Disassemble Game Freak logo intro

1 files changed, 376 insertions, 0 deletions

diff --git a/engine/movie/gamefreak_presents.asm b/engine/movie/gamefreak_presents.asm
new file mode 100644
index 00000000..6b15472f
--- /dev/null
+++ b/engine/movie/gamefreak_presents.asm
@@ -0,0 +1,376 @@
+Copyright_GFPresents: ; e49a8 (39:49a8)
+; Play the copyright screen and GameFreak Presents sequence.
+; Return carry if user cancels animation by pressing a button.
+
+	call ClearBGPalettes
+	call ClearTileMap
+
+	ld a, HIGH(vBGMap0)
+	ld [hBGMapAddress + 1], a
+	xor a ; LOW(vBGMap0)
+	ld [hBGMapAddress], a
+
+	ld [hJoyDown], a
+	ld [hSCX], a
+	ld [hSCY], a
+
+	ld a, SCREEN_HEIGHT_PX
+	ld [hWY], a
+
+	call WaitBGMap
+
+	ld b, SCGB_GAMEFREAK_LOGO
+	call GetSGBLayout
+
+	call SetPalettes
+
+	ld c, 10
+	call DelayFrames
+
+	callfar Copyright
+
+	call WaitBGMap
+
+	ld c, 100
+	call DelayFrames
+
+	call ClearTileMap
+	call GFPresents_Init
+
+.loop
+	call GFPresents_PlayFrame
+	jr nc, .loop
+
+	; high bits of wJumpTableIndex are recycled for some flags
+	; this was set if user canceled by pressing a button
+	ld a, [wJumpTableIndex]
+	bit 6, a
+	jr nz, .canceled
+
+	; clear carry flag from GFPresents_PlayFrame
+	and a
+	ret
+
+.canceled
+	scf
+	ret
+
+GFPresents_Init: ; e49f3 (39:49f3)
+; Load gfx and initialize variables
+
+	ld de, GFPresentsGFX1
+	ld hl, vTiles1
+	lb bc, BANK(GFPresentsGFX1), 28
+	call Get1bpp
+
+	ld de, GFPresentsGFX2
+	ld hl, vTiles1 tile 28
+	lb bc, BANK(GFPresentsGFX2), 5
+	call Request2bpp
+
+	farcall ClearAnimatedObjectBuffer
+
+	ld hl, wAnimatedObjectDynamicVTileOffsets
+	ld a, 6
+	ld [hli], a
+	ld a, $8d
+	ld [hl], a
+
+	xor a
+	ld [wJumpTableIndex], a
+	ld [$ce64], a
+	ld [wIntroSceneTimer], a
+	ld [hSCX], a
+	ld [hSCY], a
+
+	ld a, 1
+	ld [hBGMapMode], a
+
+	ld a, SCREEN_HEIGHT_PX
+	ld [hWY], a
+
+	lb de, %00100100, %11111000
+	call DmgToCgbObjPals
+	ret
+
+GFPresents_PlayFrame: ; e4a37 (39:4a37)
+; Play one frame of GFPresents sequence.
+; Return carry when the sequence completes or is canceled.
+
+	call JoyTextDelay
+	ld a, [hJoyLast]
+	and BUTTONS
+	jr nz, .pressed_button
+
+	; high bits of wJumpTableIndex are recycled for some flags
+	; this is set when the sequence finished
+	ld a, [wJumpTableIndex]
+	bit 7, a
+	jr nz, .finish
+
+	farcall AnimatedObjects_PlayFrame
+
+	call GFPresents_HandleFrame
+	call DelayFrame
+
+	; ensure carry is cleared
+	and a
+	ret
+
+.pressed_button
+	; high bits of wJumpTableIndex are recycled for some flags
+	ld hl, wJumpTableIndex
+	set 6, [hl]
+
+.finish
+	callfar ClearAnimatedObjectBuffer
+	call ClearTileMap
+	call ClearSprites
+
+	ld c, 16
+	call DelayFrames
+
+	scf
+	ret
+
+GFPresents_HandleFrame: ; e4a6d (39:4a6d)
+; Dispatch to the current scene handler
+
+	ld a, [wJumpTableIndex]
+	ld e, a
+	ld d, 0
+	ld hl, .scenes
+	add hl, de
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	jp hl
+
+.scenes
+	dw GFPresents_Star
+	dw GFPresents_PlaceLogo
+	dw GFPresents_LogoSparkles
+	dw GFPresents_PlacePresents
+	dw GFPresents_WaitForTimer
+	dw GFPresents_SetDoneFlag
+
+GFPresents_NextScene: ; e4a88 (39:4a88)
+	ld hl, wJumpTableIndex
+	inc [hl]
+	ret
+
+; unused?
+Func_e4a8d: ; e4a8d (39:4a8d)
+	ld c, 64
+	call DelayFrames
+	call GFPresents_NextScene
+	ret
+
+GFPresents_Star: ; e4a96 (39:4a96)
+
+	; tell GFPresents_PlaceLogo we haven't finished yet
+	xor a
+	ld [$ce64], a
+
+	depixel 10, 11, 4, 0
+	ld a, $16
+	call InitAnimatedObjectStruct
+
+	; TODO set some flag in the struct?
