Completed home/overworld.asm with other related functions

1 files changed, 440 insertions, 440 deletions

diff --git a/engine/overworld/map_sprites.asm b/engine/overworld/map_sprites.asm
index df39d112..54312c6f 100755
--- a/engine/overworld/map_sprites.asm
+++ b/engine/overworld/map_sprites.asm
@@ -1,440 +1,440 @@
-; Loads tile patterns for map's sprites.
-; For outside maps, it loads one of several fixed sets of sprites.
-; For inside maps, it loads each sprite picture ID used in the map header.
-; This is also called after displaying text because loading
-; text tile patterns overwrites half of the sprite tile pattern data.
-; Note on notation:
-; $C1X* and $C2X* are used to denote wSpriteStateData1-wSpriteStateData1 + $ff and wSpriteStateData2 + $00-wSpriteStateData2 + $ff sprite slot
-; fields, respectively, within loops. The X is the loop index.
-; If there is an inner loop, Y is the inner loop index, i.e. $C1Y* and $C2Y*
-; denote fields of the sprite slots interated over in the inner loop.
-InitMapSprites: ; 1785b (5:785b)
-	call InitOutsideMapSprites
-	ret c ; return if the map is an outside map (already handled by above call)
-; if the map is an inside map (i.e. mapID >= $25)
-	ld hl,wSpriteStateData1
-	ld de,wSpriteStateData2 + $0d
-; Loop to copy picture ID's from $C1X0 to $C2XD for LoadMapSpriteTilePatterns.
-.copyPictureIDLoop
-	ld a,[hl] ; $C1X0 (picture ID)
-	ld [de],a ; $C2XD
-	ld a,$10
-	add e
-	ld e,a
-	ld a,$10
-	add l
-	ld l,a
-	jr nz,.copyPictureIDLoop
-
-; This is used for both inside and outside maps, since it is called by
-; InitOutsideMapSprites.
-; Loads tile pattern data for sprites into VRAM.
-LoadMapSpriteTilePatterns: ; 17871 (5:7871)
-	ld a,[W_NUMSPRITES]
-	and a ; are there any sprites?
-	jr nz,.spritesExist
-	ret
-.spritesExist
-	ld c,a ; c = [W_NUMSPRITES]
-	ld b,$10 ; number of sprite slots
-	ld hl,wSpriteStateData2 + $0d
-	xor a
-	ld [$ff8e],a ; 4-tile sprite counter
-.copyPictureIDLoop ; loop to copy picture ID from $C2XD to $C2XE
-	ld a,[hli] ; $C2XD (sprite picture ID)
-	ld [hld],a ; $C2XE
-	ld a,l
-	add a,$10
-	ld l,a
-	dec b
-	jr nz,.copyPictureIDLoop
-	ld hl,wSpriteStateData2 + $1e
-.loadTilePatternLoop
-	ld de,wSpriteStateData2 + $1d
-; Check if the current picture ID has already had its tile patterns loaded.
-; This done by looping through the previous sprite slots and seeing if any of
-; their picture ID's match that of the current sprite slot.
-.checkIfAlreadyLoadedLoop
-	ld a,e
-	and a,$f0
-	ld b,a ; b = offset of the wSpriteStateData2 sprite slot being checked against
-	ld a,l
-	and a,$f0 ; a = offset of current wSpriteStateData2 sprite slot
-	cp b ; done checking all previous sprite slots?
-	jr z,.notAlreadyLoaded
-	ld a,[de] ; picture ID of the wSpriteStateData2 sprite slot being checked against
-	cp [hl] ; do the picture ID's match?
-	jp z,.alreadyLoaded
-	ld a,e
-	add a,$10
-	ld e,a
-	jr .checkIfAlreadyLoadedLoop
-.notAlreadyLoaded
-	ld de,wSpriteStateData2 + $0e
-	ld b,$01
-; loop to find the highest tile pattern VRAM slot (among the first 10 slots) used by a previous sprite slot
