First Commit

Upload literally everything from the pokecrystal16 expand-move-ID branch

engine/overworld/cmd_queue.asm

@@ -0,0 +1,301 @@
+ClearCmdQueue::
+	ld hl, wCmdQueue
+	ld de, CMDQUEUE_ENTRY_SIZE
+	ld c, CMDQUEUE_CAPACITY
+	xor a
+.loop
+	ld [hl], a
+	add hl, de
+	dec c
+	jr nz, .loop
+	ret
+
+HandleCmdQueue::
+	ld hl, wCmdQueue
+	xor a
+.loop
+	ldh [hMapObjectIndex], a
+	ld a, [hl]
+	and a
+	jr z, .skip
+	push hl
+	ld b, h
+	ld c, l
+	call HandleQueuedCommand
+	pop hl
+
+.skip
+	ld de, CMDQUEUE_ENTRY_SIZE
+	add hl, de
+	ldh a, [hMapObjectIndex]
+	inc a
+	cp CMDQUEUE_CAPACITY
+	jr nz, .loop
+	ret
+
+GetNthCmdQueueEntry: ; unreferenced
+	ld hl, wCmdQueue
+	ld bc, CMDQUEUE_ENTRY_SIZE
+	call AddNTimes
+	ld b, h
+	ld c, l
+	ret
+
+WriteCmdQueue::
+	push bc
+	push de
+	call .GetNextEmptyEntry
+	ld d, h
+	ld e, l
+	pop hl
+	pop bc
+	ret c
+	ld a, b
+	ld bc, CMDQUEUE_ENTRY_SIZE - 1
+	call FarCopyBytes
+	xor a
+	ld [hl], a
+	ret
+
+.GetNextEmptyEntry:
+	ld hl, wCmdQueue
+	ld de, CMDQUEUE_ENTRY_SIZE
+	ld c, CMDQUEUE_CAPACITY
+.loop
+	ld a, [hl]
+	and a
+	jr z, .done
+	add hl, de
+	dec c
+	jr nz, .loop
+	scf
+	ret
+
+.done
+	ld a, CMDQUEUE_CAPACITY
+	sub c
+	and a
+	ret
+
+DelCmdQueue::
+	ld hl, wCmdQueue
+	ld de, CMDQUEUE_ENTRY_SIZE
+	ld c, CMDQUEUE_CAPACITY
+.loop
+	ld a, [hl]
+	cp b
+	jr z, .done
+	add hl, de
+	dec c
+	jr nz, .loop
+	and a
+	ret
+
+.done
+	xor a
+	ld [hl], a
+	scf
+	ret
+
+_DelCmdQueue:
+	ld hl, CMDQUEUE_TYPE
+	add hl, bc
+	ld [hl], 0
+	ret
+
+HandleQueuedCommand:
+	ld hl, CMDQUEUE_TYPE
+	add hl, bc
+	ld a, [hl]
+	cp NUM_CMDQUEUE_TYPES
+	jr c, .okay
+	xor a
+
+.okay
+	ld e, a
+	ld d, 0
+	ld hl, .Jumptable
+	add hl, de
+	add hl, de
+	add hl, de
+	ld a, [hli]
+	push af
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	pop af
+	rst FarCall
+	ret
+
+.Jumptable:
+	dba CmdQueue_Null
+	dba CmdQueue_Type1
+	dba CmdQueue_StoneTable
+	dba CmdQueue_Type3
+	dba CmdQueue_Type4
+
+CmdQueues_AnonJumptable:
+	ld hl, CMDQUEUE_JUMPTABLE_INDEX
+	add hl, bc
+	ld a, [hl]
+	pop hl
+	rst JumpTable
+	ret
+
+CmdQueues_IncAnonJumptableIndex:
+	ld hl, CMDQUEUE_JUMPTABLE_INDEX
+	add hl, bc
+	inc [hl]
+	ret
+
+CmdQueues_DecAnonJumptableIndex:
+	ld hl, CMDQUEUE_JUMPTABLE_INDEX
+	add hl, bc
+	dec [hl]
+	ret
+
+CmdQueue_Null:
+	ret
+
+CmdQueue_Type1:
+	ret
+
+CmdQueue_Type4:
+	call CmdQueues_AnonJumptable
+.anon_dw
+	dw .zero
+	dw .one
+
+.zero
+	ldh a, [hSCY]
+	ld hl, CMDQUEUE_04
+	add hl, bc
+	ld [hl], a
+	call CmdQueues_IncAnonJumptableIndex
+.one
+	ld hl, CMDQUEUE_ADDR
+	add hl, bc
+	ld a, [hl]
+	dec a
+	ld [hl], a
+	jr z, .finish
+	and 1
+	jr z, .add
+	ld hl, CMDQUEUE_02
+	add hl, bc
+	ldh a, [hSCY]
+	sub [hl]
+	ldh [hSCY], a
+	ret
+
+.add
+	ld hl, CMDQUEUE_02
+	add hl, bc
+	ldh a, [hSCY]
+	add [hl]
+	ldh [hSCY], a
+	ret
+
+.finish
+	ld hl, CMDQUEUE_04
+	add hl, bc
+	ld a, [hl]
+	ldh [hSCY], a
+	call _DelCmdQueue
+	ret
+
+CmdQueue_Type3:
+	call CmdQueues_AnonJumptable
+.anon_dw
+	dw .zero
+	dw .one
+	dw .two
+
+.zero
+	call .IsPlayerFacingDown
+	jr z, .PlayerNotFacingDown
+	call CmdQueues_IncAnonJumptableIndex
+.one
+	call .IsPlayerFacingDown
+	jr z, .PlayerNotFacingDown
+	call CmdQueues_IncAnonJumptableIndex
+
+	ld hl, CMDQUEUE_02
+	add hl, bc
+	ld a, [hl]
+	ld [wd173], a
+	ret
+
+.two
+	call .IsPlayerFacingDown
+	jr z, .PlayerNotFacingDown
+	call CmdQueues_DecAnonJumptableIndex
+
+	ld hl, CMDQUEUE_03
+	add hl, bc
+	ld a, [hl]
+	ld [wd173], a
+	ret
+
+.PlayerNotFacingDown:
+	ld a, $7f
+	ld [wd173], a
+	ld hl, CMDQUEUE_JUMPTABLE_INDEX
+	add hl, bc
+	ld [hl], 0
+	ret
+
+.IsPlayerFacingDown:
+	push bc
+	ld bc, wPlayerStruct
+	call GetSpriteDirection
+	and a
+	pop bc
+	ret
+
+CmdQueue_StoneTable:
+	ld de, wPlayerStruct
+	ld a, NUM_OBJECT_STRUCTS
+.loop
+	push af
+
+	ld hl, OBJECT_SPRITE
+	add hl, de
+	ld a, [hl]
+	and a
+	jr z, .next
+
+	ld hl, OBJECT_MOVEMENT_TYPE
+	add hl, de
+	ld a, [hl]
+	cp SPRITEMOVEDATA_STRENGTH_BOULDER
+	jr nz, .next
+
+	ld hl, OBJECT_TILE
+	add hl, de
+	ld a, [hl]
+	call CheckPitTile
+	jr nz, .next
+
+	ld hl, OBJECT_WALKING
+	add hl, de
+	ld a, [hl]
+	cp STANDING
+	jr nz, .next
+	call HandleStoneQueue
+	jr c, .fall_down_hole
+
+.next
+	ld hl, OBJECT_LENGTH
+	add hl, de
+	ld d, h
+	ld e, l
+
+	pop af
+	dec a
+	jr nz, .loop
+	ret
+
+.fall_down_hole
+	pop af
+	ret

engine/overworld/init_map.asm

@@ -0,0 +1,104 @@
+ReanchorBGMap_NoOAMUpdate::
+	call DelayFrame
+	ldh a, [hOAMUpdate]
+	push af
+
+	ld a, $1
+	ldh [hOAMUpdate], a
+	ldh a, [hBGMapMode]
+	push af
+	xor a
+	ldh [hBGMapMode], a
+
+	call .ReanchorBGMap
+
+	pop af
+	ldh [hBGMapMode], a
+	pop af
+	ldh [hOAMUpdate], a
+
+	ld hl, wVramState
+	set 6, [hl]
+	ret
+
+.ReanchorBGMap:
+	xor a
+	ldh [hLCDCPointer], a
+	ldh [hBGMapMode], a
+	ld a, $90
+	ldh [hWY], a
+	call OverworldTextModeSwitch
+	ld a, HIGH(vBGMap1)
+	call .LoadBGMapAddrIntoHRAM
+	call _OpenAndCloseMenu_HDMATransferTilemapAndAttrmap
+	farcall LoadOW_BGPal7
+	farcall ApplyPals
+	ld a, TRUE
+	ldh [hCGBPalUpdate], a
+	xor a
+	ldh [hBGMapMode], a
+	ldh [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
+	ldh [hSCX], a
+	ldh [hSCY], a
+	call ApplyBGMapAnchorToObjects
+	ret
+
+.LoadBGMapAddrIntoHRAM:
+	ldh [hBGMapAddress + 1], a
+	xor a
+	ldh [hBGMapAddress], a
+	ret
+
+LoadFonts_NoOAMUpdate::
+	ldh a, [hOAMUpdate]
+	push af
+	ld a, $1
+	ldh [hOAMUpdate], a
+
+	call .LoadGFX
+
+	pop af
+	ldh [hOAMUpdate], a
+	ret
+
+.LoadGFX:
+	call LoadFontsExtra
+	ld a, $90
+	ldh [hWY], a
+	call SafeUpdateSprites
+	call LoadStandardFont
+	ret
+
+HDMATransfer_FillBGMap0WithBlack:
+	ldh a, [rSVBK]
+	push af
+	ld a, BANK(wDecompressScratch)
+	ldh [rSVBK], a
+
+	ld a, "■"
+	ld hl, wDecompressScratch
+	ld bc, wScratchAttrmap - wDecompressScratch
+	call ByteFill
+	ld a, HIGH(wDecompressScratch)
+	ldh [rHDMA1], a
+	ld a, LOW(wDecompressScratch)
+	ldh [rHDMA2], a
+	ld a, HIGH(vBGMap0 - VRAM_Begin)
+	ldh [rHDMA3], a
+	ld a, LOW(vBGMap0 - VRAM_Begin)
+	ldh [rHDMA4], a
+	ld a, $3f
+	ldh [hDMATransfer], a
+	call DelayFrame
+
+	pop af
+	ldh [rSVBK], a
+	ret

engine/overworld/landmarks.asm

@@ -0,0 +1,82 @@
+GetLandmarkCoords:
+; 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
+
+GetLandmarkName::
+; 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
+
+INCLUDE "data/maps/landmarks.asm"
+
+RegionCheck:
+; 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 LANDMARK_FAST_SHIP ; S.S. Aqua
+	jr z, .johto
+	cp LANDMARK_SPECIAL
+	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 LANDMARK_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::
+	ld hl, wSurroundingTiles
+	ld a, [wPlayerMetatileY]
+	and a
+	jr z, .top_row
+	ld bc, SURROUNDING_WIDTH * 2
+	add hl, bc
+
+.top_row
+	ld a, [wPlayerMetatileX]
+	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 +1,298 @@
+ObjectActionPairPointers:
+; entries correspond to OBJECT_ACTION_* constants (see constants/map_object_constants.asm)
+	table_width 2 + 2, ObjectActionPairPointers
+	;  normal action,                  frozen action
+	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
+	assert_table_length NUM_OBJECT_ACTIONS
+
+SetFacingStanding:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+SetFacingCurrent:
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingStandAction:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld a, [hl]
+	and 1
+	jr nz, SetFacingStepAction
+	jp SetFacingCurrent
+
+SetFacingStepAction:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING_F, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	inc a
+	and %00001111
+	ld [hl], a
+
+	rrca
+	rrca
+	maskbits NUM_DIRECTIONS
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingSkyfall:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING_F, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	add 2
+	and %00001111
+	ld [hl], a
+
+	rrca
+	rrca
+	maskbits NUM_DIRECTIONS
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingBumpAction:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit SLIDING_F, [hl]
+	jp nz, SetFacingCurrent
+
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+
+	ld a, [hl]
+	rrca
+	rrca
+	rrca
+	maskbits NUM_DIRECTIONS
+	ld d, a
+
+	call GetSpriteDirection
+	or FACING_STEP_DOWN_0 ; useless
+	or d
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingCounterclockwiseSpin:
+	call CounterclockwiseSpinAction
+	ld hl, OBJECT_DIRECTION
+	add hl, bc
+	ld a, [hl]
+	or FACING_STEP_DOWN_0 ; useless
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingCounterclockwiseSpin2:
+	call CounterclockwiseSpinAction
+	jp SetFacingStanding
+
+CounterclockwiseSpinAction:
+; 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, .facings
+	add hl, de
+	ld a, [hl]
+	ld hl, OBJECT_DIRECTION
+	add hl, bc
+	ld [hl], a
+	ret
+
+.facings:
+	db OW_DOWN
+	db OW_RIGHT
+	db OW_UP
+	db OW_LEFT
+
+SetFacingFish:
+	call GetSpriteDirection
+	rrca
+	rrca
+	add FACING_FISH_DOWN
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingShadow:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], FACING_SHADOW
+	ret
+
+SetFacingEmote:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], FACING_EMOTE
+	ret
+
+SetFacingBigDollSym:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], FACING_BIG_DOLL_SYM
+	ret
+
+SetFacingBounce:
+	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
+	add hl, bc
+	ld [hl], FACING_STEP_UP_0
+	ret
+
+SetFacingFreezeBounce:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], FACING_STEP_DOWN_0
+	ret
+
+SetFacingWeirdTree:
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld a, [hl]
+	inc a
+	ld [hl], a
+	maskbits NUM_DIRECTIONS, 2
+	rrca
+	rrca
+	add FACING_WEIRD_TREE_0
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], a
+	ret
+
+SetFacingBigDollAsym:
+	ld hl, OBJECT_FACING
+	add hl, bc
+	ld [hl], FACING_BIG_DOLL_ASYM
+	ret
+
+SetFacingBigDoll:
+	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
+	add hl, bc
+	ld [hl], d
+	ret
+
+SetFacingBoulderDust:
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+	ld a, [hl]
+
+	ld hl, OBJECT_FACING
+	add hl, bc
+	and 2
+	ld a, FACING_BOULDER_DUST_1
+	jr z, .ok
+	inc a
+	assert FACING_BOULDER_DUST_1 + 1 == FACING_BOULDER_DUST_2
+.ok
+	ld [hl], a
+	ret
+
+SetFacingGrassShake:
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	inc [hl]
+	ld a, [hl]
+	ld hl, OBJECT_FACING
+	add hl, bc
+	and 4
+	ld a, FACING_GRASS_1
+	jr z, .ok
+	inc a ; FACING_GRASS_2
+
+.ok
+	ld [hl], a
+	ret

engine/overworld/map_objects_2.asm

@@ -0,0 +1,70 @@
+LoadObjectMasks:
+	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, MAPOBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	pop af
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop
+	ret
+
+CheckObjectFlag:
+	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:
+	call CheckObjectTime
+	ld a, -1
+	ret c
+	xor a
+	ret

engine/overworld/map_setup.asm

@@ -0,0 +1,200 @@
+RunMapSetupScript::
+	ldh 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
+
+INCLUDE "data/maps/setup_scripts.asm"
+
+ReadMapSetupScript:
+.loop
+	ld a, [hli]
+	cp -1 ; end?
+	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
+
+INCLUDE "data/maps/setup_script_pointers.asm"
+
+EnableTextAcceleration:
+	xor a
+	ld [wDisableTextAcceleration], a
+	ret
+
+ActivateMapAnims:
+	ld a, TRUE
+	ldh [hMapAnims], a
+	ret
+
+SuspendMapAnims:
+	xor a ; FALSE
+	ldh [hMapAnims], a
+	ret
+
+LoadMapObjects:
+	ld a, MAPCALLBACK_OBJECTS
+	call RunMapCallback
+	farcall LoadObjectMasks
+	farcall InitializeVisibleSprites
+	ret
+
+MapSetup_DummyFunction: ; unreferenced
+	ret
+
+ResetPlayerObjectAction:
+	ld hl, wPlayerSpriteSetupFlags
+	set PLAYERSPRITESETUP_RESET_ACTION_F, [hl]
+	ret
+
+SkipUpdateMapSprites:
+	ld hl, wPlayerSpriteSetupFlags
+	set PLAYERSPRITESETUP_SKIP_RELOAD_GFX_F, [hl]
+	ret
+
+CheckUpdatePlayerSprite:
+	nop
+	call .CheckBiking
+	jr c, .ok
+	call .CheckSurfing
+	jr c, .ok
+	call .CheckSurfing2
+	jr c, .ok
+	ret
+
+.ok
+	call UpdatePlayerSprite
+	ret
+
+.CheckBiking:
+	and a
+	ld hl, wBikeFlags
+	bit BIKEFLAGS_ALWAYS_ON_BIKE_F, [hl]
+	ret z
+	ld a, PLAYER_BIKE
+	ld [wPlayerState], a
+	scf
+	ret
+
+.CheckSurfing2:
+	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, .no_biking
+	cp ENVIRONMENT_5
+	jr z, .no_biking
+	cp DUNGEON
+	jr z, .no_biking
+	jr .nope
+.no_biking
+	ld a, [wPlayerState]
+	cp PLAYER_BIKE
+	jr nz, .nope
+.surfing
+	ld a, PLAYER_NORMAL
+	ld [wPlayerState], a
+	scf
+	ret
+
+.nope
+	and a
+	ret
+
+.CheckSurfing:
+	call CheckOnWater
+	jr nz, .nope2
+	ld a, [wPlayerState]
+	cp PLAYER_SURF
+	jr z, .is_surfing
+	cp PLAYER_SURF_PIKA
+	jr z, .is_surfing
+	ld a, PLAYER_SURF
+	ld [wPlayerState], a
+.is_surfing
+	scf
+	ret
+
+.nope2
+	and a
+	ret
+
+FadeOutMapMusic:
+	ld a, 6
+	call SkipMusic
+	ret
+
+ApplyMapPalettes:
+	farcall _UpdateTimePals
+	ret
+
+FadeMapMusicAndPalettes:
+	ld e, LOW(MUSIC_NONE)
+	ld a, [wMusicFadeID]
+	ld d, HIGH(MUSIC_NONE)
+	ld a, [wMusicFadeID + 1]
+	ld a, $4
+	ld [wMusicFade], a
+	call RotateThreePalettesRight
+	ret
+
+ForceMapMusic:
+	ld a, [wPlayerState]
+	cp PLAYER_BIKE
+	jr nz, .notbiking
+	call MinVolume
+	ld a, $88
+	ld [wMusicFade], a
+.notbiking
+	call TryRestartMapMusic
+	ret

