Use more hardware and graphics constants (#532)

- Use `OBJ_SIZE` and `TILE_SIZE` from hardware.inc.
- `SPRITESTATEDATA1_LENGTH`, `NUM_SPRITESTATEDATA_STRUCTS`
  and `TILE_1BPP_SIZE` are used in some places.
- Highlight an oversight in `OakSpeech` where several
  direct MBC bank switches are requested.
- Remove redundant comments in home/overworld.asm.
- Add unreferenced `FillBgMap` function to avoid a byte
  of dead code.
- Some constants added in wram.asm.
- Correctly separate the commented code in `SaveMainData`.

6 files changed, 23 insertions, 13 deletions

diff --git a/engine/movie/credits.asm b/engine/movie/credits.asm
index 1a68a7b5..b1ca7c91 100644
--- a/engine/movie/credits.asm
+++ b/engine/movie/credits.asm
@@ -11,7 +11,7 @@ HallOfFamePC:
 	ld bc, ($20 tiles) / 2
 	call ZeroMemory
 	ld hl, vChars2 tile $7e
-	ld bc, 1 tiles
+	ld bc, TILE_SIZE
 	ld a, $ff ; solid black
 	call FillMemory
 	hlcoord 0, 0
@@ -246,7 +246,7 @@ Credits:
 	pop de
 	ld de, TheEndGfx
 	ld hl, vChars2 tile $60
-	lb bc, BANK(TheEndGfx), (TheEndGfxEnd - TheEndGfx) / $10
+	lb bc, BANK(TheEndGfx), (TheEndGfxEnd - TheEndGfx) / TILE_SIZE
 	call CopyVideoData
 	hlcoord 4, 8
 	ld de, TheEndTextString
diff --git a/engine/movie/intro.asm b/engine/movie/intro.asm
index 00316018..2fa442f9 100644
--- a/engine/movie/intro.asm
+++ b/engine/movie/intro.asm
@@ -439,12 +439,12 @@ IntroNidorinoAnimation7:
 GameFreakIntro:
 	INCBIN "gfx/splash/gamefreak_presents.2bpp"
 	INCBIN "gfx/splash/gamefreak_logo.2bpp"
-	ds 16, $00 ; blank tile
+	ds TILE_SIZE, $00 ; blank tile
 GameFreakIntroEnd:
 
 FightIntroBackMon:
 	INCBIN "gfx/intro/gengar.2bpp"
-	ds 16, $00 ; blank tile
+	ds TILE_SIZE, $00 ; blank tile
 FightIntroBackMonEnd:
 
 IF DEF(_RED)
diff --git a/engine/movie/oak_speech/oak_speech.asm b/engine/movie/oak_speech/oak_speech.asm
index 02826b98..a5f13def 100644
--- a/engine/movie/oak_speech/oak_speech.asm
+++ b/engine/movie/oak_speech/oak_speech.asm
@@ -117,6 +117,9 @@ OakSpeech:
 	ld a, SFX_SHRINK
 	call PlaySound
 	pop af
+; bug: switching ROM Bank should not happen outside of Home Bank
+; This code does nothing, as PlaySound does all necessary Bank switch
+; It looks like a leftover from an early development stage
 	ldh [hLoadedROMBank], a
 	ld [rROMB], a
 	ld c, 4
@@ -145,6 +148,7 @@ OakSpeech:
 	ld [wNewSoundID], a
 	call PlaySound
 	pop af
+; bug: switching ROM Bank should not happen outside of Home Bank
 	ldh [hLoadedROMBank], a
 	ld [rROMB], a
 	ld c, 20
@@ -160,21 +164,26 @@ OakSpeech:
 	call DelayFrames
 	call GBFadeOutToWhite
 	jp ClearScreen
+
 OakSpeechText1:
 	text_far _OakSpeechText1
 	text_end
+
 OakSpeechText2:
 	text_far _OakSpeechText2A
 	; BUG: The cry played does not match the sprite displayed.
 	sound_cry_nidorina
 	text_far _OakSpeechText2B
 	text_end
+
 IntroducePlayerText:
 	text_far _IntroducePlayerText
 	text_end
+
 IntroduceRivalText:
 	text_far _IntroduceRivalText
 	text_end
+
 OakSpeechText3:
 	text_far _OakSpeechText3
 	text_end
@@ -226,7 +235,7 @@ IntroDisplayPicCenteredOrUpperRight:
 	call UncompressSpriteFromDE
 	ld hl, sSpriteBuffer1
 	ld de, sSpriteBuffer0
-	ld bc, $310
+	ld bc, 2 * SPRITEBUFFERSIZE
 	call CopyData
 	ld de, vFrontPic
 	call InterlaceMergeSpriteBuffers
diff --git a/engine/movie/splash.asm b/engine/movie/splash.asm
index da3fec0d..7f06c68b 100644
--- a/engine/movie/splash.asm
+++ b/engine/movie/splash.asm
@@ -13,7 +13,7 @@ LoadShootingStarGraphics:
 	call CopyVideoData
 	ld de, FallingStar
 	ld hl, vChars1 tile $22
-	lb bc, BANK(FallingStar), (FallingStarEnd - FallingStar) / $10
+	lb bc, BANK(FallingStar), (FallingStarEnd - FallingStar) / TILE_SIZE
 	call CopyVideoData
 	ld hl, GameFreakLogoOAMData
 	ld de, wShadowOAMSprite24
@@ -60,11 +60,11 @@ AnimateShootingStar:
 	jr nz, .bigStarLoop
 
