Separate ending art from GHZ/make Ending load alternate art

(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!