From f275790aec4a796ed969b099364abfdf25385967 Mon Sep 17 00:00:00 2001
From: Rangi <remy.oukaour+rangi42@gmail.com>
Date: Thu, 2 Jul 2020 23:30:21 -0400
Subject: Add subdirectories to engine/ similar to pokecrystal

---
 engine/overworld/auto_movement.asm         | 292 +++++++++++++++++++++++
 engine/overworld/cable_club_npc.asm        | 151 ------------
 engine/overworld/card_key.asm              | 112 ---------
 engine/overworld/cinnabar_lab.asm          | 123 ----------
 engine/overworld/dust_smoke.asm            |  93 ++++++++
 engine/overworld/hidden_items.asm          | 161 -------------
 engine/overworld/item.asm                  |  54 -----
 engine/overworld/map_sprite_functions1.asm | 356 -----------------------------
 engine/overworld/npc_movement.asm          | 292 -----------------------
 engine/overworld/oaks_aide.asm             |  71 ------
 engine/overworld/oam.asm                   | 189 ---------------
 engine/overworld/pathfinding.asm           | 201 ++++++++++++++++
 engine/overworld/pewter_guys.asm           | 102 ---------
 engine/overworld/poison.asm                | 112 ---------
 engine/overworld/pokecenter.asm            |  68 ------
 engine/overworld/pokemart.asm              | 272 ----------------------
 engine/overworld/saffron_guards.asm        |  15 --
 engine/overworld/set_blackout_map.asm      |  25 --
 engine/overworld/special_warps.asm         | 149 ++++++++++++
 engine/overworld/sprite_collisions.asm     | 356 +++++++++++++++++++++++++++++
 engine/overworld/ssanne.asm                |  93 --------
 engine/overworld/tileset_header.asm        |  60 -----
 engine/overworld/tilesets.asm              |  60 +++++
 engine/overworld/trainer_sight.asm         | 349 ++++++++++++++++++++++++++++
 engine/overworld/trainers.asm              | 349 ----------------------------
 engine/overworld/turn_sprite.asm           |  25 ++
 26 files changed, 1525 insertions(+), 2605 deletions(-)
 create mode 100755 engine/overworld/auto_movement.asm
 delete mode 100755 engine/overworld/cable_club_npc.asm
 delete mode 100755 engine/overworld/card_key.asm
 delete mode 100755 engine/overworld/cinnabar_lab.asm
 create mode 100755 engine/overworld/dust_smoke.asm
 delete mode 100755 engine/overworld/hidden_items.asm
 delete mode 100644 engine/overworld/item.asm
 delete mode 100644 engine/overworld/map_sprite_functions1.asm
 delete mode 100755 engine/overworld/npc_movement.asm
 delete mode 100755 engine/overworld/oaks_aide.asm
 delete mode 100644 engine/overworld/oam.asm
 create mode 100644 engine/overworld/pathfinding.asm
 delete mode 100755 engine/overworld/pewter_guys.asm
 delete mode 100644 engine/overworld/poison.asm
 delete mode 100755 engine/overworld/pokecenter.asm
 delete mode 100755 engine/overworld/pokemart.asm
 delete mode 100755 engine/overworld/saffron_guards.asm
 delete mode 100644 engine/overworld/set_blackout_map.asm
 create mode 100644 engine/overworld/special_warps.asm
 create mode 100644 engine/overworld/sprite_collisions.asm
 delete mode 100755 engine/overworld/ssanne.asm
 delete mode 100644 engine/overworld/tileset_header.asm
 create mode 100644 engine/overworld/tilesets.asm
 create mode 100755 engine/overworld/trainer_sight.asm
 delete mode 100755 engine/overworld/trainers.asm
 create mode 100755 engine/overworld/turn_sprite.asm

(limited to 'engine/overworld')

diff --git a/engine/overworld/auto_movement.asm b/engine/overworld/auto_movement.asm
new file mode 100755
index 00000000..e478c9ad
--- /dev/null
+++ b/engine/overworld/auto_movement.asm
@@ -0,0 +1,292 @@
+PlayerStepOutFromDoor::
+	ld hl, wd730
+	res 1, [hl]
+	call IsPlayerStandingOnDoorTile
+	jr nc, .notStandingOnDoor
+	ld a, $fc
+	ld [wJoyIgnore], a
+	ld hl, wd736
+	set 1, [hl]
+	ld a, $1
+	ld [wSimulatedJoypadStatesIndex], a
+	ld a, D_DOWN
+	ld [wSimulatedJoypadStatesEnd], a
+	xor a
+	ld [wSpriteStateData1 + 2], a
+	call StartSimulatingJoypadStates
+	ret
+.notStandingOnDoor
+	xor a
+	ld [wWastedByteCD3A], a
+	ld [wSimulatedJoypadStatesIndex], a
+	ld [wSimulatedJoypadStatesEnd], a
+	ld hl, wd736
+	res 0, [hl]
+	res 1, [hl]
+	ld hl, wd730
+	res 7, [hl]
+	ret
+
+_EndNPCMovementScript::
+	ld hl, wd730
+	res 7, [hl]
+	ld hl, wd72e
+	res 7, [hl]
+	ld hl, wd736
+	res 0, [hl]
+	res 1, [hl]
+	xor a
+	ld [wNPCMovementScriptSpriteOffset], a
+	ld [wNPCMovementScriptPointerTableNum], a
+	ld [wNPCMovementScriptFunctionNum], a
+	ld [wWastedByteCD3A], a
+	ld [wSimulatedJoypadStatesIndex], a
+	ld [wSimulatedJoypadStatesEnd], a
+	ret
+
+PalletMovementScriptPointerTable::
+	dw PalletMovementScript_OakMoveLeft
+	dw PalletMovementScript_PlayerMoveLeft
+	dw PalletMovementScript_WaitAndWalkToLab
+	dw PalletMovementScript_WalkToLab
+	dw PalletMovementScript_Done
+
+PalletMovementScript_OakMoveLeft:
+	ld a, [wXCoord]
+	sub $a
+	ld [wNumStepsToTake], a
+	jr z, .playerOnLeftTile
+; The player is on the right tile of the northern path out of Pallet Town and
+; Prof. Oak is below.
+; Make Prof. Oak step to the left.
+	ld b, 0
+	ld c, a
+	ld hl, wNPCMovementDirections2
+	ld a, NPC_MOVEMENT_LEFT
+	call FillMemory
+	ld [hl], $ff
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	ld de, wNPCMovementDirections2
+	call MoveSprite
+	ld a, $1
+	ld [wNPCMovementScriptFunctionNum], a
+	jr .done
+; The player is on the left tile of the northern path out of Pallet Town and
+; Prof. Oak is below.
+; Prof. Oak is already where he needs to be.
+.playerOnLeftTile
+	ld a, $3
+	ld [wNPCMovementScriptFunctionNum], a
+.done
+	ld hl, wFlags_D733
+	set 1, [hl]
+	ld a, $fc
+	ld [wJoyIgnore], a
+	ret
+
+PalletMovementScript_PlayerMoveLeft:
+	ld a, [wd730]
+	bit 0, a ; is an NPC being moved by a script?
+	ret nz ; return if Oak is still moving
+	ld a, [wNumStepsToTake]
+	ld [wSimulatedJoypadStatesIndex], a
+	ld [hNPCMovementDirections2Index], a
+	predef ConvertNPCMovementDirectionsToJoypadMasks
+	call StartSimulatingJoypadStates
+	ld a, $2
+	ld [wNPCMovementScriptFunctionNum], a
+	ret
+
+PalletMovementScript_WaitAndWalkToLab:
+	ld a, [wSimulatedJoypadStatesIndex]
+	and a ; is the player done moving left yet?
+	ret nz
+
+PalletMovementScript_WalkToLab:
+	xor a
+	ld [wOverrideSimulatedJoypadStatesMask], a
+	ld a, [wSpriteIndex]
+	swap a
+	ld [wNPCMovementScriptSpriteOffset], a
+	xor a
+	ld [wSpriteStateData2 + $06], a
+	ld hl, wSimulatedJoypadStatesEnd
+	ld de, RLEList_PlayerWalkToLab
+	call DecodeRLEList
+	dec a
+	ld [wSimulatedJoypadStatesIndex], a
+	ld hl, wNPCMovementDirections2
+	ld de, RLEList_ProfOakWalkToLab
+	call DecodeRLEList
+	ld hl, wd72e
+	res 7, [hl]
+	ld hl, wd730
+	set 7, [hl]
+	ld a, $4
+	ld [wNPCMovementScriptFunctionNum], a
+	ret
+
+RLEList_ProfOakWalkToLab:
+	db NPC_MOVEMENT_DOWN, $05
+	db NPC_MOVEMENT_LEFT, $01
+	db NPC_MOVEMENT_DOWN, $05
+	db NPC_MOVEMENT_RIGHT, $03
+	db NPC_MOVEMENT_UP, $01
+	db $E0, $01 ; stand still
+	db $FF
+
+RLEList_PlayerWalkToLab:
+	db D_UP, $02
+	db D_RIGHT, $03
+	db D_DOWN, $05
+	db D_LEFT, $01
+	db D_DOWN, $06
+	db $FF
+
+PalletMovementScript_Done:
+	ld a, [wSimulatedJoypadStatesIndex]
+	and a
+	ret nz
+	ld a, HS_PALLET_TOWN_OAK
+	ld [wMissableObjectIndex], a
+	predef HideObject
+	ld hl, wd730
+	res 7, [hl]
+	ld hl, wd72e
+	res 7, [hl]
+	jp EndNPCMovementScript
+
+PewterMuseumGuyMovementScriptPointerTable::
+	dw PewterMovementScript_WalkToMuseum
+	dw PewterMovementScript_Done
+
+PewterMovementScript_WalkToMuseum:
+	ld a, BANK(Music_MuseumGuy)
+	ld [wAudioROMBank], a
+	ld [wAudioSavedROMBank], a
+	ld a, MUSIC_MUSEUM_GUY
+	ld [wNewSoundID], a
+	call PlaySound
+	ld a, [wSpriteIndex]
+	swap a
+	ld [wNPCMovementScriptSpriteOffset], a
+	call StartSimulatingJoypadStates
+	ld hl, wSimulatedJoypadStatesEnd
+	ld de, RLEList_PewterMuseumPlayer
+	call DecodeRLEList
+	dec a
+	ld [wSimulatedJoypadStatesIndex], a
+	xor a
+	ld [wWhichPewterGuy], a
+	predef PewterGuys
+	ld hl, wNPCMovementDirections2
+	ld de, RLEList_PewterMuseumGuy
+	call DecodeRLEList
+	ld hl, wd72e
+	res 7, [hl]
+	ld a, $1
+	ld [wNPCMovementScriptFunctionNum], a
+	ret
+
+RLEList_PewterMuseumPlayer:
+	db 0, $01
+	db D_UP, $03
+	db D_LEFT, $0D
+	db D_UP, $06
+	db $FF
+
+RLEList_PewterMuseumGuy:
+	db NPC_MOVEMENT_UP, $06
+	db NPC_MOVEMENT_LEFT, $0D
+	db NPC_MOVEMENT_UP, $03
+	db NPC_MOVEMENT_LEFT, $01
+	db $FF
+
+PewterMovementScript_Done:
+	ld a, [wSimulatedJoypadStatesIndex]
+	and a
+	ret nz
+	ld hl, wd730
+	res 7, [hl]
+	ld hl, wd72e
+	res 7, [hl]
+	jp EndNPCMovementScript
+
+PewterGymGuyMovementScriptPointerTable::
+	dw PewterMovementScript_WalkToGym
+	dw PewterMovementScript_Done
+
+PewterMovementScript_WalkToGym:
+	ld a, BANK(Music_MuseumGuy)
+	ld [wAudioROMBank], a
+	ld [wAudioSavedROMBank], a
+	ld a, MUSIC_MUSEUM_GUY
+	ld [wNewSoundID], a
+	call PlaySound
+	ld a, [wSpriteIndex]
+	swap a
+	ld [wNPCMovementScriptSpriteOffset], a
+	xor a
+	ld [wSpriteStateData2 + $06], a
+	ld hl, wSimulatedJoypadStatesEnd
+	ld de, RLEList_PewterGymPlayer
+	call DecodeRLEList
+	dec a
+	ld [wSimulatedJoypadStatesIndex], a
+	ld a, 1
+	ld [wWhichPewterGuy], a
+	predef PewterGuys
+	ld hl, wNPCMovementDirections2
+	ld de, RLEList_PewterGymGuy
+	call DecodeRLEList
+	ld hl, wd72e
+	res 7, [hl]
+	ld hl, wd730
+	set 7, [hl]
+	ld a, $1
+	ld [wNPCMovementScriptFunctionNum], a
+	ret
+
+RLEList_PewterGymPlayer:
+	db 0, $01
+	db D_RIGHT, $02
+	db D_DOWN, $05
+	db D_LEFT, $0B
+	db D_UP, $05
+	db D_LEFT, $0F
+	db $FF
+
+RLEList_PewterGymGuy:
+	db NPC_MOVEMENT_DOWN, $02
+	db NPC_MOVEMENT_LEFT, $0F
+	db NPC_MOVEMENT_UP, $05
+	db NPC_MOVEMENT_LEFT, $0B
+	db NPC_MOVEMENT_DOWN, $05
+	db NPC_MOVEMENT_RIGHT, $03
+	db $FF
+
+FreezeEnemyTrainerSprite::
+	ld a, [wCurMap]
+	cp POKEMON_TOWER_7F
+	ret z ; the Rockets on Pokemon Tower 7F leave after battling, so don't freeze them
+	ld hl, RivalIDs
+	ld a, [wEngagedTrainerClass]
+	ld b, a
+.loop
+	ld a, [hli]
+	cp $ff
+	jr z, .notRival
+	cp b
+	ret z ; the rival leaves after battling, so don't freeze him
+	jr .loop
+.notRival
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	jp SetSpriteMovementBytesToFF
+
+RivalIDs:
+	db OPP_SONY1
+	db OPP_SONY2
+	db OPP_SONY3
+	db $ff
diff --git a/engine/overworld/cable_club_npc.asm b/engine/overworld/cable_club_npc.asm
deleted file mode 100755
index bb0f7680..00000000
--- a/engine/overworld/cable_club_npc.asm
+++ /dev/null
@@ -1,151 +0,0 @@
-CableClubNPC::
-	ld hl, CableClubNPCWelcomeText
-	call PrintText
-	CheckEvent EVENT_GOT_POKEDEX
-	jp nz, .receivedPokedex
-; if the player hasn't received the pokedex
-	ld c, 60
-	call DelayFrames
-	ld hl, CableClubNPCMakingPreparationsText
-	call PrintText
-	jp .didNotConnect
-.receivedPokedex
-	ld a, $1
-	ld [wMenuJoypadPollCount], a
-	ld a, 90
-	ld [wLinkTimeoutCounter], a
-.establishConnectionLoop
-	ld a, [hSerialConnectionStatus]
-	cp USING_INTERNAL_CLOCK
-	jr z, .establishedConnection
-	cp USING_EXTERNAL_CLOCK
-	jr z, .establishedConnection
-	ld a, CONNECTION_NOT_ESTABLISHED
-	ld [hSerialConnectionStatus], a
-	ld a, ESTABLISH_CONNECTION_WITH_EXTERNAL_CLOCK
-	ld [rSB], a
-	xor a
-	ld [hSerialReceiveData], a
-	ld a, START_TRANSFER_EXTERNAL_CLOCK
-	ld [rSC], a
-	ld a, [wLinkTimeoutCounter]
-	dec a
-	ld [wLinkTimeoutCounter], a
-	jr z, .failedToEstablishConnection
-	ld a, ESTABLISH_CONNECTION_WITH_INTERNAL_CLOCK
-	ld [rSB], a
-	ld a, START_TRANSFER_INTERNAL_CLOCK
-	ld [rSC], a
-	call DelayFrame
-	jr .establishConnectionLoop
-.establishedConnection
-	call Serial_SendZeroByte
-	call DelayFrame
-	call Serial_SendZeroByte
-	ld c, 50
-	call DelayFrames
-	ld hl, CableClubNPCPleaseApplyHereHaveToSaveText
-	call PrintText
-	xor a
-	ld [wMenuJoypadPollCount], a
-	call YesNoChoice
-	ld a, $1
-	ld [wMenuJoypadPollCount], a
-	ld a, [wCurrentMenuItem]
-	and a
-	jr nz, .choseNo
-	callab SaveSAVtoSRAM
-	call WaitForSoundToFinish
