Add constants and table macros for the map sprite sets (#392)

Fixes #391

5 files changed, 150 insertions, 125 deletions

diff --git a/constants.asm b/constants.asm
index a307549b..b9445784 100644
--- a/constants.asm
+++ b/constants.asm
@@ -28,6 +28,7 @@ INCLUDE "constants/map_constants.asm"
 INCLUDE "constants/map_data_constants.asm"
 INCLUDE "constants/map_object_constants.asm"
 INCLUDE "constants/hide_show_constants.asm"
+INCLUDE "constants/sprite_set_constants.asm"
 INCLUDE "constants/credits_constants.asm"
 INCLUDE "constants/audio_constants.asm"
 INCLUDE "constants/music_constants.asm"
diff --git a/constants/sprite_set_constants.asm b/constants/sprite_set_constants.asm
new file mode 100644
index 00000000..4f617c4a
--- /dev/null
+++ b/constants/sprite_set_constants.asm
@@ -0,0 +1,38 @@
+; sprite set ids
+; indexes for SpriteSets (see data/maps/sprite_sets.asm)
+; values for MapSpriteSets and SplitMapSpriteSets (see data/maps/sprite_sets.asm)
+	const_def 1
+	const SPRITESET_PALLET_VIRIDIAN ; 01
+	const SPRITESET_PEWTER_CERULEAN ; 02
+	const SPRITESET_LAVENDER        ; 03
+	const SPRITESET_VERMILION       ; 04
+	const SPRITESET_CELADON         ; 05
+	const SPRITESET_INDIGO          ; 06
+	const SPRITESET_SAFFRON         ; 07
+	const SPRITESET_SILENCE_BRIDGE  ; 08
+	const SPRITESET_CYCLING_ROAD    ; 09
+	const SPRITESET_FUCHSIA         ; 0a
+DEF NUM_SPRITE_SETS EQU const_value - 1
+
+; split sprite set ids
+; indexes for SplitMapSpriteSets (see data/maps/sprite_sets.asm)
+; values for MapSpriteSets (see data/maps/sprite_sets.asm)
+	const_next $f1
+DEF FIRST_SPLIT_SET EQU const_value
+	const SPLITSET_ROUTE_2  ; f1
+	const SPLITSET_ROUTE_10 ; f2
+	const SPLITSET_ROUTE_11 ; f3
+	const SPLITSET_ROUTE_12 ; f4
+	const SPLITSET_ROUTE_15 ; f5
+	const SPLITSET_ROUTE_16 ; f6
+	const SPLITSET_ROUTE_18 ; f7
+	const SPLITSET_ROUTE_20 ; f8
+	const SPLITSET_ROUTE_5  ; f9
+	const SPLITSET_ROUTE_6  ; fa
+	const SPLITSET_ROUTE_7  ; fb
+	const SPLITSET_ROUTE_8  ; fc
+DEF NUM_SPLIT_SETS EQU const_value - FIRST_SPLIT_SET
+
+; split directions
+DEF EAST_WEST   EQU 1
+DEF NORTH_SOUTH EQU 2
diff --git a/data/maps/sprite_sets.asm b/data/maps/sprite_sets.asm
index 755ed2fc..23274aa2 100644
--- a/data/maps/sprite_sets.asm
+++ b/data/maps/sprite_sets.asm
@@ -1,73 +1,72 @@
+; Valid sprite IDs for each outdoor map.