engine/overworld/movement.asm

@@ -0,0 +1,778 @@
+MovementPointers:
+; entries correspond to movement_* constants (see macros/scripts/movement.asm)
+	table_width 2, MovementPointers
+	dw Movement_turn_head_down        ; 00
+	dw Movement_turn_head_up          ; 01
+	dw Movement_turn_head_left        ; 02
+	dw Movement_turn_head_right       ; 03
+	dw Movement_turn_step_down        ; 04
+	dw Movement_turn_step_up          ; 05
+	dw Movement_turn_step_left        ; 06
+	dw Movement_turn_step_right       ; 07
+	dw Movement_slow_step_down        ; 08
+	dw Movement_slow_step_up          ; 09
+	dw Movement_slow_step_left        ; 0a
+	dw Movement_slow_step_right       ; 0b
+	dw Movement_step_down             ; 0c
+	dw Movement_step_up               ; 0d
+	dw Movement_step_left             ; 0e
+	dw Movement_step_right            ; 0f
+	dw Movement_big_step_down         ; 10
+	dw Movement_big_step_up           ; 11
+	dw Movement_big_step_left         ; 12
+	dw Movement_big_step_right        ; 13
+	dw Movement_slow_slide_step_down  ; 14
+	dw Movement_slow_slide_step_up    ; 15
+	dw Movement_slow_slide_step_left  ; 16
+	dw Movement_slow_slide_step_right ; 17
+	dw Movement_slide_step_down       ; 18
+	dw Movement_slide_step_up         ; 19
+	dw Movement_slide_step_left       ; 1a
+	dw Movement_slide_step_right      ; 1b
+	dw Movement_fast_slide_step_down  ; 1c
+	dw Movement_fast_slide_step_up    ; 1d
+	dw Movement_fast_slide_step_left  ; 1e
+	dw Movement_fast_slide_step_right ; 1f
+	dw Movement_turn_away_down        ; 20
+	dw Movement_turn_away_up          ; 21
+	dw Movement_turn_away_left        ; 22
+	dw Movement_turn_away_right       ; 23
+	dw Movement_turn_in_down          ; 24
+	dw Movement_turn_in_up            ; 25
+	dw Movement_turn_in_left          ; 26
+	dw Movement_turn_in_right         ; 27
+	dw Movement_turn_waterfall_down   ; 28
+	dw Movement_turn_waterfall_up     ; 29
+	dw Movement_turn_waterfall_left   ; 2a
+	dw Movement_turn_waterfall_right  ; 2b
+	dw Movement_slow_jump_step_down   ; 2c
+	dw Movement_slow_jump_step_up     ; 2d
+	dw Movement_slow_jump_step_left   ; 2e
+	dw Movement_slow_jump_step_right  ; 2f
+	dw Movement_jump_step_down        ; 30
+	dw Movement_jump_step_up          ; 31
+	dw Movement_jump_step_left        ; 32
+	dw Movement_jump_step_right       ; 33
+	dw Movement_fast_jump_step_down   ; 34
+	dw Movement_fast_jump_step_up     ; 35
+	dw Movement_fast_jump_step_left   ; 36
+	dw Movement_fast_jump_step_right  ; 37
+	dw Movement_remove_sliding        ; 38
+	dw Movement_set_sliding           ; 39
+	dw Movement_remove_fixed_facing   ; 3a
+	dw Movement_fix_facing            ; 3b
+	dw Movement_show_object           ; 3c
+	dw Movement_hide_object           ; 3d
+	dw Movement_step_sleep_1          ; 3e
+	dw Movement_step_sleep_2          ; 3f
+	dw Movement_step_sleep_3          ; 40
+	dw Movement_step_sleep_4          ; 41
+	dw Movement_step_sleep_5          ; 42
+	dw Movement_step_sleep_6          ; 43
+	dw Movement_step_sleep_7          ; 44
+	dw Movement_step_sleep_8          ; 45
+	dw Movement_step_sleep            ; 46
+	dw Movement_step_end              ; 47
+	dw Movement_48                    ; 48
+	dw Movement_remove_object         ; 49
+	dw Movement_step_loop             ; 4a
+	dw Movement_4b                    ; 4b
+	dw Movement_teleport_from         ; 4c
+	dw Movement_teleport_to           ; 4d
+	dw Movement_skyfall               ; 4e
+	dw Movement_step_dig              ; 4f
+	dw Movement_step_bump             ; 50
+	dw Movement_fish_got_bite         ; 51
+	dw Movement_fish_cast_rod         ; 52
+	dw Movement_hide_emote            ; 53
+	dw Movement_show_emote            ; 54
+	dw Movement_step_shake            ; 55
+	dw Movement_tree_shake            ; 56
+	dw Movement_rock_smash            ; 57
+	dw Movement_return_dig            ; 58
+	dw Movement_skyfall_top           ; 59
+	assert_table_length NUM_MOVEMENT_CMDS
+
+Movement_teleport_from:
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_TELEPORT_FROM
+	ret
+
+Movement_teleport_to:
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_TELEPORT_TO
+	ret
+
+Movement_skyfall:
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SKYFALL
+	ret
+
+Movement_skyfall_top:
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SKYFALL_TOP
+	ret
+
+Movement_step_dig:
+	call GetSpriteDirection
+	rlca
+	rlca
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld [hl], a
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_SPIN
+	call JumpMovementPointer
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SLEEP
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+Movement_return_dig:
+	call GetSpriteDirection
+	rlca
+	rlca
+	ld hl, OBJECT_STEP_FRAME
+	add hl, bc
+	ld [hl], a
+	call JumpMovementPointer
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_RETURN_DIG
+	ret
+
+Movement_fish_got_bite:
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_FISHING
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_GOT_BITE
+	ret
+
+Movement_rock_smash:
+	call JumpMovementPointer
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STAND
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_ROCK_SMASH
+	ret
+
+Movement_fish_cast_rod:
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_FISHING
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_FROM_MOVEMENT
+	ret
+
+Movement_step_loop:
+	ld hl, OBJECT_MOVEMENT_INDEX
+	add hl, bc
+	ld [hl], $0
+	jp ContinueReadingMovement
+
+Movement_step_end:
+	call RestoreDefaultMovement
+	ld hl, OBJECT_MOVEMENT_TYPE
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_MOVEMENT_INDEX
+	add hl, bc
+	ld [hl], $0
+
+	ld hl, wVramState
+	res 7, [hl]
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_FROM_MOVEMENT
+	ret
+
+Movement_48:
+	call RestoreDefaultMovement
+	ld hl, OBJECT_MOVEMENT_TYPE
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_MOVEMENT_INDEX
+	add hl, bc
+	ld [hl], $0
+
+	call JumpMovementPointer
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SLEEP
+
+	ld hl, wVramState
+	res 7, [hl]
+	ret
+
+Movement_remove_object:
+	call DeleteMapObject
+	ld hl, wObjectFollow_Leader
+	ldh a, [hMapObjectIndex]
+	cp [hl]
+	jr nz, .not_leading
+	ld [hl], -1
+
+.not_leading
+	ld hl, wVramState
+	res 7, [hl]
+	ret
+
+Movement_4b:
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STAND
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_STANDING
+
+	ld hl, wVramState
+	res 7, [hl]
+	ret
+
+Movement_step_sleep_1:
+	ld a, 1
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_2:
+	ld a, 2
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_3:
+	ld a, 3
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_4:
+	ld a, 4
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_5:
+	ld a, 5
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_6:
+	ld a, 6
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_7:
+	ld a, 7
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_8:
+	ld a, 8
+	jr Movement_step_sleep_common
+
+Movement_step_sleep:
+; parameters:
+;	duration (DecimalParam)
+
+	call JumpMovementPointer
+	jr Movement_step_sleep_common
+
+Movement_step_sleep_common:
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SLEEP
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STAND
+
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+Movement_step_bump:
+	ld a, 1
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_BUMP
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_BUMP
+
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+Movement_tree_shake:
+	ld a, 24
+	ld hl, OBJECT_STEP_DURATION
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_SLEEP
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_WEIRD_TREE
+
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+Movement_remove_sliding:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	res SLIDING_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_set_sliding:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	set SLIDING_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_remove_fixed_facing:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	res FIXED_FACING_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_fix_facing:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	set FIXED_FACING_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_show_object:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	res INVISIBLE_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_hide_object:
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	set INVISIBLE_F, [hl]
+	jp ContinueReadingMovement
+
+Movement_hide_emote:
+	call DespawnEmote
+	jp ContinueReadingMovement
+
+Movement_show_emote:
+	call SpawnEmote
+	jp ContinueReadingMovement
+
+Movement_step_shake:
+; parameters:
+;	displacement (DecimalParam)
+
+	call JumpMovementPointer
+	call ShakeScreen
+	jp ContinueReadingMovement
+
+Movement_turn_head_down:
+	ld a, OW_DOWN
+	jr TurnHead
+
+Movement_turn_head_up:
+	ld a, OW_UP
+	jr TurnHead
+
+Movement_turn_head_left:
+	ld a, OW_LEFT
+	jr TurnHead
+
+Movement_turn_head_right:
+	ld a, OW_RIGHT
+	jr TurnHead
+
+TurnHead:
+	ld hl, OBJECT_DIRECTION
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STAND
+
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld [hl], STANDING
+	ret
+
+Movement_slow_step_down:
+	ld a, STEP_SLOW << 2 | DOWN
+	jp NormalStep
+
+Movement_slow_step_up:
+	ld a, STEP_SLOW << 2 | UP
+	jp NormalStep
+
+Movement_slow_step_left:
+	ld a, STEP_SLOW << 2 | LEFT
+	jp NormalStep
+
+Movement_slow_step_right:
+	ld a, STEP_SLOW << 2 | RIGHT
+	jp NormalStep
+
+Movement_step_down:
+	ld a, STEP_WALK << 2 | DOWN
+	jp NormalStep
+
+Movement_step_up:
+	ld a, STEP_WALK << 2 | UP
+	jp NormalStep
+
+Movement_step_left:
+	ld a, STEP_WALK << 2 | LEFT
+	jp NormalStep
+
+Movement_step_right:
+	ld a, STEP_WALK << 2 | RIGHT
+	jp NormalStep
+
+Movement_big_step_down:
+	ld a, STEP_BIKE << 2 | DOWN
+	jp NormalStep
+
+Movement_big_step_up:
+	ld a, STEP_BIKE << 2 | UP
+	jp NormalStep
+
+Movement_big_step_left:
+	ld a, STEP_BIKE << 2 | LEFT
+	jp NormalStep
+
+Movement_big_step_right:
+	ld a, STEP_BIKE << 2 | RIGHT
+	jp NormalStep
+
+Movement_turn_away_down:
+	ld a, STEP_SLOW << 2 | DOWN
+	jp TurningStep
+
+Movement_turn_away_up:
+	ld a, STEP_SLOW << 2 | UP
+	jp TurningStep
+
+Movement_turn_away_left:
+	ld a, STEP_SLOW << 2 | LEFT
+	jp TurningStep
+
+Movement_turn_away_right:
+	ld a, STEP_SLOW << 2 | RIGHT
+	jp TurningStep
+
+Movement_turn_in_down:
+	ld a, STEP_WALK << 2 | DOWN
+	jp TurningStep
+
+Movement_turn_in_up:
+	ld a, STEP_WALK << 2 | UP
+	jp TurningStep
+
+Movement_turn_in_left:
+	ld a, STEP_WALK << 2 | LEFT
+	jp TurningStep
+
+Movement_turn_in_right:
+	ld a, STEP_WALK << 2 | RIGHT
+	jp TurningStep
+
+Movement_turn_waterfall_down:
+	ld a, STEP_BIKE << 2 | DOWN
+	jp TurningStep
+
+Movement_turn_waterfall_up:
+	ld a, STEP_BIKE << 2 | UP
+	jp TurningStep
+
+Movement_turn_waterfall_left:
+	ld a, STEP_BIKE << 2 | LEFT
+	jp TurningStep
+
+Movement_turn_waterfall_right:
+	ld a, STEP_BIKE << 2 | RIGHT
+	jp TurningStep
+
+Movement_slow_slide_step_down:
+	ld a, STEP_SLOW << 2 | DOWN
+	jp SlideStep
+
+Movement_slow_slide_step_up:
+	ld a, STEP_SLOW << 2 | UP
+	jp SlideStep
+
+Movement_slow_slide_step_left:
+	ld a, STEP_SLOW << 2 | LEFT
+	jp SlideStep
+
+Movement_slow_slide_step_right:
+	ld a, STEP_SLOW << 2 | RIGHT
+	jp SlideStep
+
+Movement_slide_step_down:
+	ld a, STEP_WALK << 2 | DOWN
+	jp SlideStep
+
+Movement_slide_step_up:
+	ld a, STEP_WALK << 2 | UP
+	jp SlideStep
+
+Movement_slide_step_left:
+	ld a, STEP_WALK << 2 | LEFT
+	jp SlideStep
+
+Movement_slide_step_right:
+	ld a, STEP_WALK << 2 | RIGHT
+	jp SlideStep
+
+Movement_fast_slide_step_down:
+	ld a, STEP_BIKE << 2 | DOWN
+	jp SlideStep
+
+Movement_fast_slide_step_up:
+	ld a, STEP_BIKE << 2 | UP
+	jp SlideStep
+
+Movement_fast_slide_step_left:
+	ld a, STEP_BIKE << 2 | LEFT
+	jp SlideStep
+
+Movement_fast_slide_step_right:
+	ld a, STEP_BIKE << 2 | RIGHT
+	jp SlideStep
+
+Movement_slow_jump_step_down:
+	ld a, STEP_SLOW << 2 | DOWN
+	jp JumpStep
+
+Movement_slow_jump_step_up:
+	ld a, STEP_SLOW << 2 | UP
+	jp JumpStep
+
+Movement_slow_jump_step_left:
+	ld a, STEP_SLOW << 2 | LEFT
+	jp JumpStep
+
+Movement_slow_jump_step_right:
+	ld a, STEP_SLOW << 2 | RIGHT
+	jp JumpStep
+
+Movement_jump_step_down:
+	ld a, STEP_WALK << 2 | DOWN
+	jp JumpStep
+
+Movement_jump_step_up:
+	ld a, STEP_WALK << 2 | UP
+	jp JumpStep
+
+Movement_jump_step_left:
+	ld a, STEP_WALK << 2 | LEFT
+	jp JumpStep
+
+Movement_jump_step_right:
+	ld a, STEP_WALK << 2 | RIGHT
+	jp JumpStep
+
+Movement_fast_jump_step_down:
+	ld a, STEP_BIKE << 2 | DOWN
+	jp JumpStep
+
+Movement_fast_jump_step_up:
+	ld a, STEP_BIKE << 2 | UP
+	jp JumpStep
+
+Movement_fast_jump_step_left:
+	ld a, STEP_BIKE << 2 | LEFT
+	jp JumpStep
+
+Movement_fast_jump_step_right:
+	ld a, STEP_BIKE << 2 | RIGHT
+	jp JumpStep
+
+Movement_turn_step_down:
+	ld a, OW_DOWN
+	jr TurnStep
+
+Movement_turn_step_up:
+	ld a, OW_UP
+	jr TurnStep
+
+Movement_turn_step_left:
+	ld a, OW_LEFT
+	jr TurnStep
+
+Movement_turn_step_right:
+	ld a, OW_RIGHT
+	jr TurnStep
+
+TurnStep:
+	ld hl, OBJECT_1D ; new facing
+	add hl, bc
+	ld [hl], a
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STEP
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_TURN
+	ret
+
+NormalStep:
+	call InitStep
+	call UpdateTallGrassFlags
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STEP
+
+	ld hl, OBJECT_TILE
+	add hl, bc
+	ld a, [hl]
+	call CheckSuperTallGrassTile
+	jr z, .shake_grass
+
+	call CheckGrassTile
+	jr c, .skip_grass
+
+.shake_grass
+	call ShakeGrass
+
+.skip_grass
+	ld hl, wCenteredObject
+	ldh a, [hMapObjectIndex]
+	cp [hl]
+	jr z, .player
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_NPC_WALK
+	ret
+
+.player
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_PLAYER_WALK
+	ret
+
+TurningStep:
+	call InitStep
+	call UpdateTallGrassFlags
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_SPIN
+
+	ld hl, wCenteredObject
+	ldh a, [hMapObjectIndex]
+	cp [hl]
+	jr z, .player
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_NPC_WALK
+	ret
+
+.player
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_PLAYER_WALK
+	ret
+
+SlideStep:
+	call InitStep
+	call UpdateTallGrassFlags
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STAND
+
+	ld hl, wCenteredObject
+	ldh a, [hMapObjectIndex]
+	cp [hl]
+	jr z, .player
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_NPC_WALK
+	ret
+
+.player
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_PLAYER_WALK
+	ret
+
+JumpStep:
+	call InitStep
+	ld hl, OBJECT_JUMP_HEIGHT
+	add hl, bc
+	ld [hl], $0
+
+	ld hl, OBJECT_FLAGS2
+	add hl, bc
+	res OVERHEAD_F, [hl]
+
+	ld hl, OBJECT_ACTION
+	add hl, bc
+	ld [hl], OBJECT_ACTION_STEP
+
+	call SpawnShadow
+
+	ld hl, wCenteredObject
+	ldh a, [hMapObjectIndex]
+	cp [hl]
+	jr z, .player
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_NPC_JUMP
+	ret
+
+.player
+	ld hl, OBJECT_STEP_TYPE
+	add hl, bc
+	ld [hl], STEP_TYPE_PLAYER_JUMP
+	ret