-; this is done in order to find the first free VRAM slot available
-.findNextVRAMSlotLoop
-	ld a,e
-	add a,$10
-	ld e,a
-	ld a,l
-	cp e ; reached current slot?
-	jr z,.foundNextVRAMSlot
-	ld a,[de] ; $C2YE (VRAM slot)
-	cp a,11 ; is it one of the first 10 slots?
-	jr nc,.findNextVRAMSlotLoop
-	cp b ; compare the slot being checked to the current max
-	jr c,.findNextVRAMSlotLoop ; if the slot being checked is less than the current max
-; if the slot being checked is greater than or equal to the current max
-	ld b,a ; store new max VRAM slot
-	jr .findNextVRAMSlotLoop
-.foundNextVRAMSlot
-	inc b ; increment previous max value to get next VRAM tile pattern slot
-	ld a,b ; a = next VRAM tile pattern slot
-	push af
-	ld a,[hl] ; $C2XE (sprite picture ID)
-	ld b,a ; b = current sprite picture ID
-	cp a,SPRITE_BALL ; is it a 4-tile sprite?
-	jr c,.notFourTileSprite
-	pop af
-	ld a,[$ff8e] ; 4-tile sprite counter
-	add a,11
-	jr .storeVRAMSlot
-.notFourTileSprite
-	pop af
-.storeVRAMSlot
-	ld [hl],a ; store VRAM slot at $C2XE
-	ld [$ff8d],a ; used to determine if it's 4-tile sprite later
-	ld a,b ; a = current sprite picture ID
-	dec a
-	add a
-	add a
-	push bc
-	push hl
-	ld hl,SpriteSheetPointerTable
-	jr nc,.noCarry
-	inc h
-.noCarry
-	add l
-	ld l,a
-	jr nc,.noCarry2
-	inc h
-.noCarry2
-	push hl
-	call ReadSpriteSheetData
-	push af
-	push de
-	push bc
-	ld hl,vNPCSprites ; VRAM base address
-	ld bc,$c0 ; number of bytes per VRAM slot
-	ld a,[$ff8d]
-	cp a,11 ; is it a 4-tile sprite?
-	jr nc,.fourTileSpriteVRAMAddr
-	ld d,a
-	dec d
-; Equivalent to multiplying $C0 (number of bytes in 12 tiles) times the VRAM
-; slot and adding the result to $8000 (the VRAM base address).
-.calculateVRAMAddrLoop
-	add hl,bc
-	dec d
-	jr nz,.calculateVRAMAddrLoop
-	jr .loadStillTilePattern
-.fourTileSpriteVRAMAddr
-	ld hl,vSprites + $7c0 ; address for second 4-tile sprite
-	ld a,[$ff8e] ; 4-tile sprite counter
-	and a ; is it the first 4-tile sprite?
-	jr nz,.loadStillTilePattern
-; if it's the first 4-tile sprite
-	ld hl,vSprites + $780 ; address for first 4-tile sprite
-	inc a
-	ld [$ff8e],a ; 4-tile sprite counter
-.loadStillTilePattern
-	pop bc
-	pop de
-	pop af
-	push hl
-	push hl
-	ld h,d
-	ld l,e
-	pop de
-	ld b,a
-	ld a,[wFontLoaded]
-	bit 0,a ; reloading upper half of tile patterns after displaying text?
-	jr nz,.skipFirstLoad ; if so, skip loading data into the lower half
-	ld a,b
-	ld b,0
-	call FarCopyData2 ; load tile pattern data for sprite when standing still
-.skipFirstLoad
-	pop de
-	pop hl
-	ld a,[$ff8d]
-	cp a,11 ; is it a 4-tile sprite?
-	jr nc,.skipSecondLoad ; if so, there is no second block
-	push de
-	call ReadSpriteSheetData
-	push af
-	ld a,$c0
-	add e
-	ld e,a
-	jr nc,.noCarry3
-	inc d
-.noCarry3
-	ld a,[wFontLoaded]
-	bit 0,a ; reloading upper half of tile patterns after displaying text?
-	jr nz,.loadWhileLCDOn
-	pop af
-	pop hl
-	set 3,h ; add $800 to hl
-	push hl
-	ld h,d
-	ld l,e
-	pop de
-	call FarCopyData2 ; load tile pattern data for sprite when walking
-	jr .skipSecondLoad
-; When reloading the upper half of tile patterns after diplaying text, the LCD
