OAM animation of gaining or losing coins during blue/red space effect (#22)

constants/misc_constants.asm

@@ -39,6 +39,7 @@ DEF START_COINS     EQU 100
 DEF MOM_COINS              EQU 2300
 DEF MAX_COINS              EQU 999999
 DEF MAX_LEVEL_COINS        EQU 99999
+DEF MAX_DELTA_COINS_DIGITS EQU 5
 DEF MAX_CHIPS              EQU 9999
 
 ; link record

constants/wram_constants.asm

@@ -14,6 +14,7 @@ DEF AUTO_INPUT EQU $ff
 	const SECONDARYSPRITES_BRANCH_SPACE_F       ; 3
 	const SECONDARYSPRITES_VIEW_MAP_MODE_F      ; 4
 	const SECONDARYSPRITES_TALKER_EVENT_F       ; 5
+	const SECONDARYSPRITES_GAIN_OR_LOSE_COINS_F ; 6
 
 ; wCurDexMode::
 	const_def

data/events/special_pointers.asm

@@ -113,6 +113,8 @@ SpecialsPointers::
 	add_special FadeOutMusic
 	add_special Diploma
 	add_special PrintDiploma
+	add_special PrintGainCoins
+	add_special PrintLoseCoins
 
 ; Crystal only
 	add_special Reset ; bank 0

engine/board/spaces.asm

@@ -6,6 +6,7 @@ BlueSpaceScript::
 	scall LandedInRegularSpaceScript_BeforeSpaceEffect
 	givecoins CUR_LEVEL_COINS, BLUE_RED_SPACE_COINS
 	playsound SFX_TRANSACTION
+	special PrintGainCoins
 	scall LandedInRegularSpaceScript_AfterSpaceEffect
 .not_landed
 	end
@@ -16,6 +17,7 @@ RedSpaceScript::
 	scall LandedInRegularSpaceScript_BeforeSpaceEffect
 	takecoins CUR_LEVEL_COINS, BLUE_RED_SPACE_COINS
 	playsound SFX_TRANSACTION
+	special PrintLoseCoins
 	scall LandedInRegularSpaceScript_AfterSpaceEffect
 .not_landed
 	end
@@ -315,4 +317,43 @@ UnionSpaceScript::
 	call LoadCurSpaceData
 	ret
 
+PrintGainCoins:
+	ld hl, wStringBuffer1
+	ld a, "<COIN>"
+	ld [hli], a
+	ld a, "<PLUS>"
+	ld [hli], a
+	jr PrintGainOrLoseCoins
+
+PrintLoseCoins:
+	ld hl, wStringBuffer1
+	ld a, "<COIN>"
+	ld [hli], a
+	ld a, "<MINUS>"
+	ld [hli], a
+	; fallthrough
+
+PrintGainOrLoseCoins:
+	push hl
+ ; fill string space with "@" to ensure that it is terminated with at least one "@"
+	ld a, "@"
+	ld c, MAX_DELTA_COINS_DIGITS + 1
+.loop
+	ld [hli], a
+	dec c
+	jr nz, .loop
+	pop hl
+; copy coins amount string to wStringBuffer1 + $2
+	ld de, hCoinsTemp
+	lb bc, 3 | 1 << 6, MAX_DELTA_COINS_DIGITS ; 3 bytes, left aligned, no leading zeros, 5 digits
+	call PrintNum
+	ld hl, wDisplaySecondarySprites
+	set SECONDARYSPRITES_GAIN_OR_LOSE_COINS_F, [hl]
+	call UpdateActiveSprites
+	ld c, 45 ; 750 ms
+	call DelayFrames
+	ld hl, wDisplaySecondarySprites
+	res SECONDARYSPRITES_GAIN_OR_LOSE_COINS_F, [hl]
+	ret
+
 INCLUDE "engine/board/disabled_spaces.asm"

engine/overworld/map_objects.asm

@@ -3118,6 +3118,8 @@ InitSecondarySprites:
 	call nz, InitViewMapModeSprites
 	bit SECONDARYSPRITES_TALKER_EVENT_F, a
 	call nz, InitTalkerEventSprites
+	bit SECONDARYSPRITES_GAIN_OR_LOSE_COINS_F, a
+	call nz, InitGainOrLoseCoinsSprites
 	ret
 
 InitBoardMenuSprites:
@@ -3374,6 +3376,8 @@ InitViewMapModeSprites:
 	ret
 
 InitTalkerEventSprites:
+	push af
+
 ; find the beginning of free space in OAM, and assure there's space for 8 objects
 	ldh a, [hUsedSpriteIndex]
 	cp (NUM_SPRITE_OAM_STRUCTS * SPRITEOAMSTRUCT_LENGTH) - (8 * SPRITEOAMSTRUCT_LENGTH) + 1
@@ -3406,4 +3410,74 @@ InitTalkerEventSprites:
 	pop af
 	ret
 
+InitGainOrLoseCoinsSprites:
+	push af
+
+; print string at wStringBuffer1 as OAM
+; get string length
+	ld hl, wStringBuffer1
+	ld c, 0
+.get_length_loop
+	ld a, [hli]
+	cp "@"
+	jr z, .got_length
+	inc c
+	ld a, c
+	cp $2 + MAX_DELTA_COINS_DIGITS + 1
+	jr nz, .get_length_loop
+
+.got_length
+	ld e, c
+; find the beginning of free space in OAM, and assure there's space for c objects
+	ld a, (NUM_SPRITE_OAM_STRUCTS * SPRITEOAMSTRUCT_LENGTH) + 1
+	sla c ;
+	sla c ; c *= SPRITEOAMSTRUCT_LENGTH
+	sub c
+	ld b, a ; b = (NUM_SPRITE_OAM_STRUCTS * SPRITEOAMSTRUCT_LENGTH) - (c * SPRITEOAMSTRUCT_LENGTH) + 1
+	ldh a, [hUsedSpriteIndex]
+	cp b
+	jr nc, .oam_full
+
+; align OAM in the X axis according to the string length (e)
+	ld a, 10 * TILE_WIDTH
+	ld c, TILE_WIDTH / 2
+.x_coord_loop
+	sub c
+	dec e
+	jr nz, .x_coord_loop
+; b = SPRITEOAMSTRUCT_XCOORD
+	ld b, a
+; c = SPRITEOAMSTRUCT_YCOORD
+	ld c, 8 * TILE_WIDTH
+; de = address within wShadowOAM
+	ld a, [hUsedSpriteIndex]
+	ld e, a
+	ld d, HIGH(wShadowOAM)
+	ld hl, wStringBuffer1
+.print_oam_loop
+	ld a, c
+	ld [de], a ; SPRITEOAMSTRUCT_YCOORD
+	inc de
+	ld a, b
+	ld [de], a ; SPRITEOAMSTRUCT_XCOORD
+	inc de
+	add 1 * TILE_WIDTH
+	ld b, a
+	ld a, [hli]
+	ld [de], a ; SPRITEOAMSTRUCT_TILE_ID
+	inc de
+	ld a, PAL_OW_MISC
+	ld [de], a ; SPRITEOAMSTRUCT_ATTRIBUTES
+	inc de
+	ld a, [hl]
+	cp "@"
+	jr nz, .print_oam_loop
+
+	ld a, e
+	ld [hUsedSpriteIndex], a
+
+.oam_full
+	pop af
+	ret
+
 INCLUDE "data/sprites/secondary_sprites.asm"