engine/overworld/npc_movement.asm

@@ -0,0 +1,562 @@
+CanObjectMoveInDirection:
+	ld hl, OBJECT_PALETTE
+	add hl, bc
+	bit SWIMMING_F, [hl]
+	jr z, .not_swimming
+
+; BUG: Swimming NPCs aren't limited by their movement radius (see docs/bugs_and_glitches.md)
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit NOCLIP_TILES_F, [hl]
+	push hl
+	push bc
+	call WillObjectBumpIntoLand
+	pop bc
+	pop hl
+	ret c
+	jr .continue
+
+.not_swimming
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit NOCLIP_TILES_F, [hl]
+	jr nz, .noclip_tiles
+	push hl
+	push bc
+	call WillObjectBumpIntoWater
+	pop bc
+	pop hl
+	ret c
+
+.noclip_tiles
+.continue
+	bit NOCLIP_OBJS_F, [hl]
+	jr nz, .noclip_objs
+
+	push hl
+	push bc
+	call WillObjectBumpIntoSomeoneElse
+	pop bc
+	pop hl
+	ret c
+
+.noclip_objs
+	bit MOVE_ANYWHERE_F, [hl]
+	jr nz, .move_anywhere
+	push hl
+	call HasObjectReachedMovementLimit
+	pop hl
+	ret c
+
+	push hl
+	call IsObjectMovingOffEdgeOfScreen
+	pop hl
+	ret c
+
+.move_anywhere
+	and a
+	ret
+
+WillObjectBumpIntoWater:
+	call CanObjectLeaveTile
+	ret c
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	ld hl, OBJECT_PALETTE
+	add hl, bc
+	bit OAM_PRIORITY, [hl]
+	jp nz, WillObjectRemainOnWater
+	ld hl, OBJECT_TILE
+	add hl, bc
+	ld a, [hl]
+	ld d, a
+	call GetTileCollision
+	and a ; LAND_TILE
+	jr z, WillObjectBumpIntoTile
+	scf
+	ret
+
+WillObjectBumpIntoLand:
+	call CanObjectLeaveTile
+	ret c
+	ld hl, OBJECT_TILE
+	add hl, bc
+	ld a, [hl]
+	call GetTileCollision
+	cp WATER_TILE
+	jr z, WillObjectBumpIntoTile
+	scf
+	ret
+
+WillObjectBumpIntoTile:
+	ld hl, OBJECT_TILE
+	add hl, bc
+	ld a, [hl]
+	call GetSideWallDirectionMask
+	ret nc
+	push af
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld a, [hl]
+	maskbits NUM_DIRECTIONS
+	ld e, a
+	ld d, 0
+	ld hl, .dir_masks
+	add hl, de
+	pop af
+	and [hl]
+	ret z
+	scf
+	ret
+
+.dir_masks
+	db DOWN_MASK  ; DOWN
+	db UP_MASK    ; UP
+	db RIGHT_MASK ; LEFT
+	db LEFT_MASK  ; RIGHT
+
+CanObjectLeaveTile:
+	ld hl, OBJECT_LAST_TILE
+	add hl, bc
+	ld a, [hl]
+	call GetSideWallDirectionMask
+	ret nc
+	push af
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	maskbits NUM_DIRECTIONS
+	ld e, a
+	ld d, 0
+	ld hl, .dir_masks
+	add hl, de
+	pop af
+	and [hl]
+	ret z
+	scf
+	ret
+
+.dir_masks
+	db UP_MASK    ; DOWN
+	db DOWN_MASK  ; UP
+	db LEFT_MASK  ; LEFT
+	db RIGHT_MASK ; RIGHT
+
+GetSideWallDirectionMask:
+	ld d, a
+	and $f0
+	cp HI_NYBBLE_SIDE_WALLS
+	jr z, .continue
+	cp HI_NYBBLE_SIDE_BUOYS
+	jr z, .continue
+	xor a
+	ret
+
+.continue
+	ld a, d
+	and $7
+	ld e, a
+	ld d, 0
+	ld hl, .side_wall_masks
+	add hl, de
+	ld a, [hl]
+	scf
+	ret
+
+.side_wall_masks
+	db RIGHT_MASK             ; COLL_RIGHT_WALL/BUOY
+	db LEFT_MASK              ; COLL_LEFT_WALL/BUOY
+	db DOWN_MASK              ; COLL_UP_WALL/BUOY
+	db UP_MASK                ; COLL_DOWN_WALL/BUOY
+	db UP_MASK | RIGHT_MASK   ; COLL_DOWN_RIGHT_WALL/BUOY
+	db UP_MASK | LEFT_MASK    ; COLL_DOWN_LEFT_WALL/BUOY
+	db DOWN_MASK | RIGHT_MASK ; COLL_UP_RIGHT_WALL/BUOY
+	db DOWN_MASK | LEFT_MASK  ; COLL_UP_LEFT_WALL/BUOY
+
+WillObjectRemainOnWater:
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld a, [hl]
+	maskbits NUM_DIRECTIONS
+	jr z, .down
+	dec a
+	jr z, .up
+	dec a
+	jr z, .left
+	jr .right
+
+.down
+	inc e
+	push de
+	inc d
+	jr .continue
+
+.up
+	push de
+	inc d
+	jr .continue
+
+.left
+	push de
+	inc e
+	jr .continue
+
+.right
+	inc d
+	push de
+	inc e
+
+.continue
+	call GetCoordTile
+	call GetTileCollision
+	pop de
+	and a ; LAND_TILE
+	jr nz, .not_land
+	call GetCoordTile
+	call GetTileCollision
+	and a ; LAND_TILE
+	jr nz, .not_land
+	xor a
+	ret
+
+.not_land
+	scf
+	ret
+
+CheckFacingObject::
+	call GetFacingTileCoord
+
+; Double the distance for counter tiles.
+	call CheckCounterTile
+	jr nz, .not_counter
+
+	ld a, [wPlayerMapX]
+	sub d
+	cpl
+	inc a
+	add d
+	ld d, a
+
+	ld a, [wPlayerMapY]
+	sub e
+	cpl
+	inc a
+	add e
+	ld e, a
+
+.not_counter
+	ld bc, wObjectStructs ; redundant
+	ld a, 0
+	ldh [hMapObjectIndex], a
+	call IsNPCAtCoord
+	ret nc
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld a, [hl]
+	cp STANDING
+	jr z, .standing
+	xor a
+	ret
+
+.standing
+	scf
+	ret
+
+WillObjectBumpIntoSomeoneElse:
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	jr IsNPCAtCoord
+
+IsObjectFacingSomeoneElse: ; unreferenced
+	ldh a, [hMapObjectIndex]
+	call GetObjectStruct
+	call .GetFacingCoords
+	call IsNPCAtCoord
+	ret
+
+.GetFacingCoords:
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	call GetSpriteDirection
+	and a ; OW_DOWN?
+	jr z, .down
+	cp OW_UP
+	jr z, .up
+	cp OW_LEFT
+	jr z, .left
+	; OW_RIGHT
+	inc d
+	ret
+
+.down
+	inc e
+	ret
+
+.up
+	dec e
+	ret
+
+.left
+	dec d
+	ret
+
+IsNPCAtCoord:
+	ld bc, wObjectStructs
+	xor a
+.loop
+	ldh [hObjectStructIndex], a
+	call DoesObjectHaveASprite
+	jr z, .next
+
+	ld hl, OBJECT_FLAGS1
+	add hl, bc
+	bit 7, [hl]
+	jr nz, .next
+
+	ld hl, OBJECT_PALETTE
+	add hl, bc
+	bit BIG_OBJECT_F, [hl]
+	jr z, .not_big
+	call WillObjectIntersectBigObject
+	jr nc, .check_current_coords
+	jr .continue
+
+.not_big
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr nz, .check_current_coords
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, [hl]
+	cp e
+	jr nz, .check_current_coords
+
+.continue
+	ldh a, [hMapObjectIndex]
+	ld l, a
+	ldh a, [hObjectStructIndex]
+	cp l
+	jr nz, .yes
+
+.check_current_coords
+	ld hl, OBJECT_LAST_MAP_X
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr nz, .next
+	ld hl, OBJECT_LAST_MAP_Y
+	add hl, bc
+	ld a, [hl]
+	cp e
+	jr nz, .next
+	ldh a, [hMapObjectIndex]
+	ld l, a
+	ldh a, [hObjectStructIndex]
+	cp l
+	jr nz, .yes
+
+.next
+	ld hl, OBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	ldh a, [hObjectStructIndex]
+	inc a
+	cp NUM_OBJECT_STRUCTS
+	jr nz, .loop
+	and a
+	ret
+
+.yes
+	scf
+	ret
+
+HasObjectReachedMovementLimit:
+	ld hl, OBJECT_RADIUS
+	add hl, bc
+	ld a, [hl]
+	and a
+	jr z, .nope
+	and $f
+	jr z, .check_y
+	ld e, a
+	ld d, a
+	ld hl, OBJECT_INIT_X
+	add hl, bc
+	ld a, [hl]
+	sub d
+	ld d, a
+	ld a, [hl]
+	add e
+	ld e, a
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr z, .yes
+	cp e
+	jr z, .yes
+
+.check_y
+	ld hl, OBJECT_RADIUS
+	add hl, bc
+	ld a, [hl]
+	swap a
+	and $f
+	jr z, .nope
+	ld e, a
+	ld d, a
+	ld hl, OBJECT_INIT_Y
+	add hl, bc
+	ld a, [hl]
+	sub d
+	ld d, a
+	ld a, [hl]
+	add e
+	ld e, a
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr z, .yes
+	cp e
+	jr z, .yes
+
+.nope
+	xor a
+	ret
+
+.yes
+	scf
+	ret
+
+IsObjectMovingOffEdgeOfScreen:
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [wXCoord]
+	cp [hl]
+	jr z, .check_y
+	jr nc, .yes
+	add $9
+	cp [hl]
+	jr c, .yes
+
+.check_y
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, [wYCoord]
+	cp [hl]
+	jr z, .nope
+	jr nc, .yes
+	add $8
+	cp [hl]
+	jr c, .yes
+
+.nope
+	and a
+	ret
+
+.yes
+	scf
+	ret
+
+IsNPCAtPlayerCoord: ; unreferenced
+	ld a, [wPlayerMapX]
+	ld d, a
+	ld a, [wPlayerMapY]
+	ld e, a
+	ld bc, wObjectStructs
+	xor a
+.loop
+	ldh [hObjectStructIndex], a
+	call DoesObjectHaveASprite
+	jr z, .next
+
+	ld hl, OBJECT_MOVEMENT_TYPE
+	add hl, bc
+	ld a, [hl]
+	cp SPRITEMOVEDATA_BIGDOLLSYM
+	jr nz, .not_big
+	call WillObjectIntersectBigObject
+	jr c, .yes
+	jr .next
+
+.not_big
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, [hl]
+	cp e
+	jr nz, .check_current_coords
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr nz, .check_current_coords
+	ldh a, [hObjectStructIndex]
+	cp PLAYER_OBJECT
+	jr z, .next
+	jr .yes
+
+.check_current_coords
+	ld hl, OBJECT_LAST_MAP_Y
+	add hl, bc
+	ld a, [hl]
+	cp e
+	jr nz, .next
+	ld hl, OBJECT_LAST_MAP_X
+	add hl, bc
+	ld a, [hl]
+	cp d
+	jr nz, .next
+	jr .yes
+
+.next
+	ld hl, OBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	ldh a, [hObjectStructIndex]
+	inc a
+	cp NUM_OBJECT_STRUCTS
+	jr nz, .loop
+	xor a
+	ret
+
+.yes
+	scf
+	ret
+
+WillObjectIntersectBigObject:
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, d
+	sub [hl]
+	jr c, .nope
+	cp 2 ; big doll width
+	jr nc, .nope
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, e
+	sub [hl]
+	jr c, .nope
+	cp 2 ; big doll height
+	jr nc, .nope
+	scf
+	ret
+
+.nope
+	and a
+	ret