-; will be on, so CopyVideoData (which writes to VRAM only during V-blank) must
-; be used instead of FarCopyData2.
-.loadWhileLCDOn
-	pop af
-	pop hl
-	set 3,h ; add $800 to hl
-	ld b,a
-	swap c
-	call CopyVideoData ; load tile pattern data for sprite when walking
-.skipSecondLoad
-	pop hl
-	pop bc
-	jr .nextSpriteSlot
-.alreadyLoaded ; if the current picture ID has already had its tile patterns loaded
-	inc de
-	ld a,[de] ; a = VRAM slot for the current picture ID (from $C2YE)
-	ld [hl],a ; store VRAM slot in current wSpriteStateData2 sprite slot (at $C2XE)
-.nextSpriteSlot
-	ld a,l
-	add a,$10
-	ld l,a
-	dec c
-	jp nz,.loadTilePatternLoop
-	ld hl,wSpriteStateData2 + $0d
-	ld b,$10
-; the pictures ID's stored at $C2XD are no longer needed, so zero them
-.zeroStoredPictureIDLoop
-	xor a
-	ld [hl],a ; $C2XD
-	ld a,$10
-	add l
-	ld l,a
-	dec b
-	jr nz,.zeroStoredPictureIDLoop
-	ret
-
-; reads data from SpriteSheetPointerTable
-; INPUT:
-; hl = address of sprite sheet entry
-; OUTPUT:
-; de = pointer to sprite sheet
-; bc = length in bytes
-; a = ROM bank
-ReadSpriteSheetData: ; 17971 (5:7971)
-	ld a,[hli]
-	ld e,a
-	ld a,[hli]
-	ld d,a
-	ld a,[hli]
-	ld c,a
-	xor a
-	ld b,a
-	ld a,[hli]
-	ret
-
-; Loads sprite set for outside maps (cities and routes) and sets VRAM slots.
-; sets carry if the map is a city or route, unsets carry if not
-InitOutsideMapSprites: ; 1797b (5:797b)
-	ld a,[W_CURMAP]
-	cp a,REDS_HOUSE_1F ; is the map a city or a route (map ID less than $25)?
-	ret nc ; if not, return
-	ld hl,MapSpriteSets
-	add l
-	ld l,a
-	jr nc,.noCarry
-	inc h
-.noCarry
-	ld a,[hl] ; a = spriteSetID
-	cp a,$f0 ; does the map have 2 sprite sets?
-	call nc,GetSplitMapSpriteSetID ; if so, choose the appropriate one
-	ld b,a ; b = spriteSetID
-	ld a,[wFontLoaded]
-	bit 0,a ; reloading upper half of tile patterns after displaying text?
-	jr nz,.loadSpriteSet ; if so, forcibly reload the sprite set
-	ld a,[W_SPRITESETID]
-	cp b ; has the sprite set ID changed?
-	jr z,.skipLoadingSpriteSet ; if not, don't load it again
-.loadSpriteSet
-	ld a,b
-	ld [W_SPRITESETID],a
-	dec a
-	ld b,a
-	sla a
-	ld c,a
-	sla a
-	sla a
-	add c
-	add b ; a = (spriteSetID - 1) * 11
-	ld de,SpriteSets
-; add a to de to get offset of sprite set
-	add e
-	ld e,a
-	jr nc,.noCarry2
-	inc d
-.noCarry2
-	ld hl,wSpriteStateData2 + $0d
-	ld a,SPRITE_RED
-	ld [hl],a
-	ld bc,W_SPRITESET
-; Load the sprite set into RAM.
-; This loop also fills $C2XD (sprite picture ID) where X is from $0 to $A
-; with picture ID's. This is done so that LoadMapSpriteTilePatterns will
-; load tile patterns for all sprite pictures in the sprite set.
-.loadSpriteSetLoop
-	ld a,$10
-	add l
-	ld l,a
-	ld a,[de] ; sprite picture ID from sprite set
-	ld [hl],a ; $C2XD (sprite picture ID)
-	ld [bc],a
-	inc de
-	inc bc
-	ld a,l
-	cp a,$bd ; reached 11th sprite slot?
-	jr nz,.loadSpriteSetLoop
-	ld b,4 ; 4 remaining sprite slots
-.zeroRemainingSlotsLoop ; loop to zero the picture ID's of the remaining sprite slots
-	ld a,$10
-	add l
-	ld l,a
-	xor a
-	ld [hl],a ; $C2XD (sprite picture ID)