-	ld a, SFX_SAVE
-	call PlaySoundWaitForCurrent
-	ld hl, CableClubNPCPleaseWaitText
-	call PrintText
-	ld hl, wUnknownSerialCounter
-	ld a, $3
-	ld [hli], a
-	xor a
-	ld [hl], a
-	ld [hSerialReceivedNewData], a
-	ld [wSerialExchangeNybbleSendData], a
-	call Serial_SyncAndExchangeNybble
-	ld hl, wUnknownSerialCounter
-	ld a, [hli]
-	inc a
-	jr nz, .connected
-	ld a, [hl]
-	inc a
-	jr nz, .connected
-	ld b, 10
-.syncLoop
-	call DelayFrame
-	call Serial_SendZeroByte
-	dec b
-	jr nz, .syncLoop
-	call CloseLinkConnection
-	ld hl, CableClubNPCLinkClosedBecauseOfInactivityText
-	call PrintText
-	jr .didNotConnect
-.failedToEstablishConnection
-	ld hl, CableClubNPCAreaReservedFor2FriendsLinkedByCableText
-	call PrintText
-	jr .didNotConnect
-.choseNo
-	call CloseLinkConnection
-	ld hl, CableClubNPCPleaseComeAgainText
-	call PrintText
-.didNotConnect
-	xor a
-	ld hl, wUnknownSerialCounter
-	ld [hli], a
-	ld [hl], a
-	ld hl, wd72e
-	res 6, [hl]
-	xor a
-	ld [wMenuJoypadPollCount], a
-	ret
-.connected
-	xor a
-	ld [hld], a
-	ld [hl], a
-	jpab LinkMenu
-
-CableClubNPCAreaReservedFor2FriendsLinkedByCableText:
-	TX_FAR _CableClubNPCAreaReservedFor2FriendsLinkedByCableText
-	db "@"
-
-CableClubNPCWelcomeText:
-	TX_FAR _CableClubNPCWelcomeText
-	db "@"
-
-CableClubNPCPleaseApplyHereHaveToSaveText:
-	TX_FAR _CableClubNPCPleaseApplyHereHaveToSaveText
-	db "@"
-
-CableClubNPCPleaseWaitText:
-	TX_FAR _CableClubNPCPleaseWaitText
-	TX_DELAY
-	db "@"
-
-CableClubNPCLinkClosedBecauseOfInactivityText:
-	TX_FAR _CableClubNPCLinkClosedBecauseOfInactivityText
-	db "@"
-
-CableClubNPCPleaseComeAgainText:
-	TX_FAR _CableClubNPCPleaseComeAgainText
-	db "@"
-
-CableClubNPCMakingPreparationsText:
-	TX_FAR _CableClubNPCMakingPreparationsText
-	db "@"
-
-CloseLinkConnection:
-	call Delay3
-	ld a, CONNECTION_NOT_ESTABLISHED
-	ld [hSerialConnectionStatus], a
-	ld a, ESTABLISH_CONNECTION_WITH_EXTERNAL_CLOCK
-	ld [rSB], a
-	xor a
-	ld [hSerialReceiveData], a
-	ld a, START_TRANSFER_EXTERNAL_CLOCK
-	ld [rSC], a
-	ret
diff --git a/engine/overworld/card_key.asm b/engine/overworld/card_key.asm
deleted file mode 100755
index c77d5fcd..00000000
--- a/engine/overworld/card_key.asm
+++ /dev/null
@@ -1,112 +0,0 @@
-PrintCardKeyText:
-	ld hl, SilphCoMapList
-	ld a, [wCurMap]
-	ld b, a
-.silphCoMapListLoop
-	ld a, [hli]
-	cp $ff
-	ret z
-	cp b
-	jr nz, .silphCoMapListLoop
-	predef GetTileAndCoordsInFrontOfPlayer
-	ld a, [wTileInFrontOfPlayer]
-	cp $18
-	jr z, .cardKeyDoorInFrontOfPlayer
-	cp $24
-	jr z, .cardKeyDoorInFrontOfPlayer
-	ld b, a
-	ld a, [wCurMap]
-	cp SILPH_CO_11F
-	ret nz
-	ld a, b
-	cp $5e
-	ret nz
-.cardKeyDoorInFrontOfPlayer
-	ld b, CARD_KEY
-	call IsItemInBag
-	jr z, .noCardKey
-	call GetCoordsInFrontOfPlayer
-	push de
-	tx_pre_id CardKeySuccessText
-	ld [hSpriteIndexOrTextID], a
-	call PrintPredefTextID
-	pop de
-	srl d
-	ld a, d
-	ld b, a
-	ld [wCardKeyDoorY], a
-	srl e
-	ld a, e
-	ld c, a
-	ld [wCardKeyDoorX], a
-	ld a, [wCurMap]
-	cp SILPH_CO_11F
-	jr nz, .notSilphCo11F
-	ld a, $3
-	jr .replaceCardKeyDoorTileBlock
-.notSilphCo11F
-	ld a, $e
-.replaceCardKeyDoorTileBlock
-	ld [wNewTileBlockID], a
-	predef ReplaceTileBlock
-	ld hl, wCurrentMapScriptFlags
-	set 5, [hl]
-	ld a, SFX_GO_INSIDE
-	jp PlaySound
-.noCardKey
-	tx_pre_id CardKeyFailText
-	ld [hSpriteIndexOrTextID], a
-	jp PrintPredefTextID
-
-SilphCoMapList:
-	db SILPH_CO_2F
-	db SILPH_CO_3F
-	db SILPH_CO_4F
-	db SILPH_CO_5F
-	db SILPH_CO_6F
-	db SILPH_CO_7F
-	db SILPH_CO_8F
-	db SILPH_CO_9F
-	db SILPH_CO_10F
-	db SILPH_CO_11F
-	db $FF
-
-CardKeySuccessText::
-	TX_FAR _CardKeySuccessText1
-	TX_SFX_ITEM_1
-	TX_FAR _CardKeySuccessText2
-	db "@"
-
-CardKeyFailText::
-	TX_FAR _CardKeyFailText
-	db "@"
-
-; d = Y
-; e = X
-GetCoordsInFrontOfPlayer:
-	ld a, [wYCoord]
-	ld d, a
-	ld a, [wXCoord]
-	ld e, a
-	ld a, [wSpriteStateData1 + 9] ; player's sprite facing direction
-	and a
-	jr nz, .notFacingDown
-; facing down
-	inc d
-	ret
-.notFacingDown
-	cp SPRITE_FACING_UP
-	jr nz, .notFacingUp
-; facing up
-	dec d
-	ret
-.notFacingUp
-	cp SPRITE_FACING_LEFT
-	jr nz, .notFacingLeft
-; facing left
-	dec e
-	ret
-.notFacingLeft
-; facing right
-	inc e
-	ret
diff --git a/engine/overworld/cinnabar_lab.asm b/engine/overworld/cinnabar_lab.asm
deleted file mode 100755
index e642840d..00000000
--- a/engine/overworld/cinnabar_lab.asm
+++ /dev/null
@@ -1,123 +0,0 @@
-GiveFossilToCinnabarLab::
-	ld hl, wd730
-	set 6, [hl]
-	xor a
-	ld [wCurrentMenuItem], a
-	ld a, A_BUTTON | B_BUTTON
-	ld [wMenuWatchedKeys], a
-	ld a, [wFilteredBagItemsCount]
-	dec a
-	ld [wMaxMenuItem], a
-	ld a, 2
-	ld [wTopMenuItemY], a
-	ld a, 1
-	ld [wTopMenuItemX], a
-	ld a, [wFilteredBagItemsCount]
-	dec a
-	ld bc, 2
-	ld hl, 3
-	call AddNTimes
-	dec l
-	ld b, l
-	ld c, $d
-	coord hl, 0, 0
-	call TextBoxBorder
-	call UpdateSprites
-	call PrintFossilsInBag
-	ld hl, wd730
-	res 6, [hl]
-	call HandleMenuInput
-	bit 1, a ; pressed B?
-	jr nz, .cancelledGivingFossil
-	ld hl, wFilteredBagItems
-	ld a, [wCurrentMenuItem]
-	ld d, 0
-	ld e, a
-	add hl, de
-	ld a, [hl]
-	ld [$ffdb], a
-	cp DOME_FOSSIL
-	jr z, .choseDomeFossil
-	cp HELIX_FOSSIL
-	jr z, .choseHelixFossil
-	ld b, AERODACTYL
-	jr .fossilSelected
-.choseHelixFossil
-	ld b, OMANYTE
-	jr .fossilSelected
-.choseDomeFossil
-	ld b, KABUTO
-.fossilSelected
-	ld [wFossilItem], a
-	ld a, b
-	ld [wFossilMon], a
-	call LoadFossilItemAndMonName
-	ld hl, LabFossil_610ae
-	call PrintText
-	call YesNoChoice
-	ld a, [wCurrentMenuItem]
-	and a
-	jr nz, .cancelledGivingFossil
-	ld hl, LabFossil_610b3
-	call PrintText
-	ld a, [wFossilItem]
-	ld [hItemToRemoveID], a
-	callba RemoveItemByID
-	ld hl, LabFossil_610b8
-	call PrintText
-	SetEvents EVENT_GAVE_FOSSIL_TO_LAB, EVENT_LAB_STILL_REVIVING_FOSSIL
-	ret
-.cancelledGivingFossil
-	ld hl, LabFossil_610bd
-	call PrintText
-	ret
-
-LabFossil_610ae:
-	TX_FAR _Lab4Text_610ae
-	db "@"
-
-LabFossil_610b3:
-	TX_FAR _Lab4Text_610b3
-	db "@"
-
-LabFossil_610b8:
-	TX_FAR _Lab4Text_610b8
-	db "@"
-
-LabFossil_610bd:
-	TX_FAR _Lab4Text_610bd
-	db "@"
-
-PrintFossilsInBag:
-; Prints each fossil in the player's bag on a separate line in the menu.
-	ld hl, wFilteredBagItems
-	xor a
-	ld [hItemCounter], a
-.loop
-	ld a, [hli]
-	cp $ff
-	ret z
-	push hl
-	ld [wd11e], a
-	call GetItemName
-	coord hl, 2, 2
-	ld a, [hItemCounter]
-	ld bc, SCREEN_WIDTH * 2
-	call AddNTimes
-	ld de, wcd6d
-	call PlaceString
-	ld hl, hItemCounter
-	inc [hl]
-	pop hl
-	jr .loop
-
-; loads the names of the fossil item and the resulting mon
-LoadFossilItemAndMonName::
-	ld a, [wFossilMon]
-	ld [wd11e], a
-	call GetMonName
-	call CopyStringToCF4B
-	ld a, [wFossilItem]
-	ld [wd11e], a
-	call GetItemName
-	ret
diff --git a/engine/overworld/dust_smoke.asm b/engine/overworld/dust_smoke.asm
new file mode 100755
index 00000000..6c26b712
--- /dev/null
+++ b/engine/overworld/dust_smoke.asm
@@ -0,0 +1,93 @@
+AnimateBoulderDust:
+	ld a, $1
+	ld [wWhichAnimationOffsets], a ; select the boulder dust offsets
+	ld a, [wUpdateSpritesEnabled]
+	push af
+	ld a, $ff
+	ld [wUpdateSpritesEnabled], a
+	ld a, %11100100
+	ld [rOBP1], a
+	call LoadSmokeTileFourTimes
+	callba WriteCutOrBoulderDustAnimationOAMBlock
+	ld c, 8 ; number of steps in animation
+.loop
+	push bc
+	call GetMoveBoulderDustFunctionPointer
+	ld bc, .returnAddress
+	push bc
+	ld c, 4
+	jp hl
+.returnAddress
+	ld a, [rOBP1]
+	xor %01100100
+	ld [rOBP1], a
+	call Delay3
+	pop bc
+	dec c
+	jr nz, .loop
+	pop af
+	ld [wUpdateSpritesEnabled], a
+	jp LoadPlayerSpriteGraphics
+
+GetMoveBoulderDustFunctionPointer:
+	ld a, [wSpriteStateData1 + 9] ; player's sprite facing direction
+	ld hl, MoveBoulderDustFunctionPointerTable
+	ld c, a
+	ld b, $0
+	add hl, bc
+	ld a, [hli]
+	ld [wCoordAdjustmentAmount], a
+	ld a, [hli]
+	ld e, a
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	push hl
+	ld hl, wOAMBuffer + $90
+	ld d, $0
+	add hl, de
+	ld e, l
+	ld d, h
+	pop hl
+	ret
+
+MoveBoulderDustFunctionPointerTable:
+; facing down
+	db $FF,$00
+	dw AdjustOAMBlockYPos
+
+; facing up
+	db $01,$00
+	dw AdjustOAMBlockYPos
+
+; facing left
+	db $01,$01
+	dw AdjustOAMBlockXPos
+
+; facing right
+	db $FF,$01
+	dw AdjustOAMBlockXPos
+
+LoadSmokeTileFourTimes::
+	ld hl, vChars1 + $7c0
+	ld c, $4
+.loop
+	push bc
+	push hl
+	call LoadSmokeTile
+	pop hl
+	ld bc, $10
+	add hl, bc
+	pop bc
+	dec c
+	jr nz, .loop
+	ret
+
+LoadSmokeTile:
+	ld de, SSAnneSmokePuffTile
+	lb bc, BANK(SSAnneSmokePuffTile), (SSAnneSmokePuffTileEnd - SSAnneSmokePuffTile) / $10
+	jp CopyVideoData
+
+SSAnneSmokePuffTile:
+	INCBIN "gfx/overworld/smoke.2bpp"
+SSAnneSmokePuffTileEnd:
diff --git a/engine/overworld/hidden_items.asm b/engine/overworld/hidden_items.asm
deleted file mode 100755
index e40b0ac7..00000000
--- a/engine/overworld/hidden_items.asm
+++ /dev/null
@@ -1,161 +0,0 @@
-HiddenItems:
-	ld hl, HiddenItemCoords
-	call FindHiddenItemOrCoinsIndex
-	ld [wHiddenItemOrCoinsIndex], a
-	ld hl, wObtainedHiddenItemsFlags
-	ld a, [wHiddenItemOrCoinsIndex]
-	ld c, a
-	ld b, FLAG_TEST
-	predef FlagActionPredef
-	ld a, c
-	and a
-	ret nz
-	call EnableAutoTextBoxDrawing
-	ld a, 1
-	ld [wDoNotWaitForButtonPressAfterDisplayingText], a
-	ld a, [wHiddenObjectFunctionArgument] ; item ID
-	ld [wd11e], a
-	call GetItemName
-	tx_pre_jump FoundHiddenItemText
-
-INCLUDE "data/hidden_item_coords.asm"
-
-FoundHiddenItemText::
-	TX_FAR _FoundHiddenItemText
-	TX_ASM
-	ld a, [wHiddenObjectFunctionArgument] ; item ID
-	ld b, a
-	ld c, 1
-	call GiveItem
-	jr nc, .bagFull
-	ld hl, wObtainedHiddenItemsFlags
-	ld a, [wHiddenItemOrCoinsIndex]
-	ld c, a
-	ld b, FLAG_SET
-	predef FlagActionPredef
-	ld a, SFX_GET_ITEM_2
-	call PlaySoundWaitForCurrent
-	call WaitForSoundToFinish
-	jp TextScriptEnd
-.bagFull
-	call WaitForTextScrollButtonPress ; wait for button press
-	xor a
-	ld [wDoNotWaitForButtonPressAfterDisplayingText], a
-	ld hl, HiddenItemBagFullText
-	call PrintText
-	jp TextScriptEnd
-
-HiddenItemBagFullText::
-	TX_FAR _HiddenItemBagFullText
-	db "@"
-
-HiddenCoins:
-	ld b, COIN_CASE
-	predef GetQuantityOfItemInBag
-	ld a, b
-	and a
-	ret z
-	ld hl, HiddenCoinCoords
-	call FindHiddenItemOrCoinsIndex
-	ld [wHiddenItemOrCoinsIndex], a
-	ld hl, wObtainedHiddenCoinsFlags
-	ld a, [wHiddenItemOrCoinsIndex]
-	ld c, a
-	ld b, FLAG_TEST
-	predef FlagActionPredef
-	ld a, c
-	and a
-	ret nz
-	xor a
-	ld [hUnusedCoinsByte], a
-	ld [hCoins], a
-	ld [hCoins + 1], a
-	ld a, [wHiddenObjectFunctionArgument]
-	sub COIN
-	cp 10
-	jr z, .bcd10
-	cp 20
-	jr z, .bcd20
-	cp 40
-	jr z, .bcd20 ; should be bcd40
-	jr .bcd100
-.bcd10
-	ld a, $10
-	ld [hCoins + 1], a
-	jr .bcdDone
-.bcd20
-	ld a, $20
-	ld [hCoins + 1], a
-	jr .bcdDone
-.bcd40 ; due to a typo, this is never used
-	ld a, $40
-	ld [hCoins + 1], a
-	jr .bcdDone
-.bcd100
-	ld a, $1
-	ld [hCoins], a
-.bcdDone
-	ld de, wPlayerCoins + 1
-	ld hl, hCoins + 1
-	ld c, $2
-	predef AddBCDPredef
-	ld hl, wObtainedHiddenCoinsFlags
-	ld a, [wHiddenItemOrCoinsIndex]
-	ld c, a
-	ld b, FLAG_SET
-	predef FlagActionPredef
-	call EnableAutoTextBoxDrawing
-	ld a, [wPlayerCoins]
-	cp $99
-	jr nz, .roomInCoinCase
-	ld a, [wPlayerCoins + 1]
-	cp $99
-	jr nz, .roomInCoinCase
-	tx_pre_id DroppedHiddenCoinsText
-	jr .done
-.roomInCoinCase
-	tx_pre_id FoundHiddenCoinsText
-.done
-	jp PrintPredefTextID
-
-INCLUDE "data/hidden_coins.asm"
-
-FoundHiddenCoinsText::
-	TX_FAR _FoundHiddenCoinsText
-	TX_SFX_ITEM_2
-	db "@"
-
-DroppedHiddenCoinsText::
-	TX_FAR _FoundHiddenCoins2Text
-	TX_SFX_ITEM_2
-	TX_FAR _DroppedHiddenCoinsText
-	db "@"
-
-FindHiddenItemOrCoinsIndex:
-	ld a, [wHiddenObjectY]
-	ld d, a
-	ld a, [wHiddenObjectX]
-	ld e, a
-	ld a, [wCurMap]
-	ld b, a
-	ld c, -1
-.loop
-	inc c
-	ld a, [hli]
-	cp $ff ; end of the list?
