Editing Lagrange Point tiles

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emuman
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Editing Lagrange Point tiles

Post by emuman »

How can I edit Lagrange Point tiles?
I've tried several editors, but the tiles appear scrambled. I also posted a print of the tile visualization using the Mesen debug.

Image
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Gilbert
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Re: Editing Lagrange Point tiles

Post by Gilbert »

Lagrange Point uses CHR-RAM, so the tile graphics data are probably compressed in PRG-ROM. Don't know whether anyone has figured out the compression scheme yet, but even then you need ways to decompress -> edit -> compress -> inject back into the ROM, which I think no one has done yet.
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Yave Yu
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Re: Editing Lagrange Point tiles

Post by Yave Yu »

Yes, this game compressed many tiles, including font, which made me can’t modify them to Mega Man font entirely (such as P, Y).
emuman
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Re: Editing Lagrange Point tiles

Post by emuman »

Gilbert wrote: Tue Apr 16, 2024 7:05 pm Lagrange Point uses CHR-RAM, so the tile graphics data are probably compressed in PRG-ROM. Don't know whether anyone has figured out the compression scheme yet, but even then you need ways to decompress -> edit -> compress -> inject back into the ROM, which I think no one has done yet.

This game was only released in Japan. However, it was translated by a translation group. So this translation group somehow managed to do that.
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Gilbert
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Re: Editing Lagrange Point tiles

Post by Gilbert »

I know there are translations, but I've never checked them out (and wouldn't be needed to).
If the translations do not change any graphics (like for example, the original graphics already contains all the necessary letters) all they need to modify are the text scripts. The compression scheme of the text messages is already well known.
But usually the compression scheme for text is different from that used for graphics, so even if you can edit the scripts you still aren't able to modify the graphics unless you figure out how they are stored.
tepples
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Re: Editing Lagrange Point tiles

Post by tepples »

Many Konami games contain graphics compressed using a form of run-length encoding (RLE) compatible with a compression tool called GraveyardDuck.
emuman
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Re: Editing Lagrange Point tiles

Post by emuman »

Gilbert wrote: Wed Apr 17, 2024 5:16 am I know there are translations, but I've never checked them out (and wouldn't be needed to).
If the translations do not change any graphics (like for example, the original graphics already contains all the necessary letters) all they need to modify are the text scripts. The compression scheme of the text messages is already well known.
But usually the compression scheme for text is different from that used for graphics, so even if you can edit the scripts you still aren't able to modify the graphics unless you figure out how they are stored.
The original ROM has only Japanese character tiles, which have been replaced with Western letters. So the tiles were changed. Regarding the scripting part, I'm already quite advanced, and I had previously found this site that you mentioned.
Last edited by emuman on Fri Apr 19, 2024 2:00 pm, edited 1 time in total.
emuman
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Re: Editing Lagrange Point tiles

Post by emuman »

tepples wrote: Wed Apr 17, 2024 10:10 am Many Konami games contain graphics compressed using a form of run-length encoding (RLE) compatible with a compression tool called GraveyardDuck.
Thanks, I'll try to understand how to unpack graphics from this ROM using RLE.
emuman
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Re: Editing Lagrange Point tiles

Post by emuman »

I figured out how to do this. I understood that there are two types of ROM, one with PRG+CHR ROM, and the other with just PRG ROM, where the CHR is extracted at run time, in this case CHR RAM. I discovered this when comparing two games and noticing that Y's 3 had a different Mesen Memory Viewer (CHR ROM) option.

So I went back to Lagrange Point, and used Mesen itself to export the CHR RAM. So it was just a matter of using a tile editor.
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