-	dec b
-	jr nz,.zeroRemainingSlotsLoop
-	ld a,[W_NUMSPRITES]
-	push af ; save number of sprites
-	ld a,11 ; 11 sprites in sprite set
-	ld [W_NUMSPRITES],a
-	call LoadMapSpriteTilePatterns
-	pop af
-	ld [W_NUMSPRITES],a ; restore number of sprites
-	ld hl,wSpriteStateData2 + $1e
-	ld b,$0f
-; The VRAM tile pattern slots that LoadMapSpriteTilePatterns set are in the
-; order of the map's sprite set, not the order of the actual sprites loaded
-; for the current map. So, they are not needed and are zeroed by this loop.
-.zeroVRAMSlotsLoop
-	xor a
-	ld [hl],a ; $C2XE (VRAM slot)
-	ld a,$10
-	add l
-	ld l,a
-	dec b
-	jr nz,.zeroVRAMSlotsLoop
-.skipLoadingSpriteSet
-	ld hl,wSpriteStateData1 + $10
-; This loop stores the correct VRAM tile pattern slots according the sprite
-; data from the map's header. Since the VRAM tile pattern slots are filled in
-; the order of the sprite set, in order to find the VRAM tile pattern slot
-; for a sprite slot, the picture ID for the sprite is looked up within the
-; sprite set. The index of the picture ID within the sprite set plus one
-; (since the Red sprite always has the first VRAM tile pattern slot) is the
-; VRAM tile pattern slot.
-.storeVRAMSlotsLoop
-	ld c,0
-	ld a,[hl] ; $C1X0 (picture ID) (zero if sprite slot is not used)
-	and a ; is the sprite slot used?
-	jr z,.skipGettingPictureIndex ; if the sprite slot is not used
-	ld b,a ; b = picture ID
-	ld de,W_SPRITESET
-; Loop to find the index of the sprite's picture ID within the sprite set.
-.getPictureIndexLoop
-	inc c
-	ld a,[de]
-	inc de
-	cp b ; does the picture ID match?
-	jr nz,.getPictureIndexLoop
-	inc c
-.skipGettingPictureIndex
-	push hl
-	inc h
-	ld a,$0e
-	add l
-	ld l,a
-	ld a,c ; a = VRAM slot (zero if sprite slot is not used)
-	ld [hl],a ; $C2XE (VRAM slot)
-	pop hl
-	ld a,$10
-	add l
-	ld l,a
-	and a
-	jr nz,.storeVRAMSlotsLoop
-	scf
-	ret
-
-; Chooses the correct sprite set ID depending on the player's position within
-; the map for maps with two sprite sets.
-GetSplitMapSpriteSetID: ; 17a1a (5:7a1a)
-	cp a,$f8
-	jr z,.route20
-	ld hl,SplitMapSpriteSets
-	and a,$0f
-	dec a
-	sla a
-	sla a
-	add l
-	ld l,a
-	jr nc,.noCarry
-	inc h
-.noCarry
-	ld a,[hli] ; determines whether the map is split East/West or North/South
-	cp a,$01
-	ld a,[hli] ; position of dividing line
-	ld b,a
-	jr z,.eastWestDivide
-.northSouthDivide
-	ld a,[W_YCOORD]
-	jr .compareCoord
-.eastWestDivide
-	ld a,[W_XCOORD]
-.compareCoord
-	cp b
-	jr c,.loadSpriteSetID
-; if in the East side or South side
-	inc hl
-.loadSpriteSetID
-	ld a,[hl]
-	ret
-; Uses sprite set $01 for West side and $0A for East side.
-; Route 20 is a special case because the two map sections have a more complex
-; shape instead of the map simply being split horizontally or vertically.
-.route20
-	ld hl,W_XCOORD
-	ld a,[hl]
-	cp a,$2b
-	ld a,$01
-	ret c
-	ld a,[hl]
-	cp a,$3e
-	ld a,$0a
-	ret nc
-	ld a,[hl]
-	cp a,$37
-	ld b,$08
-	jr nc,.next
-	ld b,$0d
-.next
-	ld a,[W_YCOORD]
-	cp b
-	ld a,$0a
-	ret c
-	ld a,$01
-	ret
-
-INCLUDE "data/sprite_sets.asm"
+; Loads tile patterns for map's sprites.