-	ret z  ; if so, we're done here
-	cp b
-	jr nz, .next1
-	ld a, [hli]
-	cp d
-	jr nz, .next2
-	ld a, [hli]
-	cp e
-	jr nz, .loop
-	ld a, c
-	ret
-.next1
-	inc hl
-.next2
-	inc hl
-	jr .loop
diff --git a/engine/overworld/item.asm b/engine/overworld/item.asm
deleted file mode 100644
index 9f19100a..00000000
--- a/engine/overworld/item.asm
+++ /dev/null
@@ -1,54 +0,0 @@
-PickUpItem:
-	call EnableAutoTextBoxDrawing
-
-	ld a, [hSpriteIndexOrTextID]
-	ld b, a
-	ld hl, wMissableObjectList
-.missableObjectsListLoop
-	ld a, [hli]
-	cp $ff
-	ret z
-	cp b
-	jr z, .isMissable
-	inc hl
-	jr .missableObjectsListLoop
-
-.isMissable
-	ld a, [hl]
-	ld [$ffdb], a
-
-	ld hl, wMapSpriteExtraData
-	ld a, [hSpriteIndexOrTextID]
-	dec a
-	add a
-	ld d, 0
-	ld e, a
-	add hl, de
-	ld a, [hl]
-	ld b, a ; item
-	ld c, 1 ; quantity
-	call GiveItem
-	jr nc, .BagFull
-
-	ld a, [$ffdb]
-	ld [wMissableObjectIndex], a
-	predef HideObject
-	ld a, 1
-	ld [wDoNotWaitForButtonPressAfterDisplayingText], a
-	ld hl, FoundItemText
-	jr .print
-
-.BagFull
-	ld hl, NoMoreRoomForItemText
-.print
-	call PrintText
-	ret
-
-FoundItemText:
-	TX_FAR _FoundItemText
-	TX_SFX_ITEM_1
-	db "@"
-
-NoMoreRoomForItemText:
-	TX_FAR _NoMoreRoomForItemText
-	db "@"
diff --git a/engine/overworld/map_sprite_functions1.asm b/engine/overworld/map_sprite_functions1.asm
deleted file mode 100644
index 0e6b2d06..00000000
--- a/engine/overworld/map_sprite_functions1.asm
+++ /dev/null
@@ -1,356 +0,0 @@
-_UpdateSprites::
-	ld h, $c1
-	inc h
-	ld a, $e    ; wSpriteStateData2 + $0e
-.spriteLoop
-	ld l, a
-	sub $e
-	ld c, a
-	ld [H_CURRENTSPRITEOFFSET], a
-	ld a, [hl]
-	and a
-	jr z, .skipSprite   ; tests $c2Xe
-	push hl
-	push de
-	push bc
-	call .updateCurrentSprite
-	pop bc
-	pop de
-	pop hl
-.skipSprite
-	ld a, l
-	add $10             ; move to next sprite
-	cp $e               ; test for overflow (back at $0e)
-	jr nz, .spriteLoop
-	ret
-.updateCurrentSprite
-	cp $1
-	jp nz, UpdateNonPlayerSprite
-	jp UpdatePlayerSprite
-
-UpdateNonPlayerSprite:
-	dec a
-	swap a
-	ld [$ff93], a  ; $10 * sprite#
-	ld a, [wNPCMovementScriptSpriteOffset] ; some sprite offset?
-	ld b, a
-	ld a, [H_CURRENTSPRITEOFFSET]
-	cp b
-	jr nz, .unequal
-	jp DoScriptedNPCMovement
-.unequal
-	jp UpdateNPCSprite
-
-; This detects if the current sprite (whose offset is at H_CURRENTSPRITEOFFSET)
-; is going to collide with another sprite by looping over the other sprites.
-; The current sprite's offset will be labelled with i (e.g. $c1i0).
-; The loop sprite's offset will labelled with j (e.g. $c1j0).
-;
-; Note that the Y coordinate of the sprite (in [$c1k4]) is one of the following
-; 9 values when the sprite is aligned with the grid: $fc, $0c, $1c, $2c, ..., $7c.
-; The reason that 4 is added below to the coordinate is to make it align with a
-; multiple of $10 to make comparisons easier.
-DetectCollisionBetweenSprites:
-	nop
-
-	ld h, wSpriteStateData1 / $100
-	ld a, [H_CURRENTSPRITEOFFSET]
-	add wSpriteStateData1 % $100
-	ld l, a
-
-	ld a, [hl] ; a = [$c1i0] (picture) (0 if slot is unused)
-	and a ; is this sprite slot slot used?
-	ret z ; return if not used
-
-	ld a, l
-	add 3
-	ld l, a
-
-	ld a, [hli] ; a = [$c1i3] (delta Y) (-1, 0, or 1)
-	call SetSpriteCollisionValues
-
-	ld a, [hli] ; a = [$C1i4] (Y screen coordinate)
-	add 4 ; align with multiple of $10
-
-; The effect of the following 3 lines is to
-; add 7 to a if moving south or
-; subtract 7 from a if moving north.
-	add b
-	and $f0
-	or c
-
-	ld [$ff90], a ; store Y coordinate adjusted for direction of movement
-
-	ld a, [hli] ; a = [$c1i5] (delta X) (-1, 0, or 1)
-	call SetSpriteCollisionValues
-	ld a, [hl] ; a = [$C1i6] (X screen coordinate)
-
-; The effect of the following 3 lines is to
-; add 7 to a if moving east or
-; subtract 7 from a if moving west.
-	add b
-	and $f0
-	or c
-
-	ld [$ff91], a ; store X coordinate adjusted for direction of movement
-
-	ld a, l
-	add 7
-	ld l, a
-
-	xor a
-	ld [hld], a ; zero [$c1id] XXX what's [$c1id] for?
-	ld [hld], a ; zero [$c1ic] (directions in which collisions occurred)
-
-	ld a, [$ff91]
-	ld [hld], a ; [$c1ib] = adjusted X coordinate
-	ld a, [$ff90]
-	ld [hl], a ; [$c1ia] = adjusted Y coordinate
-
-	xor a ; zero the loop counter
-
-.loop
-	ld [$ff8f], a ; store loop counter
-	swap a
-	ld e, a
-	ld a, [H_CURRENTSPRITEOFFSET]
-	cp e ; does the loop sprite match the current sprite?
-	jp z, .next ; go to the next sprite if they match
-
-	ld d, h
-	ld a, [de] ; a = [$c1j0] (picture) (0 if slot is unused)
-	and a ; is this sprite slot slot used?
-	jp z, .next ; go the next sprite if not used
-
-	inc e
-	inc e
-	ld a, [de] ; a = [$c1j2] ($ff means the sprite is offscreen)
-	inc a
-	jp z, .next ; go the next sprite if offscreen
-
-	ld a, [H_CURRENTSPRITEOFFSET]
-	add 10
-	ld l, a
-
-	inc e
-	ld a, [de] ; a = [$c1j3] (delta Y)
-	call SetSpriteCollisionValues
-
-	inc e
-	ld a, [de] ; a = [$C1j4] (Y screen coordinate)
-	add 4 ; align with multiple of $10
-
-; The effect of the following 3 lines is to
-; add 7 to a if moving south or
-; subtract 7 from a if moving north.
-	add b
-	and $f0
-	or c
-
-	sub [hl] ; subtract the adjusted Y coordinate of sprite i ([$c1ia]) from that of sprite j
-
-; calculate the absolute value of the difference to get the distance
-	jr nc, .noCarry1
-	cpl
-	inc a
-.noCarry1
-	ld [$ff90], a ; store the distance between the two sprites' adjusted Y values
-
-; Use the carry flag set by the above subtraction to determine which sprite's
-; Y coordinate is larger. This information is used later to set [$c1ic],
-; which stores which direction the collision occurred in.
-; The following 5 lines set the lowest 2 bits of c, which are later shifted left by 2.
-; If sprite i's Y is larger, set lowest 2 bits of c to 10.
-; If sprite j's Y is larger or both are equal, set lowest 2 bits of c to 01.
-	push af
-	rl c
-	pop af
-	ccf
-	rl c
-
-; If sprite i's delta Y is 0, then b = 7, else b = 9.
-	ld b, 7
-	ld a, [hl] ; a = [$c1ia] (adjusted Y coordinate)
-	and $f
-	jr z, .next1
-	ld b, 9
-
-.next1
-	ld a, [$ff90] ; a = distance between adjusted Y coordinates
-	sub b
-	ld [$ff92], a ; store distance adjusted using sprite i's direction
-	ld a, b
-	ld [$ff90], a ; store 7 or 9 depending on sprite i's delta Y
-	jr c, .checkXDistance
-
-; If sprite j's delta Y is 0, then b = 7, else b = 9.
-	ld b, 7
-	dec e
-	ld a, [de] ; a = [$c1j3] (delta Y)
-	inc e
-	and a
-	jr z, .next2
-	ld b, 9
-
-.next2
-	ld a, [$ff92] ; a = distance adjusted using sprite i's direction
-	sub b ; adjust distance using sprite j's direction
-	jr z, .checkXDistance
-	jr nc, .next ; go to next sprite if distance is still positive after both adjustments
-
-.checkXDistance
-	inc e
-	inc l
-	ld a, [de] ; a = [$c1j5] (delta X)
-
-	push bc
-
-	call SetSpriteCollisionValues
-	inc e
-	ld a, [de] ; a = [$c1j6] (X screen coordinate)
-
-; The effect of the following 3 lines is to
-; add 7 to a if moving east or
-; subtract 7 from a if moving west.
-	add b
-	and $f0
-	or c
-
-	pop bc
-
-	sub [hl] ; subtract the adjusted X coordinate of sprite i ([$c1ib]) from that of sprite j
-
-; calculate the absolute value of the difference to get the distance
-	jr nc, .noCarry2
-	cpl
-	inc a
-.noCarry2
-	ld [$ff91], a ; store the distance between the two sprites' adjusted X values
-
-; Use the carry flag set by the above subtraction to determine which sprite's
-; X coordinate is larger. This information is used later to set [$c1ic],
-; which stores which direction the collision occurred in.
-; The following 5 lines set the lowest 2 bits of c.
-; If sprite i's X is larger, set lowest 2 bits of c to 10.
-; If sprite j's X is larger or both are equal, set lowest 2 bits of c to 01.
-	push af
-	rl c
-	pop af
-	ccf
-	rl c
-
-; If sprite i's delta X is 0, then b = 7, else b = 9.
-	ld b, 7
-	ld a, [hl] ; a = [$c1ib] (adjusted X coordinate)
-	and $f
-	jr z, .next3
-	ld b, 9
-
-.next3
-	ld a, [$ff91] ; a = distance between adjusted X coordinates
-	sub b
-	ld [$ff92], a ; store distance adjusted using sprite i's direction
-	ld a, b
-	ld [$ff91], a ; store 7 or 9 depending on sprite i's delta X
-	jr c, .collision
-
-; If sprite j's delta X is 0, then b = 7, else b = 9.
-	ld b, 7
-	dec e
-	ld a, [de] ; a = [$c1j5] (delta X)
-	inc e
-	and a
-	jr z, .next4
-	ld b, 9
-
-.next4
-	ld a, [$ff92] ; a = distance adjusted using sprite i's direction
-	sub b ; adjust distance using sprite j's direction
-	jr z, .collision
-	jr nc, .next ; go to next sprite if distance is still positive after both adjustments
-
-.collision
-	ld a, [$ff91] ; a = 7 or 9 depending on sprite i's delta X
-	ld b, a
-	ld a, [$ff90] ; a = 7 or 9 depending on sprite i's delta Y
-	inc l
-
-; If delta X isn't 0 and delta Y is 0, then b = %0011, else b = %1100.
-; (note that normally if delta X isn't 0, then delta Y must be 0 and vice versa)
-	cp b
-	jr c, .next5
-	ld b, %1100
-	jr .next6
-.next5
-	ld b, %0011
-
-.next6
-	ld a, c ; c has 2 bits set (one of bits 0-1 is set for the X axis and one of bits 2-3 for the Y axis)
-	and b ; we select either the bit in bits 0-1 or bits 2-3 based on the calculation immediately above
-	or [hl] ; or with existing collision direction bits in [$c1ic]
-	ld [hl], a ; store new value
-	ld a, c ; useless code because a is overwritten before being used again
-
-; set bit in [$c1ie] or [$c1if] to indicate which sprite the collision occurred with
-	inc l
-	inc l
-	ld a, [$ff8f] ; a = loop counter
-	ld de, SpriteCollisionBitTable
-	add a
-	add e
-	ld e, a
-	jr nc, .noCarry3
-	inc d
-.noCarry3
-	ld a, [de]
-	or [hl]
-	ld [hli], a
-	inc de
-	ld a, [de]
-	or [hl]
-	ld [hl], a
-
-.next
-	ld a, [$ff8f] ; a = loop counter
-	inc a
-	cp $10
-	jp nz, .loop
-	ret
-
-; takes delta X or delta Y in a
-; b = delta X/Y
-; c = 0 if delta X/Y is 0
-; c = 7 if delta X/Y is 1
-; c = 9 if delta X/Y is -1
-SetSpriteCollisionValues:
-	and a
-	ld b, 0
-	ld c, 0
-	jr z, .done
-	ld c, 9
-	cp -1
-	jr z, .ok
-	ld c, 7
-	ld a, 0
-.ok
-	ld b, a
-.done
-	ret
-
-SpriteCollisionBitTable:
-	db %00000000,%00000001
-	db %00000000,%00000010
-	db %00000000,%00000100
-	db %00000000,%00001000
-	db %00000000,%00010000
-	db %00000000,%00100000
-	db %00000000,%01000000
-	db %00000000,%10000000
-	db %00000001,%00000000
-	db %00000010,%00000000
-	db %00000100,%00000000
-	db %00001000,%00000000
-	db %00010000,%00000000
-	db %00100000,%00000000
-	db %01000000,%00000000
-	db %10000000,%00000000
diff --git a/engine/overworld/npc_movement.asm b/engine/overworld/npc_movement.asm
deleted file mode 100755
index e478c9ad..00000000
--- a/engine/overworld/npc_movement.asm
+++ /dev/null
@@ -1,292 +0,0 @@
-PlayerStepOutFromDoor::
-	ld hl, wd730
-	res 1, [hl]
-	call IsPlayerStandingOnDoorTile
-	jr nc, .notStandingOnDoor
-	ld a, $fc
-	ld [wJoyIgnore], a
-	ld hl, wd736
-	set 1, [hl]
-	ld a, $1
-	ld [wSimulatedJoypadStatesIndex], a
-	ld a, D_DOWN
-	ld [wSimulatedJoypadStatesEnd], a
-	xor a
-	ld [wSpriteStateData1 + 2], a
-	call StartSimulatingJoypadStates
-	ret
-.notStandingOnDoor
-	xor a
-	ld [wWastedByteCD3A], a
-	ld [wSimulatedJoypadStatesIndex], a
-	ld [wSimulatedJoypadStatesEnd], a
-	ld hl, wd736
-	res 0, [hl]
-	res 1, [hl]
-	ld hl, wd730
-	res 7, [hl]
-	ret
-
-_EndNPCMovementScript::
-	ld hl, wd730
-	res 7, [hl]
-	ld hl, wd72e
-	res 7, [hl]
-	ld hl, wd736
-	res 0, [hl]
-	res 1, [hl]
-	xor a
-	ld [wNPCMovementScriptSpriteOffset], a
-	ld [wNPCMovementScriptPointerTableNum], a
-	ld [wNPCMovementScriptFunctionNum], a
-	ld [wWastedByteCD3A], a
-	ld [wSimulatedJoypadStatesIndex], a
-	ld [wSimulatedJoypadStatesEnd], a
-	ret
-
-PalletMovementScriptPointerTable::
-	dw PalletMovementScript_OakMoveLeft
-	dw PalletMovementScript_PlayerMoveLeft
-	dw PalletMovementScript_WaitAndWalkToLab
-	dw PalletMovementScript_WalkToLab
-	dw PalletMovementScript_Done
-
-PalletMovementScript_OakMoveLeft:
-	ld a, [wXCoord]
-	sub $a
-	ld [wNumStepsToTake], a
-	jr z, .playerOnLeftTile
-; The player is on the right tile of the northern path out of Pallet Town and
-; Prof. Oak is below.
-; Make Prof. Oak step to the left.
-	ld b, 0
-	ld c, a
-	ld hl, wNPCMovementDirections2
-	ld a, NPC_MOVEMENT_LEFT
-	call FillMemory
-	ld [hl], $ff
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	ld de, wNPCMovementDirections2
-	call MoveSprite
-	ld a, $1
-	ld [wNPCMovementScriptFunctionNum], a
-	jr .done
-; The player is on the left tile of the northern path out of Pallet Town and
-; Prof. Oak is below.
-; Prof. Oak is already where he needs to be.
-.playerOnLeftTile
-	ld a, $3
-	ld [wNPCMovementScriptFunctionNum], a
-.done
-	ld hl, wFlags_D733
-	set 1, [hl]
-	ld a, $fc
-	ld [wJoyIgnore], a
-	ret
-
-PalletMovementScript_PlayerMoveLeft:
-	ld a, [wd730]
-	bit 0, a ; is an NPC being moved by a script?
-	ret nz ; return if Oak is still moving
-	ld a, [wNumStepsToTake]
-	ld [wSimulatedJoypadStatesIndex], a
-	ld [hNPCMovementDirections2Index], a
-	predef ConvertNPCMovementDirectionsToJoypadMasks
-	call StartSimulatingJoypadStates
-	ld a, $2
-	ld [wNPCMovementScriptFunctionNum], a
-	ret
-
-PalletMovementScript_WaitAndWalkToLab:
-	ld a, [wSimulatedJoypadStatesIndex]
-	and a ; is the player done moving left yet?