+
 MapSpriteSets:
 	table_width 1, MapSpriteSets
-	db $01 ; PALLET_TOWN
-	db $01 ; VIRIDIAN_CITY
-	db $02 ; PEWTER_CITY
-	db $02 ; CERULEAN_CITY
-	db $03 ; LAVENDER_TOWN
-	db $04 ; VERMILION_CITY
-	db $05 ; CELADON_CITY
-	db $0a ; FUCHSIA_CITY
-	db $01 ; CINNABAR_ISLAND
-	db $06 ; INDIGO_PLATEAU
-	db $07 ; SAFFRON_CITY
-	db $01 ; unused map ID
-	db $01 ; ROUTE_1
-	db $f1 ; ROUTE_2
-	db $02 ; ROUTE_3
-	db $02 ; ROUTE_4
-	db $f9 ; ROUTE_5
-	db $fa ; ROUTE_6
-	db $fb ; ROUTE_7
-	db $fc ; ROUTE_8
-	db $02 ; ROUTE_9
-	db $f2 ; ROUTE_10
-	db $f3 ; ROUTE_11
-	db $f4 ; ROUTE_12
-	db $08 ; ROUTE_13
-	db $08 ; ROUTE_14
-	db $f5 ; ROUTE_15
-	db $f6 ; ROUTE_16
-	db $09 ; ROUTE_17
-	db $f7 ; ROUTE_18
-	db $0a ; ROUTE_19
-	db $f8 ; ROUTE_20
-	db $01 ; ROUTE_21
-	db $01 ; ROUTE_22
-	db $06 ; ROUTE_23
-	db $02 ; ROUTE_24
-	db $02 ; ROUTE_25
+	db SPRITESET_PALLET_VIRIDIAN ; PALLET_TOWN
+	db SPRITESET_PALLET_VIRIDIAN ; VIRIDIAN_CITY
+	db SPRITESET_PEWTER_CERULEAN ; PEWTER_CITY
+	db SPRITESET_PEWTER_CERULEAN ; CERULEAN_CITY
+	db SPRITESET_LAVENDER        ; LAVENDER_TOWN
+	db SPRITESET_VERMILION       ; VERMILION_CITY
+	db SPRITESET_CELADON         ; CELADON_CITY
+	db SPRITESET_FUCHSIA         ; FUCHSIA_CITY
+	db SPRITESET_PALLET_VIRIDIAN ; CINNABAR_ISLAND
+	db SPRITESET_INDIGO          ; INDIGO_PLATEAU
+	db SPRITESET_SAFFRON         ; SAFFRON_CITY
+	db SPRITESET_PALLET_VIRIDIAN ; UNUSED_MAP_0B
+	db SPRITESET_PALLET_VIRIDIAN ; ROUTE_1
+	db SPLITSET_ROUTE_2          ; ROUTE_2
+	db SPRITESET_PEWTER_CERULEAN ; ROUTE_3
+	db SPRITESET_PEWTER_CERULEAN ; ROUTE_4
+	db SPLITSET_ROUTE_5          ; ROUTE_5
+	db SPLITSET_ROUTE_6          ; ROUTE_6
+	db SPLITSET_ROUTE_7          ; ROUTE_7
+	db SPLITSET_ROUTE_8          ; ROUTE_8
+	db SPRITESET_PEWTER_CERULEAN ; ROUTE_9
+	db SPLITSET_ROUTE_10         ; ROUTE_10
+	db SPLITSET_ROUTE_11         ; ROUTE_11
+	db SPLITSET_ROUTE_12         ; ROUTE_12
+	db SPRITESET_SILENCE_BRIDGE  ; ROUTE_13
+	db SPRITESET_SILENCE_BRIDGE  ; ROUTE_14
+	db SPLITSET_ROUTE_15         ; ROUTE_15
+	db SPLITSET_ROUTE_16         ; ROUTE_16
+	db SPRITESET_CYCLING_ROAD    ; ROUTE_17
+	db SPLITSET_ROUTE_18         ; ROUTE_18
+	db SPRITESET_FUCHSIA         ; ROUTE_19
+	db SPLITSET_ROUTE_20         ; ROUTE_20
+	db SPRITESET_PALLET_VIRIDIAN ; ROUTE_21
+	db SPRITESET_PALLET_VIRIDIAN ; ROUTE_22
+	db SPRITESET_INDIGO          ; ROUTE_23
+	db SPRITESET_PEWTER_CERULEAN ; ROUTE_24
+	db SPRITESET_PEWTER_CERULEAN ; ROUTE_25
 	assert_table_length FIRST_INDOOR_MAP
 
-DEF EAST_WEST   EQU 1
-DEF NORTH_SOUTH EQU 2
-
 ; Format:
-; 00: determines whether the map is split EAST_WEST or NORTH_SOUTH
-; 01: coordinate of dividing line
-; 02: sprite set ID if in the West or North side
-; 03: sprite set ID if in the East or South side
+; #1: whether the map is split EAST_WEST or NORTH_SOUTH
+; #2: coordinate of dividing line
+; #3: sprite set ID if on the west or north side
+; #4: sprite set ID if on the east or south side
 SplitMapSpriteSets:
-	db NORTH_SOUTH, 37, $02, $01 ; $f1
-	db NORTH_SOUTH, 50, $02, $03 ; $f2
-	db EAST_WEST,   57, $04, $08 ; $f3