+; For outside maps, it loads one of several fixed sets of sprites.

+; For inside maps, it loads each sprite picture ID used in the map header.

+; This is also called after displaying text because loading

+; text tile patterns overwrites half of the sprite tile pattern data.

+; Note on notation:

+; $C1X* and $C2X* are used to denote wSpriteStateData1-wSpriteStateData1 + $ff and wSpriteStateData2 + $00-wSpriteStateData2 + $ff sprite slot

+; fields, respectively, within loops. The X is the loop index.

+; If there is an inner loop, Y is the inner loop index, i.e. $C1Y* and $C2Y*

+; denote fields of the sprite slots interated over in the inner loop.

+_InitMapSprites: ; 1785b (5:785b)

+	call InitOutsideMapSprites

+	ret c ; return if the map is an outside map (already handled by above call)

+; if the map is an inside map (i.e. mapID >= $25)

+	ld hl,wSpriteStateData1

+	ld de,wSpriteStateData2 + $0d

+; Loop to copy picture ID's from $C1X0 to $C2XD for LoadMapSpriteTilePatterns.

+.copyPictureIDLoop

+	ld a,[hl] ; $C1X0 (picture ID)

+	ld [de],a ; $C2XD

+	ld a,$10

+	add e

+	ld e,a

+	ld a,$10

+	add l

+	ld l,a

+	jr nz,.copyPictureIDLoop

+

+; This is used for both inside and outside maps, since it is called by

+; InitOutsideMapSprites.

+; Loads tile pattern data for sprites into VRAM.

+LoadMapSpriteTilePatterns: ; 17871 (5:7871)

+	ld a,[W_NUMSPRITES]

+	and a ; are there any sprites?

+	jr nz,.spritesExist

+	ret

+.spritesExist

+	ld c,a ; c = [W_NUMSPRITES]

+	ld b,$10 ; number of sprite slots

+	ld hl,wSpriteStateData2 + $0d

+	xor a

+	ld [$ff8e],a ; 4-tile sprite counter

+.copyPictureIDLoop ; loop to copy picture ID from $C2XD to $C2XE

+	ld a,[hli] ; $C2XD (sprite picture ID)

+	ld [hld],a ; $C2XE

+	ld a,l

+	add a,$10

+	ld l,a

+	dec b

+	jr nz,.copyPictureIDLoop

+	ld hl,wSpriteStateData2 + $1e

+.loadTilePatternLoop

+	ld de,wSpriteStateData2 + $1d

+; Check if the current picture ID has already had its tile patterns loaded.

+; This done by looping through the previous sprite slots and seeing if any of

+; their picture ID's match that of the current sprite slot.

+.checkIfAlreadyLoadedLoop

+	ld a,e

+	and a,$f0

+	ld b,a ; b = offset of the wSpriteStateData2 sprite slot being checked against

+	ld a,l

+	and a,$f0 ; a = offset of current wSpriteStateData2 sprite slot

+	cp b ; done checking all previous sprite slots?

+	jr z,.notAlreadyLoaded

+	ld a,[de] ; picture ID of the wSpriteStateData2 sprite slot being checked against

+	cp [hl] ; do the picture ID's match?

+	jp z,.alreadyLoaded

+	ld a,e

+	add a,$10

+	ld e,a

+	jr .checkIfAlreadyLoadedLoop

+.notAlreadyLoaded

+	ld de,wSpriteStateData2 + $0e

+	ld b,$01

+; loop to find the highest tile pattern VRAM slot (among the first 10 slots) used by a previous sprite slot

+; this is done in order to find the first free VRAM slot available

+.findNextVRAMSlotLoop

+	ld a,e

+	add a,$10

+	ld e,a

+	ld a,l

+	cp e ; reached current slot?

+	jr z,.foundNextVRAMSlot

+	ld a,[de] ; $C2YE (VRAM slot)

+	cp a,11 ; is it one of the first 10 slots?