-	ret nz
-
-PalletMovementScript_WalkToLab:
-	xor a
-	ld [wOverrideSimulatedJoypadStatesMask], a
-	ld a, [wSpriteIndex]
-	swap a
-	ld [wNPCMovementScriptSpriteOffset], a
-	xor a
-	ld [wSpriteStateData2 + $06], a
-	ld hl, wSimulatedJoypadStatesEnd
-	ld de, RLEList_PlayerWalkToLab
-	call DecodeRLEList
-	dec a
-	ld [wSimulatedJoypadStatesIndex], a
-	ld hl, wNPCMovementDirections2
-	ld de, RLEList_ProfOakWalkToLab
-	call DecodeRLEList
-	ld hl, wd72e
-	res 7, [hl]
-	ld hl, wd730
-	set 7, [hl]
-	ld a, $4
-	ld [wNPCMovementScriptFunctionNum], a
-	ret
-
-RLEList_ProfOakWalkToLab:
-	db NPC_MOVEMENT_DOWN, $05
-	db NPC_MOVEMENT_LEFT, $01
-	db NPC_MOVEMENT_DOWN, $05
-	db NPC_MOVEMENT_RIGHT, $03
-	db NPC_MOVEMENT_UP, $01
-	db $E0, $01 ; stand still
-	db $FF
-
-RLEList_PlayerWalkToLab:
-	db D_UP, $02
-	db D_RIGHT, $03
-	db D_DOWN, $05
-	db D_LEFT, $01
-	db D_DOWN, $06
-	db $FF
-
-PalletMovementScript_Done:
-	ld a, [wSimulatedJoypadStatesIndex]
-	and a
-	ret nz
-	ld a, HS_PALLET_TOWN_OAK
-	ld [wMissableObjectIndex], a
-	predef HideObject
-	ld hl, wd730
-	res 7, [hl]
-	ld hl, wd72e
-	res 7, [hl]
-	jp EndNPCMovementScript
-
-PewterMuseumGuyMovementScriptPointerTable::
-	dw PewterMovementScript_WalkToMuseum
-	dw PewterMovementScript_Done
-
-PewterMovementScript_WalkToMuseum:
-	ld a, BANK(Music_MuseumGuy)
-	ld [wAudioROMBank], a
-	ld [wAudioSavedROMBank], a
-	ld a, MUSIC_MUSEUM_GUY
-	ld [wNewSoundID], a
-	call PlaySound
-	ld a, [wSpriteIndex]
-	swap a
-	ld [wNPCMovementScriptSpriteOffset], a
-	call StartSimulatingJoypadStates
-	ld hl, wSimulatedJoypadStatesEnd
-	ld de, RLEList_PewterMuseumPlayer
-	call DecodeRLEList
-	dec a
-	ld [wSimulatedJoypadStatesIndex], a
-	xor a
-	ld [wWhichPewterGuy], a
-	predef PewterGuys
-	ld hl, wNPCMovementDirections2
-	ld de, RLEList_PewterMuseumGuy
-	call DecodeRLEList
-	ld hl, wd72e
-	res 7, [hl]
-	ld a, $1
-	ld [wNPCMovementScriptFunctionNum], a
-	ret
-
-RLEList_PewterMuseumPlayer:
-	db 0, $01
-	db D_UP, $03
-	db D_LEFT, $0D
-	db D_UP, $06
-	db $FF
-
-RLEList_PewterMuseumGuy:
-	db NPC_MOVEMENT_UP, $06
-	db NPC_MOVEMENT_LEFT, $0D
-	db NPC_MOVEMENT_UP, $03
-	db NPC_MOVEMENT_LEFT, $01
-	db $FF
-
-PewterMovementScript_Done:
-	ld a, [wSimulatedJoypadStatesIndex]
-	and a
-	ret nz
-	ld hl, wd730
-	res 7, [hl]
-	ld hl, wd72e
-	res 7, [hl]
-	jp EndNPCMovementScript
-
-PewterGymGuyMovementScriptPointerTable::
-	dw PewterMovementScript_WalkToGym
-	dw PewterMovementScript_Done
-
-PewterMovementScript_WalkToGym:
-	ld a, BANK(Music_MuseumGuy)
-	ld [wAudioROMBank], a
-	ld [wAudioSavedROMBank], a
-	ld a, MUSIC_MUSEUM_GUY
-	ld [wNewSoundID], a
-	call PlaySound
-	ld a, [wSpriteIndex]
-	swap a
-	ld [wNPCMovementScriptSpriteOffset], a
-	xor a
-	ld [wSpriteStateData2 + $06], a
-	ld hl, wSimulatedJoypadStatesEnd
-	ld de, RLEList_PewterGymPlayer
-	call DecodeRLEList
-	dec a
-	ld [wSimulatedJoypadStatesIndex], a
-	ld a, 1
-	ld [wWhichPewterGuy], a
-	predef PewterGuys
-	ld hl, wNPCMovementDirections2
-	ld de, RLEList_PewterGymGuy
-	call DecodeRLEList
-	ld hl, wd72e
-	res 7, [hl]
-	ld hl, wd730
-	set 7, [hl]
-	ld a, $1
-	ld [wNPCMovementScriptFunctionNum], a
-	ret
-
-RLEList_PewterGymPlayer:
-	db 0, $01
-	db D_RIGHT, $02
-	db D_DOWN, $05
-	db D_LEFT, $0B
-	db D_UP, $05
-	db D_LEFT, $0F
-	db $FF
-
-RLEList_PewterGymGuy:
-	db NPC_MOVEMENT_DOWN, $02
-	db NPC_MOVEMENT_LEFT, $0F
-	db NPC_MOVEMENT_UP, $05
-	db NPC_MOVEMENT_LEFT, $0B
-	db NPC_MOVEMENT_DOWN, $05
-	db NPC_MOVEMENT_RIGHT, $03
-	db $FF
-
-FreezeEnemyTrainerSprite::
-	ld a, [wCurMap]
-	cp POKEMON_TOWER_7F
-	ret z ; the Rockets on Pokemon Tower 7F leave after battling, so don't freeze them
-	ld hl, RivalIDs
-	ld a, [wEngagedTrainerClass]
-	ld b, a
-.loop
-	ld a, [hli]
-	cp $ff
-	jr z, .notRival
-	cp b
-	ret z ; the rival leaves after battling, so don't freeze him
-	jr .loop
-.notRival
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	jp SetSpriteMovementBytesToFF
-
-RivalIDs:
-	db OPP_SONY1
-	db OPP_SONY2
-	db OPP_SONY3
-	db $ff
diff --git a/engine/overworld/oaks_aide.asm b/engine/overworld/oaks_aide.asm
deleted file mode 100755
index f5068fda..00000000
--- a/engine/overworld/oaks_aide.asm
+++ /dev/null
@@ -1,71 +0,0 @@
-OaksAideScript:
-	ld hl, OaksAideHiText
-	call PrintText
-	call YesNoChoice
-	ld a, [wCurrentMenuItem]
-	and a
-	jr nz, .choseNo
-	ld hl, wPokedexOwned
-	ld b, wPokedexOwnedEnd - wPokedexOwned
-	call CountSetBits
-	ld a, [wNumSetBits]
-	ld [hOaksAideNumMonsOwned], a
-	ld b, a
-	ld a, [hOaksAideRequirement]
-	cp b
-	jr z, .giveItem
-	jr nc, .notEnoughOwnedMons
-.giveItem
-	ld hl, OaksAideHereYouGoText
-	call PrintText
-	ld a, [hOaksAideRewardItem]
-	ld b, a
-	ld c, 1
-	call GiveItem
-	jr nc, .bagFull
-	ld hl, OaksAideGotItemText
-	call PrintText
-	ld a, $1
-	jr .done
-.bagFull
-	ld hl, OaksAideNoRoomText
-	call PrintText
-	xor a
-	jr .done
-.notEnoughOwnedMons
-	ld hl, OaksAideUhOhText
-	call PrintText
-	ld a, $80
-	jr .done
-.choseNo
-	ld hl, OaksAideComeBackText
-	call PrintText
-	ld a, $ff
-.done
-	ld [hOaksAideResult], a
-	ret
-
-OaksAideHiText:
-	TX_FAR _OaksAideHiText
-	db "@"
-
-OaksAideUhOhText:
-	TX_FAR _OaksAideUhOhText
-	db "@"
-
-OaksAideComeBackText:
-	TX_FAR _OaksAideComeBackText
-	db "@"
-
-OaksAideHereYouGoText:
-	TX_FAR _OaksAideHereYouGoText
-	db "@"
-
-OaksAideGotItemText:
-	TX_FAR _OaksAideGotItemText
-	TX_SFX_ITEM_1
-	db "@"
-
-OaksAideNoRoomText:
-	TX_FAR _OaksAideNoRoomText
-	db "@"
diff --git a/engine/overworld/oam.asm b/engine/overworld/oam.asm
deleted file mode 100644
index 68128413..00000000
--- a/engine/overworld/oam.asm
+++ /dev/null
@@ -1,189 +0,0 @@
-PrepareOAMData::
-; Determine OAM data for currently visible
-; sprites and write it to wOAMBuffer.
-
-	ld a, [wUpdateSpritesEnabled]
-	dec a
-	jr z, .updateEnabled
-
-	cp -1
-	ret nz
-	ld [wUpdateSpritesEnabled], a
-	jp HideSprites
-
-.updateEnabled
-	xor a
-	ld [hOAMBufferOffset], a
-
-.spriteLoop
-	ld [hSpriteOffset2], a
-
-	ld d, wSpriteStateData1 / $100
-	ld a, [hSpriteOffset2]
-	ld e, a
-	ld a, [de] ; c1x0
-	and a
-	jp z, .nextSprite
-
-	inc e
-	inc e
-	ld a, [de] ; c1x2 (facing/anim)
-	ld [wd5cd], a
-	cp $ff ; off-screen (don't draw)
-	jr nz, .visible
-
-	call GetSpriteScreenXY
-	jr .nextSprite
-
-.visible
-	cp $a0 ; is the sprite unchanging like an item ball or boulder?
-	jr c, .usefacing
-
-; unchanging
-	and $f
-	add $10 ; skip to the second half of the table which doesn't account for facing direction
-	jr .next
-
-.usefacing
-	and $f
-
-.next
-	ld l, a
-
-; get sprite priority
-	push de
-	inc d
-	ld a, e
-	add $5
-	ld e, a
-	ld a, [de] ; c2x7
-	and $80
-	ld [hSpritePriority], a ; temp store sprite priority
-	pop de
-
-; read the entry from the table
-	ld h, 0
-	ld bc, SpriteFacingAndAnimationTable
-	add hl, hl
-	add hl, hl
-	add hl, bc
-	ld a, [hli]
-	ld c, a
-	ld a, [hli]
-	ld b, a
-	ld a, [hli]
-	ld h, [hl]
-	ld l, a
-
-	call GetSpriteScreenXY
-
-	ld a, [hOAMBufferOffset]
-	ld e, a
-	ld d, wOAMBuffer / $100
-
-.tileLoop
-	ld a, [hSpriteScreenY]   ; temp for sprite Y position
-	add $10                  ; Y=16 is top of screen (Y=0 is invisible)
-	add [hl]                 ; add Y offset from table
-	ld [de], a               ; write new sprite OAM Y position
-	inc hl
-	ld a, [hSpriteScreenX]   ; temp for sprite X position
-	add $8                   ; X=8 is left of screen (X=0 is invisible)
-	add [hl]                 ; add X offset from table
-	inc e
-	ld [de], a               ; write new sprite OAM X position
-	inc e
-	ld a, [bc]               ; read pattern number offset (accommodates orientation (offset 0,4 or 8) and animation (offset 0 or $80))
-	inc bc
-	push bc
-	ld b, a
-
-	ld a, [wd5cd]            ; temp copy of c1x2
-	swap a                   ; high nybble determines sprite used (0 is always player sprite, next are some npcs)
-	and $f
-
-	; Sprites $a and $b have one face (and therefore 4 tiles instead of 12).
-	; As a result, sprite $b's tile offset is less than normal.
-	cp $b
-	jr nz, .notFourTileSprite
-	ld a, $a * 12 + 4
-	jr .next2
-
-.notFourTileSprite
-	; a *= 12
-	sla a
-	sla a
-	ld c, a
-	sla a
-	add c
-
-.next2
-	add b ; add the tile offset from the table (based on frame and facing direction)
-	pop bc
-	ld [de], a ; tile id
-	inc hl
-	inc e
-	ld a, [hl]
-	bit 1, a ; is the tile allowed to set the sprite priority bit?
-	jr z, .skipPriority
-	ld a, [hSpritePriority]
-	or [hl]
-.skipPriority
-	inc hl
-	ld [de], a
-	inc e
-	bit 0, a ; OAMFLAG_ENDOFDATA
-	jr z, .tileLoop
-
-	ld a, e
-	ld [hOAMBufferOffset], a
-
-.nextSprite
-	ld a, [hSpriteOffset2]
-	add $10
-	cp $100 % $100
-	jp nz, .spriteLoop
-
-	; Clear unused OAM.
-	ld a, [hOAMBufferOffset]
-	ld l, a
-	ld h, wOAMBuffer / $100
-	ld de, $4
-	ld b, $a0
-	ld a, [wd736]
-	bit 6, a ; jumping down ledge or fishing animation?
-	ld a, $a0
-	jr z, .clear
-
-; Don't clear the last 4 entries because they are used for the shadow in the
-; jumping down ledge animation and the rod in the fishing animation.
-	ld a, $90
-
-.clear
-	cp l
-	ret z
-	ld [hl], b
-	add hl, de
-	jr .clear
-
-GetSpriteScreenXY:
-	inc e
-	inc e
-	ld a, [de] ; c1x4
-	ld [hSpriteScreenY], a
-	inc e
-	inc e
-	ld a, [de] ; c1x6
-	ld [hSpriteScreenX], a
-	ld a, 4
-	add e
-	ld e, a
-	ld a, [hSpriteScreenY]
-	add 4
-	and $f0
-	ld [de], a ; c1xa (y)
-	inc e
-	ld a, [hSpriteScreenX]
-	and $f0
-	ld [de], a  ; c1xb (x)
-	ret
diff --git a/engine/overworld/pathfinding.asm b/engine/overworld/pathfinding.asm
new file mode 100644
index 00000000..ba052d38
--- /dev/null
+++ b/engine/overworld/pathfinding.asm
@@ -0,0 +1,201 @@
+FindPathToPlayer:
+	xor a
+	ld hl, hFindPathNumSteps
+	ld [hli], a ; hFindPathNumSteps
+	ld [hli], a ; hFindPathFlags
+	ld [hli], a ; hFindPathYProgress
+	ld [hl], a  ; hFindPathXProgress
+	ld hl, wNPCMovementDirections2
+	ld de, $0
+.loop
+	ld a, [hFindPathYProgress]
+	ld b, a
+	ld a, [hNPCPlayerYDistance] ; Y distance in steps
+	call CalcDifference
+	ld d, a
+	and a
+	jr nz, .asm_f8da
+	ld a, [hFindPathFlags]
+	set 0, a ; current end of path matches the player's Y coordinate
+	ld [hFindPathFlags], a
+.asm_f8da
+	ld a, [hFindPathXProgress]
+	ld b, a
+	ld a, [hNPCPlayerXDistance] ; X distance in steps
+	call CalcDifference
+	ld e, a
+	and a
+	jr nz, .asm_f8ec
+	ld a, [hFindPathFlags]
+	set 1, a ; current end of path matches the player's X coordinate
+	ld [hFindPathFlags], a
+.asm_f8ec
+	ld a, [hFindPathFlags]
+	cp $3 ; has the end of the path reached the player's position?
+	jr z, .done
+; Compare whether the X distance between the player and the current of the path
+; is greater or if the Y distance is. Then, try to reduce whichever is greater.
