View source for Make an Alternative Title Screen

{{GuideBy|JcFerggy}}

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

<syntaxhighlight lang="asm">; ---------------------------------------------------------------------------
; 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</syntaxhighlight>
Next, copy the "Blk16_GHZ", "Blk256_GHZ", and "Nem_GHZ_1st", and change "GHZ" to "TS". It should look something like this:

<syntaxhighlight lang="asm">; ---------------------------------------------------------------------------
; 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</syntaxhighlight>
Now search for "Title_LoadText:". You should see this

<syntaxhighlight lang="asm">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 palette 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 palette
		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</syntaxhighlight>
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:

<syntaxhighlight lang="asm">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 palette 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 palette
		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</syntaxhighlight>
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 one of those to projects:

<pre>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:			  ..\palette\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-</pre>

If you are having only a black screen when loading this project, use this one instead:

<pre>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: 2

  Palette 1-

   Start index:        0
   Number of entries: 16
   File:              ..\pallet\sonic.bin

  Palette 2-

   Start index:       16
   Number of entries: 48
   File:              ..\pallet\ghz.bin

Angle Array:             ..\collide\anglemap.bin
Collision Array:         ..\collide\carray_n.bin
Rotated Collision Array: ..\collide\carray_r.bin

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

-EOF-</pre>

And that should be everything to get you on your way.

{{S1Howtos}}
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