engine/overworld/overworld.asm

@@ -0,0 +1,672 @@
+GetEmote2bpp:
+	ld a, $1
+	ldh [rVBK], a
+	call Get2bpp
+	xor a
+	ldh [rVBK], a
+	ret
+
+_UpdatePlayerSprite::
+	call GetPlayerSprite
+	ld a, [wUsedSprites]
+	ldh [hUsedSpriteIndex], a
+	ld a, [wUsedSprites + 1]
+	ldh [hUsedSpriteTile], a
+	call GetUsedSprite
+	ret
+
+_RefreshSprites: ; mobile
+	ld hl, wSpriteFlags
+	ld a, [hl]
+	push af
+	res 7, [hl]
+	set 6, [hl]
+	call LoadUsedSpritesGFX
+	pop af
+	ld [wSpriteFlags], a
+	ret
+
+_ClearSprites: ; mobile
+	ld hl, wSpriteFlags
+	ld a, [hl]
+	push af
+	set 7, [hl]
+	res 6, [hl]
+	call LoadUsedSpritesGFX
+	pop af
+	ld [wSpriteFlags], a
+	ret
+
+RefreshSprites::
+	call .Refresh
+	call LoadUsedSpritesGFX
+	ret
+
+.Refresh:
+	xor a
+	ld bc, wUsedSpritesEnd - wUsedSprites
+	ld hl, wUsedSprites
+	call ByteFill
+	call GetPlayerSprite
+	call AddMapSprites
+	call LoadAndSortSprites
+	ret
+
+GetPlayerSprite:
+; Get Chris or Kris's sprite.
+	ld hl, ChrisStateSprites
+	ld a, [wPlayerSpriteSetupFlags]
+	bit PLAYERSPRITESETUP_FEMALE_TO_MALE_F, a
+	jr nz, .go
+	ld a, [wPlayerGender]
+	bit PLAYERGENDER_FEMALE_F, a
+	jr z, .go
+	ld hl, KrisStateSprites
+
+.go
+	ld a, [wPlayerState]
+	ld c, a
+.loop
+	ld a, [hli]
+	cp c
+	jr z, .good
+	inc hl
+	cp -1
+	jr nz, .loop
+
+; Any player state not in the array defaults to Chris's sprite.
+	xor a ; ld a, PLAYER_NORMAL
+	ld [wPlayerState], a
+	ld a, SPRITE_CHRIS
+	jr .finish
+
+.good
+	ld a, [hl]
+
+.finish
+	ld [wUsedSprites + 0], a
+	ld [wPlayerSprite], a
+	ld [wPlayerObjectSprite], a
+	ret
+
+INCLUDE "data/sprites/player_sprites.asm"
+
+AddMapSprites:
+	call GetMapEnvironment
+	call CheckOutdoorMap
+	jr z, .outdoor
+	call AddIndoorSprites
+	ret
+
+.outdoor
+	call AddOutdoorSprites
+	ret
+
+AddIndoorSprites:
+	ld hl, wMap1ObjectSprite
+	ld a, 1
+.loop
+	push af
+	ld a, [hl]
+	call AddSpriteGFX
+	ld de, MAPOBJECT_LENGTH
+	add hl, de
+	pop af
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop
+	ret
+
+AddOutdoorSprites:
+	ld a, [wMapGroup]
+	dec a
+	ld c, a
+	ld b, 0
+	ld hl, OutdoorSprites
+	add hl, bc
+	add hl, bc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld c, MAX_OUTDOOR_SPRITES
+.loop
+	push bc
+	ld a, [hli]
+	call AddSpriteGFX
+	pop bc
+	dec c
+	jr nz, .loop
+	ret
+
+LoadUsedSpritesGFX:
+	ld a, MAPCALLBACK_SPRITES
+	call RunMapCallback
+	call GetUsedSprites
+	call LoadMiscTiles
+	ret
+
+LoadMiscTiles:
+	ld a, [wSpriteFlags]
+	bit 6, a
+	ret nz
+
+	ld c, EMOTE_SHADOW
+	farcall LoadEmote
+	call GetMapEnvironment
+	call CheckOutdoorMap
+	ld c, EMOTE_GRASS_RUSTLE
+	jr z, .outdoor
+	ld c, EMOTE_BOULDER_DUST
+.outdoor
+	farcall LoadEmote
+	ret
+
+SafeGetSprite:
+	push hl
+	call GetSprite
+	pop hl
+	ret
+
+GetSprite:
+	call GetMonSprite
+	ret c
+
+	ld hl, OverworldSprites + SPRITEDATA_ADDR
+	dec a
+	ld c, a
+	ld b, 0
+	ld a, NUM_SPRITEDATA_FIELDS
+	call AddNTimes
+	; load the address into de
+	ld a, [hli]
+	ld e, a
+	ld a, [hli]
+	ld d, a
+	; load the length into c
+	ld a, [hli]
+	swap a
+	ld c, a
+	; load the sprite bank into both b and h
+	ld b, [hl]
+	ld a, [hli]
+	; load the sprite type into l
+	ld l, [hl]
+	ld h, a
+	ret
+
+GetMonSprite:
+; Return carry if a monster sprite was loaded.
+
+	cp SPRITE_POKEMON
+	jr c, .Normal
+	cp SPRITE_DAY_CARE_MON_1
+	jr z, .BreedMon1
+	cp SPRITE_DAY_CARE_MON_2
+	jr z, .BreedMon2
+	cp SPRITE_VARS
+	jr nc, .Variable
+	jr .Icon
+
+.Normal:
+	and a
+	ret
+
+.Icon:
+	sub SPRITE_POKEMON
+	ld e, a
+	ld d, 0
+	ld hl, SpriteMons
+	add hl, de
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	call GetPokemonIDFromIndex
+	jr .Mon
+
+.BreedMon1
+	ld a, [wBreedMon1Species]
+	jr .Mon
+
+.BreedMon2
+	ld a, [wBreedMon2Species]
+
+.Mon:
+	ld e, a
+	and a
+	jr z, .NoBreedmon
+
+	farcall LoadOverworldMonIcon
+
+	ld l, WALKING_SPRITE
+	ld h, 0
+	scf
+	ret
+
+.Variable:
+	sub SPRITE_VARS
+	ld e, a
+	ld d, 0
+	ld hl, wVariableSprites
+	add hl, de
+	ld a, [hl]
+	and a
+	jp nz, GetMonSprite
+
+.NoBreedmon:
+	ld a, WALKING_SPRITE
+	ld l, WALKING_SPRITE
+	ld h, 0
+	and a
+	ret
+
+_DoesSpriteHaveFacings::
+; Checks to see whether we can apply a facing to a sprite.
+; Returns carry unless the sprite is a Pokemon or a Still Sprite.
+	cp SPRITE_POKEMON
+	jr nc, .only_down
+
+	push hl
+	push bc
+	ld hl, OverworldSprites + SPRITEDATA_TYPE
+	dec a
+	ld c, a
+	ld b, 0
+	ld a, NUM_SPRITEDATA_FIELDS
+	call AddNTimes
+	ld a, [hl]
+	pop bc
+	pop hl
+	cp STILL_SPRITE
+	jr nz, .only_down
+	scf
+	ret
+
+.only_down
+	and a
+	ret
+
+_GetSpritePalette::
+	ld a, c
+	call GetMonSprite
+	jr c, .is_pokemon
+
+	ld hl, OverworldSprites + SPRITEDATA_PALETTE
+	dec a
+	ld c, a
+	ld b, 0
+	ld a, NUM_SPRITEDATA_FIELDS
+	call AddNTimes
+	ld c, [hl]
+	ret
+
+.is_pokemon
+	xor a
+	ld c, a
+	ret
+
+LoadAndSortSprites:
+	call LoadSpriteGFX
+	call SortUsedSprites
+	call ArrangeUsedSprites
+	ret
+
+AddSpriteGFX:
+; Add any new sprite ids to a list of graphics to be loaded.
+; Return carry if the list is full.
+
+	push hl
+	push bc
+	ld b, a
+	ld hl, wUsedSprites + 2
+	ld c, SPRITE_GFX_LIST_CAPACITY - 1
+.loop
+	ld a, [hl]
+	cp b
+	jr z, .exists
+	and a
+	jr z, .new
+	inc hl
+	inc hl
+	dec c
+	jr nz, .loop
+
+	pop bc
+	pop hl
+	scf
+	ret
+
+.exists
+	pop bc
+	pop hl
+	and a
+	ret
+
+.new
+	ld [hl], b
+	pop bc
+	pop hl
+	and a
+	ret
+
+LoadSpriteGFX:
+	ld hl, wUsedSprites
+	ld b, SPRITE_GFX_LIST_CAPACITY
+.loop
+	ld a, [hli]
+	and a
+	jr z, .done
+	push hl
+	call .LoadSprite
+	pop hl
+	ld [hli], a
+	dec b
+	jr nz, .loop
+
+.done
+	ret
+
+.LoadSprite:
+	push bc
+	call GetSprite
+	pop bc
+	ld a, l
+	ret
+
+SortUsedSprites:
+; Bubble-sort sprites by type.
+
+; Run backwards through wUsedSprites to find the last one.
+
+	ld c, SPRITE_GFX_LIST_CAPACITY
+	ld de, wUsedSprites + (SPRITE_GFX_LIST_CAPACITY - 1) * 2
+.FindLastSprite:
+	ld a, [de]
+	and a
+	jr nz, .FoundLastSprite
+	dec de
+	dec de
+	dec c
+	jr nz, .FindLastSprite
+.FoundLastSprite:
+	dec c
+	jr z, .quit
+
+; If the length of the current sprite is
+; higher than a later one, swap them.
+
+	inc de
+	ld hl, wUsedSprites + 1
+
+.CheckSprite:
+	push bc
+	push de
+	push hl
+
+.CheckFollowing:
+	ld a, [de]
+	cp [hl]
+	jr nc, .loop
+
+; Swap the two sprites.
+
+	ld b, a
+	ld a, [hl]
+	ld [hl], b
+	ld [de], a
+	dec de
+	dec hl
+	ld a, [de]
+	ld b, a
+	ld a, [hl]
+	ld [hl], b
+	ld [de], a
+	inc de
+	inc hl
+
+; Keep doing this until everything's in order.
+
+.loop
+	dec de
+	dec de
+	dec c
+	jr nz, .CheckFollowing
+
+	pop hl
+	inc hl
+	inc hl
+	pop de
+	pop bc
+	dec c
+	jr nz, .CheckSprite
+
+.quit
+	ret
+
+ArrangeUsedSprites:
+; Get the length of each sprite and space them out in VRAM.
+; Crystal introduces a second table in VRAM bank 0.
+
+	ld hl, wUsedSprites
+	ld c, SPRITE_GFX_LIST_CAPACITY
+	ld b, 0
+.FirstTableLength:
+; Keep going until the end of the list.
+	ld a, [hli]
+	and a
+	jr z, .quit
+
+	ld a, [hl]
+	call GetSpriteLength
+
+; Spill over into the second table after $80 tiles.
+	add b
+	cp $80
+	jr z, .loop
+	jr nc, .SecondTable
+
+.loop
+	ld [hl], b
+	inc hl
+	ld b, a
+
+; Assumes the next table will be reached before c hits 0.
+	dec c
+	jr nz, .FirstTableLength
+
+.SecondTable:
+; The second tile table starts at tile $80.
+	ld b, $80
+	dec hl
+.SecondTableLength:
+; Keep going until the end of the list.
+	ld a, [hli]
+	and a
+	jr z, .quit
+
+	ld a, [hl]
+	call GetSpriteLength
+
+; There are only two tables, so don't go any further than that.
+	add b
+	jr c, .quit
+
+	ld [hl], b
+	ld b, a
+	inc hl
+
+	dec c
+	jr nz, .SecondTableLength
+
+.quit
+	ret
+
+GetSpriteLength:
+; Return the length of sprite type a in tiles.
+
+	cp WALKING_SPRITE
+	jr z, .AnyDirection
+	cp STANDING_SPRITE
+	jr z, .AnyDirection
+	cp STILL_SPRITE
+	jr z, .OneDirection
+
+	ld a, 12
+	ret
+
+.AnyDirection:
+	ld a, 12
+	ret
+
+.OneDirection:
+	ld a, 4
+	ret
+
+GetUsedSprites:
+	ld hl, wUsedSprites
+	ld c, SPRITE_GFX_LIST_CAPACITY
+
+.loop
+	ld a, [wSpriteFlags]
+	res 5, a
+	ld [wSpriteFlags], a
+
+	ld a, [hli]
+	and a
+	jr z, .done
+	ldh [hUsedSpriteIndex], a
+
+	ld a, [hli]
+	ldh [hUsedSpriteTile], a
+
+	bit 7, a
+	jr z, .dont_set
+
+	ld a, [wSpriteFlags]
+	set 5, a ; load VBank0
+	ld [wSpriteFlags], a
+
+.dont_set
+	push bc
+	push hl
+	call GetUsedSprite
+	pop hl
+	pop bc
+	dec c
+	jr nz, .loop
+
+.done
+	ret
+
+GetUsedSprite:
+	ldh a, [hUsedSpriteIndex]
+	call SafeGetSprite
+	ldh a, [hUsedSpriteTile]
+	call .GetTileAddr
+	push hl
+	push de
+	push bc
+	ld a, [wSpriteFlags]
+	bit 7, a
+	jr nz, .skip
+	call .CopyToVram
+
+.skip
+	pop bc
+	ld l, c
+	ld h, $0
+rept 4
+	add hl, hl
+endr
+	pop de
+	add hl, de
+	ld d, h
+	ld e, l
+	pop hl
+
+	ld a, [wSpriteFlags]
+	bit 5, a
+	jr nz, .done
+	bit 6, a
+	jr nz, .done
+
+	ldh a, [hUsedSpriteIndex]
+	call _DoesSpriteHaveFacings
+	jr c, .done
+
+	ld a, h
+	add HIGH(vTiles1 - vTiles0)
+	ld h, a
+	call .CopyToVram
+
+.done
+	ret
+
+.GetTileAddr:
+; Return the address of tile (a) in (hl).
+	and $7f
+	ld l, a
+	ld h, 0
+rept 4
+	add hl, hl
+endr
+	ld a, l
+	add LOW(vTiles0)
+	ld l, a
+	ld a, h
+	adc HIGH(vTiles0)
+	ld h, a
+	ret
+
+.CopyToVram:
+	ldh a, [rVBK]
+	push af
+	ld a, [wSpriteFlags]
+	bit 5, a
+	ld a, $1
+	jr z, .bankswitch
+	ld a, $0
+
+.bankswitch
+	ldh [rVBK], a
+	call Get2bpp
+	pop af
+	ldh [rVBK], a
+	ret
+
+LoadEmote::
+; Get the address of the pointer to emote c.
+	ld a, c
+	ld bc, EMOTE_LENGTH
+	ld hl, Emotes
+	call AddNTimes
+; Load the emote address into de
+	ld e, [hl]
+	inc hl
+	ld d, [hl]
+; load the length of the emote (in tiles) into c
+	inc hl
+	ld c, [hl]
+	swap c
+; load the emote pointer bank into b
+	inc hl
+	ld b, [hl]
+; load the VRAM destination into hl
+	inc hl
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+; if the emote has a length of 0, do not proceed (error handling)
+	ld a, c
+	and a
+	ret z
+	call GetEmote2bpp
+	ret
+
+INCLUDE "data/sprites/emotes.asm"
+
+INCLUDE "data/sprites/sprite_mons.asm"
+
+INCLUDE "data/maps/outdoor_sprites.asm"
+
+INCLUDE "data/sprites/sprites.asm"