+	ld a, e
+	cp d
+	jr c, .yDistanceGreater
+; x distance is greater
+	ld a, [hNPCPlayerRelativePosFlags]
+	bit 1, a
+	jr nz, .playerIsLeftOfNPC
+	ld d, NPC_MOVEMENT_RIGHT
+	jr .next1
+.playerIsLeftOfNPC
+	ld d, NPC_MOVEMENT_LEFT
+.next1
+	ld a, [hFindPathXProgress]
+	add 1
+	ld [hFindPathXProgress], a
+	jr .storeDirection
+.yDistanceGreater
+	ld a, [hNPCPlayerRelativePosFlags]
+	bit 0, a
+	jr nz, .playerIsAboveNPC
+	ld d, NPC_MOVEMENT_DOWN
+	jr .next2
+.playerIsAboveNPC
+	ld d, NPC_MOVEMENT_UP
+.next2
+	ld a, [hFindPathYProgress]
+	add 1
+	ld [hFindPathYProgress], a
+.storeDirection
+	ld a, d
+	ld [hli], a
+	ld a, [hFindPathNumSteps]
+	inc a
+	ld [hFindPathNumSteps], a
+	jp .loop
+.done
+	ld [hl], $ff
+	ret
+
+CalcPositionOfPlayerRelativeToNPC:
+	xor a
+	ld [hNPCPlayerRelativePosFlags], a
+	ld a, [wSpriteStateData1 + 4] ; player's sprite screen Y position in pixels
+	ld d, a
+	ld a, [wSpriteStateData1 + 6] ; player's sprite screen X position in pixels
+	ld e, a
+	ld hl, wSpriteStateData1
+	ld a, [hNPCSpriteOffset]
+	add l
+	add $4
+	ld l, a
+	jr nc, .noCarry
+	inc h
+.noCarry
+	ld a, d
+	ld b, a
+	ld a, [hli] ; NPC sprite screen Y position in pixels
+	call CalcDifference
+	jr nc, .NPCSouthOfOrAlignedWithPlayer
+.NPCNorthOfPlayer
+	push hl
+	ld hl, hNPCPlayerRelativePosFlags
+	bit 0, [hl]
+	set 0, [hl]
+	pop hl
+	jr .divideYDistance
+.NPCSouthOfOrAlignedWithPlayer
+	push hl
+	ld hl, hNPCPlayerRelativePosFlags
+	bit 0, [hl]
+	res 0, [hl]
+	pop hl
+.divideYDistance
+	push hl
+	ld hl, hDividend2
+	ld [hli], a
+	ld a, 16
+	ld [hli], a
+	call DivideBytes ; divide Y absolute distance by 16
+	ld a, [hl] ; quotient
+	ld [hNPCPlayerYDistance], a
+	pop hl
+	inc hl
+	ld b, e
+	ld a, [hl] ; NPC sprite screen X position in pixels
+	call CalcDifference
+	jr nc, .NPCEastOfOrAlignedWithPlayer
+.NPCWestOfPlayer
+	push hl
+	ld hl, hNPCPlayerRelativePosFlags
+	bit 1, [hl]
+	set 1, [hl]
+	pop hl
+	jr .divideXDistance
+.NPCEastOfOrAlignedWithPlayer
+	push hl
+	ld hl, hNPCPlayerRelativePosFlags
+	bit 1, [hl]
+	res 1, [hl]
+	pop hl
+.divideXDistance
+	ld [hDividend2], a
+	ld a, 16
+	ld [hDivisor2], a
+	call DivideBytes ; divide X absolute distance by 16
+	ld a, [hQuotient2]
+	ld [hNPCPlayerXDistance], a
+	ld a, [hNPCPlayerRelativePosPerspective]
+	and a
+	ret z
+	ld a, [hNPCPlayerRelativePosFlags]
+	cpl
+	and $3
+	ld [hNPCPlayerRelativePosFlags], a
+	ret
+
+ConvertNPCMovementDirectionsToJoypadMasks:
+	ld a, [hNPCMovementDirections2Index]
+	ld [wNPCMovementDirections2Index], a
+	dec a
+	ld de, wSimulatedJoypadStatesEnd
+	ld hl, wNPCMovementDirections2
+	add l
+	ld l, a
+	jr nc, .loop
+	inc h
+.loop
+	ld a, [hld]
+	call ConvertNPCMovementDirectionToJoypadMask
+	ld [de], a
+	inc de
+	ld a, [hNPCMovementDirections2Index]
+	dec a
+	ld [hNPCMovementDirections2Index], a
+	jr nz, .loop
+	ret
+
+ConvertNPCMovementDirectionToJoypadMask:
+	push hl
+	ld b, a
+	ld hl, NPCMovementDirectionsToJoypadMasksTable
+.loop
+	ld a, [hli]
+	cp $ff
+	jr z, .done
+	cp b
+	jr z, .loadJoypadMask
+	inc hl
+	jr .loop
+.loadJoypadMask
+	ld a, [hl]
+.done
+	pop hl
+	ret
+
+NPCMovementDirectionsToJoypadMasksTable:
+	db NPC_MOVEMENT_UP, D_UP
+	db NPC_MOVEMENT_DOWN, D_DOWN
+	db NPC_MOVEMENT_LEFT, D_LEFT
+	db NPC_MOVEMENT_RIGHT, D_RIGHT
+	db $ff
+
+; unreferenced
+	ret
diff --git a/engine/overworld/pewter_guys.asm b/engine/overworld/pewter_guys.asm
deleted file mode 100755
index 532fa4bf..00000000
--- a/engine/overworld/pewter_guys.asm
+++ /dev/null
@@ -1,102 +0,0 @@
-PewterGuys:
-	ld hl, wSimulatedJoypadStatesEnd
-	ld a, [wSimulatedJoypadStatesIndex]
-	dec a ; this decrement causes it to overwrite the last byte before $FF in the list
-	ld [wSimulatedJoypadStatesIndex], a
-	ld d, 0
-	ld e, a
-	add hl, de
-	ld d, h
-	ld e, l
-	ld hl, PointerTable_37ce6
-	ld a, [wWhichPewterGuy]
-	add a
-	ld b, 0
-	ld c, a
-	add hl, bc
-	ld a, [hli]
-	ld h, [hl]
-	ld l, a
-	ld a, [wYCoord]
-	ld b, a
-	ld a, [wXCoord]
-	ld c, a
-.findMatchingCoordsLoop
-	ld a, [hli]
-	cp b
-	jr nz, .nextEntry1
-	ld a, [hli]
-	cp c
-	jr nz, .nextEntry2
-	ld a, [hli]
-	ld h, [hl]
-	ld l, a
-.copyMovementDataLoop
-	ld a, [hli]
-	cp $ff
-	ret z
-	ld [de], a
-	inc de
-	ld a, [wSimulatedJoypadStatesIndex]
-	inc a
-	ld [wSimulatedJoypadStatesIndex], a
-	jr .copyMovementDataLoop
-.nextEntry1
-	inc hl
-.nextEntry2
-	inc hl
-	inc hl
-	jr .findMatchingCoordsLoop
-
-PointerTable_37ce6:
-	dw PewterMuseumGuyCoords
-	dw PewterGymGuyCoords
-
-; these are the four coordinates of the spaces below, above, to the left and
-; to the right of the museum guy, and pointers to different movements for
-; the player to make to get positioned before the main movement.
-PewterMuseumGuyCoords:
-	db 18, 27
-	dw .down
-	db 16, 27
-	dw .up
-	db 17, 26
-	dw .left
-	db 17, 28
-	dw .right
-
-.down
-	db D_UP, D_UP, $ff
-.up
-	db D_RIGHT, D_LEFT, $ff
-.left
-	db D_UP, D_RIGHT, $ff
-.right
-	db D_UP, D_LEFT, $ff
-
-; these are the five coordinates which trigger the gym guy and pointers to
-; different movements for the player to make to get positioned before the
-; main movement
-; $00 is a pause
-PewterGymGuyCoords:
-	db 16, 34
-	dw .one
-	db 17, 35
-	dw .two
-	db 18, 37
-	dw .three
-	db 19, 37
-	dw .four
-	db 17, 36
-	dw .five
-
-.one
-	db D_LEFT, D_DOWN, D_DOWN, D_RIGHT, $ff
-.two
-	db D_LEFT, D_DOWN, D_RIGHT, D_LEFT, $ff
-.three
-	db D_LEFT, D_LEFT, D_LEFT, $00, $00, $00, $00, $00, $00, $00, $00, $ff
-.four
-	db D_LEFT, D_LEFT, D_UP, D_LEFT, $ff
-.five
-	db D_LEFT, D_DOWN, D_LEFT, $00, $00, $00, $00, $00, $00, $00, $00, $ff
diff --git a/engine/overworld/poison.asm b/engine/overworld/poison.asm
deleted file mode 100644
index 5d8eb9fd..00000000
--- a/engine/overworld/poison.asm
+++ /dev/null
@@ -1,112 +0,0 @@
-ApplyOutOfBattlePoisonDamage:
-	ld a, [wd730]
-	add a
-	jp c, .noBlackOut ; no black out if joypad states are being simulated
-	ld a, [wPartyCount]
-	and a
-	jp z, .noBlackOut
-	call IncrementDayCareMonExp
-	ld a, [wStepCounter]
-	and $3 ; is the counter a multiple of 4?
-	jp nz, .noBlackOut ; only apply poison damage every fourth step
-	ld [wWhichPokemon], a
-	ld hl, wPartyMon1Status
-	ld de, wPartySpecies
-.applyDamageLoop
-	ld a, [hl]
-	and (1 << PSN)
-	jr z, .nextMon2 ; not poisoned
-	dec hl
-	dec hl
-	ld a, [hld]
-	ld b, a
-	ld a, [hli]
-	or b
-	jr z, .nextMon ; already fainted
-; subtract 1 from HP
-	ld a, [hl]
-	dec a
-	ld [hld], a
-	inc a
-	jr nz, .noBorrow
-; borrow 1 from upper byte of HP
-	dec [hl]
-	inc hl
-	jr .nextMon
-.noBorrow
-	ld a, [hli]
-	or [hl]
-	jr nz, .nextMon ; didn't faint from damage
-; the mon fainted from the damage
-	push hl
-	inc hl
-	inc hl
-	ld [hl], a
-	ld a, [de]
-	ld [wd11e], a
-	push de
-	ld a, [wWhichPokemon]
-	ld hl, wPartyMonNicks
-	call GetPartyMonName
-	xor a
-	ld [wJoyIgnore], a
-	call EnableAutoTextBoxDrawing
-	ld a, TEXT_MON_FAINTED
-	ld [hSpriteIndexOrTextID], a
-	call DisplayTextID
-	pop de
-	pop hl
-.nextMon
-	inc hl
-	inc hl
-.nextMon2
-	inc de
-	ld a, [de]
-	inc a
-	jr z, .applyDamageLoopDone
-	ld bc, wPartyMon2 - wPartyMon1
-	add hl, bc
-	push hl
-	ld hl, wWhichPokemon
-	inc [hl]
-	pop hl
-	jr .applyDamageLoop
-.applyDamageLoopDone
-	ld hl, wPartyMon1Status
-	ld a, [wPartyCount]
-	ld d, a
-	ld e, 0
-.countPoisonedLoop
-	ld a, [hl]
-	and (1 << PSN)
-	or e
-	ld e, a
-	ld bc, wPartyMon2 - wPartyMon1
-	add hl, bc
-	dec d
-	jr nz, .countPoisonedLoop
-	ld a, e
-	and a ; are any party members poisoned?
-	jr z, .skipPoisonEffectAndSound
-	ld b, $2
-	predef ChangeBGPalColor0_4Frames ; change BG white to dark grey for 4 frames
-	ld a, SFX_POISONED
-	call PlaySound
-.skipPoisonEffectAndSound
-	predef AnyPartyAlive
-	ld a, d
-	and a
-	jr nz, .noBlackOut
-	call EnableAutoTextBoxDrawing
-	ld a, TEXT_BLACKED_OUT
-	ld [hSpriteIndexOrTextID], a
-	call DisplayTextID
-	ld hl, wd72e
-	set 5, [hl]
-	ld a, $ff
-	jr .done
-.noBlackOut
-	xor a
-.done
-	ld [wOutOfBattleBlackout], a
-	ret
diff --git a/engine/overworld/pokecenter.asm b/engine/overworld/pokecenter.asm
deleted file mode 100755
index f340e06d..00000000
--- a/engine/overworld/pokecenter.asm
+++ /dev/null
@@ -1,68 +0,0 @@
-DisplayPokemonCenterDialogue_::
-	call SaveScreenTilesToBuffer1 ; save screen
-	ld hl, PokemonCenterWelcomeText
-	call PrintText
-	ld hl, wd72e
-	bit 2, [hl]
-	set 1, [hl]
-	set 2, [hl]
-	jr nz, .skipShallWeHealYourPokemon
-	ld hl, ShallWeHealYourPokemonText
-	call PrintText
-.skipShallWeHealYourPokemon
-	call YesNoChoicePokeCenter ; yes/no menu
-	ld a, [wCurrentMenuItem]
-	and a
-	jr nz, .declinedHealing ; if the player chose No
-	call SetLastBlackoutMap
-	call LoadScreenTilesFromBuffer1 ; restore screen
-	ld hl, NeedYourPokemonText
-	call PrintText
-	ld a, $18
-	ld [wSpriteStateData1 + $12], a ; make the nurse turn to face the machine
-	call Delay3
-	predef HealParty
-	callba AnimateHealingMachine ; do the healing machine animation
-	xor a
-	ld [wAudioFadeOutControl], a
-	ld a, [wAudioSavedROMBank]
-	ld [wAudioROMBank], a
-	ld a, [wMapMusicSoundID]
-	ld [wLastMusicSoundID], a
-	ld [wNewSoundID], a
-	call PlaySound
-	ld hl, PokemonFightingFitText
-	call PrintText
-	ld a, $14
-	ld [wSpriteStateData1 + $12], a ; make the nurse bow
-	ld c, a
-	call DelayFrames
-	jr .done
-.declinedHealing
-	call LoadScreenTilesFromBuffer1 ; restore screen
-.done
-	ld hl, PokemonCenterFarewellText
-	call PrintText
-	jp UpdateSprites
-
-PokemonCenterWelcomeText:
-	TX_FAR _PokemonCenterWelcomeText
-	db "@"
-
-ShallWeHealYourPokemonText:
-	TX_DELAY
-	TX_FAR _ShallWeHealYourPokemonText
-	db "@"
-
-NeedYourPokemonText:
-	TX_FAR _NeedYourPokemonText
-	db "@"
-
-PokemonFightingFitText:
-	TX_FAR _PokemonFightingFitText
-	db "@"
-
-PokemonCenterFarewellText:
-	TX_DELAY
-	TX_FAR _PokemonCenterFarewellText
-	db "@"
diff --git a/engine/overworld/pokemart.asm b/engine/overworld/pokemart.asm
deleted file mode 100755
index 177e8a09..00000000
--- a/engine/overworld/pokemart.asm
+++ /dev/null
@@ -1,272 +0,0 @@
-DisplayPokemartDialogue_::
-	ld a, [wListScrollOffset]
-	ld [wSavedListScrollOffset], a
-	call UpdateSprites
-	xor a
-	ld [wBoughtOrSoldItemInMart], a
-.loop
-	xor a
-	ld [wListScrollOffset], a
-	ld [wCurrentMenuItem], a
-	ld [wPlayerMonNumber], a
-	inc a
-	ld [wPrintItemPrices], a
-	ld a, MONEY_BOX
-	ld [wTextBoxID], a
-	call DisplayTextBoxID
-	ld a, BUY_SELL_QUIT_MENU
-	ld [wTextBoxID], a
-	call DisplayTextBoxID
-
-; This code is useless. It copies the address of the pokemart's inventory to hl,
-; but the address is never used.
-	ld hl, wItemListPointer
-	ld a, [hli]
-	ld l, [hl]
-	ld h, a
-
-	ld a, [wMenuExitMethod]
-	cp CANCELLED_MENU
-	jp z, .done
-	ld a, [wChosenMenuItem]
-	and a ; buying?
-	jp z, .buyMenu
-	dec a ; selling?
-	jp z, .sellMenu
-	dec a ; quitting?
-	jp z, .done
-.sellMenu
-
-; the same variables are set again below, so this code has no effect
-	xor a
-	ld [wPrintItemPrices], a
-	ld a, INIT_BAG_ITEM_LIST
-	ld [wInitListType], a
-	callab InitList
-
-	ld a, [wNumBagItems]
-	and a
-	jp z, .bagEmpty
-	ld hl, PokemonSellingGreetingText
-	call PrintText
-	call SaveScreenTilesToBuffer1 ; save screen
-.sellMenuLoop
-	call LoadScreenTilesFromBuffer1 ; restore saved screen
-	ld a, MONEY_BOX
-	ld [wTextBoxID], a
-	call DisplayTextBoxID ; draw money text box
-	ld hl, wNumBagItems
-	ld a, l
-	ld [wListPointer], a
-	ld a, h
-	ld [wListPointer + 1], a
-	xor a
-	ld [wPrintItemPrices], a
-	ld [wCurrentMenuItem], a
-	ld a, ITEMLISTMENU
-	ld [wListMenuID], a
-	call DisplayListMenuID
-	jp c, .returnToMainPokemartMenu ; if the player closed the menu
-.confirmItemSale ; if the player is trying to sell a specific item
-	call IsKeyItem
-	ld a, [wIsKeyItem]
-	and a
-	jr nz, .unsellableItem
-	ld a, [wcf91]
-	call IsItemHM
-	jr c, .unsellableItem
-	ld a, PRICEDITEMLISTMENU
-	ld [wListMenuID], a
-	ld [hHalveItemPrices], a ; halve prices when selling
-	call DisplayChooseQuantityMenu
-	inc a
-	jr z, .sellMenuLoop ; if the player closed the choose quantity menu with the B button
-	ld hl, PokemartTellSellPriceText
-	lb bc, 14, 1 ; location that PrintText always prints to, this is useless
-	call PrintText
-	coord hl, 14, 7
-	lb bc, 8, 15
-	ld a, TWO_OPTION_MENU
-	ld [wTextBoxID], a
-	call DisplayTextBoxID ; yes/no menu
-	ld a, [wMenuExitMethod]
-	cp CHOSE_SECOND_ITEM
-	jr z, .sellMenuLoop ; if the player chose No or pressed the B button
-
-; The following code is supposed to check if the player chose No, but the above
-; check already catches it.
-	ld a, [wChosenMenuItem]
-	dec a
-	jr z, .sellMenuLoop
-
-.sellItem
-	ld a, [wBoughtOrSoldItemInMart]
-	and a
-	jr nz, .skipSettingFlag1
-	inc a
-	ld [wBoughtOrSoldItemInMart], a
-.skipSettingFlag1
-	call AddAmountSoldToMoney
-	ld hl, wNumBagItems
-	call RemoveItemFromInventory
-	jp .sellMenuLoop
-.unsellableItem
-	ld hl, PokemartUnsellableItemText
-	call PrintText
-	jp .returnToMainPokemartMenu
-.bagEmpty
-	ld hl, PokemartItemBagEmptyText
-	call PrintText
-	call SaveScreenTilesToBuffer1
-	jp .returnToMainPokemartMenu
-.buyMenu
-
-; the same variables are set again below, so this code has no effect
-	ld a, 1
-	ld [wPrintItemPrices], a
-	ld a, INIT_OTHER_ITEM_LIST
-	ld [wInitListType], a
-	callab InitList
-
-	ld hl, PokemartBuyingGreetingText
-	call PrintText
-	call SaveScreenTilesToBuffer1
-.buyMenuLoop
-	call LoadScreenTilesFromBuffer1
-	ld a, MONEY_BOX
-	ld [wTextBoxID], a
-	call DisplayTextBoxID
-	ld hl, wItemList
-	ld a, l
-	ld [wListPointer], a
-	ld a, h
-	ld [wListPointer + 1], a
-	xor a
-	ld [wCurrentMenuItem], a
-	inc a
-	ld [wPrintItemPrices], a
-	inc a ; a = 2 (PRICEDITEMLISTMENU)
-	ld [wListMenuID], a
-	call DisplayListMenuID
-	jr c, .returnToMainPokemartMenu ; if the player closed the menu
-	ld a, 99
-	ld [wMaxItemQuantity], a
-	xor a
-	ld [hHalveItemPrices], a ; don't halve item prices when buying
-	call DisplayChooseQuantityMenu
-	inc a
-	jr z, .buyMenuLoop ; if the player closed the choose quantity menu with the B button
-	ld a, [wcf91] ; item ID
-	ld [wd11e], a ; store item ID for GetItemName
-	call GetItemName
-	call CopyStringToCF4B ; copy name to wcf4b
-	ld hl, PokemartTellBuyPriceText
-	call PrintText
-	coord hl, 14, 7
-	lb bc, 8, 15
-	ld a, TWO_OPTION_MENU
-	ld [wTextBoxID], a
-	call DisplayTextBoxID ; yes/no menu
-	ld a, [wMenuExitMethod]
-	cp CHOSE_SECOND_ITEM
-	jp z, .buyMenuLoop ; if the player chose No or pressed the B button
-
-; The following code is supposed to check if the player chose No, but the above
-; check already catches it.