+	jr nc,.findNextVRAMSlotLoop

+	cp b ; compare the slot being checked to the current max

+	jr c,.findNextVRAMSlotLoop ; if the slot being checked is less than the current max

+; if the slot being checked is greater than or equal to the current max

+	ld b,a ; store new max VRAM slot

+	jr .findNextVRAMSlotLoop

+.foundNextVRAMSlot

+	inc b ; increment previous max value to get next VRAM tile pattern slot

+	ld a,b ; a = next VRAM tile pattern slot

+	push af

+	ld a,[hl] ; $C2XE (sprite picture ID)

+	ld b,a ; b = current sprite picture ID

+	cp a,SPRITE_BALL ; is it a 4-tile sprite?

+	jr c,.notFourTileSprite

+	pop af

+	ld a,[$ff8e] ; 4-tile sprite counter

+	add a,11

+	jr .storeVRAMSlot

+.notFourTileSprite

+	pop af

+.storeVRAMSlot

+	ld [hl],a ; store VRAM slot at $C2XE

+	ld [$ff8d],a ; used to determine if it's 4-tile sprite later

+	ld a,b ; a = current sprite picture ID

+	dec a

+	add a

+	add a

+	push bc

+	push hl

+	ld hl,SpriteSheetPointerTable

+	jr nc,.noCarry

+	inc h

+.noCarry

+	add l

+	ld l,a

+	jr nc,.noCarry2

+	inc h

+.noCarry2

+	push hl

+	call ReadSpriteSheetData

+	push af

+	push de

+	push bc

+	ld hl,vNPCSprites ; VRAM base address

+	ld bc,$c0 ; number of bytes per VRAM slot

+	ld a,[$ff8d]

+	cp a,11 ; is it a 4-tile sprite?

+	jr nc,.fourTileSpriteVRAMAddr

+	ld d,a

+	dec d

+; Equivalent to multiplying $C0 (number of bytes in 12 tiles) times the VRAM

+; slot and adding the result to $8000 (the VRAM base address).

+.calculateVRAMAddrLoop

+	add hl,bc

+	dec d

+	jr nz,.calculateVRAMAddrLoop

+	jr .loadStillTilePattern

+.fourTileSpriteVRAMAddr

+	ld hl,vSprites + $7c0 ; address for second 4-tile sprite

+	ld a,[$ff8e] ; 4-tile sprite counter

+	and a ; is it the first 4-tile sprite?

+	jr nz,.loadStillTilePattern

+; if it's the first 4-tile sprite

+	ld hl,vSprites + $780 ; address for first 4-tile sprite

+	inc a

+	ld [$ff8e],a ; 4-tile sprite counter

+.loadStillTilePattern

+	pop bc

+	pop de

+	pop af

+	push hl

+	push hl

+	ld h,d

+	ld l,e

+	pop de

+	ld b,a

+	ld a,[wFontLoaded]

+	bit 0,a ; reloading upper half of tile patterns after displaying text?

+	jr nz,.skipFirstLoad ; if so, skip loading data into the lower half

+	ld a,b

+	ld b,0

+	call FarCopyData2 ; load tile pattern data for sprite when standing still

+.skipFirstLoad

+	pop de

+	pop hl

+	ld a,[$ff8d]

+	cp a,11 ; is it a 4-tile sprite?

+	jr nc,.skipSecondLoad ; if so, there is no second block

+	push de

+	call ReadSpriteSheetData

+	push af

+	ld a,$c0

+	add e

+	ld e,a

+	jr nc,.noCarry3

+	inc d

+.noCarry3

+	ld a,[wFontLoaded]

+	bit 0,a ; reloading upper half of tile patterns after displaying text?

+	jr nz,.loadWhileLCDOn

+	pop af

+	pop hl

+	set 3,h ; add $800 to hl

+	push hl

+	ld h,d

+	ld l,e

+	pop de

+	call FarCopyData2 ; load tile pattern data for sprite when walking

+	jr .skipSecondLoad

+; When reloading the upper half of tile patterns after diplaying text, the LCD

+; will be on, so CopyVideoData (which writes to VRAM only during V-blank) must

+; be used instead of FarCopyData2.

