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Research: Fire Red Overworld Unknown Byte

Akiba

Akiba

[img]http://i.imgur.com/o3RYT4v.png[/img]
    • 4,262
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    I have been doing some research on the Unknown Values for Overworld Strings in Fire Red.

    This thread may also serve as a somewhat sketchy Advanced Tutorial for OW Palette modification.

    For reference on adding new OWs: [Other] Adding New Overworlds into FireRed for Dummies
    For reference on adding new OW Palettes: [Other] New palettes in Fire Red for OW's!

    In the game, the first byte after the two FF bytes coincides with the ID of the Palette used by the overworld. However, editing this byte by itself does not seem to affect the game. I have tested and confirmed this. Instead, the first byte of the four OAM data bytes appear to dictate which palette is used by the OW.

    The byte conversion originally appears to be [Palette ID]+[0xF].
    (Refer to the latter section of the post)

    Following this pattern, Palette 0x20 should be called with byte 0x2F.

    However, when that is put into practice:
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    We get this:
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    That Axew seems a bit black, does it not?


    After experimentation, I found that Palette 0x20 is called with byte 0x2A:
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    And we get this:
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    Much better.


    But now, we must play a game of Psychiatrist, and deduce how this unknown byte actually points to the Palette of our desire.

    Consider the following strings from the original Fire Red:

    Palette 0x0 is called with byte 0x10.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    Palette 0x3 is called with byte 0x12.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    Palette 0x4 is called with byte 0x13.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte



    However, as I insert my own palettes and new tables, the pattern becomes increasingly elusive.

    Palette 0x21 is called with byte 0x22.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    Palette 0x23 is called with byte 0x30.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte



    Furthermore, as I add more sprites and palettes, I must constantly change the bytes, as they seem to point to different palettes each time.

    If anyone has a revelation about this, please contribute to this research.
     
    Last edited:
    At first I added a new pallet but it came up like so:
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    I used pallet 0x20 or 32 in dec. so I changed the unknown to 23 and it worked.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    But when I exited a battle it became the hero's pallet so at least that's a start!
     
    Oh god. If you have posted it a few days back, my old project wouldn't have been cancelled. Anyways, thanks for sharing this information.
     
    DeltaSalamence said:
    You're welcome, I guess. Sorry about your hack...

    Also, I seem to have found a pattern in the bytes, most likely pointing to an encryption.
    Click to expand...
    Don't leave us hanging mang! I need this too, so if you have a pattern it would help to post it, even if it's not right.
     
    The second byte's lower half, that you have highlighted in Blue, was found by JPAN to control which palette slot the palette was put into. This allowed for fixing the problems that come into play when two different OWs are using the same slot but different palettes. The most often example is the player's palette being changed to match the palette of another on screen OW because of this.

    However, the upper half of the byte is a still a mystery.

    So, if you made it XY, then X is the mystery and Y is the palette slot.

    Have you learned anything more about this encryption you were researching?


    Edit: Knizz has found a routine that uses the first byte in Y. He doesn't know what it does yet, but he has found something that uses it.
     
    Last edited:
    As soon as I step into the grass an OW pal changes color to this.
    [PokeCommunity.com] Fire Red Overworld Unknown Byte


    Just an FYI, pal 2D is the pal for grass, so changing an OW pal to it makes that happen when interacting with grass.
     
    Sorry for double posting, but when using the Bag, Trainer card, Option, Pokemon, or Pokedex selections, all the new palettes get reverted to the original ones from the game until you encounter other OWs. I think it's a bug with the actual hacked engine, but either way, it's a glitch.
     
