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SCHG How-to

Make an Alternative Title Screen

From Sonic Retro

(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:

; ---------------------------------------------------------------------------
; 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:

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

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

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:

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

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:

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-

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

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-

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

SCHG How-To Guide: Sonic the Hedgehog (16-bit)
Fixing Bugs
Fix Demo Playback | Fix a Race Condition with Pattern Load Cues | Fix the SEGA Sound | Display the Press Start Button Text | Fix the Level Select Menu | Fix the Hidden Points Bug | Fix Accidental Deletion of Scattered Rings | Fix Ring Timers | Fix the Walk-Jump Bug | Correct Drowning Bugs | Fix the Death Boundary Bug | Fix the Camera Follow Bug | Fix Song Restoration Bugs | Fix the HUD Blinking | Fix the Level Select Graphics Bug
Changing Design Choices
Change Spike Behavior | Fix Special Stage Jumping Physics | Improve the Fade In\Fade Out Progression Routines | Fix Scattered Rings' Underwater Physics | Remove the Speed Cap | Port the REV01 Background Effects | Port Sonic 2's Level Art Loader | Retain Rings Between Acts | Add Sonic 2 (Simon Wai Prototype) Level Select | Improve ObjectMove Subroutines
Adding Features
Add Spin Dash ( Part 1 / Part 2 / Part 3 / Part 4 ) | Add Eggman Monitor
Sound Features
Expand Music Index From $94 to $9F | Extend Music Slots | Play Different Songs Per Act | Expand Music Index to Start at $00 | Port Sonic 2 Final Sound Driver | Port Sonic 3's Sound Driver
Extending the Game
Load Chunks From ROM | Add Extra Characters | Make an Alternative Title Screen | Use Dynamic Tilesets | Make GHZ Load Alternate Art | Add a New Zone | Set Up the Goggle Monitor | Add New Moves | Add a Dynamic Collision System | Dynamic Special Stage Walls System | Extend Sprite Mappings and Art Limit | Enigma Credits
Miscellaneous
Convert the Hivebrain 2005 Disassembly to ASM68K
Split Disassembly Guides
Set Up a Split Disassembly | Basic Level Editing | Basic Art Editing | Basic ASM Editing (Spin Dash)