+.loadWhileLCDOn

+	pop af

+	pop hl

+	set 3,h ; add $800 to hl

+	ld b,a

+	swap c

+	call CopyVideoData ; load tile pattern data for sprite when walking

+.skipSecondLoad

+	pop hl

+	pop bc

+	jr .nextSpriteSlot

+.alreadyLoaded ; if the current picture ID has already had its tile patterns loaded

+	inc de

+	ld a,[de] ; a = VRAM slot for the current picture ID (from $C2YE)

+	ld [hl],a ; store VRAM slot in current wSpriteStateData2 sprite slot (at $C2XE)

+.nextSpriteSlot

+	ld a,l

+	add a,$10

+	ld l,a

+	dec c

+	jp nz,.loadTilePatternLoop

+	ld hl,wSpriteStateData2 + $0d

+	ld b,$10

+; the pictures ID's stored at $C2XD are no longer needed, so zero them

+.zeroStoredPictureIDLoop

+	xor a

+	ld [hl],a ; $C2XD

+	ld a,$10

+	add l

+	ld l,a

+	dec b

+	jr nz,.zeroStoredPictureIDLoop

+	ret

+

+; reads data from SpriteSheetPointerTable

+; INPUT:

+; hl = address of sprite sheet entry

+; OUTPUT:

+; de = pointer to sprite sheet

+; bc = length in bytes

+; a = ROM bank

+ReadSpriteSheetData: ; 17971 (5:7971)

+	ld a,[hli]

+	ld e,a

+	ld a,[hli]

+	ld d,a

+	ld a,[hli]

+	ld c,a

+	xor a

+	ld b,a

+	ld a,[hli]

+	ret

+

+; Loads sprite set for outside maps (cities and routes) and sets VRAM slots.

+; sets carry if the map is a city or route, unsets carry if not

+InitOutsideMapSprites: ; 1797b (5:797b)

+	ld a,[W_CURMAP]

+	cp a,REDS_HOUSE_1F ; is the map a city or a route (map ID less than $25)?

+	ret nc ; if not, return

+	ld hl,MapSpriteSets

+	add l

+	ld l,a

+	jr nc,.noCarry

+	inc h

+.noCarry

+	ld a,[hl] ; a = spriteSetID

+	cp a,$f0 ; does the map have 2 sprite sets?

+	call nc,GetSplitMapSpriteSetID ; if so, choose the appropriate one

+	ld b,a ; b = spriteSetID

+	ld a,[wFontLoaded]

+	bit 0,a ; reloading upper half of tile patterns after displaying text?

+	jr nz,.loadSpriteSet ; if so, forcibly reload the sprite set

+	ld a,[W_SPRITESETID]

+	cp b ; has the sprite set ID changed?

+	jr z,.skipLoadingSpriteSet ; if not, don't load it again

+.loadSpriteSet

+	ld a,b

+	ld [W_SPRITESETID],a

+	dec a

+	ld b,a

+	sla a

+	ld c,a

+	sla a

+	sla a

+	add c

+	add b ; a = (spriteSetID - 1) * 11

+	ld de,SpriteSets

+; add a to de to get offset of sprite set

+	add e

+	ld e,a

+	jr nc,.noCarry2

+	inc d

+.noCarry2

+	ld hl,wSpriteStateData2 + $0d

+	ld a,SPRITE_RED

+	ld [hl],a

+	ld bc,W_SPRITESET

+; Load the sprite set into RAM.

+; This loop also fills $C2XD (sprite picture ID) where X is from $0 to $A

+; with picture ID's. This is done so that LoadMapSpriteTilePatterns will

+; load tile patterns for all sprite pictures in the sprite set.

+.loadSpriteSetLoop

+	ld a,$10

+	add l

+	ld l,a

+	ld a,[de] ; sprite picture ID from sprite set

+	ld [hl],a ; $C2XD (sprite picture ID)

+	ld [bc],a

+	inc de

+	inc bc

+	ld a,l

+	cp a,$bd ; reached 11th sprite slot?