engine/overworld/player_movement.asm

@@ -0,0 +1,816 @@
+DoPlayerMovement::
+	call .GetDPad
+	ld a, movement_step_sleep
+	ld [wMovementAnimation], a
+	xor a
+	ld [wWalkingIntoEdgeWarp], a
+	call .TranslateIntoMovement
+	ld c, a
+	ld a, [wMovementAnimation]
+	ld [wPlayerNextMovement], a
+	ret
+
+.GetDPad:
+	ldh a, [hJoyDown]
+	ld [wCurInput], a
+
+; Standing downhill instead moves down.
+
+	ld hl, wBikeFlags
+	bit BIKEFLAGS_DOWNHILL_F, [hl]
+	ret z
+
+	ld c, a
+	and D_PAD
+	ret nz
+
+	ld a, c
+	or D_DOWN
+	ld [wCurInput], a
+	ret
+
+.TranslateIntoMovement:
+	ld a, [wPlayerState]
+	cp PLAYER_NORMAL
+	jr z, .Normal
+	cp PLAYER_SURF
+	jr z, .Surf
+	cp PLAYER_SURF_PIKA
+	jr z, .Surf
+	cp PLAYER_BIKE
+	jr z, .Normal
+	cp PLAYER_SKATE
+	jr z, .Ice
+
+.Normal:
+	call .CheckForced
+	call .GetAction
+	call .CheckTile
+	ret c
+	call .CheckTurning
+	ret c
+	call .TryStep
+	ret c
+	call .TryJump
+	ret c
+	call .CheckWarp
+	ret c
+	jr .NotMoving
+
+.Surf:
+	call .CheckForced
+	call .GetAction
+	call .CheckTile
+	ret c
+	call .CheckTurning
+	ret c
+	call .TrySurf
+	ret c
+	jr .NotMoving
+
+.Ice:
+	call .CheckForced
+	call .GetAction
+	call .CheckTile
+	ret c
+	call .CheckTurning
+	ret c
+	call .TryStep
+	ret c
+	call .TryJump
+	ret c
+	call .CheckWarp
+	ret c
+	ld a, [wWalkingDirection]
+	cp STANDING
+	jr z, .HitWall
+	call .BumpSound
+.HitWall:
+	call .StandInPlace
+	xor a
+	ret
+
+.NotMoving:
+	ld a, [wWalkingDirection]
+	cp STANDING
+	jr z, .Standing
+
+; Walking into an edge warp won't bump.
+	ld a, [wWalkingIntoEdgeWarp]
+	and a
+	jr nz, .CantMove
+	call .BumpSound
+.CantMove:
+	call ._WalkInPlace
+	xor a
+	ret
+
+.Standing:
+	call .StandInPlace
+	xor a
+	ret
+
+.CheckTile:
+; Tiles such as waterfalls and warps move the player
+; in a given direction, overriding input.
+
+	ld a, [wPlayerTile]
+	ld c, a
+	call CheckWhirlpoolTile
+	jr c, .not_whirlpool
+	ld a, PLAYERMOVEMENT_FORCE_TURN
+	scf
+	ret
+
+.not_whirlpool
+	and $f0
+	cp HI_NYBBLE_CURRENT
+	jr z, .water
+	cp HI_NYBBLE_WALK
+	jr z, .land1
+	cp HI_NYBBLE_WALK_ALT
+	jr z, .land2
+	cp HI_NYBBLE_WARPS
+	jr z, .warps
+	jr .no_walk
+
+.water
+	ld a, c
+	maskbits NUM_DIRECTIONS
+	ld c, a
+	ld b, 0
+	ld hl, .water_table
+	add hl, bc
+	ld a, [hl]
+	ld [wWalkingDirection], a
+	jr .continue_walk
+
+.water_table
+	db RIGHT ; COLL_WATERFALL_RIGHT
+	db LEFT  ; COLL_WATERFALL_LEFT
+	db UP    ; COLL_WATERFALL_UP
+	db DOWN  ; COLL_WATERFALL
+
+.land1
+	ld a, c
+	and 7
+	ld c, a
+	ld b, 0
+	ld hl, .land1_table
+	add hl, bc
+	ld a, [hl]
+	cp STANDING
+	jr z, .no_walk
+	ld [wWalkingDirection], a
+	jr .continue_walk
+
+.land1_table
+	db STANDING ; COLL_BRAKE
+	db RIGHT    ; COLL_WALK_RIGHT
+	db LEFT     ; COLL_WALK_LEFT
+	db UP       ; COLL_WALK_UP
+	db DOWN     ; COLL_WALK_DOWN
+	db STANDING ; COLL_BRAKE_45
+	db STANDING ; COLL_BRAKE_46
+	db STANDING ; COLL_BRAKE_47
+
+.land2
+	ld a, c
+	and 7
+	ld c, a
+	ld b, 0
+	ld hl, .land2_table
+	add hl, bc
+	ld a, [hl]
+	cp STANDING
+	jr z, .no_walk
+	ld [wWalkingDirection], a
+	jr .continue_walk
+
+.land2_table
+	db RIGHT    ; COLL_WALK_RIGHT_ALT
+	db LEFT     ; COLL_WALK_LEFT_ALT
+	db UP       ; COLL_WALK_UP_ALT
+	db DOWN     ; COLL_WALK_DOWN_ALT
+	db STANDING ; COLL_BRAKE_ALT
+	db STANDING ; COLL_BRAKE_55
+	db STANDING ; COLL_BRAKE_56
+	db STANDING ; COLL_BRAKE_57
+
+.warps
+	ld a, c
+	cp COLL_DOOR
+	jr z, .down
+	cp COLL_DOOR_79
+	jr z, .down
+	cp COLL_STAIRCASE
+	jr z, .down
+	cp COLL_CAVE
+	jr nz, .no_walk
+
+.down
+	ld a, DOWN
+	ld [wWalkingDirection], a
+	jr .continue_walk
+
+.no_walk
+	xor a
+	ret
+
+.continue_walk
+	ld a, STEP_WALK
+	call .DoStep
+	ld a, PLAYERMOVEMENT_CONTINUE
+	scf
+	ret
+
+.CheckTurning:
+; If the player is turning, change direction first. This also lets
+; the player change facing without moving by tapping a direction.
+
+	ld a, [wPlayerTurningDirection]
+	cp 0
+	jr nz, .not_turning
+	ld a, [wWalkingDirection]
+	cp STANDING
+	jr z, .not_turning
+
+	ld e, a
+	ld a, [wPlayerDirection]
+	rrca
+	rrca
+	maskbits NUM_DIRECTIONS
+	cp e
+	jr z, .not_turning
+
+	ld a, STEP_TURN
+	call .DoStep
+	ld a, PLAYERMOVEMENT_TURN
+	scf
+	ret
+
+.not_turning
+	xor a
+	ret
+
+.TryStep:
+; Surfing actually calls .TrySurf directly instead of passing through here.
+	ld a, [wPlayerState]
+	cp PLAYER_SURF
+	jr z, .TrySurf
+	cp PLAYER_SURF_PIKA
+	jr z, .TrySurf
+
+	call .CheckLandPerms
+	jr c, .bump
+
+	call .CheckNPC
+	and a
+	jr z, .bump
+	cp 2
+	jr z, .bump
+
+	ld a, [wPlayerTile]
+	call CheckIceTile
+	jr nc, .ice
+
+; Downhill riding is slower when not moving down.
+	call .BikeCheck
+	jr nz, .walk
+
+	ld hl, wBikeFlags
+	bit BIKEFLAGS_DOWNHILL_F, [hl]
+	jr z, .fast
+
+	ld a, [wWalkingDirection]
+	cp DOWN
+	jr z, .fast
+
+	ld a, STEP_WALK
+	call .DoStep
+	scf
+	ret
+
+.fast
+	ld a, STEP_BIKE
+	call .DoStep
+	scf
+	ret
+
+.walk
+	ld a, STEP_WALK
+	call .DoStep
+	scf
+	ret
+
+.ice
+	ld a, STEP_ICE
+	call .DoStep
+	scf
+	ret
+
+.unused ; unreferenced
+	xor a
+	ret
+
+.bump
+	xor a
+	ret
+
+.TrySurf:
+	call .CheckSurfPerms
+	ld [wWalkingIntoLand], a
+	jr c, .surf_bump
+
+	call .CheckNPC
+	ld [wWalkingIntoNPC], a
+	and a
+	jr z, .surf_bump
+	cp 2
+	jr z, .surf_bump
+
+	ld a, [wWalkingIntoLand]
+	and a
+	jr nz, .ExitWater
+
+	ld a, STEP_WALK
+	call .DoStep
+	scf
+	ret
+
+.ExitWater:
+	call .GetOutOfWater
+	call PlayMapMusic
+	ld a, STEP_WALK
+	call .DoStep
+	ld a, PLAYERMOVEMENT_EXIT_WATER
+	scf
+	ret
+
+.surf_bump
+	xor a
+	ret
+
+.TryJump:
+	ld a, [wPlayerTile]
+	ld e, a
+	and $f0
+	cp HI_NYBBLE_LEDGES
+	jr nz, .DontJump
+
+	ld a, e
+	and 7
+	ld e, a
+	ld d, 0
+	ld hl, .ledge_table
+	add hl, de
+	ld a, [wFacingDirection]
+	and [hl]
+	jr z, .DontJump
+
+	ld de, SFX_JUMP_OVER_LEDGE
+	call PlaySFX
+	ld a, STEP_LEDGE
+	call .DoStep
+	ld a, PLAYERMOVEMENT_JUMP
+	scf
+	ret
+
+.DontJump:
+	xor a
+	ret
+
+.ledge_table
+	db FACE_RIGHT             ; COLL_HOP_RIGHT
+	db FACE_LEFT              ; COLL_HOP_LEFT
+	db FACE_UP                ; COLL_HOP_UP
+	db FACE_DOWN              ; COLL_HOP_DOWN
+	db FACE_RIGHT | FACE_DOWN ; COLL_HOP_DOWN_RIGHT
+	db FACE_DOWN | FACE_LEFT  ; COLL_HOP_DOWN_LEFT
+	db FACE_UP | FACE_RIGHT   ; COLL_HOP_UP_RIGHT
+	db FACE_UP | FACE_LEFT    ; COLL_HOP_UP_LEFT
+
+.CheckWarp:
+; BUG: No bump noise if standing on tile $3E (see docs/bugs_and_glitches.md)
+
+	ld a, [wWalkingDirection]
+	ld e, a
+	ld d, 0
+	ld hl, .EdgeWarps
+	add hl, de
+	ld a, [wPlayerTile]
+	cp [hl]
+	jr nz, .not_warp
+
+	ld a, TRUE
+	ld [wWalkingIntoEdgeWarp], a
+	ld a, [wWalkingDirection]
+	cp STANDING
+	jr z, .not_warp
+
+	ld e, a
+	ld a, [wPlayerDirection]
+	rrca
+	rrca
+	maskbits NUM_DIRECTIONS
+	cp e
+	jr nz, .not_warp
+	call WarpCheck
+	jr nc, .not_warp
+
+	call .StandInPlace
+	scf
+	ld a, PLAYERMOVEMENT_WARP
+	ret
+
+.not_warp
+	xor a ; PLAYERMOVEMENT_NORMAL
+	ret
+
+.EdgeWarps:
+	db COLL_WARP_CARPET_DOWN
+	db COLL_WARP_CARPET_UP
+	db COLL_WARP_CARPET_LEFT
+	db COLL_WARP_CARPET_RIGHT
+
+.DoStep:
+	ld e, a
+	ld d, 0
+	ld hl, .Steps
+	add hl, de
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+	ld a, [wWalkingDirection]
+	ld e, a
+	cp STANDING
+	jp z, .StandInPlace
+
+	add hl, de
+	ld a, [hl]
+	ld [wMovementAnimation], a
+
+	ld hl, .FinishFacing
+	add hl, de
+	ld a, [hl]
+	ld [wPlayerTurningDirection], a
+
+	ld a, PLAYERMOVEMENT_FINISH
+	ret
+
+.Steps:
+; entries correspond to STEP_* constants (see constants/map_object_constants.asm)
+	table_width 2, DoPlayerMovement.Steps
+	dw .SlowStep
+	dw .NormalStep
+	dw .FastStep
+	dw .JumpStep
+	dw .SlideStep
+	dw .TurningStep
+	dw .BackJumpStep
+	dw .FinishFacing
+	assert_table_length NUM_STEPS
+
+.SlowStep:
+	slow_step DOWN
+	slow_step UP
+	slow_step LEFT
+	slow_step RIGHT
+.NormalStep:
+	step DOWN
+	step UP
+	step LEFT
+	step RIGHT
+.FastStep:
+	big_step DOWN
+	big_step UP
+	big_step LEFT
+	big_step RIGHT
+.JumpStep:
+	jump_step DOWN
+	jump_step UP
+	jump_step LEFT
+	jump_step RIGHT
+.SlideStep:
+	fast_slide_step DOWN
+	fast_slide_step UP
+	fast_slide_step LEFT
+	fast_slide_step RIGHT
+.BackJumpStep:
+	jump_step UP
+	jump_step DOWN
+	jump_step RIGHT
+	jump_step LEFT
+.TurningStep:
+	turn_step DOWN
+	turn_step UP
+	turn_step LEFT
+	turn_step RIGHT
+.FinishFacing:
+	db $80 | DOWN
+	db $80 | UP
+	db $80 | LEFT
+	db $80 | RIGHT
+
+.StandInPlace:
+	ld a, 0
+	ld [wPlayerTurningDirection], a
+	ld a, movement_step_sleep
+	ld [wMovementAnimation], a
+	xor a
+	ret
+
+._WalkInPlace:
+	ld a, 0
+	ld [wPlayerTurningDirection], a
+	ld a, movement_step_bump
+	ld [wMovementAnimation], a
+	xor a
+	ret
+
+.CheckForced:
+; When sliding on ice, input is forced to remain in the same direction.
+
+	call CheckStandingOnIce
+	ret nc
+
+	ld a, [wPlayerTurningDirection]
+	cp 0
+	ret z
+
+	maskbits NUM_DIRECTIONS
+	ld e, a
+	ld d, 0
+	ld hl, .forced_dpad
+	add hl, de
+	ld a, [wCurInput]
+	and BUTTONS
+	or [hl]
+	ld [wCurInput], a
+	ret
+
+.forced_dpad
+	db D_DOWN, D_UP, D_LEFT, D_RIGHT
+
+.GetAction:
+; Poll player input and update movement info.
+
+	ld hl, .action_table
+	ld de, .action_table_1_end - .action_table_1
+	ld a, [wCurInput]
+	bit D_DOWN_F, a
+	jr nz, .d_down
+	bit D_UP_F, a
+	jr nz, .d_up
+	bit D_LEFT_F, a
+	jr nz, .d_left
+	bit D_RIGHT_F, a
+	jr nz, .d_right
+; Standing
+	jr .update
+
+.d_down
+	add hl, de
+.d_up
+	add hl, de
+.d_left
+	add hl, de
+.d_right
+	add hl, de
+.update
+	ld a, [hli]
+	ld [wWalkingDirection], a
+	ld a, [hli]
+	ld [wFacingDirection], a
+	ld a, [hli]
+	ld [wWalkingX], a
+	ld a, [hli]
+	ld [wWalkingY], a
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [hl]
+	ld [wWalkingTile], a
+	ret
+
+MACRO player_action
+; walk direction, facing, x movement, y movement, tile collision pointer
+	db \1, \2, \3, \4
+	dw \5
+ENDM
+
+.action_table:
+.action_table_1
+	player_action STANDING, FACE_CURRENT, 0,  0, wPlayerTile
+.action_table_1_end
+	player_action RIGHT,    FACE_RIGHT,   1,  0, wTileRight
+	player_action LEFT,     FACE_LEFT,   -1,  0, wTileLeft
+	player_action UP,       FACE_UP,      0, -1, wTileUp
+	player_action DOWN,     FACE_DOWN,    0,  1, wTileDown
+
+.CheckNPC:
+; Returns 0 if there is an NPC in front that you can't move
+; Returns 1 if there is no NPC in front
+; Returns 2 if there is a movable NPC in front. The game actually treats
+; this the same as an NPC in front (bump).
+	ld a, 0
+	ldh [hMapObjectIndex], a
+; Load the next X coordinate into d
+	ld a, [wPlayerMapX]
+	ld d, a
+	ld a, [wWalkingX]
+	add d
+	ld d, a
+; Load the next Y coordinate into e
+	ld a, [wPlayerMapY]
+	ld e, a
+	ld a, [wWalkingY]
+	add e
+	ld e, a
+; Find an object struct with coordinates equal to d,e
+	ld bc, wObjectStructs ; redundant
+	farcall IsNPCAtCoord
+	jr nc, .no_npc
+	call .CheckStrengthBoulder
+	jr c, .no_bump
+
+	xor a ; bump
+	ret
+
+.no_npc
+	ld a, 1
+	ret
+
+.no_bump
+	ld a, 2
+	ret
+
+.CheckStrengthBoulder:
+	ld hl, wBikeFlags
+	bit BIKEFLAGS_STRENGTH_ACTIVE_F, [hl]
+	jr z, .not_boulder
+
+	ld hl, OBJECT_WALKING
+	add hl, bc
+	ld a, [hl]
+	cp STANDING
+	jr nz, .not_boulder
+
+	ld hl, OBJECT_PALETTE
+	add hl, bc
+	bit STRENGTH_BOULDER_F, [hl]
+	jr z, .not_boulder
+
+	ld hl, OBJECT_FLAGS2
+	add hl, bc
+	set 2, [hl]
+
+	ld a, [wWalkingDirection]
+	ld d, a
+	ld hl, OBJECT_RANGE
+	add hl, bc
+	ld a, [hl]
+	and %11111100
+	or d
+	ld [hl], a
+
+	scf
+	ret
+
+.not_boulder
+	xor a
+	ret
+
+.CheckLandPerms:
+; Return 0 if walking onto land and tile permissions allow it.
+; Otherwise, return carry.
+
+	ld a, [wTilePermissions]
+	ld d, a
+	ld a, [wFacingDirection]
+	and d
+	jr nz, .NotWalkable
+
+	ld a, [wWalkingTile]
+	call .CheckWalkable
+	jr c, .NotWalkable
+
+	xor a
+	ret
+
+.NotWalkable:
+	scf
+	ret
+
+.CheckSurfPerms:
+; Return 0 if moving in water, or 1 if moving onto land.
+; Otherwise, return carry.
+
+	ld a, [wTilePermissions]
+	ld d, a
+	ld a, [wFacingDirection]
+	and d
+	jr nz, .NotSurfable
+
+	ld a, [wWalkingTile]
+	call .CheckSurfable
+	jr c, .NotSurfable
+
+	and a
+	ret
+
+.NotSurfable:
+	scf
+	ret
+
+.BikeCheck:
+	ld a, [wPlayerState]
+	cp PLAYER_BIKE
+	ret z
+	cp PLAYER_SKATE
+	ret
+
+.CheckWalkable:
+; Return 0 if tile a is land. Otherwise, return carry.
+
+	call GetTileCollision
+	and a ; LAND_TILE
+	ret z
+	scf
+	ret
+
+.CheckSurfable:
+; Return 0 if tile a is water, or 1 if land.
+; Otherwise, return carry.
+
+	call GetTileCollision
+	cp WATER_TILE
+	jr z, .Water
+
+; Can walk back onto land from water.
+	and a ; LAND_TILE
+	jr z, .Land
+
+	jr .Neither
+
+.Water:
+	xor a
+	ret
+
+.Land:
+	ld a, 1
+	and a
+	ret
+
+.Neither:
+	scf
+	ret
+
+.BumpSound:
+	call CheckSFX
+	ret c
+	ld de, SFX_BUMP
+	call PlaySFX
+	ret
+
+.GetOutOfWater:
+	push bc
+	ld a, PLAYER_NORMAL
+	ld [wPlayerState], a
+	call UpdatePlayerSprite ; UpdateSprites
+	pop bc
+	ret
+
+CheckStandingOnIce::
+	ld a, [wPlayerTurningDirection]
+	cp 0
+	jr z, .not_ice
+	cp $f0
+	jr z, .not_ice
+	ld a, [wPlayerTile]
+	call CheckIceTile
+	jr nc, .yep
+	ld a, [wPlayerState]
+	cp PLAYER_SKATE
+	jr nz, .not_ice
+
+.yep
+	scf
+	ret
+
+.not_ice
+	and a
+	ret
+
+StopPlayerForEvent::
+	ld hl, wPlayerNextMovement
+	ld a, movement_step_sleep
+	cp [hl]
+	ret z
+
+	ld [hl], a
+	ld a, 0
+	ld [wPlayerTurningDirection], a
+	ret