 ; Clear big star OAM.
-	ld hl, wShadowOAM
+	ld hl, wShadowOAMSprite00YCoord
 	ld c, 4
-	ld de, 4
+	ld de, OBJ_SIZE
 .clearOAMLoop
-	ld [hl], 160
+	ld [hl], SCREEN_HEIGHT_PX + OAM_Y_OFS
 	add hl, de
 	dec c
 	jr nz, .clearOAMLoop
diff --git a/engine/movie/title.asm b/engine/movie/title.asm
index 698dd5e0..c9ea4b47 100644
--- a/engine/movie/title.asm
+++ b/engine/movie/title.asm
@@ -104,7 +104,7 @@ DisplayTitleScreen:
 ; place tiles for title screen copyright
 	hlcoord 2, 17
 	ld de, .tileScreenCopyrightTiles
-	ld b, $10
+	ld b, .tileScreenCopyrightTilesEnd - .tileScreenCopyrightTiles
 .tileScreenCopyrightTilesLoop
 	ld a, [de]
 	ld [hli], a
@@ -116,6 +116,7 @@ DisplayTitleScreen:
 
 .tileScreenCopyrightTiles
 	db $41,$42,$43,$42,$44,$42,$45,$46,$47,$48,$49,$4A,$4B,$4C,$4D,$4E ; ©'95.'96.'98 GAME FREAK inc.
+.tileScreenCopyrightTilesEnd
 
 .next
 	call SaveScreenTilesToBuffer2
@@ -380,7 +381,7 @@ LoadCopyrightAndTextBoxTiles:
 LoadCopyrightTiles:
 	ld de, NintendoCopyrightLogoGraphics
 	ld hl, vChars2 tile $60
-	lb bc, BANK(NintendoCopyrightLogoGraphics), (GameFreakLogoGraphicsEnd - NintendoCopyrightLogoGraphics) / $10
+	lb bc, BANK(NintendoCopyrightLogoGraphics), (GameFreakLogoGraphicsEnd - NintendoCopyrightLogoGraphics) / TILE_SIZE
 	call CopyVideoData
 	hlcoord 2, 7
 	ld de, CopyrightTextString
diff --git a/engine/movie/trade.asm b/engine/movie/trade.asm
index bf77f21e..292f47cd 100644
--- a/engine/movie/trade.asm
+++ b/engine/movie/trade.asm
@@ -316,7 +316,7 @@ Trade_AnimateBallEnteringLinkCable:
 	ld [wLinkCableAnimBulgeToggle], a
 	add $7e
 	ld hl, wShadowOAMSprite00TileID
-	ld de, 4
+	ld de, OBJ_SIZE
 	ld c, e
 .cycleLinkCableBulgeTile
 	ld [hl], a
@@ -602,7 +602,7 @@ Trade_AnimCircledMon:
 	xor $3c ; make link cable flash
 	ldh [rBGP], a
 	ld hl, wShadowOAMSprite00TileID
-	ld de, $4
+	ld de, OBJ_SIZE
 	ld c, $14
 .loop
 	ld a, [hl]