-	db NORTH_SOUTH, 21, $03, $08 ; $f4
-	db EAST_WEST,    8, $0A, $08 ; $f5
-	db EAST_WEST,   24, $09, $05 ; $f6
-	db EAST_WEST,   34, $09, $0A ; $f7
-	db EAST_WEST,   53, $01, $0A ; $f8
-	db NORTH_SOUTH, 33, $02, $07 ; $f9
-	db NORTH_SOUTH,  2, $07, $04 ; $fa
-	db EAST_WEST,   17, $05, $07 ; $fb
-	db EAST_WEST,    3, $07, $03 ; $fc
+	table_width 4, SplitMapSpriteSets
+	db NORTH_SOUTH, 37, SPRITESET_PEWTER_CERULEAN, SPRITESET_PALLET_VIRIDIAN ; SPLITSET_ROUTE_2
+	db NORTH_SOUTH, 50, SPRITESET_PEWTER_CERULEAN, SPRITESET_LAVENDER        ; SPLITSET_ROUTE_10
+	db EAST_WEST,   57, SPRITESET_VERMILION,       SPRITESET_SILENCE_BRIDGE  ; SPLITSET_ROUTE_11
+	db NORTH_SOUTH, 21, SPRITESET_LAVENDER,        SPRITESET_SILENCE_BRIDGE  ; SPLITSET_ROUTE_12
+	db EAST_WEST,    8, SPRITESET_FUCHSIA,         SPRITESET_SILENCE_BRIDGE  ; SPLITSET_ROUTE_15
+	db EAST_WEST,   24, SPRITESET_CYCLING_ROAD,    SPRITESET_CELADON         ; SPLITSET_ROUTE_16
+	db EAST_WEST,   34, SPRITESET_CYCLING_ROAD,    SPRITESET_FUCHSIA         ; SPLITSET_ROUTE_18
+	db EAST_WEST,   53, SPRITESET_PALLET_VIRIDIAN, SPRITESET_FUCHSIA         ; SPLITSET_ROUTE_20
+	db NORTH_SOUTH, 33, SPRITESET_PEWTER_CERULEAN, SPRITESET_SAFFRON         ; SPLITSET_ROUTE_5
+	db NORTH_SOUTH,  2, SPRITESET_SAFFRON,         SPRITESET_VERMILION       ; SPLITSET_ROUTE_6
+	db EAST_WEST,   17, SPRITESET_CELADON,         SPRITESET_SAFFRON         ; SPLITSET_ROUTE_7
+	db EAST_WEST,    3, SPRITESET_SAFFRON,         SPRITESET_LAVENDER        ; SPLITSET_ROUTE_8
+	assert_table_length NUM_SPLIT_SETS
 
 SpriteSets:
+	; each sprite set has 9 walking sprites and 2 still sprites
+	table_width 9 + 2, SpriteSets
 
-; each sprite set has 9 walking sprites and 2 still sprites
-DEF SPRITE_SET_LENGTH EQU 9 + 2
-
-; sprite set $01
-	table_width 1
+; SPRITESET_PALLET_VIRIDIAN
 	db SPRITE_BLUE
 	db SPRITE_YOUNGSTER
 	db SPRITE_GIRL
@@ -79,10 +78,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_SWIMMER
 	db SPRITE_POKE_BALL
 	db SPRITE_GAMBLER_ASLEEP
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $02
-	table_width 1
+; SPRITESET_PEWTER_CERULEAN
 	db SPRITE_YOUNGSTER
 	db SPRITE_ROCKET
 	db SPRITE_SUPER_NERD
@@ -94,10 +91,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_COOLTRAINER_M
 	db SPRITE_POKE_BALL
 	db SPRITE_UNUSED_GAMBLER_ASLEEP_2
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $03
-	table_width 1
+; SPRITESET_LAVENDER
 	db SPRITE_LITTLE_GIRL
 	db SPRITE_GIRL
 	db SPRITE_SUPER_NERD
@@ -109,10 +104,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_GUARD
 	db SPRITE_POKE_BALL
 	db SPRITE_UNUSED_GAMBLER_ASLEEP_2
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $04
-	table_width 1
+; SPRITESET_VERMILION
 	db SPRITE_BEAUTY
 	db SPRITE_SUPER_NERD
 	db SPRITE_YOUNGSTER
@@ -124,10 +117,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_COOLTRAINER_M
 	db SPRITE_POKE_BALL
 	db SPRITE_UNUSED_GAMBLER_ASLEEP_2
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $05
-	table_width 1
+; SPRITESET_CELADON
 	db SPRITE_LITTLE_GIRL
 	db SPRITE_LITTLE_BOY
