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Author Topic: Legend of Zelda... compressed graphics?  (Read 3940 times)

Reaper Man

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Legend of Zelda... compressed graphics?
« on: February 22, 2011, 05:19:28 am »
Okay, so I've looked at the LoZ rom and I can't help but notice that there are what looks to be RLE encoded graphics tiles, but I could be wrong.  Is there a complete map of where the graphics are in this game?  I kinda need to know for my rom corruption project.

RetroHelix

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Re: Legend of Zelda... compressed graphics?
« Reply #1 on: February 22, 2011, 05:52:47 am »

Reaper Man

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Re: Legend of Zelda... compressed graphics?
« Reply #2 on: February 22, 2011, 06:30:26 am »
sounds great, cept for the fact that said document is for A Link to the Past, and not for the original NES game.

Azkadellia

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Re: Legend of Zelda... compressed graphics?
« Reply #3 on: February 22, 2011, 06:57:20 am »
http://datacrystal.romhacking.net/wiki/The_Legend_of_Zelda Hope this helps. Has a ROM and Ram map.
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Reaper Man

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Re: Legend of Zelda... compressed graphics?
« Reply #4 on: February 22, 2011, 07:07:28 am »
Yeah I saw that, but the ROM map looks a bit incomplete.

I'm probably going to open the ROM up again and compare addresses and see if the locations I'm wondering about are defined in the map.

February 22, 2011, 07:56:55 am - (Auto Merged - Double Posts are not allowed before 7 days.)
I took another look.  Apparently, LoZ has some really fucking strange graphics offsets which to me looked like some odd compression, as my graphics viewer wasn't aligned.

What still puzzles me is what the hell is the data located around 0x1C000?  Anyone know?
« Last Edit: February 22, 2011, 07:56:55 am by Reaper Man »

never-obsolete

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Re: Legend of Zelda... compressed graphics?
« Reply #5 on: February 22, 2011, 11:54:20 am »
The game uses chr-ram, so they aren't exactly aligned in rom. Offset them by a few bytes here or there and they should show up correctly.

The data starting at 0x1C000 are DMC samples. The first one is used for the sword sound fx. I'm not sure where the samples end or what chunk of data is for what sound.

Here's an incomplete dissassembly if it will be of any help.

Reaper Man

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Re: Legend of Zelda... compressed graphics?
« Reply #6 on: February 22, 2011, 01:19:52 pm »
Ah, so that's what it is.  I guess I could corrupt that too, but it probably won't do too much.

As for the disassembly, I won't need it for what I'm doing.  Thanks anyway.