_0x1c1cf3
+	db "@"
+; 13345
+
+
+CheckRegisteredItem: ; 13345
+
+	ld a, [wWhichRegisteredItem]
+	and a
+	jr z, .NoRegisteredItem
+	and REGISTERED_POCKET
+	rlca
+	rlca
+	ld hl, .Pockets
+	rst JumpTable
+	ret
+
+.Pockets:
+; entries correspond to *_POCKET constants
+	dw .CheckItem
+	dw .CheckBall
+	dw .CheckKeyItem
+	dw .CheckTMHM
+
+.CheckItem:
+	ld hl, wNumItems
+	call .CheckRegisteredNo
+	jr c, .NoRegisteredItem
+	inc hl
+	ld e, a
+	ld d, 0
+	add hl, de
+	add hl, de
+	call .IsSameItem
+	jr c, .NoRegisteredItem
+	and a
+	ret
+
+.CheckKeyItem:
+	ld a, [wRegisteredItem]
+	ld hl, wKeyItems
+	ld de, 1
+	call IsInArray
+	jr nc, .NoRegisteredItem
+	ld a, [wRegisteredItem]
+	ld [wCurItem], a
+	and a
+	ret
+
+.CheckBall:
+	ld hl, wNumBalls
+	call .CheckRegisteredNo
+	jr nc, .NoRegisteredItem
+	inc hl
+	ld e, a
+	ld d, 0
+	add hl, de
+	add hl, de
+	call .IsSameItem
+	jr c, .NoRegisteredItem
+	ret
+
+.CheckTMHM:
+	jr .NoRegisteredItem
+
+.NoRegisteredItem:
+	xor a
+	ld [wWhichRegisteredItem], a
+	ld [wRegisteredItem], a
+	scf
+	ret
+; 133a6
+
+
+.CheckRegisteredNo: ; 133a6
+	ld a, [wWhichRegisteredItem]
+	and REGISTERED_NUMBER
+	dec a
+	cp [hl]
+	jr nc, .NotEnoughItems
+	ld [wCurItemQuantity], a
+	and a
+	ret
+
+.NotEnoughItems:
+	scf
+	ret
+; 133b6
+
+
+.IsSameItem: ; 133b6
+	ld a, [wRegisteredItem]
+	cp [hl]
+	jr nz, .NotSameItem
+	ld [wCurItem], a
+	and a
+	ret
+
+.NotSameItem:
+	scf
+	ret
+; 133c3
+
+
+UseRegisteredItem: ; 133c3
+
+	farcall CheckItemMenu
+	ld a, [wItemAttributeParamBuffer]
+	ld hl, .SwitchTo
+	rst JumpTable
+	ret
+
+.SwitchTo:
+; entries correspond to ITEMMENU_* constants
+	dw .CantUse
+	dw .NoFunction
+	dw .NoFunction
+	dw .NoFunction
+	dw .Current
+	dw .Party
+	dw .Overworld
+; 133df
+
+.NoFunction: ; 133df
+	call OpenText
+	call CantUseItem
+	call CloseText
+	and a
+	ret
+; 133ea
+
+.Current: ; 133ea
+	call OpenText
+	call DoItemEffect
+	call CloseText
+	and a
+	ret
+; 133f5
+
+.Party: ; 133f5
+	call RefreshScreen
+	call FadeToMenu
+	call DoItemEffect
+	call CloseSubmenu
+	call CloseText
+	and a
+	ret
+; 13406
+
+.Overworld: ; 13406
+	call RefreshScreen
+	ld a, 1
+	ld [wUsingItemWithSelect], a
+	call DoItemEffect
+	xor a
+	ld [wUsingItemWithSelect], a
+	ld a, [wItemEffectSucceeded]
+	cp 1
+	jr nz, ._cantuse
+	scf
+	ld a, HMENURETURN_SCRIPT
+	ld [hMenuReturn], a
+	ret
+; 13422
+
+.CantUse: ; 13422
+	call RefreshScreen
+
+._cantuse
+	call CantUseItem
+	call CloseText
+	and a
+	ret
+; 1342d