    Some OW:
    Code: 
    083A3BB0  FF FF 00 11 [B]02 11[/B] 00 02  10 00 20 00 10 01 00 00
083A3BC0  10 37 3A 08 9C 37 3A 08  70 34 3A 08 A0 00 3A 08
083A3BD0  FC 1C 23 08

    Afaik the highlighed value is looked up in this table to get the pointer to the palette:

    Code: 
    083A5158  28 D8 36 08 03 11 00 00  48 D8 36 08 04 11 00 00
083A5168  68 D8 36 08 05 11 00 00  88 D8 36 08 06 11 00 00
083A5178  A8 D8 36 08 07 11 00 00  C8 D8 36 08 08 11 00 00
083A5188  E8 D8 36 08 09 11 00 00  08 D9 36 08 0A 11 00 00
083A5198  68 B9 35 08 00 11 00 00  68 E9 35 08 01 11 00 00
083A51A8  [U]88 E9 35 08[/U] [B]02 11[/B] 00 00  08 80 39 08 0B 11 00 00
083A51B8  28 80 39 08 0C 11 00 00  68 B9 35 08 10 11 00 00
083A51C8  68 E9 35 08 11 11 00 00  A8 4E 39 08 13 11 00 00
083A51D8  E8 5A 39 08 15 11 00 00  C8 52 39 08 14 11 00 00
083A51E8  00 00 00 00 00 00 00 00  01 11 01 11 01 11 01 11

    I didn't test it. I hope that helps
     
    knizz said:
    Some OW:
    Code: 
    083A3BB0  FF FF 00 11 [B]02 11[/B] 00 02  10 00 20 00 10 01 00 00
083A3BC0  10 37 3A 08 9C 37 3A 08  70 34 3A 08 A0 00 3A 08
083A3BD0  FC 1C 23 08

    Afaik the highlighed value is looked up in this table to get the pointer to the palette:

    Code: 
    083A5158  28 D8 36 08 03 11 00 00  48 D8 36 08 04 11 00 00
083A5168  68 D8 36 08 05 11 00 00  88 D8 36 08 06 11 00 00
083A5178  A8 D8 36 08 07 11 00 00  C8 D8 36 08 08 11 00 00
083A5188  E8 D8 36 08 09 11 00 00  08 D9 36 08 0A 11 00 00
083A5198  68 B9 35 08 00 11 00 00  68 E9 35 08 01 11 00 00
083A51A8  [U]88 E9 35 08[/U] [B]02 11[/B] 00 00  08 80 39 08 0B 11 00 00
083A51B8  28 80 39 08 0C 11 00 00  68 B9 35 08 10 11 00 00
083A51C8  68 E9 35 08 11 11 00 00  A8 4E 39 08 13 11 00 00
083A51D8  E8 5A 39 08 15 11 00 00  C8 52 39 08 14 11 00 00
083A51E8  00 00 00 00 00 00 00 00  01 11 01 11 01 11 01 11

    I didn't test it. I hope that helps
    Click to expand...

    That was already known. It is a different byte being discussed here.



    Edit: since I last visited this thread, I have learned that the game does this on the palette slot byte:

    Byte AND 0xF -> Palette Slot

    The upper half is completely disregarded.
     
    Well, idk if this its relevant, but I make some little investigation and the OW inserted by me only overwrite the palette 0xA or 0x0 just in some cases, with the anothers, just uses whathever it was load before (Even if there its nothing, just black)

    So I star to look how can I make than my OW overwrite the palete there... I don't know how, but if we can do this we can use all the pals...


    (MEABE, relevant) I was chequing out some things, and I figured out than when using the 0 pal slot (Hero's one) sometimes It get replaced, sometimes not... So I try to see why... I try with two diferents Ows (Than I Insert) one replace it, and the another not, when I go to the data, the only differece was the pal number and the sprites pointer... So I try changing the pal number and it works, now both replace the pal (using the 20, btw) but when I try with both using the 23, nothing happens, the new ows use the heros pal, what makes me think that game dosn't load them...

    Hope This Help!
     
    sooo... anybody figured out how those UNKNOWNs are calculated? im having problems with this glitch.

    i followed this tutorial and manage to create 4 new palettes. successfully put it in OWE and it worked fine. but ingame, whenever i placed i place a sprite w/ new palette... it gets bugged.

    i have been trying to do the [pal # + 0xf] and it wont work.
     
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