engine/overworld/player_object.asm

@@ -0,0 +1,857 @@
+BlankScreen:
+	call DisableSpriteUpdates
+	xor a
+	ldh [hBGMapMode], a
+	call ClearBGPalettes
+	call ClearSprites
+	hlcoord 0, 0
+	ld bc, wTilemapEnd - wTilemap
+	ld a, " "
+	call ByteFill
+	hlcoord 0, 0, wAttrmap
+	ld bc, wAttrmapEnd - wAttrmap
+	ld a, $7
+	call ByteFill
+	call WaitBGMap2
+	call SetPalettes
+	ret
+
+SpawnPlayer:
+	ld a, -1
+	ld [wObjectFollow_Leader], a
+	ld [wObjectFollow_Follower], a
+	ld a, PLAYER
+	ld hl, PlayerObjectTemplate
+	call CopyPlayerObjectTemplate
+	ld b, PLAYER
+	call PlayerSpawn_ConvertCoords
+	ld a, PLAYER_OBJECT
+	call GetMapObject
+	ld hl, MAPOBJECT_PALETTE
+	add hl, bc
+	ln e, PAL_NPC_RED, OBJECTTYPE_SCRIPT
+	ld a, [wPlayerSpriteSetupFlags]
+	bit PLAYERSPRITESETUP_FEMALE_TO_MALE_F, a
+	jr nz, .ok
+	ld a, [wPlayerGender]
+	bit PLAYERGENDER_FEMALE_F, a
+	jr z, .ok
+	ln e, PAL_NPC_BLUE, OBJECTTYPE_SCRIPT
+
+.ok
+	ld [hl], e
+	ld a, PLAYER_OBJECT
+	ldh [hMapObjectIndex], a
+	ld bc, wMapObjects
+	ld a, PLAYER_OBJECT
+	ldh [hObjectStructIndex], a
+	ld de, wObjectStructs
+	call CopyMapObjectToObjectStruct
+	ld a, PLAYER
+	ld [wCenteredObject], a
+	ret
+
+PlayerObjectTemplate:
+; A dummy map object used to initialize the player object.
+; Shorter than the actual amount copied by two bytes.
+; Said bytes seem to be unused.
+	object_event -4, -4, SPRITE_CHRIS, SPRITEMOVEDATA_PLAYER, 15, 15, -1, -1, 0, OBJECTTYPE_SCRIPT, 0, 0, -1
+
+CopyDECoordsToMapObject::
+	push de
+	ld a, b
+	call GetMapObject
+	pop de
+	ld hl, MAPOBJECT_X_COORD
+	add hl, bc
+	ld [hl], d
+	ld hl, MAPOBJECT_Y_COORD
+	add hl, bc
+	ld [hl], e
+	ret
+
+PlayerSpawn_ConvertCoords:
+	push bc
+	ld a, [wXCoord]
+	add 4
+	ld d, a
+	ld a, [wYCoord]
+	add 4
+	ld e, a
+	pop bc
+	call CopyDECoordsToMapObject
+	ret
+
+WriteObjectXY::
+	ld a, b
+	call CheckObjectVisibility
+	ret c
+
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	ldh a, [hMapObjectIndex]
+	ld b, a
+	call CopyDECoordsToMapObject
+	and a
+	ret
+
+RefreshPlayerCoords:
+	ld a, [wXCoord]
+	add 4
+	ld d, a
+	ld hl, wPlayerMapX
+	sub [hl]
+	ld [hl], d
+	ld hl, wMapObjects + MAPOBJECT_X_COORD
+	ld [hl], d
+	ld hl, wPlayerLastMapX
+	ld [hl], d
+	ld d, a
+	ld a, [wYCoord]
+	add 4
+	ld e, a
+	ld hl, wPlayerMapY
+	sub [hl]
+	ld [hl], e
+	ld hl, wMapObjects + MAPOBJECT_Y_COORD
+	ld [hl], e
+	ld hl, wPlayerLastMapY
+	ld [hl], e
+	ld e, a
+; the next three lines are useless
+	ld a, [wObjectFollow_Leader]
+	cp PLAYER
+	ret nz
+	ret
+
+CopyObjectStruct::
+	call CheckObjectMask
+	and a
+	ret nz ; masked
+
+	ld hl, wObjectStructs + OBJECT_LENGTH * 1
+	ld a, 1
+	ld de, OBJECT_LENGTH
+.loop
+	ldh [hObjectStructIndex], a
+	ld a, [hl]
+	and a
+	jr z, .done
+	add hl, de
+	ldh a, [hObjectStructIndex]
+	inc a
+	cp NUM_OBJECT_STRUCTS
+	jr nz, .loop
+	scf
+	ret ; overflow
+
+.done
+	ld d, h
+	ld e, l
+	call CopyMapObjectToObjectStruct
+	ld hl, wVramState
+	bit 7, [hl]
+	ret z
+
+	ld hl, OBJECT_FLAGS2
+	add hl, de
+	set 5, [hl]
+	ret
+
+CopyMapObjectToObjectStruct:
+	call .CopyMapObjectToTempObject
+	call CopyTempObjectToObjectStruct
+	ret
+
+.CopyMapObjectToTempObject:
+	ldh a, [hObjectStructIndex]
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld [hl], a
+
+	ldh a, [hMapObjectIndex]
+	ld [wTempObjectCopyMapObjectIndex], a
+
+	ld hl, MAPOBJECT_SPRITE
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopySprite], a
+
+	call GetSpriteVTile
+	ld [wTempObjectCopySpriteVTile], a
+
+	ld a, [hl]
+	call GetSpritePalette
+	ld [wTempObjectCopyPalette], a
+
+	ld hl, MAPOBJECT_PALETTE
+	add hl, bc
+	ld a, [hl]
+	and MAPOBJECT_PALETTE_MASK
+	jr z, .skip_color_override
+	swap a
+	and PALETTE_MASK
+	ld [wTempObjectCopyPalette], a
+
+.skip_color_override
+	ld hl, MAPOBJECT_MOVEMENT
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopyMovement], a
+
+	ld hl, MAPOBJECT_SIGHT_RANGE
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopyRange], a
+
+	ld hl, MAPOBJECT_X_COORD
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopyX], a
+
+	ld hl, MAPOBJECT_Y_COORD
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopyY], a
+
+	ld hl, MAPOBJECT_RADIUS
+	add hl, bc
+	ld a, [hl]
+	ld [wTempObjectCopyRadius], a
+	ret
+
+InitializeVisibleSprites:
+	ld bc, wMap1Object
+	ld a, 1
+.loop
+	ldh [hMapObjectIndex], a
+	ld hl, MAPOBJECT_SPRITE
+	add hl, bc
+	ld a, [hl]
+	and a
+	jr z, .next
+
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	cp -1
+	jr nz, .next
+
+	ld a, [wXCoord]
+	ld d, a
+	ld a, [wYCoord]
+	ld e, a
+
+	ld hl, MAPOBJECT_X_COORD
+	add hl, bc
+	ld a, [hl]
+	add 1
+	sub d
+	jr c, .next
+
+	cp MAPOBJECT_SCREEN_WIDTH
+	jr nc, .next
+
+	ld hl, MAPOBJECT_Y_COORD
+	add hl, bc
+	ld a, [hl]
+	add 1
+	sub e
+	jr c, .next
+
+	cp MAPOBJECT_SCREEN_HEIGHT
+	jr nc, .next
+
+	push bc
+	call CopyObjectStruct
+	pop bc
+	jp c, .ret
+
+.next
+	ld hl, MAPOBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	ldh a, [hMapObjectIndex]
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop
+	ret
+
+.ret
+	ret
+
+CheckObjectEnteringVisibleRange::
+	nop
+	ld a, [wPlayerStepDirection]
+	cp STANDING
+	ret z
+	ld hl, .dw
+	rst JumpTable
+	ret
+
+.dw
+	dw .Down
+	dw .Up
+	dw .Left
+	dw .Right
+
+.Up:
+	ld a, [wYCoord]
+	sub 1
+	jr .Vertical
+
+.Down:
+	ld a, [wYCoord]
+	add 9
+.Vertical:
+	ld d, a
+	ld a, [wXCoord]
+	ld e, a
+	ld bc, wMap1Object
+	ld a, 1
+.loop_v
+	ldh [hMapObjectIndex], a
+	ld hl, MAPOBJECT_SPRITE
+	add hl, bc
+	ld a, [hl]
+	and a
+	jr z, .next_v
+	ld hl, MAPOBJECT_Y_COORD
+	add hl, bc
+	ld a, d
+	cp [hl]
+	jr nz, .next_v
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	cp -1
+	jr nz, .next_v
+	ld hl, MAPOBJECT_X_COORD
+	add hl, bc
+	ld a, [hl]
+	add 1
+	sub e
+	jr c, .next_v
+	cp MAPOBJECT_SCREEN_WIDTH
+	jr nc, .next_v
+	push de
+	push bc
+	call CopyObjectStruct
+	pop bc
+	pop de
+
+.next_v
+	ld hl, MAPOBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	ldh a, [hMapObjectIndex]
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop_v
+	ret
+
+.Left:
+	ld a, [wXCoord]
+	sub 1
+	jr .Horizontal
+
+.Right:
+	ld a, [wXCoord]
+	add 10
+.Horizontal:
+	ld e, a
+	ld a, [wYCoord]
+	ld d, a
+	ld bc, wMap1Object
+	ld a, 1
+.loop_h
+	ldh [hMapObjectIndex], a
+	ld hl, MAPOBJECT_SPRITE
+	add hl, bc
+	ld a, [hl]
+	and a
+	jr z, .next_h
+	ld hl, MAPOBJECT_X_COORD
+	add hl, bc
+	ld a, e
+	cp [hl]
+	jr nz, .next_h
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	cp -1
+	jr nz, .next_h
+	ld hl, MAPOBJECT_Y_COORD
+	add hl, bc
+	ld a, [hl]
+	add 1
+	sub d
+	jr c, .next_h
+	cp MAPOBJECT_SCREEN_HEIGHT
+	jr nc, .next_h
+	push de
+	push bc
+	call CopyObjectStruct
+	pop bc
+	pop de
+
+.next_h
+	ld hl, MAPOBJECT_LENGTH
+	add hl, bc
+	ld b, h
+	ld c, l
+	ldh a, [hMapObjectIndex]
+	inc a
+	cp NUM_OBJECTS
+	jr nz, .loop_h
+	ret
+
+CopyTempObjectToObjectStruct:
+	ld a, [wTempObjectCopyMapObjectIndex]
+	ld hl, OBJECT_MAP_OBJECT_INDEX
+	add hl, de
+	ld [hl], a
+
+	ld a, [wTempObjectCopyMovement]
+	call CopySpriteMovementData
+
+	ld a, [wTempObjectCopyPalette]
+	ld hl, OBJECT_PALETTE
+	add hl, de
+	or [hl]
+	ld [hl], a
+
+	ld a, [wTempObjectCopyY]
+	call .InitYCoord
+
+	ld a, [wTempObjectCopyX]
+	call .InitXCoord
+
+	ld a, [wTempObjectCopySprite]
+	ld hl, OBJECT_SPRITE
+	add hl, de
+	ld [hl], a
+
+	ld a, [wTempObjectCopySpriteVTile]
+	ld hl, OBJECT_SPRITE_TILE
+	add hl, de
+	ld [hl], a
+
+	ld hl, OBJECT_STEP_TYPE
+	add hl, de
+	ld [hl], STEP_TYPE_RESET
+
+	ld hl, OBJECT_FACING
+	add hl, de
+	ld [hl], STANDING
+
+	ld a, [wTempObjectCopyRadius]
+	call .InitRadius
+
+	ld a, [wTempObjectCopyRange]
+	ld hl, OBJECT_RANGE
+	add hl, de
+	ld [hl], a
+
+	and a
+	ret
+
+.InitYCoord:
+	ld hl, OBJECT_INIT_Y
+	add hl, de
+	ld [hl], a
+
+	ld hl, OBJECT_MAP_Y
+	add hl, de
+	ld [hl], a
+
+	ld hl, wYCoord
+	sub [hl]
+	and $f
+	swap a
+	ld hl, wPlayerBGMapOffsetY
+	sub [hl]
+	ld hl, OBJECT_SPRITE_Y
+	add hl, de
+	ld [hl], a
+	ret
+
+.InitXCoord:
+	ld hl, OBJECT_INIT_X
+	add hl, de
+	ld [hl], a
+	ld hl, OBJECT_MAP_X
+	add hl, de
+	ld [hl], a
+	ld hl, wXCoord
+	sub [hl]
+	and $f
+	swap a
+	ld hl, wPlayerBGMapOffsetX
+	sub [hl]
+	ld hl, OBJECT_SPRITE_X
+	add hl, de
+	ld [hl], a
+	ret
+
+.InitRadius:
+	ld h, a
+	inc a
+	and $f
+	ld l, a
+	ld a, h
+	add $10
+	and $f0
+	or l
+	ld hl, OBJECT_RADIUS
+	add hl, de
+	ld [hl], a
+	ret
+
+TrainerWalkToPlayer:
+	ldh a, [hLastTalked]
+	call InitMovementBuffer
+	ld a, movement_step_sleep
+	call AppendToMovementBuffer
+	ld a, [wSeenTrainerDistance]
+	dec a
+	jr z, .TerminateStep
+	ldh a, [hLastTalked]
+	ld b, a
+	ld c, PLAYER
+	ld d, 1
+	call .GetPathToPlayer
+	call DecrementMovementBufferCount
+
+.TerminateStep:
+	ld a, movement_step_end
+	call AppendToMovementBuffer
+	ret
+
+.GetPathToPlayer:
+	push de
+	push bc
+; get player object struct, load to de
+	ld a, c
+	call GetMapObject
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	call GetObjectStruct
+	ld d, b
+	ld e, c
+
+; get last talked object struct, load to bc
+	pop bc
+	ld a, b
+	call GetMapObject
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	call GetObjectStruct
+
+; get last talked coords, load to bc
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld c, [hl]
+	ld b, a
+
+; get player coords, load to de
+	ld hl, OBJECT_MAP_X
+	add hl, de
+	ld a, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, de
+	ld e, [hl]
+	ld d, a
+
+	pop af
+	call ComputePathToWalkToPlayer
+	ret
+
+SurfStartStep:
+	call InitMovementBuffer
+	call .GetMovementData
+	call AppendToMovementBuffer
+	ld a, movement_step_end
+	call AppendToMovementBuffer
+	ret
+
+.GetMovementData:
+	ld a, [wPlayerDirection]
+	srl a
+	srl a
+	maskbits NUM_DIRECTIONS
+	ld e, a
+	ld d, 0
+	ld hl, .movement_data
+	add hl, de
+	ld a, [hl]
+	ret
+
+.movement_data
+	slow_step DOWN
+	slow_step UP
+	slow_step LEFT
+	slow_step RIGHT
+
+FollowNotExact::
+	push bc
+	ld a, c
+	call CheckObjectVisibility
+	ld d, b
+	ld e, c
+	pop bc
+	ret c
+
+	ld a, b
+	call CheckObjectVisibility
+	ret c
+
+; object 2 is now in bc, object 1 is now in de
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld c, [hl]
+	ld b, a
+
+	ld hl, OBJECT_MAP_X
+	add hl, de
+	ld a, [hl]
+	cp b
+	jr z, .same_x
+	jr c, .to_the_left
+	inc b
+	jr .continue
+
+.to_the_left
+	dec b
+	jr .continue
+
+.same_x
+	ld hl, OBJECT_MAP_Y
+	add hl, de
+	ld a, [hl]
+	cp c
+	jr z, .continue
+	jr c, .below
+	inc c
+	jr .continue
+
+.below
+	dec c
+
+.continue
+	ld hl, OBJECT_MAP_X
+	add hl, de
+	ld [hl], b
+	ld a, b
+	ld hl, wXCoord
+	sub [hl]
+	and $f
+	swap a
+	ld hl, wPlayerBGMapOffsetX
+	sub [hl]
+	ld hl, OBJECT_SPRITE_X
+	add hl, de
+	ld [hl], a
+	ld hl, OBJECT_MAP_Y
+	add hl, de
+	ld [hl], c
+	ld a, c
+	ld hl, wYCoord
+	sub [hl]
+	and $f
+	swap a
+	ld hl, wPlayerBGMapOffsetY
+	sub [hl]
+	ld hl, OBJECT_SPRITE_Y
+	add hl, de
+	ld [hl], a
+	ldh a, [hObjectStructIndex]
+	ld hl, OBJECT_RANGE
+	add hl, de
+	ld [hl], a
+	ld hl, OBJECT_MOVEMENT_TYPE
+	add hl, de
+	ld [hl], SPRITEMOVEDATA_FOLLOWNOTEXACT
+	ld hl, OBJECT_STEP_TYPE
+	add hl, de
+	ld [hl], STEP_TYPE_RESET
+	ret
+
+GetRelativeFacing::
+; Determines which way map object e would have to turn to face map object d.  Returns carry if it's impossible for whatever reason.
+	ld a, d
+	call GetMapObject
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	cp NUM_OBJECT_STRUCTS
+	jr nc, .carry
+	ld d, a
+	ld a, e
+	call GetMapObject
+	ld hl, MAPOBJECT_OBJECT_STRUCT_ID
+	add hl, bc
+	ld a, [hl]
+	cp NUM_OBJECT_STRUCTS
+	jr nc, .carry
+	ld e, a
+	call .GetFacing_e_relativeto_d
+	ret
+
+.carry
+	scf
+	ret
+
+.GetFacing_e_relativeto_d:
+; Determines which way object e would have to turn to face object d.  Returns carry if it's impossible.
+; load the coordinates of object d into bc
+	ld a, d
+	call GetObjectStruct
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld c, [hl]
+	ld b, a
+	push bc
+; load the coordinates of object e into de
+	ld a, e
+	call GetObjectStruct
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	pop bc
+; |x1 - x2|
+	ld a, b
+	sub d
+	jr z, .same_x_1
+	jr nc, .b_right_of_d_1
+	cpl
+	inc a
+
+.b_right_of_d_1
+; |y1 - y2|
+	ld h, a
+	ld a, c
+	sub e
+	jr z, .same_y_1
+	jr nc, .c_below_e_1
+	cpl
+	inc a
+
+.c_below_e_1
+; |y1 - y2| - |x1 - x2|
+	sub h
+	jr c, .same_y_1
+
+.same_x_1
+; compare the y coordinates
+	ld a, c
+	cp e
+	jr z, .same_x_and_y
+	jr c, .c_directly_below_e
+; c directly above e
+	ld d, DOWN
+	and a
+	ret
+
+.c_directly_below_e
+	ld d, UP
+	and a
+	ret
+
+.same_y_1
+	ld a, b
+	cp d
+	jr z, .same_x_and_y
+	jr c, .b_directly_right_of_d
+; b directly left of d
+	ld d, RIGHT
+	and a
+	ret
+
+.b_directly_right_of_d
+	ld d, LEFT
+	and a
+	ret
+
+.same_x_and_y
+	scf
+	ret
+
+QueueFollowerFirstStep:
+	call .QueueFirstStep
+	jr c, .same
+	ld [wFollowMovementQueue], a
+	xor a
+	ld [wFollowerMovementQueueLength], a
+	ret
+
+.same
+	ld a, -1
+	ld [wFollowerMovementQueueLength], a
+	ret
+
+.QueueFirstStep:
+	ld a, [wObjectFollow_Leader]
+	call GetObjectStruct
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld d, [hl]
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld e, [hl]
+	ld a, [wObjectFollow_Follower]
+	call GetObjectStruct
+	ld hl, OBJECT_MAP_X
+	add hl, bc
+	ld a, d
+	cp [hl]
+	jr z, .check_y
+	jr c, .left
+	and a
+	ld a, movement_step + RIGHT
+	ret
+
+.left
+	and a
+	ld a, movement_step + LEFT
+	ret
+
+.check_y
+	ld hl, OBJECT_MAP_Y
+	add hl, bc
+	ld a, e
+	cp [hl]
+	jr z, .same_xy
+	jr c, .up
+	and a
+	ld a, movement_step + DOWN
+	ret
+
+.up
+	and a
+	ld a, movement_step + UP
+	ret
+
+.same_xy
+	scf
+	ret