+	jr nz,.loadSpriteSetLoop

+	ld b,4 ; 4 remaining sprite slots

+.zeroRemainingSlotsLoop ; loop to zero the picture ID's of the remaining sprite slots

+	ld a,$10

+	add l

+	ld l,a

+	xor a

+	ld [hl],a ; $C2XD (sprite picture ID)

+	dec b

+	jr nz,.zeroRemainingSlotsLoop

+	ld a,[W_NUMSPRITES]

+	push af ; save number of sprites

+	ld a,11 ; 11 sprites in sprite set

+	ld [W_NUMSPRITES],a

+	call LoadMapSpriteTilePatterns

+	pop af

+	ld [W_NUMSPRITES],a ; restore number of sprites

+	ld hl,wSpriteStateData2 + $1e

+	ld b,$0f

+; The VRAM tile pattern slots that LoadMapSpriteTilePatterns set are in the

+; order of the map's sprite set, not the order of the actual sprites loaded

+; for the current map. So, they are not needed and are zeroed by this loop.

+.zeroVRAMSlotsLoop

+	xor a

+	ld [hl],a ; $C2XE (VRAM slot)

+	ld a,$10

+	add l

+	ld l,a

+	dec b

+	jr nz,.zeroVRAMSlotsLoop

+.skipLoadingSpriteSet

+	ld hl,wSpriteStateData1 + $10

+; This loop stores the correct VRAM tile pattern slots according the sprite

+; data from the map's header. Since the VRAM tile pattern slots are filled in

+; the order of the sprite set, in order to find the VRAM tile pattern slot

+; for a sprite slot, the picture ID for the sprite is looked up within the

+; sprite set. The index of the picture ID within the sprite set plus one

+; (since the Red sprite always has the first VRAM tile pattern slot) is the

+; VRAM tile pattern slot.

+.storeVRAMSlotsLoop

+	ld c,0

+	ld a,[hl] ; $C1X0 (picture ID) (zero if sprite slot is not used)

+	and a ; is the sprite slot used?

+	jr z,.skipGettingPictureIndex ; if the sprite slot is not used

+	ld b,a ; b = picture ID

+	ld de,W_SPRITESET

+; Loop to find the index of the sprite's picture ID within the sprite set.

+.getPictureIndexLoop

+	inc c

+	ld a,[de]

+	inc de

+	cp b ; does the picture ID match?

+	jr nz,.getPictureIndexLoop

+	inc c

+.skipGettingPictureIndex

+	push hl

+	inc h

+	ld a,$0e

+	add l

+	ld l,a

+	ld a,c ; a = VRAM slot (zero if sprite slot is not used)

+	ld [hl],a ; $C2XE (VRAM slot)

+	pop hl

+	ld a,$10

+	add l

+	ld l,a

+	and a

+	jr nz,.storeVRAMSlotsLoop

+	scf

+	ret

+

+; Chooses the correct sprite set ID depending on the player's position within

+; the map for maps with two sprite sets.

+GetSplitMapSpriteSetID: ; 17a1a (5:7a1a)

+	cp a,$f8

+	jr z,.route20

+	ld hl,SplitMapSpriteSets

+	and a,$0f

+	dec a

+	sla a

+	sla a

+	add l

+	ld l,a

+	jr nc,.noCarry

+	inc h

+.noCarry

+	ld a,[hli] ; determines whether the map is split East/West or North/South

+	cp a,$01

+	ld a,[hli] ; position of dividing line

+	ld b,a

+	jr z,.eastWestDivide

+.northSouthDivide

+	ld a,[W_YCOORD]

+	jr .compareCoord

+.eastWestDivide

+	ld a,[W_XCOORD]

+.compareCoord

+	cp b

+	jr c,.loadSpriteSetID

+; if in the East side or South side

+	inc hl

+.loadSpriteSetID

+	ld a,[hl]

+	ret

+; Uses sprite set $01 for West side and $0A for East side.

+; Route 20 is a special case because the two map sections have a more complex

+; shape instead of the map simply being split horizontally or vertically.

+.route20

+	ld hl,W_XCOORD

+	ld a,[hl]

+	cp a,$2b

+	ld a,$01

+	ret c

+	ld a,[hl]

+	cp a,$3e

+	ld a,$0a

+	ret nc

+	ld a,[hl]

+	cp a,$37

+	ld b,$08

+	jr nc,.next

+	ld b,$0d

+.next

+	ld a,[W_YCOORD]

+	cp b

+	ld a,$0a

+	ret c

+	ld a,$01

+	ret

+

+INCLUDE "data/sprite_sets.asm"