-	ld a, [wChosenMenuItem]
-	dec a
-	jr z, .buyMenuLoop
-
-.buyItem
-	call .isThereEnoughMoney
-	jr c, .notEnoughMoney
-	ld hl, wNumBagItems
-	call AddItemToInventory
-	jr nc, .bagFull
-	call SubtractAmountPaidFromMoney
-	ld a, [wBoughtOrSoldItemInMart]
-	and a
-	jr nz, .skipSettingFlag2
-	ld a, 1
-	ld [wBoughtOrSoldItemInMart], a
-.skipSettingFlag2
-	ld a, SFX_PURCHASE
-	call PlaySoundWaitForCurrent
-	call WaitForSoundToFinish
-	ld hl, PokemartBoughtItemText
-	call PrintText
-	jp .buyMenuLoop
-.returnToMainPokemartMenu
-	call LoadScreenTilesFromBuffer1
-	ld a, MONEY_BOX
-	ld [wTextBoxID], a
-	call DisplayTextBoxID
-	ld hl, PokemartAnythingElseText
-	call PrintText
-	jp .loop
-.isThereEnoughMoney
-	ld de, wPlayerMoney
-	ld hl, hMoney
-	ld c, 3 ; length of money in bytes
-	jp StringCmp
-.notEnoughMoney
-	ld hl, PokemartNotEnoughMoneyText
-	call PrintText
-	jr .returnToMainPokemartMenu
-.bagFull
-	ld hl, PokemartItemBagFullText
-	call PrintText
-	jr .returnToMainPokemartMenu
-.done
-	ld hl, PokemartThankYouText
-	call PrintText
-	ld a, 1
-	ld [wUpdateSpritesEnabled], a
-	call UpdateSprites
-	ld a, [wSavedListScrollOffset]
-	ld [wListScrollOffset], a
-	ret
-
-PokemartBuyingGreetingText:
-	TX_FAR _PokemartBuyingGreetingText
-	db "@"
-
-PokemartTellBuyPriceText:
-	TX_FAR _PokemartTellBuyPriceText
-	db "@"
-
-PokemartBoughtItemText:
-	TX_FAR _PokemartBoughtItemText
-	db "@"
-
-PokemartNotEnoughMoneyText:
-	TX_FAR _PokemartNotEnoughMoneyText
-	db "@"
-
-PokemartItemBagFullText:
-	TX_FAR _PokemartItemBagFullText
-	db "@"
-
-PokemonSellingGreetingText:
-	TX_FAR _PokemonSellingGreetingText
-	db "@"
-
-PokemartTellSellPriceText:
-	TX_FAR _PokemartTellSellPriceText
-	db "@"
-
-PokemartItemBagEmptyText:
-	TX_FAR _PokemartItemBagEmptyText
-	db "@"
-
-PokemartUnsellableItemText:
-	TX_FAR _PokemartUnsellableItemText
-	db "@"
-
-PokemartThankYouText:
-	TX_FAR _PokemartThankYouText
-	db "@"
-
-PokemartAnythingElseText:
-	TX_FAR _PokemartAnythingElseText
-	db "@"
diff --git a/engine/overworld/saffron_guards.asm b/engine/overworld/saffron_guards.asm
deleted file mode 100755
index 091cfa1a..00000000
--- a/engine/overworld/saffron_guards.asm
+++ /dev/null
@@ -1,15 +0,0 @@
-RemoveGuardDrink::
-	ld hl, GuardDrinksList
-.drinkLoop
-	ld a, [hli]
-	ld [$ffdb], a
-	and a
-	ret z
-	push hl
-	ld b, a
-	call IsItemInBag
-	pop hl
-	jr z, .drinkLoop
-	jpba RemoveItemByID
-
-INCLUDE "data/guard_drink_items.asm"
diff --git a/engine/overworld/set_blackout_map.asm b/engine/overworld/set_blackout_map.asm
deleted file mode 100644
index 14f0ba28..00000000
--- a/engine/overworld/set_blackout_map.asm
+++ /dev/null
@@ -1,25 +0,0 @@
-SetLastBlackoutMap:
-; Set the map to return to when
-; blacking out or using Teleport or Dig.
-; Safari rest houses don't count.
-
-	push hl
-	ld hl, SafariZoneRestHouses
-	ld a, [wCurMap]
-	ld b, a
-.loop
-	ld a, [hli]
-	cp -1
-	jr z, .notresthouse
-	cp b
-	jr nz, .loop
-	jr .done
-
-.notresthouse
-	ld a, [wLastMap]
-	ld [wLastBlackoutMap], a
-.done
-	pop hl
-	ret
-
-INCLUDE "data/rest_house_maps.asm"
diff --git a/engine/overworld/special_warps.asm b/engine/overworld/special_warps.asm
new file mode 100644
index 00000000..eee85402
--- /dev/null
+++ b/engine/overworld/special_warps.asm
@@ -0,0 +1,149 @@
+SpecialWarpIn::
+	call LoadSpecialWarpData
+	predef LoadTilesetHeader
+	ld hl, wd732
+	bit 2, [hl] ; dungeon warp or fly warp?
+	res 2, [hl]
+	jr z, .next
+; if dungeon warp or fly warp
+	ld a, [wDestinationMap]
+	jr .next2
+.next
+	bit 1, [hl]
+	jr z, .next3
+	call EmptyFunc
+.next3
+	ld a, 0
+.next2
+	ld b, a
+	ld a, [wd72d]
+	and a
+	jr nz, .next4
+	ld a, b
+.next4
+	ld hl, wd732
+	bit 4, [hl] ; dungeon warp?
+	ret nz
+; if not dungeon warp
+	ld [wLastMap], a
+	ret
+
+; gets the map ID, tile block map view pointer, tileset, and coordinates
+LoadSpecialWarpData:
+	ld a, [wd72d]
+	cp TRADE_CENTER
+	jr nz, .notTradeCenter
+	ld hl, TradeCenterSpec1
+	ld a, [hSerialConnectionStatus]
+	cp USING_INTERNAL_CLOCK ; which gameboy is clocking determines who is on the left and who is on the right
+	jr z, .copyWarpData
+	ld hl, TradeCenterSpec2
+	jr .copyWarpData
+.notTradeCenter
+	cp COLOSSEUM
+	jr nz, .notColosseum
+	ld hl, ColosseumSpec1
+	ld a, [hSerialConnectionStatus]
+	cp USING_INTERNAL_CLOCK
+	jr z, .copyWarpData
+	ld hl, ColosseumSpec2
+	jr .copyWarpData
+.notColosseum
+	ld a, [wd732]
+	bit 1, a
+	jr nz, .notFirstMap
+	bit 2, a
+	jr nz, .notFirstMap
+	ld hl, FirstMapSpec
+.copyWarpData
+	ld de, wCurMap
+	ld c, $7
+.copyWarpDataLoop
+	ld a, [hli]
+	ld [de], a
+	inc de
+	dec c
+	jr nz, .copyWarpDataLoop
+	ld a, [hli]
+	ld [wCurMapTileset], a
+	xor a
+	jr .done
+.notFirstMap
+	ld a, [wLastMap] ; this value is overwritten before it's ever read
+	ld hl, wd732
+	bit 4, [hl] ; used dungeon warp (jumped down hole/waterfall)?
+	jr nz, .usedDunegonWarp
+	bit 6, [hl] ; return to last pokemon center (or player's house)?
+	res 6, [hl]
+	jr z, .otherDestination
+; return to last pokemon center or player's house
+	ld a, [wLastBlackoutMap]
+	jr .usedFlyWarp
+.usedDunegonWarp
+	ld hl, wd72d
+	res 4, [hl]
+	ld a, [wDungeonWarpDestinationMap]
+	ld b, a
+	ld [wCurMap], a
+	ld a, [wWhichDungeonWarp]
+	ld c, a
+	ld hl, DungeonWarpList
+	ld de, 0
+	ld a, 6
+	ld [wDungeonWarpDataEntrySize], a
+.dungeonWarpListLoop
+	ld a, [hli]
+	cp b
+	jr z, .matchedDungeonWarpDestinationMap
+	inc hl
+	jr .nextDungeonWarp
+.matchedDungeonWarpDestinationMap
+	ld a, [hli]
+	cp c
+	jr z, .matchedDungeonWarpID
+.nextDungeonWarp
+	ld a, [wDungeonWarpDataEntrySize]
+	add e
+	ld e, a
+	jr .dungeonWarpListLoop
+.matchedDungeonWarpID
+	ld hl, DungeonWarpData
+	add hl, de
+	jr .copyWarpData2
+.otherDestination
+	ld a, [wDestinationMap]
+.usedFlyWarp
+	ld b, a
+	ld [wCurMap], a
+	ld hl, FlyWarpDataPtr
+.flyWarpDataPtrLoop
+	ld a, [hli]
+	inc hl
+	cp b
+	jr z, .foundFlyWarpMatch
+	inc hl
+	inc hl
+	jr .flyWarpDataPtrLoop
+.foundFlyWarpMatch
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+.copyWarpData2
+	ld de, wCurrentTileBlockMapViewPointer
+	ld c, $6
+.copyWarpDataLoop2
+	ld a, [hli]
+	ld [de], a
+	inc de
+	dec c
+	jr nz, .copyWarpDataLoop2
+	xor a ; OVERWORLD
+	ld [wCurMapTileset], a
+.done
+	ld [wYOffsetSinceLastSpecialWarp], a
+	ld [wXOffsetSinceLastSpecialWarp], a
+	ld a, $ff ; the player's coordinates have already been updated using a special warp, so don't use any of the normal warps
+	ld [wDestinationWarpID], a
+	ret
+
+INCLUDE "data/special_warps.asm"
diff --git a/engine/overworld/sprite_collisions.asm b/engine/overworld/sprite_collisions.asm
new file mode 100644
index 00000000..0e6b2d06
--- /dev/null
+++ b/engine/overworld/sprite_collisions.asm
@@ -0,0 +1,356 @@
+_UpdateSprites::
+	ld h, $c1
+	inc h
+	ld a, $e    ; wSpriteStateData2 + $0e
+.spriteLoop
+	ld l, a
+	sub $e
+	ld c, a
+	ld [H_CURRENTSPRITEOFFSET], a
+	ld a, [hl]
+	and a
+	jr z, .skipSprite   ; tests $c2Xe
+	push hl
+	push de
+	push bc
+	call .updateCurrentSprite
+	pop bc
+	pop de
+	pop hl
+.skipSprite
+	ld a, l
+	add $10             ; move to next sprite
+	cp $e               ; test for overflow (back at $0e)
+	jr nz, .spriteLoop
+	ret
+.updateCurrentSprite
+	cp $1
+	jp nz, UpdateNonPlayerSprite
+	jp UpdatePlayerSprite
+
+UpdateNonPlayerSprite:
+	dec a
+	swap a
+	ld [$ff93], a  ; $10 * sprite#
+	ld a, [wNPCMovementScriptSpriteOffset] ; some sprite offset?
+	ld b, a
+	ld a, [H_CURRENTSPRITEOFFSET]
+	cp b
+	jr nz, .unequal
+	jp DoScriptedNPCMovement
+.unequal
+	jp UpdateNPCSprite
+
+; This detects if the current sprite (whose offset is at H_CURRENTSPRITEOFFSET)
+; is going to collide with another sprite by looping over the other sprites.
+; The current sprite's offset will be labelled with i (e.g. $c1i0).
+; The loop sprite's offset will labelled with j (e.g. $c1j0).
+;
+; Note that the Y coordinate of the sprite (in [$c1k4]) is one of the following
+; 9 values when the sprite is aligned with the grid: $fc, $0c, $1c, $2c, ..., $7c.
+; The reason that 4 is added below to the coordinate is to make it align with a
+; multiple of $10 to make comparisons easier.
+DetectCollisionBetweenSprites:
+	nop
+
+	ld h, wSpriteStateData1 / $100
+	ld a, [H_CURRENTSPRITEOFFSET]
+	add wSpriteStateData1 % $100
+	ld l, a
+
+	ld a, [hl] ; a = [$c1i0] (picture) (0 if slot is unused)
+	and a ; is this sprite slot slot used?
+	ret z ; return if not used
+
+	ld a, l
+	add 3
+	ld l, a
+
+	ld a, [hli] ; a = [$c1i3] (delta Y) (-1, 0, or 1)
+	call SetSpriteCollisionValues
+
+	ld a, [hli] ; a = [$C1i4] (Y screen coordinate)
+	add 4 ; align with multiple of $10
+
+; The effect of the following 3 lines is to
+; add 7 to a if moving south or
+; subtract 7 from a if moving north.
+	add b
+	and $f0
+	or c
+
+	ld [$ff90], a ; store Y coordinate adjusted for direction of movement
+
+	ld a, [hli] ; a = [$c1i5] (delta X) (-1, 0, or 1)
+	call SetSpriteCollisionValues
+	ld a, [hl] ; a = [$C1i6] (X screen coordinate)
+
+; The effect of the following 3 lines is to
+; add 7 to a if moving east or
+; subtract 7 from a if moving west.
+	add b
+	and $f0
+	or c
+
+	ld [$ff91], a ; store X coordinate adjusted for direction of movement
+
+	ld a, l
+	add 7
+	ld l, a
+
+	xor a
+	ld [hld], a ; zero [$c1id] XXX what's [$c1id] for?
+	ld [hld], a ; zero [$c1ic] (directions in which collisions occurred)
+
+	ld a, [$ff91]
+	ld [hld], a ; [$c1ib] = adjusted X coordinate
+	ld a, [$ff90]
+	ld [hl], a ; [$c1ia] = adjusted Y coordinate
+
+	xor a ; zero the loop counter
+
+.loop
+	ld [$ff8f], a ; store loop counter
+	swap a
+	ld e, a
+	ld a, [H_CURRENTSPRITEOFFSET]
+	cp e ; does the loop sprite match the current sprite?
+	jp z, .next ; go to the next sprite if they match
+
+	ld d, h
+	ld a, [de] ; a = [$c1j0] (picture) (0 if slot is unused)
+	and a ; is this sprite slot slot used?
+	jp z, .next ; go the next sprite if not used
+
+	inc e
+	inc e
+	ld a, [de] ; a = [$c1j2] ($ff means the sprite is offscreen)
+	inc a
+	jp z, .next ; go the next sprite if offscreen
+
+	ld a, [H_CURRENTSPRITEOFFSET]
+	add 10
+	ld l, a
+
+	inc e
+	ld a, [de] ; a = [$c1j3] (delta Y)
+	call SetSpriteCollisionValues
+
+	inc e
+	ld a, [de] ; a = [$C1j4] (Y screen coordinate)
+	add 4 ; align with multiple of $10
+
+; The effect of the following 3 lines is to
+; add 7 to a if moving south or
+; subtract 7 from a if moving north.
+	add b
+	and $f0
+	or c
+
+	sub [hl] ; subtract the adjusted Y coordinate of sprite i ([$c1ia]) from that of sprite j
+
+; calculate the absolute value of the difference to get the distance
+	jr nc, .noCarry1
+	cpl
+	inc a
+.noCarry1
+	ld [$ff90], a ; store the distance between the two sprites' adjusted Y values
+
+; Use the carry flag set by the above subtraction to determine which sprite's
+; Y coordinate is larger. This information is used later to set [$c1ic],
+; which stores which direction the collision occurred in.
+; The following 5 lines set the lowest 2 bits of c, which are later shifted left by 2.
+; If sprite i's Y is larger, set lowest 2 bits of c to 10.
+; If sprite j's Y is larger or both are equal, set lowest 2 bits of c to 01.
+	push af
+	rl c
+	pop af
+	ccf
+	rl c
+
+; If sprite i's delta Y is 0, then b = 7, else b = 9.
+	ld b, 7
+	ld a, [hl] ; a = [$c1ia] (adjusted Y coordinate)
+	and $f
+	jr z, .next1
+	ld b, 9
+
+.next1
+	ld a, [$ff90] ; a = distance between adjusted Y coordinates
+	sub b
+	ld [$ff92], a ; store distance adjusted using sprite i's direction
+	ld a, b
+	ld [$ff90], a ; store 7 or 9 depending on sprite i's delta Y
+	jr c, .checkXDistance
+
+; If sprite j's delta Y is 0, then b = 7, else b = 9.