engine/overworld/player_step.asm

@@ -0,0 +1,270 @@
+_HandlePlayerStep::
+	ld a, [wPlayerStepFlags]
+	and a
+	ret z
+	bit PLAYERSTEP_START_F, a
+	jr nz, .update_overworld_map
+	bit PLAYERSTEP_STOP_F, a
+	jr nz, .update_player_coords
+	bit PLAYERSTEP_CONTINUE_F, a
+	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::
+	ld a, [wPlayerStepVectorX]
+	ld d, a
+	ld a, [wPlayerStepVectorY]
+	ld e, a
+	ldh a, [hSCX]
+	add d
+	ldh [hSCX], a
+	ldh a, [hSCY]
+	add e
+	ldh [hSCY], a
+	ret
+
+HandlePlayerStep:
+	ld hl, wHandlePlayerStep
+	ld a, [hl]
+	and a
+	ret z
+	dec [hl]
+	ld a, [hl]
+	ld hl, .Jumptable
+	rst JumpTable
+	ret
+
+.Jumptable:
+	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
+	ret
+
+.mobile
+	farcall StubbedTrainerRankings_StepCount
+	ret
+
+.fail2
+	ret
+
+UpdatePlayerCoords:
+	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:
+	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 ScrollMapDown
+	ret
+
+.step_up
+	call .ScrollOverworldMapUp
+	call LoadMapPart
+	call ScrollMapUp
+	ret
+
+.step_left
+	call .ScrollOverworldMapLeft
+	call LoadMapPart
+	call ScrollMapLeft
+	ret
+
+.step_right
+	call .ScrollOverworldMapRight
+	call LoadMapPart
+	call ScrollMapRight
+	ret
+
+.ScrollOverworldMapDown:
+	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, wPlayerMetatileY
+	inc [hl]
+	ld a, [hl]
+	cp 2 ; was 1
+	jr nz, .done_down
+	ld [hl], 0
+	call .ScrollMapDataDown
+.done_down
+	ret
+
+.ScrollMapDataDown:
+	ld hl, wOverworldMapAnchor
+	ld a, [wMapWidth]
+	add 3 * 2 ; surrounding tiles
+	add [hl]
+	ld [hli], a
+	ret nc
+	inc [hl]
+	ret
+
+.ScrollOverworldMapUp:
+	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, wPlayerMetatileY
+	dec [hl]
+	ld a, [hl]
+	cp -1 ; was 0
+	jr nz, .done_up
+	ld [hl], $1
+	call .ScrollMapDataUp
+.done_up
+	ret
+
+.ScrollMapDataUp:
+	ld hl, wOverworldMapAnchor
+	ld a, [wMapWidth]
+	add 3 * 2 ; surrounding tiles
+	ld b, a
+	ld a, [hl]
+	sub b
+	ld [hli], a
+	ret nc
+	dec [hl]
+	ret
+
+.ScrollOverworldMapLeft:
+	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, wPlayerMetatileX
+	dec [hl]
+	ld a, [hl]
+	cp -1
+	jr nz, .done_left
+	ld [hl], 1
+	call .ScrollMapDataLeft
+.done_left
+	ret
+
+.ScrollMapDataLeft:
+	ld hl, wOverworldMapAnchor
+	ld a, [hl]
+	sub 1
+	ld [hli], a
+	ret nc
+	dec [hl]
+	ret
+
+.ScrollOverworldMapRight:
+	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, wPlayerMetatileX
+	inc [hl]
+	ld a, [hl]
+	cp 2
+	jr nz, .done_right
+	ld [hl], 0
+	call .ScrollMapDataRight
+.done_right
+	ret
+
+.ScrollMapDataRight:
+	ld hl, wOverworldMapAnchor
+	ld a, [hl]
+	add 1
+	ld [hli], a
+	ret nc
+	inc [hl]
+	ret

engine/overworld/select_menu.asm

@@ -0,0 +1,172 @@
+SelectMenu::
+	call CheckRegisteredItem
+	jr c, .NotRegistered
+	jp UseRegisteredItem
+
+.NotRegistered:
+	call OpenText
+	ld b, BANK(MayRegisterItemText)
+	ld hl, MayRegisterItemText
+	call MapTextbox
+	call WaitButton
+	jp CloseText
+
+MayRegisterItemText:
+	text_far _MayRegisterItemText
+	text_end
+
+CheckRegisteredItem:
+	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
+
+.CheckRegisteredNo:
+	ld a, [wWhichRegisteredItem]
+	and REGISTERED_NUMBER
+	dec a
+	cp [hl]
+	jr nc, .NotEnoughItems
+	ld [wCurItemQuantity], a
+	and a
+	ret
+
+.NotEnoughItems:
+	scf
+	ret
+
+.IsSameItem:
+	ld a, [wRegisteredItem]
+	cp [hl]
+	jr nz, .NotSameItem
+	ld [wCurItem], a
+	and a
+	ret
+
+.NotSameItem:
+	scf
+	ret
+
+UseRegisteredItem:
+	farcall CheckItemMenu
+	ld a, [wItemAttributeValue]
+	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
+
+.NoFunction:
+	call OpenText
+	call CantUseItem
+	call CloseText
+	and a
+	ret
+
+.Current:
+	call OpenText
+	call DoItemEffect
+	call CloseText
+	and a
+	ret
+
+.Party:
+	call RefreshScreen
+	call FadeToMenu
+	call DoItemEffect
+	call CloseSubmenu
+	call CloseText
+	and a
+	ret
+
+.Overworld:
+	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
+	ldh [hMenuReturn], a
+	ret
+
+.CantUse:
+	call RefreshScreen
+
+._cantuse
+	call CantUseItem
+	call CloseText
+	and a
+	ret

engine/overworld/spawn_points.asm

@@ -0,0 +1,58 @@
+INCLUDE "data/maps/spawn_points.asm"
+
+EnterMapSpawnPoint:
+	; 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
+
+IsSpawnPoint:
+; 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

engine/overworld/tile_events.asm

@@ -0,0 +1,101 @@
+CheckWarpCollision::
+; Is this tile a warp?
+	ld a, [wPlayerTile]
+	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
+
+CheckDirectionalWarp::
+; If this is a directional warp, clear carry (press the designated button to warp).
+; Else, set carry (immediate warp).
+	ld a, [wPlayerTile]
+	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
+
+CheckWarpFacingDown:
+	ld de, 1
+	ld hl, .blocks
+	ld a, [wPlayerTile]
+	call IsInArray
+	ret
+
+.blocks
+	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
+
+CheckGrassCollision::
+	ld a, [wPlayerTile]
+	ld hl, .blocks
+	ld de, 1
+	call IsInArray
+	ret
+
+.blocks
+	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
+
+CheckCutCollision:
+	ld a, c
+	ld hl, .blocks
+	ld de, 1
+	call IsInArray
+	ret
+
+.blocks
+	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
+
+GetWarpSFX::
+	ld a, [wPlayerTile]
+	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

engine/overworld/time.asm

@@ -0,0 +1,440 @@
+_InitializeStartDay:
+	call InitializeStartDay
+	ret
+
+ClearDailyTimers:
+	xor a
+	ld [wLuckyNumberDayTimer], a
+	ld [wUnusedTwoDayTimer], a
+	ld [wDailyResetTimer], a
+	ret
+
+InitCallReceiveDelay::
+	xor a
+	ld [wTimeCyclesSinceLastCall], a
+
+NextCallReceiveDelay:
+	ld a, [wTimeCyclesSinceLastCall]
+	cp 3
+	jr c, .okay
+	ld a, 3
+
+.okay
+	ld e, a
+	ld d, 0
+	ld hl, .ReceiveCallDelays
+	add hl, de
+	ld a, [hl]
+if DEF(_DEBUG)
+	ld h, a
+	ld a, BANK(sDebugTimeCyclesSinceLastCall)
+	call OpenSRAM
+	ld a, [sDebugTimeCyclesSinceLastCall]
+	call CloseSRAM
+	dec a
+	cp 2
+	jr nc, .debug_ok
+	xor 1
+	ld h, a
+.debug_ok
+	ld a, h
+endc
+	jp RestartReceiveCallDelay
+
+.ReceiveCallDelays:
+	db 20, 10, 5, 3
+
+CheckReceiveCallTimer:
+	call CheckReceiveCallDelay ; check timer
+	ret nc
+	ld hl, wTimeCyclesSinceLastCall
+	ld a, [hl]
+	cp 3
+	jr nc, .ok
+	inc [hl]
+
+.ok
+	call NextCallReceiveDelay ; restart timer
+	scf
+	ret
+
+InitOneDayCountdown:
+	ld a, 1
+
+InitNDaysCountdown:
+	ld [hl], a
+	push hl
+	call UpdateTime
+	pop hl
+	inc hl
+	call CopyDayToHL
+	ret
+
+CheckDayDependentEventHL:
+	inc hl
+	push hl
+	call CalcDaysSince
+	call GetDaysSince
+	pop hl
+	dec hl
+	call UpdateTimeRemaining
+	ret
+
+RestartReceiveCallDelay:
+	ld hl, wReceiveCallDelay_MinsRemaining
+	ld [hl], a
+	call UpdateTime
+	ld hl, wReceiveCallDelay_StartTime
+	call CopyDayHourMinToHL
+	ret
+
+CheckReceiveCallDelay:
+	ld hl, wReceiveCallDelay_StartTime
+	call CalcMinsHoursDaysSince
+	call GetMinutesSinceIfLessThan60
+	ld hl, wReceiveCallDelay_MinsRemaining
+	call UpdateTimeRemaining
+	ret
+
+RestartDailyResetTimer:
+	ld hl, wDailyResetTimer
+	jp InitOneDayCountdown
+
+CheckDailyResetTimer::
+	ld hl, wDailyResetTimer
+	call CheckDayDependentEventHL
+	ret nc
+	xor a
+	ld hl, wDailyFlags1
+	ld [hli], a ; wDailyFlags1
+	ld [hli], a ; wDailyFlags2
+	ld [hli], a ; wSwarmFlags
+	ld [hl], a  ; wSwarmFlags + 1
+	ld hl, wDailyRematchFlags
+rept 4
+	ld [hli], a
+endr
+	ld hl, wDailyPhoneItemFlags
+rept 4
+	ld [hli], a
+endr
+	ld hl, wDailyPhoneTimeOfDayFlags
+rept 4
+	ld [hli], a
+endr
+	ld hl, wKenjiBreakTimer
+	ld a, [hl]
+	and a
+	jr z, .RestartKenjiBreakCountdown
+	dec [hl]
+	jr nz, .DontRestartKenjiBreakCountdown
+.RestartKenjiBreakCountdown:
+	call SampleKenjiBreakCountdown
+.DontRestartKenjiBreakCountdown:
+	jr RestartDailyResetTimer
+
+SampleKenjiBreakCountdown:
+; Generate a random number between 3 and 6
+	call Random
+	and %11
+	add 3
+	ld [wKenjiBreakTimer], a
+	ret
+
+StartBugContestTimer:
+	ld a, BUG_CONTEST_MINUTES
+	ld [wBugContestMinsRemaining], a
+	ld a, BUG_CONTEST_SECONDS
+	ld [wBugContestSecsRemaining], a
+	call UpdateTime
+	ld hl, wBugContestStartTime
+	call CopyDayHourMinSecToHL
+	ret
+
+CheckBugContestTimer::
+	ld hl, wBugContestStartTime
+	call CalcSecsMinsHoursDaysSince
+	ld a, [wDaysSince]
+	and a
+	jr nz, .timed_out
+	ld a, [wHoursSince]
+	and a
+	jr nz, .timed_out
+	ld a, [wSecondsSince]
+	ld b, a
+	ld a, [wBugContestSecsRemaining]
+	sub b
+	jr nc, .okay
+	add 60
+
+.okay
+	ld [wBugContestSecsRemaining], a
+	ld a, [wMinutesSince]
+	ld b, a
+	ld a, [wBugContestMinsRemaining]
+	sbc b
+	ld [wBugContestMinsRemaining], a
+	jr c, .timed_out
+	and a
+	ret
+
+.timed_out
+	xor a
+	ld [wBugContestMinsRemaining], a
+	ld [wBugContestSecsRemaining], a
+	scf
+	ret
+
+InitializeStartDay:
+	call UpdateTime
+	ld hl, wTimerEventStartDay
+	call CopyDayToHL
+	ret
+
+CheckPokerusTick::
+	ld hl, wTimerEventStartDay
+	call CalcDaysSince
+	call GetDaysSince
+	and a
+	jr z, .done ; not even a day has passed since game start
+	ld b, a
+	farcall ApplyPokerusTick
+.done
+	xor a
+	ret
+
+SetUnusedTwoDayTimer: ; unreferenced
+	ld a, 2
+	ld hl, wUnusedTwoDayTimer
+	ld [hl], a
+	call UpdateTime
+	ld hl, wUnusedTwoDayTimerStartDate
+	call CopyDayToHL
+	ret
+
+CheckUnusedTwoDayTimer:
+	ld hl, wUnusedTwoDayTimerStartDate
+	call CalcDaysSince
+	call GetDaysSince
+	ld hl, wUnusedTwoDayTimer
+	call UpdateTimeRemaining
+	ret
+
+UnusedSetSwarmFlag: ; unreferenced
+	ld hl, wDailyFlags1
+	set DAILYFLAGS1_FISH_SWARM_F, [hl]
+	ret
+
+UnusedCheckSwarmFlag: ; unreferenced
+	and a
+	ld hl, wDailyFlags1
+	bit DAILYFLAGS1_FISH_SWARM_F, [hl]
+	ret nz
+	scf
+	ret
+
+RestartLuckyNumberCountdown:
+	call .GetDaysUntilNextFriday
+	ld hl, wLuckyNumberDayTimer
+	jp InitNDaysCountdown
+
+.GetDaysUntilNextFriday:
+	call GetWeekday
+	ld c, a
+	ld a, FRIDAY
+	sub c
+	jr z, .friday_saturday
+	jr nc, .earlier ; could have done "ret nc"
+
+.friday_saturday
+	add 7
+
+.earlier
+	ret
+
+_CheckLuckyNumberShowFlag:
+	ld hl, wLuckyNumberDayTimer
+	jp CheckDayDependentEventHL
+
+DoMysteryGiftIfDayHasPassed:
+	ld a, BANK(sMysteryGiftTimer)
+	call OpenSRAM
+	ld hl, sMysteryGiftTimer
+	ld a, [hli]
+	ld [wTempMysteryGiftTimer], a
+	ld a, [hl]
+	ld [wTempMysteryGiftTimer + 1], a
+	call CloseSRAM
+
+	ld hl, wTempMysteryGiftTimer
+	call CheckDayDependentEventHL
+	jr nc, .not_timed_out
+	ld hl, wTempMysteryGiftTimer
+	call InitOneDayCountdown
+	call CloseSRAM
+	farcall ResetDailyMysteryGiftLimitIfUnlocked
+
+.not_timed_out
+	ld a, BANK(sMysteryGiftTimer)
+	call OpenSRAM
+	ld hl, wTempMysteryGiftTimer
+	ld a, [hli]
+	ld [sMysteryGiftTimer], a
+	ld a, [hl]
+	ld [sMysteryGiftTimer + 1], a
+	call CloseSRAM
+	ret
+
+UpdateTimeRemaining:
+; If the amount of time elapsed exceeds the capacity of its
+; unit, skip this part.
+	cp -1
+	jr z, .set_carry
+	ld c, a
+	ld a, [hl] ; time remaining
+	sub c
+	jr nc, .ok
+	xor a
+
+.ok
+	ld [hl], a
+	jr z, .set_carry
+	xor a
+	ret
+
+.set_carry
+	xor a
+	ld [hl], a
+	scf
+	ret
+
+GetSecondsSinceIfLessThan60: ; unreferenced
+	ld a, [wDaysSince]
+	and a
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wHoursSince]
+	and a
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wMinutesSince]
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wSecondsSince]
+	ret
+
+GetMinutesSinceIfLessThan60:
+	ld a, [wDaysSince]
+	and a
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wHoursSince]
+	and a
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wMinutesSince]
+	ret
+
+GetHoursSinceIfLessThan24: ; unreferenced
+	ld a, [wDaysSince]
+	and a
+	jr nz, GetTimeElapsed_ExceedsUnitLimit
+	ld a, [wHoursSince]
+	ret
+
+GetDaysSince:
+	ld a, [wDaysSince]
+	ret
+
+GetTimeElapsed_ExceedsUnitLimit:
+	ld a, -1
+	ret
+
+CalcDaysSince:
+	xor a
+	jr _CalcDaysSince
+
+CalcHoursDaysSince: ; unreferenced
+	inc hl
+	xor a
+	jr _CalcHoursDaysSince
+
+CalcMinsHoursDaysSince:
+	inc hl
+	inc hl
+	xor a
+	jr _CalcMinsHoursDaysSince
+
+CalcSecsMinsHoursDaysSince:
+	inc hl
+	inc hl
+	inc hl
+	ldh a, [hSeconds]
+	ld c, a
+	sub [hl]
+	jr nc, .skip
+	add 60
+.skip
+	ld [hl], c ; current seconds
+	dec hl
+	ld [wSecondsSince], a ; seconds since
+
+_CalcMinsHoursDaysSince:
+	ldh a, [hMinutes]
+	ld c, a
+	sbc [hl]
+	jr nc, .skip
+	add 60
+.skip
+	ld [hl], c ; current minutes
+	dec hl
+	ld [wMinutesSince], a ; minutes since
+
+_CalcHoursDaysSince:
+	ldh a, [hHours]
+	ld c, a
+	sbc [hl]
+	jr nc, .skip
+	add MAX_HOUR
+.skip
+	ld [hl], c ; current hours
+	dec hl
+	ld [wHoursSince], a ; hours since
+
+_CalcDaysSince:
+	ld a, [wCurDay]
+	ld c, a
+	sbc [hl]
+	jr nc, .skip
+	add 20 * 7
+.skip
+	ld [hl], c ; current days
+	ld [wDaysSince], a ; days since
+	ret
+
+CopyDayHourMinSecToHL:
+	ld a, [wCurDay]
+	ld [hli], a
+	ldh a, [hHours]
+	ld [hli], a
+	ldh a, [hMinutes]
+	ld [hli], a
+	ldh a, [hSeconds]
+	ld [hli], a
+	ret
+
+CopyDayToHL:
+	ld a, [wCurDay]
+	ld [hl], a
+	ret
+
+CopyDayHourToHL: ; unreferenced
+	ld a, [wCurDay]
+	ld [hli], a
+	ldh a, [hHours]
+	ld [hli], a
+	ret
+
+CopyDayHourMinToHL:
+	ld a, [wCurDay]
+	ld [hli], a
+	ldh a, [hHours]
+	ld [hli], a
+	ldh a, [hMinutes]
+	ld [hli], a
+	ret

