02-02-2015, 10:54 PM
Greetings Lothril,
I'm going to throw a bunch of information and suggestions at you. Do with it what you will.
First off, while modding can be a lot of fun, I feel I should give you fair warning that Diablo is a very difficult game to mod relative to today's games. I don't mean to discourage you, I just want to give you some perspective here. Some modern games actually come with official tools for making changes to the game, and are specifically designed to support modifications. Diablo is not one of those games. Much of the game's data and rules are hardcoded into the executable. In the mpq you will find very little to mod besides the graphics, sounds, music and animations. In order to make more extensive changes to the game, you'll have to learn about hexadecimal so you can edit the exe code or game memory directly, and that will only enable you to modify very basic things like names, dialogue text, descriptions, and the numerical values of some properties like item values, monster health/armor, etc. To do much else you will have to get into programming and learn x86 ASM (x86 Assembly Language), one of the most complex and difficult languages one can learn and a headache to work directly with even for experienced programmers.
It's up to you to judge if you've chosen the right game based on what exactly you want to modify, but at least that information will help you assess your choice. If you're not deterred by the difficulty, or what you want to change doesn't touch areas that require you to get into more complex stuff, please read on.
Regarding diabdat.mpq, you don't have to write your changes to the diabdat.mpq file. Chances are you won't change most of the content in it no matter how extensive your mod is, so messing with it is an unnecessary hassle you can avoid. When you have patched Diablo to v1.09, you will notice a file named Patch_rt.mpq in the Diablo directory. This little guy is your friend. Carefully extract everything out of it (make sure you don't miss anything, you may want to use a modern MPQ Editor such as Ladik's, which seems capable of finding ALL the files in MPQs reliably), preserve the file path and names, and now you are ready to modify files used by the game.
Find files you want to change in the diabdat.mpq file, extract them, then put them in the same relative file path/name in your extracted Patch_rt.mpq folder contents. Later you can use an MPQ editor to build a new MPQ file out of the stuff you extracted from Patch_rt.mpq and anything else you added. This new file contains the original patch contents and your modified files. Diablo will automatically use versions of files in Patch_rt.mpq, ignoring its own in diabdat.mpq, so as long as you kept the paths and names correct, this approach is much easier, yielding a file starting at just over 1mb file to repack and distribute containing files for your mod, rather than the whopping 500mb main data file.
I'm going to throw a bunch of information and suggestions at you. Do with it what you will.
First off, while modding can be a lot of fun, I feel I should give you fair warning that Diablo is a very difficult game to mod relative to today's games. I don't mean to discourage you, I just want to give you some perspective here. Some modern games actually come with official tools for making changes to the game, and are specifically designed to support modifications. Diablo is not one of those games. Much of the game's data and rules are hardcoded into the executable. In the mpq you will find very little to mod besides the graphics, sounds, music and animations. In order to make more extensive changes to the game, you'll have to learn about hexadecimal so you can edit the exe code or game memory directly, and that will only enable you to modify very basic things like names, dialogue text, descriptions, and the numerical values of some properties like item values, monster health/armor, etc. To do much else you will have to get into programming and learn x86 ASM (x86 Assembly Language), one of the most complex and difficult languages one can learn and a headache to work directly with even for experienced programmers.
It's up to you to judge if you've chosen the right game based on what exactly you want to modify, but at least that information will help you assess your choice. If you're not deterred by the difficulty, or what you want to change doesn't touch areas that require you to get into more complex stuff, please read on.
Regarding diabdat.mpq, you don't have to write your changes to the diabdat.mpq file. Chances are you won't change most of the content in it no matter how extensive your mod is, so messing with it is an unnecessary hassle you can avoid. When you have patched Diablo to v1.09, you will notice a file named Patch_rt.mpq in the Diablo directory. This little guy is your friend. Carefully extract everything out of it (make sure you don't miss anything, you may want to use a modern MPQ Editor such as Ladik's, which seems capable of finding ALL the files in MPQs reliably), preserve the file path and names, and now you are ready to modify files used by the game.
Find files you want to change in the diabdat.mpq file, extract them, then put them in the same relative file path/name in your extracted Patch_rt.mpq folder contents. Later you can use an MPQ editor to build a new MPQ file out of the stuff you extracted from Patch_rt.mpq and anything else you added. This new file contains the original patch contents and your modified files. Diablo will automatically use versions of files in Patch_rt.mpq, ignoring its own in diabdat.mpq, so as long as you kept the paths and names correct, this approach is much easier, yielding a file starting at just over 1mb file to repack and distribute containing files for your mod, rather than the whopping 500mb main data file.