You need to download the fallout2 patch program and run it. It'll replace your fallout2.exe and include the patch000.dat
The patch000.dat includes some map files (important), some script files (really important), a replacement .pro file for the 5mm AP ammo, two .pro file replacements for critters, and a few text changes.
If you're going to edit the game's files... I suggest whenever you get this file that you use UNDAT to unpack it to your "DATA" directory and then rename the thing to something else (my favorite - patch000.dam, just in case I need it again, I can rename *.dam to *.dat).
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The patch is approximatly 5mb (and if you're not much into obtaining patches, Fallout Tactics' patch is almost 17mb).
Now you said you were a newbie too huh? What kind of editing you want to do? The simplest is .pro file editing, which can have drastic implications on game flow. For that I recommend:
*UNDAT
*UGE (universal savegame editor)
*FIME (fallout items mode editor)
You'll need to use UNDAT to unpack your monstrous master.dat file, I suggest you do it in a dummy directoy like "datafile" underneith the fallout2 directory. This will give you the .pro files and .msg (text) files you'll need to play with.
UGE is an easy to use hex editor. It can save byte locations in a file using templates and displays hexadecimal code as simple decimal (ie, like 0-255 instead of 0-FF). Before editing .pro files i'd suggest you learn about multi-byte numbers (ie, a number which takes up four bytes)... i'll explain later on in this reply.
FIME is your conventional item editor. Though I'd suggest not editing any Ammunition or Drug classifications of items... it has some problems with that (which is why I suggest you use UGE for that - that gives you much more control).
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NOTE: Whenever you place files in your fallout2/data/proto/items directory (or any directory where .pro files normally go), you have to write-protect them or fallout2 will wipe em out. To avert this I suggest you make a batch file in the fallout2 root directory which automatically write protects them and then runs fallout2 for you (for playtesting purposes, as a safety precaution).
Something like this:
cd \fallout2\data\proto\items
attrib *.* +r
cd \fallout2\data\proto\critters
attrib *.* +r
cd \fallout2
fallout2.exe
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About byte ordering:
A byte (a set of 8, 1's and 0's) can only hold a number between 0 and 255. To get a bigger number (like the pricetag on a suit of power armor), you need to use more than one byte.
To do this, the program takes the initial byte as being 0-255 in range, but each one past that is in multiples of 256. The second byte will be SETS of 256 (so a 3 there would make 768). Suffice to say that I dont think anything in fallout1 or 2 uses the third byte (which is sets of 65536, or 256^2)... or heaven forbid the fourth byte (sets of 16777216!).
Fallout uses "motorola" brand of byte ordering. Which means they're backwards. I'll give an example:
35 4 0 0 is typically 1059 (35x1 + 4x256 + 0x65535 + 0x16777216). This is how most normal programs do it.
But in fallout's .pro files it's backwards like this:
0 0 4 35
Practice problems (in motorola format, parenthesis is final answer):
0 0 3 232 (1000)
0 1 48 176 (78000)
0 0 1 44 (300)
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Now if that made your head hurt, negative numbers are possible too! How you say? Well, they take the entire range possible given four bytes (4,294,967,296... 256 to the 4th power), and they chop it in half right down the center.
The anything above 2,147,483,648 is negative, anything below is positive.
255 255 255 255 is -1. Simply subtract from those numbers to get another negative number.
ie, 255 255 255 236 is -20 (because 236 is 256-20).
Practice problems:
255 255 254 244 (-268)
255 254 240 38 (-69850)
255 255 255 206 (-50)
You'll most likely encounter negative numbers with .pro editing with:
*Drugs (examples = mentats, buffout, super stimpack).
*Ammunition (examples = the AC and DC modifier, which are very important)
*Critters (some critters like pig rats have hampers built in to limit hitpoints, actions points, etc.)
It's easy to spot a negative number - it's a big horizontal column of 255's. There are only a few instances of single-byte variables in .pro files (stuff for graphics and sounds mostly), but that stuff is relativly unimportant from your standpoint so you shouldn't worry about those (typically they're at the beginning of the file anyway - not where the juicy parts are).
You'll need to use UGE to clean up FIME's mistakes - since it does negative numbers like this:
0 0 255 255
instead of:
255 255 255 255 like it's supposed to
(it doesn't fill the first two bytes, which is disasterous - makes the poison antidote give you ~57000 poison level and you die instantly).
For ammo, the juicy data is right smack dab at the end of the file (it's only 81 bytes though, so everything past halfway is what you're looking for)
Weapons can be edited without difficulty with FIME, I dont suggest editing them with UGE (too much hassle).
F.U.C.K. (another editor) can edit critter .pro files, but it's buggy and i'd only suggest editing them with UGE (as a matter of fact, i've got a template im building for that express purpose). I'd try that one out anyway though, might be worth your while for now (look for FUCK! fallout -something critters tinKering).
Drugs are tricky. I'd edit them in FIME and then fix FIME's errors using UGE. There are lots of negative numbers in there usually (including more than just the actual values - things that represent what the values do like "current hitpoints" and "minimum of stat 2"). If your newly edited stimpacks are always giving you the maximal amount - then you need to go back and look for an incomplete negative number.
oh, and UGE can only display 255 files in it's file system, so in order to edit most of the stuff in FO2 you'll need to go copy the appropriate files to another directory ('cause the 4.7mm Caseless ammo has a file number of 00000359.pro, which when arranged by name is farther down the list than 255. Just copy the files to the root proto directory and copy them back when you're done editing them (and an easy way to group the appropriate types together is arrange files by size in the windows explorer - it'll slap all the different types of .pro files like ammo and armor together, making them easy to select).
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Neat trick for making the game easier to play:
Divide the cost of all items by 3. That way there's effectivly 3 times as much money to play with.
Ie, like an 800$ shotgun is $250 (well, i rounded down), and the $500 that balthas has to part with in modoc has the same effect as $1500 as normal in the game. Of course, quests which require you to pay up have three times the sting as normal, but then again getting money from people is 3 times as sweeter.
It does make it harder to get Vic outta jail though (unless you're female... hehe
. Though that can be solved by helping lara kick tyler's ass though.