engine/overworld/variables.asm

@@ -0,0 +1,155 @@
+_GetVarAction::
+	ld a, c
+	cp NUM_VARS
+	jr c, .valid
+	xor a
+.valid
+	ld c, a
+	ld b, 0
+	ld hl, .VarActionTable
+	add hl, bc
+	add hl, bc
+	add hl, bc
+	ld e, [hl]
+	inc hl
+	ld d, [hl]
+	inc hl
+	ld b, [hl]
+	ld a, b
+	and RETVAR_EXECUTE
+	jr nz, .call
+	ld a, b
+	and RETVAR_ADDR_DE
+	ret nz
+	ld a, [de]
+	jr .loadstringbuffer2
+
+.call
+	call _de_
+	ret
+
+.loadstringbuffer2
+	ld de, wStringBuffer2
+	ld [de], a
+	ret
+
+.VarActionTable:
+; entries correspond to VAR_* constants
+	; RETVAR_STRBUF2: copy [de] to wStringBuffer2
+	; RETVAR_ADDR_DE: return address in de
+	; RETVAR_EXECUTE: call function
+	dwb wStringBuffer2,                 RETVAR_STRBUF2
+	dwb wPartyCount,                    RETVAR_STRBUF2
+	dwb .BattleResult,                  RETVAR_EXECUTE
+	dwb wBattleType,                    RETVAR_ADDR_DE
+	dwb wTimeOfDay,                     RETVAR_STRBUF2
+	dwb .CountCaughtMons,               RETVAR_EXECUTE
+	dwb .CountSeenMons,                 RETVAR_EXECUTE
+	dwb .CountBadges,                   RETVAR_EXECUTE
+	dwb wPlayerState,                   RETVAR_ADDR_DE
+	dwb .PlayerFacing,                  RETVAR_EXECUTE
+	dwb hHours,                         RETVAR_STRBUF2
+	dwb .DayOfWeek,                     RETVAR_EXECUTE
+	dwb wMapGroup,                      RETVAR_STRBUF2
+	dwb wMapNumber,                     RETVAR_STRBUF2
+	dwb .UnownCaught,                   RETVAR_EXECUTE
+	dwb wEnvironment,                   RETVAR_STRBUF2
+	dwb .BoxFreeSpace,                  RETVAR_EXECUTE
+	dwb wBugContestMinsRemaining,       RETVAR_STRBUF2
+	dwb wXCoord,                        RETVAR_STRBUF2
+	dwb wYCoord,                        RETVAR_STRBUF2
+	dwb wSpecialPhoneCallID,            RETVAR_STRBUF2
+	dwb wNrOfBeatenBattleTowerTrainers, RETVAR_STRBUF2
+	dwb wKurtApricornQuantity,          RETVAR_STRBUF2
+	dwb wCurCaller,                     RETVAR_ADDR_DE
+	dwb wBlueCardBalance,               RETVAR_ADDR_DE
+	dwb wBuenasPassword,                RETVAR_ADDR_DE
+	dwb wKenjiBreakTimer,               RETVAR_STRBUF2
+	dwb .CountUncaughtMons,             RETVAR_EXECUTE
+
+.CountCaughtMons:
+; Caught mons. Saturate at 255.
+	ld hl, wPokedexCaught
+.count_caught_or_seen_mons
+	ld bc, wEndPokedexCaught - wPokedexCaught
+	call CountSetBits16
+	ld a, b
+.load_or_saturate
+	add a, -1
+	sbc a
+	or c
+	jp .loadstringbuffer2
+
+.CountSeenMons:
+; Seen mons. Saturate at 255.
+	ld hl, wPokedexSeen
+	jr .count_caught_or_seen_mons
+
+.CountUncaughtMons:
+; Mons left to catch. Saturate at 255.
+	ld hl, wPokedexCaught
+	ld bc, wEndPokedexCaught - wPokedexCaught
+	call CountSetBits16
+	ld a, LOW(NUM_POKEMON)
+	sub c
+	ld c, a
+	ld a, HIGH(NUM_POKEMON)
+	sbc b
+	jr .load_or_saturate
+
+.CountBadges:
+; Number of owned badges.
+	ld hl, wBadges
+	ld b, 2
+	call CountSetBits
+	ld a, [wNumSetBits]
+	jp .loadstringbuffer2
+
+.PlayerFacing:
+; The direction the player is facing.
+	ld a, [wPlayerDirection]
+	and $c
+	rrca
+	rrca
+	jp .loadstringbuffer2
+
+.DayOfWeek:
+; The day of the week.
+	call GetWeekday
+	jp .loadstringbuffer2
+
+.UnownCaught:
+; Number of unique Unown caught.
+	call .count_unown
+	ld a, b
+	jp .loadstringbuffer2
+
+.count_unown
+	ld hl, wUnownDex
+	ld b, 0
+.loop
+	ld a, [hli]
+	and a
+	ret z
+	inc b
+	ld a, b
+	cp NUM_UNOWN
+	jr c, .loop
+	ret
+
+.BoxFreeSpace:
+; Remaining slots in the current box.
+	ld a, BANK(sBoxCount)
+	call OpenSRAM
+	ld hl, sBoxCount
+	ld a, MONS_PER_BOX
+	sub [hl]
+	ld b, a
+	call CloseSRAM
+	ld a, b
+	jp .loadstringbuffer2
+
+.BattleResult:
+	ld a, [wBattleResult]
+	and ~BATTLERESULT_BITMASK
+	jp .loadstringbuffer2

engine/overworld/warp_connection.asm

@@ -0,0 +1,445 @@
+HandleNewMap:
+	call ClearUnusedMapBuffer
+	call ResetMapBufferEventFlags
+	call ResetFlashIfOutOfCave
+	call GetCurrentMapSceneID
+	call ResetBikeFlags
+	call ResetMapLockedIDs
+	ld a, MAPCALLBACK_NEWMAP
+	call RunMapCallback
+HandleContinueMap:
+	farcall ClearCmdQueue
+	ld a, MAPCALLBACK_CMDQUEUE
+	call RunMapCallback
+	call GetMapTimeOfDay
+	ld [wMapTimeOfDay], a
+	ret
+
+ResetMapLockedIDs:
+	ld e, NUM_MAP_LOCKED_MON_IDS
+.mon_loop
+	ld a, LOCKED_MON_ID_MAP_1 - 1
+	add a, e
+	ld l, a
+	xor a
+	call LockPokemonID
+	dec e
+	jr nz, .mon_loop
+	ret
+
+EnterMapConnection:
+; Return carry if a connection has been entered.
+	ld a, [wPlayerStepDirection]
+	and a ; DOWN
+	jp z, .south
+	cp UP
+	jp z, .north
+	cp LEFT
+	jp z, .west
+	cp RIGHT
+	jp z, .east
+	ret
+
+.west
+	ld a, [wWestConnectedMapGroup]
+	ld [wMapGroup], a
+	ld a, [wWestConnectedMapNumber]
+	ld [wMapNumber], a
+	ld a, [wWestConnectionStripXOffset]
+	ld [wXCoord], a
+	ld a, [wWestConnectionStripYOffset]
+	ld hl, wYCoord
+	add [hl]
+	ld [hl], a
+	ld c, a
+	ld hl, wWestConnectionWindow
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	srl c
+	jr z, .skip_to_load
+	ld a, [wWestConnectedMapWidth]
+	add 6
+	ld e, a
+	ld d, 0
+
+.loop
+	add hl, de
+	dec c
+	jr nz, .loop
+
+.skip_to_load
+	ld a, l
+	ld [wOverworldMapAnchor], a
+	ld a, h
+	ld [wOverworldMapAnchor + 1], a
+	jp .done
+
+.east
+	ld a, [wEastConnectedMapGroup]
+	ld [wMapGroup], a
+	ld a, [wEastConnectedMapNumber]
+	ld [wMapNumber], a
+	ld a, [wEastConnectionStripXOffset]
+	ld [wXCoord], a
+	ld a, [wEastConnectionStripYOffset]
+	ld hl, wYCoord
+	add [hl]
+	ld [hl], a
+	ld c, a
+	ld hl, wEastConnectionWindow
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	srl c
+	jr z, .skip_to_load2
+	ld a, [wEastConnectedMapWidth]
+	add 6
+	ld e, a
+	ld d, 0
+
+.loop2
+	add hl, de
+	dec c
+	jr nz, .loop2
+
+.skip_to_load2
+	ld a, l
+	ld [wOverworldMapAnchor], a
+	ld a, h
+	ld [wOverworldMapAnchor + 1], a
+	jp .done
+
+.north
+	ld a, [wNorthConnectedMapGroup]
+	ld [wMapGroup], a
+	ld a, [wNorthConnectedMapNumber]
+	ld [wMapNumber], a
+	ld a, [wNorthConnectionStripYOffset]
+	ld [wYCoord], a
+	ld a, [wNorthConnectionStripXOffset]
+	ld hl, wXCoord
+	add [hl]
+	ld [hl], a
+	ld c, a
+	ld hl, wNorthConnectionWindow
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld b, 0
+	srl c
+	add hl, bc
+	ld a, l
+	ld [wOverworldMapAnchor], a
+	ld a, h
+	ld [wOverworldMapAnchor + 1], a
+	jp .done
+
+.south
+	ld a, [wSouthConnectedMapGroup]
+	ld [wMapGroup], a
+	ld a, [wSouthConnectedMapNumber]
+	ld [wMapNumber], a
+	ld a, [wSouthConnectionStripYOffset]
+	ld [wYCoord], a
+	ld a, [wSouthConnectionStripXOffset]
+	ld hl, wXCoord
+	add [hl]
+	ld [hl], a
+	ld c, a
+	ld hl, wSouthConnectionWindow
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld b, 0
+	srl c
+	add hl, bc
+	ld a, l
+	ld [wOverworldMapAnchor], a
+	ld a, h
+	ld [wOverworldMapAnchor + 1], a
+.done
+	scf
+	ret
+
+EnterMapWarp:
+	call .SaveDigWarp
+	call .SetSpawn
+	ld a, [wNextWarp]
+	ld [wWarpNumber], a
+	ld a, [wNextMapGroup]
+	ld [wMapGroup], a
+	ld a, [wNextMapNumber]
+	ld [wMapNumber], a
+	ret
+
+.SaveDigWarp:
+	call GetMapEnvironment
+	call CheckOutdoorMap
+	ret nz
+	ld a, [wNextMapGroup]
+	ld b, a
+	ld a, [wNextMapNumber]
+	ld c, a
+	call GetAnyMapEnvironment
+	call CheckIndoorMap
+	ret nz
+
+; MOUNT_MOON_SQUARE and TIN_TOWER_ROOF are outdoor maps within indoor maps.
+; Dig and Escape Rope should not take you to them.
+	ld a, [wPrevMapGroup]
+	cp GROUP_MOUNT_MOON_SQUARE
+	jr nz, .not_mt_moon_square_or_tin_tower_roof
+	assert GROUP_MOUNT_MOON_SQUARE == GROUP_TIN_TOWER_ROOF
+	ld a, [wPrevMapNumber]
+	cp MAP_MOUNT_MOON_SQUARE
+	ret z
+	cp MAP_TIN_TOWER_ROOF
+	ret z
+.not_mt_moon_square_or_tin_tower_roof
+
+	ld a, [wPrevWarp]
+	ld [wDigWarpNumber], a
+	ld a, [wPrevMapGroup]
+	ld [wDigMapGroup], a
+	ld a, [wPrevMapNumber]
+	ld [wDigMapNumber], a
+	ret
+
+.SetSpawn:
+	call GetMapEnvironment
+	call CheckOutdoorMap
+	ret nz
+	ld a, [wNextMapGroup]
+	ld b, a
+	ld a, [wNextMapNumber]
+	ld c, a
+	call GetAnyMapEnvironment
+	call CheckIndoorMap
+	ret nz
+	ld a, [wNextMapGroup]
+	ld b, a
+	ld a, [wNextMapNumber]
+	ld c, a
+
+; Respawn in Pokémon Centers.
+	call GetAnyMapTileset
+	ld a, c
+	cp TILESET_POKECENTER
+	jr z, .pokecenter_pokecom
+	cp TILESET_POKECOM_CENTER
+	jr z, .pokecenter_pokecom
+	ret
+.pokecenter_pokecom
+
+	ld a, [wPrevMapGroup]
+	ld [wLastSpawnMapGroup], a
+	ld a, [wPrevMapNumber]
+	ld [wLastSpawnMapNumber], a
+	ret
+
+LoadMapTimeOfDay:
+	ld hl, wVramState
+	res 6, [hl]
+	ld a, $1
+	ld [wSpriteUpdatesEnabled], a
+	farcall ReplaceTimeOfDayPals
+	farcall UpdateTimeOfDayPal
+	call OverworldTextModeSwitch
+	call .ClearBGMap
+	call .PushAttrmap
+	ret
+
+.ClearBGMap:
+	ld a, HIGH(vBGMap0)
+	ld [wBGMapAnchor + 1], a
+	xor a ; LOW(vBGMap0)
+	ld [wBGMapAnchor], a
+	ldh [hSCY], a
+	ldh [hSCX], a
+	farcall ApplyBGMapAnchorToObjects
+
+	ldh a, [rVBK]
+	push af
+	ld a, $1
+	ldh [rVBK], a
+
+	xor a
+	ld bc, vBGMap1 - vBGMap0
+	hlbgcoord 0, 0
+	call ByteFill
+
+	pop af
+	ldh [rVBK], a
+
+	ld a, "■"
+	ld bc, vBGMap1 - vBGMap0
+	hlbgcoord 0, 0
+	call ByteFill
+	ret
+
+.PushAttrmap:
+	decoord 0, 0
+	call .copy
+	ldh a, [hCGB]
+	and a
+	ret z
+
+	decoord 0, 0, wAttrmap
+	ld a, $1
+	ldh [rVBK], a
+.copy
+	hlbgcoord 0, 0
+	ld c, SCREEN_WIDTH
+	ld b, SCREEN_HEIGHT
+.row
+	push bc
+.column
+	ld a, [de]
+	inc de
+	ld [hli], a
+	dec c
+	jr nz, .column
+	ld bc, BG_MAP_WIDTH - SCREEN_WIDTH
+	add hl, bc
+	pop bc
+	dec b
+	jr nz, .row
+	ld a, $0
+	ldh [rVBK], a
+	ret
+
+LoadMapGraphics:
+	call LoadMapTileset
+	call LoadTilesetGFX
+	xor a
+	ldh [hMapAnims], a
+	xor a
+	ldh [hTileAnimFrame], a
+	farcall RefreshSprites
+	call LoadFontsExtra
+	farcall LoadOverworldFont
+	ret
+
+LoadMapPalettes:
+	ld b, SCGB_MAPPALS
+	jp GetSGBLayout
+
+RefreshMapSprites:
+	call ClearSprites
+	farcall InitMapNameSign
+	call GetMovementPermissions
+	farcall RefreshPlayerSprite
+	farcall CheckUpdatePlayerSprite
+	ld hl, wPlayerSpriteSetupFlags
+	bit PLAYERSPRITESETUP_SKIP_RELOAD_GFX_F, [hl]
+	jr nz, .skip
+	ld hl, wVramState
+	set 0, [hl]
+	call SafeUpdateSprites
+.skip
+	ld a, [wPlayerSpriteSetupFlags]
+	and (1 << PLAYERSPRITESETUP_FEMALE_TO_MALE_F) | (1 << 3) | (1 << 4)
+	ld [wPlayerSpriteSetupFlags], a
+	ret
+
+CheckMovingOffEdgeOfMap::
+	ld a, [wPlayerStepDirection]
+	cp STANDING
+	ret z
+	and a ; DOWN
+	jr z, .down
+	cp UP
+	jr z, .up
+	cp LEFT
+	jr z, .left
+	cp RIGHT
+	jr z, .right
+	and a
+	ret
+
+.down
+	ld a, [wPlayerMapY]
+	sub 4
+	ld b, a
+	ld a, [wMapHeight]
+	add a
+	cp b
+	jr z, .ok
+	and a
+	ret
+
+.up
+	ld a, [wPlayerMapY]
+	sub 4
+	cp -1
+	jr z, .ok
+	and a
+	ret
+
+.left
+	ld a, [wPlayerMapX]
+	sub 4
+	cp -1
+	jr z, .ok
+	and a
+	ret
+
+.right
+	ld a, [wPlayerMapX]
+	sub 4
+	ld b, a
+	ld a, [wMapWidth]
+	add a
+	cp b
+	jr z, .ok
+	and a
+	ret
+
+.ok
+	scf
+	ret
+
+GetMapScreenCoords::
+	ld hl, wOverworldMapBlocks
+	ld a, [wXCoord]
+	bit 0, a
+	jr nz, .odd_x
+; even x
+	srl a
+	add 1
+	jr .got_block_x
+.odd_x
+	add 1
+	srl a
+.got_block_x
+	ld c, a
+	ld b, 0
+	add hl, bc
+	ld a, [wMapWidth]
+	add MAP_CONNECTION_PADDING_WIDTH * 2
+	ld c, a
+	ld b, 0
+	ld a, [wYCoord]
+	bit 0, a
+	jr nz, .odd_y
+; even y
+	srl a
+	add 1
+	jr .got_block_y
+.odd_y
+	add 1
+	srl a
+.got_block_y
+	call AddNTimes
+	ld a, l
+	ld [wOverworldMapAnchor], a
+	ld a, h
+	ld [wOverworldMapAnchor + 1], a
+	ld a, [wYCoord]
+	and 1
+	ld [wPlayerMetatileY], a
+	ld a, [wXCoord]
+	and 1
+	ld [wPlayerMetatileX], a
+	ret