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SCHG How-to

Separate ending art from GHZ/make Ending load alternate art

From Sonic Retro

(Original guide by JGMR)
(Based on this guide by MKAmeX and originally by Shadow05)

The title says it all. After completing the previous guide, this guide will make the Ending sequence for Sonic 1 to load a different art file, allowing you to have custom level art for the Ending sequence that won't appear in the Title or in GHZ.

Note that this guide is optional; you might not want to follow this guide unless you want the art for GHZ, the title screen and the ending sequence separated.

Hivebrain's 2005 disasssembly

First, we'll need to have a copy of GHZ's level art file:

Simply copy '8x8ghz.bin' and rename it as 8x8end.bin.

With that done, we now have our Ending sequence art (8x8end.bin), the GHZ art (8x8ghz.bin), and our Title Screen art (8x8ghz1.bin + 8x8ghz2.bin). Now we can edit the code to this art separately.

First, open _inc/Main level load blocks.asm.

Find this:

        dc.l Nem_GHZ_2nd        ; main load block for ending

Change Nem_GHZ_2nd to Nem_Ending, you should be left with this:

        dc.l Nem_Ending ; main load block for ending

This is pointless as this particular pointer is never used, but it'll keep things tidy.

Next, open sonic1.asm and look for:

Nem_GHZ:        incbin  artnem\8x8ghz.bin       ; GHZ primary patterns
                even

Add this after Nem_GHZ::

Nem_Ending:     incbin  artnem\8x8end.bin       ; Ending sequence primary patterns
                even

It should look like:

Blk16_GHZ:	incbin	map16\ghz.bin
		even
Nem_GHZ:	incbin	artnem\8x8ghz.bin	; GHZ primary patterns
		Even
Nem_Ending:	incbin	artnem\8x8end.bin	; Ending sequence primary patterns
		even
Nem_GHZ_1st:	incbin	artnem\8x8ghz1.bin	; Title Screen only
		even
Nem_GHZ_2nd:	incbin	artnem\8x8ghz2.bin	; Title Screen only
		even
Blk256_GHZ:	incbin	map256\ghz.bin
		even

Next, open _inc/Pattern load cues.asm and find:

PLC_Ending:	dc.w $E
		dc.l Nem_GHZ_1st	; GHZ main patterns
		dc.w 0
		dc.l Nem_GHZ_2nd	; GHZ secondary	patterns
		dc.w $39A0

Change Nem_GHZ_1st to Nem_Ending, remove Nem_GHZ_2nd's entry, and change the dc.w $E to dc.w $D. Your code should look like this.

PLC_Ending:	dc.w $D
		dc.l Nem_Ending	; Ending sequence main patterns
		dc.w 0

Load up your ROM and it should load correctly. Though you won't be able to tell the difference between the Ending sequence, Title screen, and GHZ art unless you edit it.

SVN/GitHub disassembly

First, we'll need to have a copy of GHZ's level art file:

Simply copy '8x8 - GHZ.bin' and rename it as 8x8 - Ending.bin.

With that done, we now have our Ending sequence art (8x8 - Ending.bin), the GHZ art (8x8 - GHZ.bin), and our Title Screen art (8x8 - GHZ1.bin + 8x8 - GHZ2.bin). Now we can edit the code to this art separately.

First, open _inc/LevelHeaders.asm.

Find this:

	lhead	0,		Nem_GHZ_2nd,	0,		Blk16_GHZ,	Blk256_GHZ,	bgm_SBZ,	palid_Ending	; Ending

Change Nem_GHZ_2nd to Nem_Ending, you should be left with this:

	lhead	0,		Nem_Ending,	0,		Blk16_GHZ,	Blk256_GHZ,	bgm_SBZ,	palid_Ending	; Ending

This is pointless as this particular pointer is never used, but it'll keep things tidy.

Next, open sonic.asm and look for:

Nem_GHZ:	incbin	"artnem\8x8 - GHZ.bin"	; GHZ primary patterns
		even

Add this after Nem_GHZ::

Nem_Ending:	incbin	"artnem\8x8 - Ending.bin"	; Ending sequence primary patterns
		even

It should look like:

Blk16_GHZ:	incbin	"map16\GHZ.bin"
		even
Nem_GHZ:	incbin	"artnem\8x8 - GHZ.bin"	; GHZ primary patterns
		even
Nem_Ending:	incbin	"artnem\8x8 - Ending.bin"	; Ending sequence primary patterns
		even
Nem_GHZ_1st:	incbin	"artnem\8x8 - GHZ1.bin"	; Title Screen only
		even
Nem_GHZ_2nd:	incbin	"artnem\8x8 - GHZ2.bin"	; Title Screen only
		even
Blk256_GHZ:	incbin	"map256\GHZ.bin"
		even

Next, go to _inc/Pattern Load Cues.asm and find:

PLC_Ending:	dc.w ((PLC_Endingend-PLC_Ending-2)/6)-1
		plcm	Nem_GHZ_1st,0		; GHZ main patterns
		plcm	Nem_GHZ_2nd, $39A0	; GHZ secondary	patterns

Change Nem_GHZ_1st to Nem_Ending and remove Nem_GHZ_2nd's entry. Your code should look like this:

PLC_Ending:	dc.w ((PLC_Endingend-PLC_Ending-2)/6)-1
		plcm	Nem_Ending,0		; Ending sequence main patterns

Load up your ROM and it should load correctly. Though you won't be able to tell the difference between the Ending sequence, Title screen, and GHZ art unless you edit it.

Also, if you're going to be editing the art, you may want to edit the blocks and chunks, but luckily those are separated between the GHZ, Ending sequence and Title screen. Have fun with your new art!

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 | Fix a remember sprite related bug
Changing Design Choices
Change Spike Behavior | Collide with Water After Being Hurt | 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 | Add Sonic 2 Level Select | Collide with Water After Being Hurt | Smooth Out Rotation in Special Stages
Adding Features
Add Spin Dash ( Part 1 (GitHub)/(Hivebrain) / Part 2 / Part 3 / Part 4 ) | Add Eggman Monitor | Add Super Sonic | Add Extended Camera | Add the Air Roll | Add 6-Button Support
Sound Features
Expand the Sound Index | Play Different Songs Per Act | Port Sonic 2 Final Sound Driver | Port Sonic 3's Sound Driver | Change The SEGA Sound | Correct PAL Music Tempo
Extending the Game
Load Chunks From ROM | Add Extra Characters | Make an Alternative Title Screen | Use Dynamic Tilesets | Make GHZ Load Alternate Art | Make Ending 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 | Use Dynamic Palettes
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)