+	ld b, 7
+	dec e
+	ld a, [de] ; a = [$c1j3] (delta Y)
+	inc e
+	and a
+	jr z, .next2
+	ld b, 9
+
+.next2
+	ld a, [$ff92] ; a = distance adjusted using sprite i's direction
+	sub b ; adjust distance using sprite j's direction
+	jr z, .checkXDistance
+	jr nc, .next ; go to next sprite if distance is still positive after both adjustments
+
+.checkXDistance
+	inc e
+	inc l
+	ld a, [de] ; a = [$c1j5] (delta X)
+
+	push bc
+
+	call SetSpriteCollisionValues
+	inc e
+	ld a, [de] ; a = [$c1j6] (X screen coordinate)
+
+; The effect of the following 3 lines is to
+; add 7 to a if moving east or
+; subtract 7 from a if moving west.
+	add b
+	and $f0
+	or c
+
+	pop bc
+
+	sub [hl] ; subtract the adjusted X coordinate of sprite i ([$c1ib]) from that of sprite j
+
+; calculate the absolute value of the difference to get the distance
+	jr nc, .noCarry2
+	cpl
+	inc a
+.noCarry2
+	ld [$ff91], a ; store the distance between the two sprites' adjusted X values
+
+; Use the carry flag set by the above subtraction to determine which sprite's
+; X coordinate is larger. This information is used later to set [$c1ic],
+; which stores which direction the collision occurred in.
+; The following 5 lines set the lowest 2 bits of c.
+; If sprite i's X is larger, set lowest 2 bits of c to 10.
+; If sprite j's X is larger or both are equal, set lowest 2 bits of c to 01.
+	push af
+	rl c
+	pop af
+	ccf
+	rl c
+
+; If sprite i's delta X is 0, then b = 7, else b = 9.
+	ld b, 7
+	ld a, [hl] ; a = [$c1ib] (adjusted X coordinate)
+	and $f
+	jr z, .next3
+	ld b, 9
+
+.next3
+	ld a, [$ff91] ; a = distance between adjusted X coordinates
+	sub b
+	ld [$ff92], a ; store distance adjusted using sprite i's direction
+	ld a, b
+	ld [$ff91], a ; store 7 or 9 depending on sprite i's delta X
+	jr c, .collision
+
+; If sprite j's delta X is 0, then b = 7, else b = 9.
+	ld b, 7
+	dec e
+	ld a, [de] ; a = [$c1j5] (delta X)
+	inc e
+	and a
+	jr z, .next4
+	ld b, 9
+
+.next4
+	ld a, [$ff92] ; a = distance adjusted using sprite i's direction
+	sub b ; adjust distance using sprite j's direction
+	jr z, .collision
+	jr nc, .next ; go to next sprite if distance is still positive after both adjustments
+
+.collision
+	ld a, [$ff91] ; a = 7 or 9 depending on sprite i's delta X
+	ld b, a
+	ld a, [$ff90] ; a = 7 or 9 depending on sprite i's delta Y
+	inc l
+
+; If delta X isn't 0 and delta Y is 0, then b = %0011, else b = %1100.
+; (note that normally if delta X isn't 0, then delta Y must be 0 and vice versa)
+	cp b
+	jr c, .next5
+	ld b, %1100
+	jr .next6
+.next5
+	ld b, %0011
+
+.next6
+	ld a, c ; c has 2 bits set (one of bits 0-1 is set for the X axis and one of bits 2-3 for the Y axis)
+	and b ; we select either the bit in bits 0-1 or bits 2-3 based on the calculation immediately above
+	or [hl] ; or with existing collision direction bits in [$c1ic]
+	ld [hl], a ; store new value
+	ld a, c ; useless code because a is overwritten before being used again
+
+; set bit in [$c1ie] or [$c1if] to indicate which sprite the collision occurred with
+	inc l
+	inc l
+	ld a, [$ff8f] ; a = loop counter
+	ld de, SpriteCollisionBitTable
+	add a
+	add e
+	ld e, a
+	jr nc, .noCarry3
+	inc d
+.noCarry3
+	ld a, [de]
+	or [hl]
+	ld [hli], a
+	inc de
+	ld a, [de]
+	or [hl]
+	ld [hl], a
+
+.next
+	ld a, [$ff8f] ; a = loop counter
+	inc a
+	cp $10
+	jp nz, .loop
+	ret
+
+; takes delta X or delta Y in a
+; b = delta X/Y
+; c = 0 if delta X/Y is 0
+; c = 7 if delta X/Y is 1
+; c = 9 if delta X/Y is -1
+SetSpriteCollisionValues:
+	and a
+	ld b, 0
+	ld c, 0
+	jr z, .done
+	ld c, 9
+	cp -1
+	jr z, .ok
+	ld c, 7
+	ld a, 0
+.ok
+	ld b, a
+.done
+	ret
+
+SpriteCollisionBitTable:
+	db %00000000,%00000001
+	db %00000000,%00000010
+	db %00000000,%00000100
+	db %00000000,%00001000
+	db %00000000,%00010000
+	db %00000000,%00100000
+	db %00000000,%01000000
+	db %00000000,%10000000
+	db %00000001,%00000000
+	db %00000010,%00000000
+	db %00000100,%00000000
+	db %00001000,%00000000
+	db %00010000,%00000000
+	db %00100000,%00000000
+	db %01000000,%00000000
+	db %10000000,%00000000
diff --git a/engine/overworld/ssanne.asm b/engine/overworld/ssanne.asm
deleted file mode 100755
index 6c26b712..00000000
--- a/engine/overworld/ssanne.asm
+++ /dev/null
@@ -1,93 +0,0 @@
-AnimateBoulderDust:
-	ld a, $1
-	ld [wWhichAnimationOffsets], a ; select the boulder dust offsets
-	ld a, [wUpdateSpritesEnabled]
-	push af
-	ld a, $ff
-	ld [wUpdateSpritesEnabled], a
-	ld a, %11100100
-	ld [rOBP1], a
-	call LoadSmokeTileFourTimes
-	callba WriteCutOrBoulderDustAnimationOAMBlock
-	ld c, 8 ; number of steps in animation
-.loop
-	push bc
-	call GetMoveBoulderDustFunctionPointer
-	ld bc, .returnAddress
-	push bc
-	ld c, 4
-	jp hl
-.returnAddress
-	ld a, [rOBP1]
-	xor %01100100
-	ld [rOBP1], a
-	call Delay3
-	pop bc
-	dec c
-	jr nz, .loop
-	pop af
-	ld [wUpdateSpritesEnabled], a
-	jp LoadPlayerSpriteGraphics
-
-GetMoveBoulderDustFunctionPointer:
-	ld a, [wSpriteStateData1 + 9] ; player's sprite facing direction
-	ld hl, MoveBoulderDustFunctionPointerTable
-	ld c, a
-	ld b, $0
-	add hl, bc
-	ld a, [hli]
-	ld [wCoordAdjustmentAmount], a
-	ld a, [hli]
-	ld e, a
-	ld a, [hli]
-	ld h, [hl]
-	ld l, a
-	push hl
-	ld hl, wOAMBuffer + $90
-	ld d, $0
-	add hl, de
-	ld e, l
-	ld d, h
-	pop hl
-	ret
-
-MoveBoulderDustFunctionPointerTable:
-; facing down
-	db $FF,$00
-	dw AdjustOAMBlockYPos
-
-; facing up
-	db $01,$00
-	dw AdjustOAMBlockYPos
-
-; facing left
-	db $01,$01
-	dw AdjustOAMBlockXPos
-
-; facing right
-	db $FF,$01
-	dw AdjustOAMBlockXPos
-
-LoadSmokeTileFourTimes::
-	ld hl, vChars1 + $7c0
-	ld c, $4
-.loop
-	push bc
-	push hl
-	call LoadSmokeTile
-	pop hl
-	ld bc, $10
-	add hl, bc
-	pop bc
-	dec c
-	jr nz, .loop
-	ret
-
-LoadSmokeTile:
-	ld de, SSAnneSmokePuffTile
-	lb bc, BANK(SSAnneSmokePuffTile), (SSAnneSmokePuffTileEnd - SSAnneSmokePuffTile) / $10
-	jp CopyVideoData
-
-SSAnneSmokePuffTile:
-	INCBIN "gfx/overworld/smoke.2bpp"
-SSAnneSmokePuffTileEnd:
diff --git a/engine/overworld/tileset_header.asm b/engine/overworld/tileset_header.asm
deleted file mode 100644
index 6e33974f..00000000
--- a/engine/overworld/tileset_header.asm
+++ /dev/null
@@ -1,60 +0,0 @@
-LoadTilesetHeader:
-	call GetPredefRegisters
-	push hl
-	ld d, 0
-	ld a, [wCurMapTileset]
-	add a
-	add a
-	ld b, a
-	add a
-	add b ; a = tileset * 12
-	jr nc, .noCarry
-	inc d
-.noCarry
-	ld e, a
-	ld hl, Tilesets
-	add hl, de
-	ld de, wTilesetBank
-	ld c, $b
-.copyTilesetHeaderLoop
-	ld a, [hli]
-	ld [de], a
-	inc de
-	dec c
-	jr nz, .copyTilesetHeaderLoop
-	ld a, [hl]
-	ld [hTilesetType], a
-	xor a
-	ld [$ffd8], a
-	pop hl
-	ld a, [wCurMapTileset]
-	push hl
-	push de
-	ld hl, DungeonTilesets
-	ld de, $1
-	call IsInArray
-	pop de
-	pop hl
-	jr c, .asm_c797
-	ld a, [wCurMapTileset]
-	ld b, a
-	ld a, [hPreviousTileset]
-	cp b
-	jr z, .done
-.asm_c797
-	ld a, [wDestinationWarpID]
-	cp $ff
-	jr z, .done
-	call LoadDestinationWarpPosition
-	ld a, [wYCoord]
-	and $1
-	ld [wYBlockCoord], a
-	ld a, [wXCoord]
-	and $1
-	ld [wXBlockCoord], a
-.done
-	ret
-
-INCLUDE "data/dungeon_tilesets.asm"
-
-INCLUDE "data/tileset_headers.asm"
diff --git a/engine/overworld/tilesets.asm b/engine/overworld/tilesets.asm
new file mode 100644
index 00000000..6e33974f
--- /dev/null
+++ b/engine/overworld/tilesets.asm
@@ -0,0 +1,60 @@
+LoadTilesetHeader:
+	call GetPredefRegisters
+	push hl
+	ld d, 0
+	ld a, [wCurMapTileset]
+	add a
+	add a
+	ld b, a
+	add a
+	add b ; a = tileset * 12
+	jr nc, .noCarry
+	inc d
+.noCarry
+	ld e, a
+	ld hl, Tilesets
+	add hl, de
+	ld de, wTilesetBank
+	ld c, $b
+.copyTilesetHeaderLoop
+	ld a, [hli]
+	ld [de], a
+	inc de
+	dec c
+	jr nz, .copyTilesetHeaderLoop
+	ld a, [hl]
+	ld [hTilesetType], a
+	xor a
+	ld [$ffd8], a
+	pop hl
+	ld a, [wCurMapTileset]
+	push hl
+	push de
+	ld hl, DungeonTilesets
+	ld de, $1
+	call IsInArray
+	pop de
+	pop hl
+	jr c, .asm_c797
+	ld a, [wCurMapTileset]
+	ld b, a
+	ld a, [hPreviousTileset]
+	cp b
+	jr z, .done
+.asm_c797
+	ld a, [wDestinationWarpID]
+	cp $ff
+	jr z, .done
+	call LoadDestinationWarpPosition
+	ld a, [wYCoord]
+	and $1
+	ld [wYBlockCoord], a
+	ld a, [wXCoord]
+	and $1
+	ld [wXBlockCoord], a
+.done
+	ret
+
+INCLUDE "data/dungeon_tilesets.asm"
+
+INCLUDE "data/tileset_headers.asm"
diff --git a/engine/overworld/trainer_sight.asm b/engine/overworld/trainer_sight.asm
new file mode 100755
index 00000000..5a68b627
--- /dev/null
+++ b/engine/overworld/trainer_sight.asm
@@ -0,0 +1,349 @@
+_GetSpritePosition1::
+	ld hl, wSpriteStateData1
+	ld de, $4
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	call GetSpriteDataPointer
+	ld a, [hli] ; c1x4 (screen Y pos)
+	ld [$ffeb], a
+	inc hl
+	ld a, [hl] ; c1x6 (screen X pos)
+	ld [$ffec], a
+	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
+	add hl, de
+	ld a, [hli] ; c2x4 (map Y pos)
+	ld [$ffed], a
+	ld a, [hl] ; c2x5 (map X pos)
+	ld [$ffee], a
+	ret
+
+_GetSpritePosition2::
+	ld hl, wSpriteStateData1
+	ld de, $4
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	call GetSpriteDataPointer
+	ld a, [hli] ; c1x4 (screen Y pos)
+	ld [wSavedSpriteScreenY], a
+	inc hl
+	ld a, [hl] ; c1x6 (screen X pos)
+	ld [wSavedSpriteScreenX], a
+	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
+	add hl, de
+	ld a, [hli] ; c2x4 (map Y pos)
+	ld [wSavedSpriteMapY], a
+	ld a, [hl] ; c2x5 (map X pos)
+	ld [wSavedSpriteMapX], a
+	ret
+
+_SetSpritePosition1::
+	ld hl, wSpriteStateData1
+	ld de, $4
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	call GetSpriteDataPointer
+	ld a, [$ffeb] ; c1x4 (screen Y pos)
+	ld [hli], a
+	inc hl
+	ld a, [$ffec] ; c1x6 (screen X pos)
+	ld [hl], a
+	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
+	add hl, de
+	ld a, [$ffed] ; c2x4 (map Y pos)
+	ld [hli], a
+	ld a, [$ffee] ; c2x5 (map X pos)
+	ld [hl], a
+	ret
+
+_SetSpritePosition2::
+	ld hl, wSpriteStateData1
+	ld de, 4
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	call GetSpriteDataPointer
+	ld a, [wSavedSpriteScreenY]
+	ld [hli], a ; c1x4 (screen Y pos)
+	inc hl
+	ld a, [wSavedSpriteScreenX]
+	ld [hl], a ; c1x6 (screen X pos)
+	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
+	add hl, de
+	ld a, [wSavedSpriteMapY]
+	ld [hli], a ; c2x4 (map Y pos)
+	ld a, [wSavedSpriteMapX]
+	ld [hl], a ; c2x5 (map X pos)
+	ret
+
+TrainerWalkUpToPlayer::
+	ld a, [wSpriteIndex]
+	swap a
+	ld [wTrainerSpriteOffset], a
+	call ReadTrainerScreenPosition
+	ld a, [wTrainerFacingDirection]
+	and a ; SPRITE_FACING_DOWN
+	jr z, .facingDown
+	cp SPRITE_FACING_UP
+	jr z, .facingUp
+	cp SPRITE_FACING_LEFT
+	jr z, .facingLeft
+	jr .facingRight
+.facingDown
+	ld a, [wTrainerScreenY]
+	ld b, a
+	ld a, $3c           ; (fixed) player screen Y pos
+	call CalcDifference
+	cp $10              ; trainer is right above player
+	ret z
+	swap a
+	dec a
+	ld c, a             ; bc = steps yet to go to reach player
+	xor a
+	ld b, a           ; a = direction to go to
+	jr .writeWalkScript
+.facingUp
+	ld a, [wTrainerScreenY]
+	ld b, a
+	ld a, $3c           ; (fixed) player screen Y pos
+	call CalcDifference
+	cp $10              ; trainer is right below player
+	ret z
+	swap a
+	dec a
+	ld c, a             ; bc = steps yet to go to reach player
+	ld b, $0
+	ld a, $40           ; a = direction to go to
+	jr .writeWalkScript
+.facingRight
+	ld a, [wTrainerScreenX]
+	ld b, a
+	ld a, $40           ; (fixed) player screen X pos
+	call CalcDifference
+	cp $10              ; trainer is directly left of player
+	ret z
+	swap a
+	dec a
+	ld c, a             ; bc = steps yet to go to reach player
+	ld b, $0
+	ld a, $c0           ; a = direction to go to
+	jr .writeWalkScript
+.facingLeft
+	ld a, [wTrainerScreenX]
+	ld b, a
+	ld a, $40           ; (fixed) player screen X pos
+	call CalcDifference
+	cp $10              ; trainer is directly right of player
+	ret z
+	swap a
+	dec a
+	ld c, a             ; bc = steps yet to go to reach player
+	ld b, $0
+	ld a, $80           ; a = direction to go to
+.writeWalkScript
+	ld hl, wNPCMovementDirections2
+	ld de, wNPCMovementDirections2
+	call FillMemory     ; write the necessary steps to reach player
+	ld [hl], $ff        ; write end of list sentinel
+	ld a, [wSpriteIndex]
+	ld [H_SPRITEINDEX], a
+	jp MoveSprite_
+
+; input: de = offset within sprite entry
+; output: hl = pointer to sprite data
+GetSpriteDataPointer:
+	push de
+	add hl, de
+	ld a, [H_SPRITEINDEX]
+	swap a
+	ld d, $0
+	ld e, a
+	add hl, de
+	pop de
+	ret
+
+; tests if this trainer is in the right position to engage the player and do so if she is.
