[Sonic 1] Alternate Title Screen

This tutorial will teach you how to make your title screen load alternate art. If used, please give me credit.


Using the June 2005 Disassembly of Sonic 1, open up sonic1.asm. Okay first search for "Nem_GHZ_1st:". You should see something like this:

Code:

; ---------------------------------------------------------------------------

; Compressed graphics - primary patterns and block mappings

; ---------------------------------------------------------------------------

Blk16_GHZ:	incbin	map16\ghz.bin

		even

Nem_GHZ_1st:	incbin	artnem\8x8ghz1.bin; GHZ primary patterns

		even

Nem_GHZ_2nd:	incbin	artnem\8x8ghz2.bin; GHZ secondary patterns

		even

Blk256_GHZ:	incbin	map256\ghz.bin

		even

Blk16_LZ:	incbin	map16\lz.bin

		even

Nem_LZ:		incbin	artnem\8x8lz.bin; LZ primary patterns

		even

Next, copy the "Blk16_GHZ", "Blk256_GHZ", and "Nem_GHZ_1st", and change "GHZ" to "TS". It should look something like this:

Code:

; ---------------------------------------------------------------------------

; Compressed graphics - primary patterns and block mappings

; ---------------------------------------------------------------------------

Blk16_GHZ:	incbin	map16\ghz.bin

		even

Nem_GHZ_1st:	incbin	artnem\8x8ghz1.bin; GHZ primary patterns

		even

Nem_GHZ_2nd:	incbin	artnem\8x8ghz2.bin; GHZ secondary patterns

		even

Blk256_GHZ:	incbin	map256\ghz.bin

		even

Blk16_TS:	incbin	map16\ts.bin

		even

Nem_TS_1st:	incbin	artnem\8x8ts1.bin; GHZ primary patterns

		even

Blk256_TS:	incbin	map256\ts.bin

		even

Blk16_LZ:	incbin	map16\lz.bin

		even

Now search for "Title_LoadText:". You should see this

Code:

Title_LoadText:

		move.w	(a5)+,(a6)

		dbf	d1,Title_LoadText; load uncompressed text patterns



		move.b	#0,($FFFFFE30).w; clear lamppost counter

		move.w	#0,($FFFFFE08).w; disable debug item placement	mode

		move.w	#0,($FFFFFFF0).w; disable debug mode

		move.w	#0,($FFFFFFEA).w

		move.w	#0,($FFFFFE10).w; set level to	GHZ (00)

		move.w	#0,($FFFFF634).w; disable pallet cycling

		bsr.w	LevelSizeLoad

		bsr.w	DeformBgLayer

		lea	($FFFFB000).w,a1

		lea	(Blk16_GHZ).l,a0; load	GHZ 16x16 mappings

		move.w	#0,d0

		bsr.w	EniDec

		lea	(Blk256_GHZ).l,a0; load GHZ 256x256 mappings

		lea	($FF0000).l,a1

		bsr.w	KosDec

		bsr.w	LevelLayoutLoad

		bsr.w	Pal_FadeFrom

		move	#$2700,sr

		bsr.w	ClearScreen

		lea	($C00004).l,a5

		lea	($C00000).l,a6

		lea	($FFFFF708).w,a3

		lea	($FFFFA440).w,a4

		move.w	#$6000,d2

		bsr.w	LoadTilesFromStart2

		lea	($FF0000).l,a1

		lea	(Eni_Title).l,a0; load	title screen mappings

		move.w	#0,d0

		bsr.w	EniDec

		lea	($FF0000).l,a1

		move.l	#$42060003,d0

		moveq	#$21,d1

		moveq	#$15,d2

		bsr.w	ShowVDPGraphics

		move.l	#$40000000,($C00004).l

		lea	(Nem_GHZ_1st).l,a0; load GHZ patterns

		bsr.w	NemDec

		moveq	#1,d0; load title screen pallet

		bsr.w	PalLoad1

		move.b	#$8A,d0; play title screen music

		bsr.w	PlaySound_Special

		move.b	#0,($FFFFFFFA).w; disable debug mode

		move.w	#$178,($FFFFF614).w; run title	screen for $178	frames

		lea	($FFFFD080).w,a1

		moveq	#0,d0

		move.w	#7,d1

In there you will see things relating to "Blk16_GHZ", "Blk256_GHZ", and "Nem_GHZ_1st". Change them from "GHZ" to "TS" also. You should now have something that looks like this:

Code:

Title_LoadText:

		move.w	(a5)+,(a6)

		dbf	d1,Title_LoadText; load uncompressed text patterns



		move.b	#0,($FFFFFE30).w; clear lamppost counter

		move.w	#0,($FFFFFE08).w; disable debug item placement	mode

		move.w	#0,($FFFFFFF0).w; disable debug mode

		move.w	#0,($FFFFFFEA).w

		move.w	#0,($FFFFFE10).w; set level to	GHZ (00)

		move.w	#0,($FFFFF634).w; disable pallet cycling

		bsr.w	LevelSizeLoad

		bsr.w	DeformBgLayer

		lea	($FFFFB000).w,a1

		lea	(Blk16_TS).l,a0; load	GHZ 16x16 mappings

		move.w	#0,d0

		bsr.w	EniDec

		lea	(Blk256_TS).l,a0; load GHZ 256x256 mappings

		lea	($FF0000).l,a1

		bsr.w	KosDec

		bsr.w	LevelLayoutLoad

		bsr.w	Pal_FadeFrom

		move	#$2700,sr

		bsr.w	ClearScreen

		lea	($C00004).l,a5

		lea	($C00000).l,a6

		lea	($FFFFF708).w,a3

		lea	($FFFFA440).w,a4

		move.w	#$6000,d2

		bsr.w	LoadTilesFromStart2

		lea	($FF0000).l,a1

		lea	(Eni_Title).l,a0; load	title screen mappings

		move.w	#0,d0

		bsr.w	EniDec

		lea	($FF0000).l,a1

		move.l	#$42060003,d0

		moveq	#$21,d1

		moveq	#$15,d2

		bsr.w	ShowVDPGraphics

		move.l	#$40000000,($C00004).l

		lea	(Nem_TS_1st).l,a0; load GHZ patterns

		bsr.w	NemDec

		moveq	#1,d0; load title screen pallet

		bsr.w	PalLoad1

		move.b	#$8A,d0; play title screen music

		bsr.w	PlaySound_Special

		move.b	#0,($FFFFFFFA).w; disable debug mode

		move.w	#$178,($FFFFF614).w; run title	screen for $178	frames

		lea	($FFFFD080).w,a1

		moveq	#0,d0

		move.w	#7,d1

Now, you will be able to load another set of files, but as of yet, you don't have any. Go into "artnem" and make a copy of "8x8ghz1.bin" and "8x8ghz2.bin" and rename them to "8x8ts1.bin" and "8x8ts2.bin". Do the same thing in "map16" and "map256", making a copy of the GHZ files, and renaming them to TS.



Now those TS files you just made will be your new background. You have to edit them the same way you do the regular GHZ files. Also, your new background will still have the layout of your GHZ background, That means the same chunk numbers have to be used. Also, if you want to load the files in SonED2, you need a new project file, so make a copy of an already exsisting one, and replace everything that is in there with this:

Code:

Type: 1	



Zone ID:	0

Act ID:	 0



Object Def: objdef\s1obj



8x8 Tiles: ..\artnem\8x8ts.bin



16x16 Tiles:   ..\map16\ts.bin



256x256 Tiles: ..\map256\ts.bin



FG Layout: ..\levels\blank.bin

BG Layout: ..\levels\ghzbg.bin



Objects:	   ..\objpos\blank.bin



Palettes-



 Number of files: 1



  Palette 1-



   Start index:	   0

   Number of entries: 64

   File:			  ..\pallet\title.bin



Angle Array:			 ..\collide\anglemap.bin

Collision Array:		 ..\collide\colarray_n.bin

Rotated Collision Array: ..\collide\colarray_r.bin



Collision Index 1: ..\collide\blank.bin



-EOF-

You have to use the 8x8's in the first half of the file, since it only loads the 8x8ts1, and not both of them, so if you load it, and some tiles looked messed up, try moving them closer to the start. And that should be everything to get you an your way.

 

This is a wonderful tutorial.


Tutorial archived.

 

Oh, and I forgot to mention that you have to use the 8x8's in the first half of the file, since it only loads the 8x8ts1, and not both of them.