 	db SPRITE_GIRL
@@ -139,10 +130,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_ROCKET
 	db SPRITE_POKE_BALL
 	db SPRITE_SNORLAX
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $06
-	table_width 1
+; SPRITESET_INDIGO
 	db SPRITE_YOUNGSTER
 	db SPRITE_GYM_GUIDE
 	db SPRITE_MONSTER
@@ -154,10 +143,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_GAMBLER
 	db SPRITE_POKE_BALL
 	db SPRITE_UNUSED_GAMBLER_ASLEEP_2
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $07
-	table_width 1
+; SPRITESET_SAFFRON
 	db SPRITE_ROCKET
 	db SPRITE_SCIENTIST
 	db SPRITE_SILPH_WORKER
@@ -169,10 +156,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_MONSTER
 	db SPRITE_POKE_BALL
 	db SPRITE_UNUSED_GAMBLER_ASLEEP_2
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $08
-	table_width 1
+; SPRITESET_SILENCE_BRIDGE
 	db SPRITE_BIKER
 	db SPRITE_SUPER_NERD
 	db SPRITE_MIDDLE_AGED_MAN
@@ -184,10 +169,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_MONSTER
 	db SPRITE_POKE_BALL
 	db SPRITE_SNORLAX
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $09
-	table_width 1
+; SPRITESET_CYCLING_ROAD
 	db SPRITE_BIKER
 	db SPRITE_COOLTRAINER_M
 	db SPRITE_SILPH_WORKER
@@ -199,10 +182,8 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_SUPER_NERD
 	db SPRITE_POKE_BALL
 	db SPRITE_SNORLAX
-	assert_table_length SPRITE_SET_LENGTH
 
-; sprite set $0a
-	table_width 1
+; SPRITESET_FUCHSIA
 	db SPRITE_BIRD
 	db SPRITE_COOLTRAINER_M
 	db SPRITE_FAIRY
@@ -214,4 +195,5 @@ DEF SPRITE_SET_LENGTH EQU 9 + 2
 	db SPRITE_YOUNGSTER
 	db SPRITE_POKE_BALL
 	db SPRITE_FOSSIL
-	assert_table_length SPRITE_SET_LENGTH
+
+	assert_table_length NUM_SPRITE_SETS
diff --git a/engine/overworld/map_sprites.asm b/engine/overworld/map_sprites.asm
index fa3a37dc..5a4c27c3 100644
--- a/engine/overworld/map_sprites.asm
+++ b/engine/overworld/map_sprites.asm
@@ -11,7 +11,7 @@
 InitMapSprites::
 	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)
+; if the map is an inside map (i.e. mapID >= FIRST_INDOOR_MAP)
 	ld hl, wSpritePlayerStateData1PictureID
 	ld de, wSpritePlayerStateData2PictureID
 ; Loop to copy picture IDs from [x#SPRITESTATEDATA1_PICTUREID]
@@ -19,10 +19,10 @@ InitMapSprites::
 .copyPictureIDLoop
 	ld a, [hl] ; a = [x#SPRITESTATEDATA1_PICTUREID]
 	ld [de], a ; [x#SPRITESTATEDATA2_PICTUREID] = a
-	ld a, $10
+	ld a, SPRITESTATEDATA1_LENGTH
 	add e
 	ld e, a
-	ld a, $10
+	ld a, SPRITESTATEDATA1_LENGTH
 	add l
 	ld l, a
 	jr nz, .copyPictureIDLoop
@@ -37,7 +37,7 @@ LoadMapSpriteTilePatterns:
 	ret
 .spritesExist
 	ld c, a ; c = [wNumSprites]
-	ld b, $10 ; number of sprite slots
+	ld b, NUM_SPRITESTATEDATA_STRUCTS
 	ld hl, wSpritePlayerStateData2PictureID
 	xor a
 	ldh [hFourTileSpriteCount], a
@@ -47,7 +47,7 @@ LoadMapSpriteTilePatterns:
 	ld a, [hli] ; a = [x#SPRITESTATEDATA2_PICTUREID]
 	ld [hld], a ; [x#SPRITESTATEDATA2_IMAGEBASEOFFSET] = a
 	ld a, l
-	add $10
+	add SPRITESTATEDATA1_LENGTH
 	ld l, a
 	dec b
 	jr nz, .copyPictureIDLoop
@@ -69,17 +69,17 @@ LoadMapSpriteTilePatterns:
 	cp [hl] ; do the picture ID's match?
