how to make a save game editor ???

Discussion in 'NDS - ROM Hacking and Translations' started by omarrrio, Aug 22, 2010.

Aug 22, 2010
  1. omarrrio
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    Member omarrrio GBAtemp Advanced Fan

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    hi guys, can anybody help me finding me a tutorial on make a save game editor for some nds games, from AR codes of course, and thank you.
     
  2. Masked Ranger

    Member Masked Ranger GBAtemp Advanced Fan

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    I'm going to toss in my $0.02 here. You'll want to use a PC emulator and work from several different save files. AR codes only change things in memory, and not the save files themselves until after you save.

    Totally random example: Memory location 0xE4567E keeps track of how many golden whatizitz you have. You don't know where in the save file while the bytes that holds that value. Your AR code to give you 5 whatizitz will not change the save file amount.

    Take your save file that has 1 whatizitz and compare it with a post-AR save with 5 whatizitz. You would want to write a program that will edit GAME.SAV at byte 3496 since you now know where the value is kept.

    So making a save editor from just AR codes, IMHO, is impossible.
     
  3. BlueFlame90

    Member BlueFlame90 GBAtemp Regular

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    It's just as Masked Ranger said: it's impossible to make a save game editor from AR codes!

    If you want to make a save game editor you need to learn:
    1. A programming language like C#, Java or C++
    2. some basics about file manipulation
    3. HEX

    Now all you need to do is find the values in the save file and write a program for it, however it's not always so easy as in Masked Rangers example.
     
  4. omarrrio
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    Member omarrrio GBAtemp Advanced Fan

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    thank you guys, but how do i compare the bytes, there are billions, is there an easy tool to do that ???
     
  5. BlueFlame90

    Member BlueFlame90 GBAtemp Regular

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    Some HEX editor have a compare function like this freeware: Hex-Editor MX
    In this program you click on search->compare and then you choose the 2 files.

    If you need help with something you can ask me anytime.
     
  6. Gaz777

    Member Gaz777 Member

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    I sometimes do a bit of save game editing and begin to write programs for it, though I get bored before I finish everything or release it.
    Damn my attention span and laziness.

    When finding value positions, what your doing now, I use HxD.

    HxD is a hex viewer/editor, it also has a useful feature that allows you to compare files, showing you all the differences.

    One thing that hasn't been mentioned is that save files will often have a checksum in them to make sure the file isn't changed externally or corrupted.
    There could be one, many or no checksums in a file.


    Think that's all I have to say for now, hope it helps.
    If you have any more questions feel free to ask, I may be able to give some guidance.

    Gaz
     
  7. Masked Ranger

    Member Masked Ranger GBAtemp Advanced Fan

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    No, there aren't "billions" of bytes. A 1MB save file will have 1,048,576 bytes. Most save files that my friends have are 512KB.

    Do what so many people have done, make your own tool.
    Do what so many people have done, search the internet.
     
  8. omarrrio
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    Member omarrrio GBAtemp Advanced Fan

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    well thank you guys, one more question what is the best/easiest tool to write a save editor ?? thank you
     
  9. BlueFlame90

    Member BlueFlame90 GBAtemp Regular

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    What you need is a Compiler/Linker fitting for the programming languange you use.
    A good one is Visual Studio.
     
  10. omarrrio
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    Member omarrrio GBAtemp Advanced Fan

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    thank you very much guys, i'll start my first sav editor right after DLing VS, request done, topic can be closed.
     

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