+	ld hl, $c
+	add hl, bc
+	ld [hl], $80
+
+	ld de, SFX_GAME_FREAK_LOGO_GS
+	call PlaySFX
+
+	call GFPresents_NextScene
+	ret
+
+GFPresents_PlaceLogo: ; e4ab2 (39:4ab2)
+; Draw the Game Freak logo (may be initially invisible due to palette)
+
+	; wait until the star animation completed
+	; TODO this is cleared above, but when is it set?
+	ld a, [$ce64]
+	and a
+	ret z
+
+	depixel 10, 11, 4, 0
+	ld a, $15
+	call InitAnimatedObjectStruct
+
+	call GFPresents_NextScene
+
+	; set timer for GFPresents_LogoSparkles
+	ld a, $80
+	ld [wIntroSceneTimer], a
+	ret
+
+GFPresents_LogoSparkles: ; e4ac8 (39:4ac8)
+
+	ld hl, wIntroSceneTimer
+	ld a, [hl]
+	and a
+	jr z, .done
+	dec [hl]
+
+	; add first text when timer passes half
+	cp $3f
+	call z, GFPresents_PlaceGameFreak
+
+	; add sparkles continuously
+	call GFPresents_Sparkle
+	ret
+
+.done
+	; set (unused?) timer for GFPresents_PlacePresents
+	ld [hl], $80
+	call GFPresents_NextScene
+	ret
+
+GFPresents_PlaceGameFreak: ; e4adf (39:4adf)
+	hlcoord 5, 12
+	ld de, .game_freak
+	call PlaceString
+	ret
+
+.game_freak
+	db $80, $81, $82, $83, $8d, $84, $85, $83, $81, $86, "@"
+
+GFPresents_PlacePresents: ; e4af4 (39:4af4)
+	hlcoord 7, 13
+	ld de, .presents
+	call PlaceString
+
+	call GFPresents_NextScene
+
+	; set timer for GFPresents_WaitForTimer
+	ld a, $80
+	ld [wIntroSceneTimer], a
+	ret
+
+.presents
+	db $87, $88, $89, $8a, $8b, $8c, "@"
+
+GFPresents_SetDoneFlag: ; e4b0d (39:4b0d)
+; Tell GFPresents_PlayFrame and TitleScreenFrame (01:63da) that we're finished.
+
+	ld hl, wJumpTableIndex
+	set 7, [hl]
+	ret
+
+GFPresents_WaitForTimer: ; e4b13 (39:4b13)
+; Wait for the timer to elapse
+
+	ld hl, wIntroSceneTimer
+	ld a, [hl]
+	and a
+	jr z, .done
+	dec [hl]
+	ret
+.done
+	call GFPresents_NextScene
+	ret
+
+GFPresents_UpdateLogoPal: ; e4b20 (39:4b20)
+; called from 29:5928
+; OBP1 was initialized at end of GFPresents_Init
+
+	; once we reached the final state, leave it alone
+	ld a, [rOBP1]
+	cp %10010000
+	ret z
+
+	; wait 16 frames before next change
+	ld a, [wIntroSceneTimer]
+	and $f
+	ret nz
+
+	; rotate OBP1 by one color slot (2 bits)
+	; DMG: logo is white, then light gray, then dark gray
+	; CGB: logo is white, then yellow
+	ld a, [rOBP1]
+	rrca
+	rrca
+	call DmgToCgbObjPal1
+	ret
+
+GFPresents_Sparkle: ; e4b33 (39:4b33)
+; Initialize and configure a sparkle sprite.
+; TODO unclear how this relates to the actual screen display,
+; seems to be called more times than there are visible sparkles?
+
+	; run only every second frame
+	ld d, a
+	and 1
+	ret nz
+
+	; shift over so our index is still changing by 1 each time
+	ld a, d
+	srl a
+
+	; set up a new sparkle sprite
+	push af
+	depixel 11, 11
+	ld a, $17
+	call InitAnimatedObjectStruct
+	pop af
+
+	; take the bottom 4 bits of a as an index into
+	; sparkle_vectors (16 entries)
+	and %00001111
+	ld e, a
+	ld d, 0
+	ld hl, .sparkle_vectors
+	add hl, de
+	add hl, de
+
+	; set the angle and distance for this sprite
+	; bc+$b <- hl (angle), bc+$c <- 0, bc+$d <- hl+1 (distance)
+	ld e, l
+	ld d, h
+	ld hl, $b
+	add hl, bc
+	ld a, [de]
+	ld [hl], a
+	inc de
+	ld hl, $c
+	add hl, bc
+	ld [hl], 0
+	inc hl
+	ld a, [de]
+	ld [hl], a
+
+	ret
+
+.sparkle_vectors
+	; values control final position of each sparkle
+	; position is automatically animated along the vector
+	; each entry emits two sparkles in opposite directions
+	; angle (6 bits) and distance (tiles?)
+	db $00, $03
+	db $08, $04
+	db $04, $03
+	db $0c, $02
+	db $10, $02
+	db $18, $03
+	db $14, $04
+	db $1c, $03
+	db $20, $02
+	db $28, $02
+	db $24, $03
+	db $2c, $04
+	db $30, $04
+	db $38, $03
+	db $34, $02
+	db $3c, $04
+
+GFPresentsGFX1:
+INCBIN "gfx/intro/gamefreak_presents.1bpp"
+INCBIN "gfx/intro/gamefreak_logo.1bpp"
+
+GFPresentsGFX2:
+INCBIN "gfx/intro/logo_star.2bpp"
+INCBIN "gfx/intro/logo_sparkle.2bpp"