 	jp z, .alreadyLoaded
 	ld a, e
-	add $10
+	add SPRITESTATEDATA1_LENGTH
 	ld e, a
 	jr .checkIfAlreadyLoadedLoop
 .notAlreadyLoaded
 	ld de, wSpritePlayerStateData2ImageBaseOffset
-	ld b, $01
+	ld b, 1
 ; 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 $10
+	add SPRITESTATEDATA1_LENGTH
 	ld e, a
 	ld a, l
 	cp e ; reached current slot?
@@ -187,7 +187,7 @@ LoadMapSpriteTilePatterns:
 	jr nz, .loadWhileLCDOn
 	pop af
 	pop hl
-	set 3, h ; add $800 to hl
+	set 3, h ; add $80 tiles to hl
 	push hl
 	ld h, d
 	ld l, e
@@ -200,7 +200,7 @@ LoadMapSpriteTilePatterns:
 .loadWhileLCDOn
 	pop af
 	pop hl
-	set 3, h ; add $800 to hl
+	set 3, h ; add $80 tiles to hl
 	ld b, a
 	swap c
 	call CopyVideoData ; load tile pattern data for sprite when walking
@@ -214,18 +214,18 @@ LoadMapSpriteTilePatterns:
 	ld [hl], a ; [x#SPRITESTATEDATA2_IMAGEBASEOFFSET] = a
 .nextSpriteSlot
 	ld a, l
-	add $10
+	add SPRITESTATEDATA2_LENGTH
 	ld l, a
 	dec c
 	jp nz, .loadTilePatternLoop
 	ld hl, wSpritePlayerStateData2PictureID
-	ld b, $10
+	ld b, NUM_SPRITESTATEDATA_STRUCTS
 ; the pictures IDs stored at [x#SPRITESTATEDATA2_PICTUREID] are no longer needed,
 ; so zero them
 .zeroStoredPictureIDLoop
 	xor a
 	ld [hl], a ; [x#SPRITESTATEDATA2_PICTUREID]
-	ld a, $10
+	ld a, SPRITESTATEDATA2_LENGTH
 	add l
 	ld l, a
 	dec b
@@ -264,7 +264,7 @@ InitOutsideMapSprites:
 	inc h
 .noCarry
 	ld a, [hl] ; a = spriteSetID
-	cp $f0 ; does the map have 2 sprite sets?
+	cp FIRST_SPLIT_SET - 1 ; does the map have 2 sprite sets?
 	call nc, GetSplitMapSpriteSetID ; if so, choose the appropriate one
 	ld b, a ; b = spriteSetID
 	ld a, [wFontLoaded]
@@ -300,7 +300,7 @@ InitOutsideMapSprites:
 ; with picture IDs. This is done so that LoadMapSpriteTilePatterns will
 ; load tile patterns for all sprite pictures in the sprite set.
 .loadSpriteSetLoop
-	ld a, $10
+	ld a, SPRITESTATEDATA2_LENGTH
 	add l
 	ld l, a
 	ld a, [de] ; sprite picture ID from sprite set
@@ -313,7 +313,7 @@ InitOutsideMapSprites:
 	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
+	ld a, SPRITESTATEDATA2_LENGTH
 	add l
 	ld l, a
 	xor a
@@ -335,7 +335,7 @@ InitOutsideMapSprites:
 .zeroVRAMSlotsLoop
 	xor a
 	ld [hl], a ; [x#SPRITESTATEDATA2_IMAGEBASEOFFSET]
-	ld a, $10
+	ld a, SPRITESTATEDATA2_LENGTH
 	add l
 	ld l, a
 	dec b
@@ -366,14 +366,14 @@ InitOutsideMapSprites:
 	inc c
 .skipGettingPictureIndex
 	push hl
-	inc h
-	ld a, $0e
+	inc h ; HIGH(wSpriteStateData2)
+	ld a, SPRITESTATEDATA2_IMAGEBASEOFFSET - SPRITESTATEDATA1_PICTUREID
 	add l
 	ld l, a
 	ld a, c ; a = VRAM slot (zero if sprite slot is not used)
 	ld [hl], a ; [x#SPRITESTATEDATA2_IMAGEBASEOFFSET]
 	pop hl
-	ld a, $10
+	ld a, SPRITESTATEDATA1_LENGTH
 	add l
 	ld l, a
 	and a
@@ -384,7 +384,7 @@ InitOutsideMapSprites:
 ; Chooses the correct sprite set ID depending on the player's position within
 ; the map for maps with two sprite sets.
