SCHG How-to:Make an Alternative Title Screen

(Original guide by 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:

<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_LZ: incbin map16\lz.bin even Nem_LZ: incbin artnem\8x8lz.bin; LZ primary patterns even</asm> Next, copy the "Blk16_GHZ", "Blk256_GHZ", and "Nem_GHZ_1st", and change "GHZ" to "TS". It should look something like this:

<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 Blk16_LZ: incbin map16\lz.bin even</asm> Now search for "Title_LoadText:". You should see this

<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</asm> 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:

<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</asm> 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:

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-

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