engine/overworld/spawn_points.asm

@@ -0,0 +1,62 @@
+INCLUDE "data/maps/spawn_points.asm"
+
+
+LoadSpawnPoint: ; 1531f
+	; loads the spawn point in wDefaultSpawnpoint
+	push hl
+	push de
+	ld a, [wDefaultSpawnpoint]
+	cp SPAWN_N_A
+	jr z, .spawn_n_a
+	ld l, a
+	ld h, 0
+	add hl, hl
+	add hl, hl
+	ld de, SpawnPoints
+	add hl, de
+	ld a, [hli]
+	ld [wMapGroup], a
+	ld a, [hli]
+	ld [wMapNumber], a
+	ld a, [hli]
+	ld [wXCoord], a
+	ld a, [hli]
+	ld [wYCoord], a
+.spawn_n_a
+	pop de
+	pop hl
+	ret
+; 15344
+
+
+IsSpawnPoint: ; 15344
+; Checks if the map loaded in de is a spawn point.  Returns carry if it's a spawn point.
+	ld hl, SpawnPoints
+	ld c, 0
+.loop
+	ld a, [hl]
+	cp SPAWN_N_A
+	jr z, .nope
+	cp d
+	jr nz, .next
+	inc hl
+	ld a, [hld]
+	cp e
+	jr z, .yes
+
+.next
+	push bc
+	ld bc, 4 ; length of a spawn table entry
+	add hl, bc
+	pop bc
+	inc c
+	jr .loop
+
+.nope
+	and a
+	ret
+
+.yes
+	scf
+	ret
+; 15363

engine/overworld/tile_events.asm

@@ -0,0 +1,110 @@
+CheckWarpCollision:: ; 1499a
+; Is this tile a warp?
+	ld a, [wPlayerStandingTile]
+	cp COLL_PIT
+	jr z, .warp
+	cp COLL_PIT_68
+	jr z, .warp
+	and $f0
+	cp HI_NYBBLE_WARPS
+	jr z, .warp
+	and a
+	ret
+
+.warp
+	scf
+	ret
+; 149af
+
+CheckDirectionalWarp:: ; 149af
+; If this is a directional warp, clear carry (press the designated button to warp).
+; Else, set carry (immediate warp).
+	ld a, [wPlayerStandingTile]
+	cp COLL_WARP_CARPET_DOWN
+	jr z, .directional
+	cp COLL_WARP_CARPET_LEFT
+	jr z, .directional
+	cp COLL_WARP_CARPET_UP
+	jr z, .directional
+	cp COLL_WARP_CARPET_RIGHT
+	jr z, .directional
+	scf
+	ret
+
+.directional
+	xor a
+	ret
+; 149c6
+
+CheckWarpFacingDown: ; 149c6
+	ld de, 1
+	ld hl, .blocks
+	ld a, [wPlayerStandingTile]
+	call IsInArray
+	ret
+; 149d3
+
+.blocks ; 149d3
+	db COLL_DOOR
+	db COLL_DOOR_79
+	db COLL_STAIRCASE
+	db COLL_STAIRCASE_73
+	db COLL_CAVE
+	db COLL_CAVE_74
+	db COLL_WARP_PANEL
+	db COLL_DOOR_75
+	db COLL_DOOR_7D
+	db -1
+; 149dd
+
+CheckGrassCollision:: ; 149dd
+	ld a, [wPlayerStandingTile]
+	ld hl, .blocks
+	ld de, 1
+	call IsInArray
+	ret
+; 149ea
+
+.blocks ; 149ea
+	db COLL_CUT_08
+	db COLL_TALL_GRASS
+	db COLL_LONG_GRASS
+	db COLL_CUT_28
+	db COLL_WATER
+	db COLL_GRASS_48
+	db COLL_GRASS_49
+	db COLL_GRASS_4A
+	db COLL_GRASS_4B
+	db COLL_GRASS_4C
+	db -1
+; 149f5
+
+CheckCutCollision: ; 149f5
+	ld a, c
+	ld hl, .blocks
+	ld de, 1
+	call IsInArray
+	ret
+; 14a00
+
+.blocks ; 14a00
+	db COLL_CUT_TREE
+	db COLL_CUT_TREE_1A
+	db COLL_TALL_GRASS_10
+	db COLL_TALL_GRASS
+	db COLL_LONG_GRASS
+	db COLL_LONG_GRASS_1C
+	db -1
+; 14a07
+
+GetWarpSFX:: ; 14a07
+	ld a, [wPlayerStandingTile]
+	ld de, SFX_ENTER_DOOR
+	cp COLL_DOOR
+	ret z
+	ld de, SFX_WARP_TO
+	cp COLL_WARP_PANEL
+	ret z
+	ld de, SFX_EXIT_BUILDING
+	ret
+; 14a1a