 GetSplitMapSpriteSetID:
-	cp $f8
+	cp SPLITSET_ROUTE_20
 	jr z, .route20
 	ld hl, SplitMapSpriteSets
 	and $0f
@@ -396,8 +396,8 @@ GetSplitMapSpriteSetID:
 	jr nc, .noCarry
 	inc h
 .noCarry
-	ld a, [hli] ; determines whether the map is split East/West or North/South
-	cp $01
+	ld a, [hli] ; whether the map is split EAST_WEST or NORTH_SOUTH
+	cp EAST_WEST
 	ld a, [hli] ; position of dividing line
 	ld b, a
 	jr z, .eastWestDivide
@@ -409,35 +409,39 @@ GetSplitMapSpriteSetID:
 .compareCoord
 	cp b
 	jr c, .loadSpriteSetID
-; if in the East side or South side
+; 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.
+; Uses sprite set SPRITESET_PALLET_VIRIDIAN for west side and SPRITESET_FUCHSIA 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, wXCoord
+	; Use SPRITESET_PALLET_VIRIDIAN if X < 43
 	ld a, [hl]
-	cp $2b
-	ld a, $01
+	cp 43
+	ld a, SPRITESET_PALLET_VIRIDIAN
 	ret c
+	; Use SPRITESET_FUCHSIA if X >= 62.
 	ld a, [hl]
-	cp $3e
-	ld a, $0a
+	cp 62
+	ld a, SPRITESET_FUCHSIA
 	ret nc
+	; If 55 <= X < 62, split Y at 8; else 43 <= X < 55, so split Y at 13
 	ld a, [hl]
-	cp $37
-	ld b, $08
+	cp 55
+	ld b, 8
 	jr nc, .next
-	ld b, $0d
+	ld b, 13
 .next
+	; Use SPRITESET_FUCHSIA if Y < split; else use SPRITESET_PALLET_VIRIDIAN
 	ld a, [wYCoord]
 	cp b
-	ld a, $0a
+	ld a, SPRITESET_FUCHSIA
 	ret c
-	ld a, $01
+	ld a, SPRITESET_PALLET_VIRIDIAN
 	ret
 
 INCLUDE "data/maps/sprite_sets.asm"
diff --git a/ram/wram.asm b/ram/wram.asm
index 3becc82a..4923ebca 100644
--- a/ram/wram.asm
+++ b/ram/wram.asm
@@ -101,7 +101,7 @@ wSpriteStateData1::
 ; - E
 ; - F
 wSpritePlayerStateData1::  spritestatedata1 wSpritePlayerStateData1 ; player is struct 0
-; wSprite02StateData1 - wSprite15StateData1
+; wSprite01StateData1 - wSprite15StateData1
 FOR n, 1, NUM_SPRITESTATEDATA_STRUCTS
 wSprite{02d:n}StateData1:: spritestatedata1 wSprite{02d:n}StateData1
 ENDR
@@ -127,7 +127,7 @@ wSpriteStateData2::
 ; - E: sprite image base offset (in video ram, player always has value 1, used to compute sprite image index)
 ; - F
 wSpritePlayerStateData2::  spritestatedata2 wSpritePlayerStateData2 ; player is struct 0
-; wSprite02StateData2 - wSprite15StateData2
+; wSprite01StateData2 - wSprite15StateData2
 FOR n, 1, NUM_SPRITESTATEDATA_STRUCTS
 wSprite{02d:n}StateData2:: spritestatedata2 wSprite{02d:n}StateData2
 ENDR