+TrainerEngage:
+	push hl
+	push de
+	ld a, [wTrainerSpriteOffset]
+	add $2
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl]             ; c1x2: sprite image index
+	sub $ff
+	jr nz, .spriteOnScreen ; test if sprite is on screen
+	jp .noEngage
+.spriteOnScreen
+	ld a, [wTrainerSpriteOffset]
+	add $9
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl]             ; c1x9: facing direction
+	ld [wTrainerFacingDirection], a
+	call ReadTrainerScreenPosition
+	ld a, [wTrainerScreenY]          ; sprite screen Y pos
+	ld b, a
+	ld a, $3c
+	cp b
+	jr z, .linedUpY
+	ld a, [wTrainerScreenX]          ; sprite screen X pos
+	ld b, a
+	ld a, $40
+	cp b
+	jr z, .linedUpX
+	xor a
+	jp .noEngage
+.linedUpY
+	ld a, [wTrainerScreenX]        ; sprite screen X pos
+	ld b, a
+	ld a, $40            ; (fixed) player X position
+	call CalcDifference  ; calc distance
+	jr z, .noEngage      ; exact same position as player
+	call CheckSpriteCanSeePlayer
+	jr c, .engage
+	xor a
+	jr .noEngage
+.linedUpX
+	ld a, [wTrainerScreenY]        ; sprite screen Y pos
+	ld b, a
+	ld a, $3c            ; (fixed) player Y position
+	call CalcDifference  ; calc distance
+	jr z, .noEngage      ; exact same position as player
+	call CheckSpriteCanSeePlayer
+	jr c, .engage
+	xor a
+	jp .noEngage
+.engage
+	call CheckPlayerIsInFrontOfSprite
+	ld a, [wTrainerSpriteOffset]
+	and a
+	jr z, .noEngage
+	ld hl, wFlags_0xcd60
+	set 0, [hl]
+	call EngageMapTrainer
+	ld a, $ff
+.noEngage
+	ld [wTrainerSpriteOffset], a
+	pop de
+	pop hl
+	ret
+
+; reads trainer's Y position to wTrainerScreenY and X position to wTrainerScreenX
+ReadTrainerScreenPosition:
+	ld a, [wTrainerSpriteOffset]
+	add $4
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl] ; c1x4 (sprite Y pos)
+	ld [wTrainerScreenY], a
+	ld a, [wTrainerSpriteOffset]
+	add $6
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl] ; c1x6 (sprite X pos)
+	ld [wTrainerScreenX], a
+	ret
+
+; checks if the sprite is properly lined up with the player with respect to the direction it's looking. Also checks the distance between player and sprite
+; note that this does not necessarily mean the sprite is seeing the player, he could be behind it's back
+; a: distance player to sprite
+CheckSpriteCanSeePlayer:
+	ld b, a
+	ld a, [wTrainerEngageDistance] ; how far the trainer can see
+	cp b
+	jr nc, .checkIfLinedUp
+	jr .notInLine         ; player too far away
+.checkIfLinedUp
+	ld a, [wTrainerFacingDirection]         ; sprite facing direction
+	cp SPRITE_FACING_DOWN
+	jr z, .checkXCoord
+	cp SPRITE_FACING_UP
+	jr z, .checkXCoord
+	cp SPRITE_FACING_LEFT
+	jr z, .checkYCoord
+	cp SPRITE_FACING_RIGHT
+	jr z, .checkYCoord
+	jr .notInLine
+.checkXCoord
+	ld a, [wTrainerScreenX]         ; sprite screen X position
+	ld b, a
+	cp $40
+	jr z, .inLine
+	jr .notInLine
+.checkYCoord
+	ld a, [wTrainerScreenY]         ; sprite screen Y position
+	ld b, a
+	cp $3c
+	jr nz, .notInLine
+.inLine
+	scf
+	ret
+.notInLine
+	and a
+	ret
+
+; tests if the player is in front of the sprite (rather than behind it)
+CheckPlayerIsInFrontOfSprite:
+	ld a, [wCurMap]
+	cp POWER_PLANT
+	jp z, .engage       ; bypass this for power plant to get voltorb fake items to work
+	ld a, [wTrainerSpriteOffset]
+	add $4
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl]          ; c1x4 (sprite screen Y pos)
+	cp $fc
+	jr nz, .notOnTopmostTile ; special case if sprite is on topmost tile (Y = $fc (-4)), make it come down a block
+	ld a, $c
+.notOnTopmostTile
+	ld [wTrainerScreenY], a
+	ld a, [wTrainerSpriteOffset]
+	add $6
+	ld d, $0
+	ld e, a
+	ld hl, wSpriteStateData1
+	add hl, de
+	ld a, [hl]          ; c1x6 (sprite screen X pos)
+	ld [wTrainerScreenX], a
+	ld a, [wTrainerFacingDirection]       ; facing direction
+	cp SPRITE_FACING_DOWN
+	jr nz, .notFacingDown
+	ld a, [wTrainerScreenY]       ; sprite screen Y pos
+	cp $3c
+	jr c, .engage       ; sprite above player
+	jr .noEngage        ; sprite below player
+.notFacingDown
+	cp SPRITE_FACING_UP
+	jr nz, .notFacingUp
+	ld a, [wTrainerScreenY]       ; sprite screen Y pos
+	cp $3c
+	jr nc, .engage      ; sprite below player
+	jr .noEngage        ; sprite above player
+.notFacingUp
+	cp SPRITE_FACING_LEFT
+	jr nz, .notFacingLeft
+	ld a, [wTrainerScreenX]       ; sprite screen X pos
+	cp $40
+	jr nc, .engage      ; sprite right of player
+	jr .noEngage        ; sprite left of player
+.notFacingLeft
+	ld a, [wTrainerScreenX]       ; sprite screen X pos
+	cp $40
+	jr nc, .noEngage    ; sprite right of player
+.engage
+	ld a, $ff
+	jr .done
+.noEngage
+	xor a
+.done
+	ld [wTrainerSpriteOffset], a
+	ret
diff --git a/engine/overworld/trainers.asm b/engine/overworld/trainers.asm
deleted file mode 100755
index 5a68b627..00000000
--- a/engine/overworld/trainers.asm
+++ /dev/null
@@ -1,349 +0,0 @@
-_GetSpritePosition1::
-	ld hl, wSpriteStateData1
-	ld de, $4
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	call GetSpriteDataPointer
-	ld a, [hli] ; c1x4 (screen Y pos)
-	ld [$ffeb], a
-	inc hl
-	ld a, [hl] ; c1x6 (screen X pos)
-	ld [$ffec], a
-	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
-	add hl, de
-	ld a, [hli] ; c2x4 (map Y pos)
-	ld [$ffed], a
-	ld a, [hl] ; c2x5 (map X pos)
-	ld [$ffee], a
-	ret
-
-_GetSpritePosition2::
-	ld hl, wSpriteStateData1
-	ld de, $4
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	call GetSpriteDataPointer
-	ld a, [hli] ; c1x4 (screen Y pos)
-	ld [wSavedSpriteScreenY], a
-	inc hl
-	ld a, [hl] ; c1x6 (screen X pos)
-	ld [wSavedSpriteScreenX], a
-	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
-	add hl, de
-	ld a, [hli] ; c2x4 (map Y pos)
-	ld [wSavedSpriteMapY], a
-	ld a, [hl] ; c2x5 (map X pos)
-	ld [wSavedSpriteMapX], a
-	ret
-
-_SetSpritePosition1::
-	ld hl, wSpriteStateData1
-	ld de, $4
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	call GetSpriteDataPointer
-	ld a, [$ffeb] ; c1x4 (screen Y pos)
-	ld [hli], a
-	inc hl
-	ld a, [$ffec] ; c1x6 (screen X pos)
-	ld [hl], a
-	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
-	add hl, de
-	ld a, [$ffed] ; c2x4 (map Y pos)
-	ld [hli], a
-	ld a, [$ffee] ; c2x5 (map X pos)
-	ld [hl], a
-	ret
-
-_SetSpritePosition2::
-	ld hl, wSpriteStateData1
-	ld de, 4
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	call GetSpriteDataPointer
-	ld a, [wSavedSpriteScreenY]
-	ld [hli], a ; c1x4 (screen Y pos)
-	inc hl
-	ld a, [wSavedSpriteScreenX]
-	ld [hl], a ; c1x6 (screen X pos)
-	ld de, (wSpriteStateData2 + $4) - (wSpriteStateData1 + $6)
-	add hl, de
-	ld a, [wSavedSpriteMapY]
-	ld [hli], a ; c2x4 (map Y pos)
-	ld a, [wSavedSpriteMapX]
-	ld [hl], a ; c2x5 (map X pos)
-	ret
-
-TrainerWalkUpToPlayer::
-	ld a, [wSpriteIndex]
-	swap a
-	ld [wTrainerSpriteOffset], a
-	call ReadTrainerScreenPosition
-	ld a, [wTrainerFacingDirection]
-	and a ; SPRITE_FACING_DOWN
-	jr z, .facingDown
-	cp SPRITE_FACING_UP
-	jr z, .facingUp
-	cp SPRITE_FACING_LEFT
-	jr z, .facingLeft
-	jr .facingRight
-.facingDown
-	ld a, [wTrainerScreenY]
-	ld b, a
-	ld a, $3c           ; (fixed) player screen Y pos
-	call CalcDifference
-	cp $10              ; trainer is right above player
-	ret z
-	swap a
-	dec a
-	ld c, a             ; bc = steps yet to go to reach player
-	xor a
-	ld b, a           ; a = direction to go to
-	jr .writeWalkScript
-.facingUp
-	ld a, [wTrainerScreenY]
-	ld b, a
-	ld a, $3c           ; (fixed) player screen Y pos
-	call CalcDifference
-	cp $10              ; trainer is right below player
-	ret z
-	swap a
-	dec a
-	ld c, a             ; bc = steps yet to go to reach player
-	ld b, $0
-	ld a, $40           ; a = direction to go to
-	jr .writeWalkScript
-.facingRight
-	ld a, [wTrainerScreenX]
-	ld b, a
-	ld a, $40           ; (fixed) player screen X pos
-	call CalcDifference
-	cp $10              ; trainer is directly left of player
-	ret z
-	swap a
-	dec a
-	ld c, a             ; bc = steps yet to go to reach player
-	ld b, $0
-	ld a, $c0           ; a = direction to go to
-	jr .writeWalkScript
-.facingLeft
-	ld a, [wTrainerScreenX]
-	ld b, a
-	ld a, $40           ; (fixed) player screen X pos
-	call CalcDifference
-	cp $10              ; trainer is directly right of player
-	ret z
-	swap a
-	dec a
-	ld c, a             ; bc = steps yet to go to reach player
-	ld b, $0
-	ld a, $80           ; a = direction to go to
-.writeWalkScript
-	ld hl, wNPCMovementDirections2
-	ld de, wNPCMovementDirections2
-	call FillMemory     ; write the necessary steps to reach player
-	ld [hl], $ff        ; write end of list sentinel
-	ld a, [wSpriteIndex]
-	ld [H_SPRITEINDEX], a
-	jp MoveSprite_
-
-; input: de = offset within sprite entry
-; output: hl = pointer to sprite data
-GetSpriteDataPointer:
-	push de
-	add hl, de
-	ld a, [H_SPRITEINDEX]
-	swap a
-	ld d, $0
-	ld e, a
-	add hl, de
-	pop de
-	ret
-
-; tests if this trainer is in the right position to engage the player and do so if she is.
-TrainerEngage:
-	push hl
-	push de
-	ld a, [wTrainerSpriteOffset]
-	add $2
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl]             ; c1x2: sprite image index
-	sub $ff
-	jr nz, .spriteOnScreen ; test if sprite is on screen
-	jp .noEngage
-.spriteOnScreen
-	ld a, [wTrainerSpriteOffset]
-	add $9
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl]             ; c1x9: facing direction
-	ld [wTrainerFacingDirection], a
-	call ReadTrainerScreenPosition
-	ld a, [wTrainerScreenY]          ; sprite screen Y pos
-	ld b, a
-	ld a, $3c
-	cp b
-	jr z, .linedUpY
-	ld a, [wTrainerScreenX]          ; sprite screen X pos
-	ld b, a
-	ld a, $40
-	cp b
-	jr z, .linedUpX
-	xor a
-	jp .noEngage
-.linedUpY
-	ld a, [wTrainerScreenX]        ; sprite screen X pos
-	ld b, a
-	ld a, $40            ; (fixed) player X position
-	call CalcDifference  ; calc distance
-	jr z, .noEngage      ; exact same position as player
-	call CheckSpriteCanSeePlayer
-	jr c, .engage
-	xor a
-	jr .noEngage
-.linedUpX
-	ld a, [wTrainerScreenY]        ; sprite screen Y pos
-	ld b, a
-	ld a, $3c            ; (fixed) player Y position
-	call CalcDifference  ; calc distance
-	jr z, .noEngage      ; exact same position as player
-	call CheckSpriteCanSeePlayer
-	jr c, .engage
-	xor a
-	jp .noEngage
-.engage
-	call CheckPlayerIsInFrontOfSprite
-	ld a, [wTrainerSpriteOffset]
-	and a
-	jr z, .noEngage
-	ld hl, wFlags_0xcd60
-	set 0, [hl]
-	call EngageMapTrainer
-	ld a, $ff
-.noEngage
-	ld [wTrainerSpriteOffset], a
-	pop de
-	pop hl
-	ret
-
-; reads trainer's Y position to wTrainerScreenY and X position to wTrainerScreenX
-ReadTrainerScreenPosition:
-	ld a, [wTrainerSpriteOffset]
-	add $4
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl] ; c1x4 (sprite Y pos)
-	ld [wTrainerScreenY], a
-	ld a, [wTrainerSpriteOffset]
-	add $6
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl] ; c1x6 (sprite X pos)
-	ld [wTrainerScreenX], a
-	ret
-
-; checks if the sprite is properly lined up with the player with respect to the direction it's looking. Also checks the distance between player and sprite
-; note that this does not necessarily mean the sprite is seeing the player, he could be behind it's back
-; a: distance player to sprite
-CheckSpriteCanSeePlayer:
-	ld b, a
-	ld a, [wTrainerEngageDistance] ; how far the trainer can see
-	cp b
-	jr nc, .checkIfLinedUp
-	jr .notInLine         ; player too far away
-.checkIfLinedUp
-	ld a, [wTrainerFacingDirection]         ; sprite facing direction
-	cp SPRITE_FACING_DOWN
-	jr z, .checkXCoord
-	cp SPRITE_FACING_UP
-	jr z, .checkXCoord
-	cp SPRITE_FACING_LEFT
-	jr z, .checkYCoord
-	cp SPRITE_FACING_RIGHT
-	jr z, .checkYCoord
-	jr .notInLine
-.checkXCoord
-	ld a, [wTrainerScreenX]         ; sprite screen X position
-	ld b, a
-	cp $40
-	jr z, .inLine
-	jr .notInLine
-.checkYCoord
-	ld a, [wTrainerScreenY]         ; sprite screen Y position
-	ld b, a
-	cp $3c
-	jr nz, .notInLine
-.inLine
-	scf
-	ret
-.notInLine
-	and a
-	ret
-
-; tests if the player is in front of the sprite (rather than behind it)
-CheckPlayerIsInFrontOfSprite:
-	ld a, [wCurMap]
-	cp POWER_PLANT
-	jp z, .engage       ; bypass this for power plant to get voltorb fake items to work
-	ld a, [wTrainerSpriteOffset]
-	add $4
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl]          ; c1x4 (sprite screen Y pos)
-	cp $fc
-	jr nz, .notOnTopmostTile ; special case if sprite is on topmost tile (Y = $fc (-4)), make it come down a block
-	ld a, $c
-.notOnTopmostTile
-	ld [wTrainerScreenY], a
-	ld a, [wTrainerSpriteOffset]
-	add $6
-	ld d, $0
-	ld e, a
-	ld hl, wSpriteStateData1
-	add hl, de
-	ld a, [hl]          ; c1x6 (sprite screen X pos)
-	ld [wTrainerScreenX], a
-	ld a, [wTrainerFacingDirection]       ; facing direction
-	cp SPRITE_FACING_DOWN
-	jr nz, .notFacingDown
-	ld a, [wTrainerScreenY]       ; sprite screen Y pos
-	cp $3c
-	jr c, .engage       ; sprite above player
-	jr .noEngage        ; sprite below player
-.notFacingDown
-	cp SPRITE_FACING_UP
-	jr nz, .notFacingUp
-	ld a, [wTrainerScreenY]       ; sprite screen Y pos
-	cp $3c
-	jr nc, .engage      ; sprite below player
-	jr .noEngage        ; sprite above player
-.notFacingUp
-	cp SPRITE_FACING_LEFT
-	jr nz, .notFacingLeft
-	ld a, [wTrainerScreenX]       ; sprite screen X pos
-	cp $40
-	jr nc, .engage      ; sprite right of player
-	jr .noEngage        ; sprite left of player
-.notFacingLeft
-	ld a, [wTrainerScreenX]       ; sprite screen X pos
-	cp $40
-	jr nc, .noEngage    ; sprite right of player
-.engage
-	ld a, $ff
-	jr .done
-.noEngage
-	xor a
-.done
-	ld [wTrainerSpriteOffset], a
-	ret
diff --git a/engine/overworld/turn_sprite.asm b/engine/overworld/turn_sprite.asm
new file mode 100755
index 00000000..c7f7712b
--- /dev/null
+++ b/engine/overworld/turn_sprite.asm
@@ -0,0 +1,25 @@
+UpdateSpriteFacingOffsetAndDelayMovement::
+	ld h, $c2
+	ld a, [H_CURRENTSPRITEOFFSET]
+	add $8
+	ld l, a
+	ld a, $7f ; maximum movement delay
+	ld [hl], a ; c2x8 (movement delay)
+	dec h
+	ld a, [H_CURRENTSPRITEOFFSET]
+	add $9
+	ld l, a
+	ld a, [hld] ; c1x9 (facing direction)
+	ld b, a
+	xor a
+	ld [hld], a
+	ld [hl], a ; c1x8 (walk animation frame)
+	ld a, [H_CURRENTSPRITEOFFSET]
+	add $2
+	ld l, a
+	ld a, [hl] ; c1x2 (facing and animation table offset)
+	or b ; or in the facing direction
+	ld [hld], a
+	ld a, $2 ; delayed movement status
+	ld [hl], a ; c1x1 (movement status)
+	ret
-- 
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