Separate title art from GHZ/make GHZ load alternate art
From Sonic Retro
Revision as of 13:35, 14 December 2017 by MarioMario456 (talk | contribs)
(Original guide by MKAmeX)
In case the title's too vague, this guide will make GHZ load a different art file to the Title Screen and the Ending. Allowing you to have custom level art for GHZ that won't appear in the Title or Ending.
Hivebrain's 2005 disasssembly
First, we'll need to merge GHZ's two level art files into one:
Open your hex editor and open '8x8ghz1.bin' and '8x8ghz2.bin', found in the artnem_u folder, and append the contents of 8x8ghz2.bin to the end of 8x8ghz1.bin. Save it as 8x8ghz.bin.
Download a compressor, and compress the file in Nemesis (save the compressed file in the "artnem" folder).
With that done, we now have our GHZ art (8x8ghz.bin), and our Title Screen & Ending art (8x8ghz1.bin + 8x8ghz2.bin). Now we can edit the code to use these two separately.
First, open _inc/Main level load blocks.asm.
Find this:
lhead plcid_GHZ, Nem_GHZ_2nd, plcid_GHZ2, Blk16_GHZ, Blk256_GHZ, bgm_GHZ, palid_GHZ ; Green Hill
Change Nem_GHZ_2nd to Nem_GHZ, you should be left with this:
lhead plcid_GHZ, Nem_GHZ, plcid_GHZ2, Blk16_GHZ, Blk256_GHZ, bgm_GHZ, palid_GHZ ; Green Hill
This is pointless as this particular pointer is never used, but it'll keep things tidy.
Next, open sonic1.asm and look for:
Blk16_GHZ: incbin "map16\ghz.bin"
even
Nem_GHZ_1st: incbin "artnem\8x8ghz1.bin" ; Title Screen and Ending only
even
Nem_GHZ_2nd: incbin "artnem\8x8ghz2.bin" ; Title Screen and Ending only
even
Blk256_GHZ: incbin "map256\ghz.bin"
even
Add this above Nem_GHZ_1st::
Nem_GHZ: incbin "artnem\8x8ghz.bin" ; GHZ 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_GHZ_1st: incbin "artnem\8x8ghz1.bin" ; Title Screen and Ending only
even
Nem_GHZ_2nd: incbin "artnem\8x8ghz2.bin" ; Title Screen and Ending only
even
Blk256_GHZ: incbin "map256\ghz.bin"
even
Next, open _inc/Pattern load cues.asm and find:
PLC_GHZ: dc.w ((PLC_GHZ2-PLC_GHZ-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_GHZ and remove Nem_GHZ_2nd's entry. Your code should look like this.
PLC_GHZ: dc.w ((PLC_GHZ2-PLC_GHZ-2)/6)-1
plcm Nem_GHZ, 0 ; GHZ main patterns
Load up your ROM and it should load correctly. Though you won't be able to tell the difference between the Title+Ending and GHZ art unless you edit it.
SVN/GitHub disassembly
First, we'll need to merge GHZ's two level art files into one:
Both files are Nemesis-compressed, so we'll need to decompress them before we merge them. Get a decompressor (you can find some here) and use them to decompress the files '8x8 - GHZ1.bin' and '8x8 - GHZ2.bin', found in the artnem folder. After that, open the two decompressed files in a hex editor, and append the contents of 8x8 - GHZ2.bin to the end of 8x8 - GHZ1.bin, and save the result as 8x8 - GHZ.bin. Compress this file in Nemesis and delete the uncompressed files, they won't be needed anymore.
With that done, we now have our GHZ art (8x8 - GHZ.bin), and our Title Screen & Ending art (8x8 - GHZ1.bin + 8x8 - GHZ2.bin). Now we can edit the code to use these two separately.
First, load _inc/LevelHeaders.asm
Find this:
lhead plcid_GHZ, Nem_GHZ_2nd, plcid_GHZ2, Blk16_GHZ, Blk256_GHZ, bgm_GHZ, palid_GHZ ; Green Hill
Change Nem_GHZ_2nd to Nem_GHZ, you should be left with this:
lhead plcid_GHZ, Nem_GHZ, plcid_GHZ2, Blk16_GHZ, Blk256_GHZ, bgm_GHZ, palid_GHZ ; Green Hill
This is pointless as this particular pointer is never used, but it'll keep things tidy.
Next, open sonic.asm and look for:
Blk16_GHZ: incbin "map16\GHZ.bin"
even
Nem_GHZ_1st: incbin "artnem\8x8 - GHZ1.bin" ; Title Screen and Ending only
even
Nem_GHZ_2nd: incbin "artnem\8x8 - GHZ2.bin" ; Title Screen and Ending only
even
Blk256_GHZ: incbin "map256\GHZ.bin"
even
Add this above Nem_GHZ_1st::
Nem_GHZ: incbin "artnem\8x8 - GHZ.bin" ; GHZ 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_GHZ_1st: incbin "artnem\8x8 - GHZ1.bin" ; Title Screen and Ending only
even
Nem_GHZ_2nd: incbin "artnem\8x8 - GHZ2.bin" ; Title Screen and Ending only
even
Blk256_GHZ: incbin "map256\GHZ.bin"
even
Next, go to _inc/Pattern Load Cues.asm and find:
PLC_GHZ: dc.w ((PLC_GHZ2-PLC_GHZ-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_GHZ and remove Nem_GHZ_2nd's entry. Your code should look like this.
PLC_GHZ: dc.w ((PLC_GHZ2-PLC_GHZ-2)/6)-1
plcm Nem_GHZ, 0 ; GHZ main patterns
Load up your ROM and it should load correctly. Though you won't be able to tell the difference between the Title+Ending 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, though those are still shared between the GHZ+Ending and Title. If you want to separate those too, look at this guide: SCHG How-to:Make an Alternative Title Screen