INSTRUCTIONS
============

For this to work you need perl. If you're running windows you can use ActivePerl, just download, install and you're ready. If you're using some other OS, you know where to get it.

QUICK START GUIDE
=================

1.  Extract .iso somewhere (umdgen program might be a good choice for this under windows. v4.00 seems to be broken for me, but v3.00 works fine).
2.  If you don't have file lzss.exe in the directory with scripts (You should have it if you downloaded archive from google code), compile it with gcc lzss.c -o lzss
3.  Chdir to WHERE_YOU_EXTRACTED/PSP_GAME/USRDIR and do this: ``perl yum-unpack.pl YUMFILE_X.BIN'' (YUMFILE_1.BIN, YUMFILE_2.BIN, or YUMFILE_3.BIN dependig on which file is there).
4.  When archive is extracted, copy files from fonts directory into WHERE_YOU_EXTRACTED/PSP_GAME/USRDIR/YUMFILE_X/pom. (This adds english font to game).
5.  Convert script files from YUMFILE_X/script with ``script-decode.pl filename.script'', edit generated .txt files or replace them with edited versions from tlwiki.
6.  Convert them back into format game understands with ``script-encode.pl filename.script''.
7.  chdir to WHERE_YOU_EXTRACTED/PSP_GAME/USRDIR and execute ``yum-unpack.pl YUMFILE_X'' (notice there's no .BIN extension this time). This will create new modified YUMFILE_X.BIN archive.
8.  Remake .iso again, replacing original YUMFILE_X with the one you created (umdgen, umdgen).
9.  Upload .iso to your PSP and play the game.
10. If you want to make more modifications, do this: ``perl isoyum-inject.pl ISO_FILE_ON_YOUR_PSP FILE_YOU_PREVIOSULY_EXTRACTED_AND_WANT_TO_INSERT_THERE'' (you don't need to rebuild yum again)


UNPACKING ARCHIVE
=================

If you want to mess with all kinds of files insude the game, you'll need to extract them from archive first. Script yum-unpack.pl does this. The archive is named YUMFILE_1.BIN. To unpack it do:

$ perl yum-unpack.pl YUMFILE_1.BIN

This will create directory YUMFILE_1 where all extracted files will be, and file YUMFILE_1.index, which will contain information about all extracted files.

When you're done messing with game files, you must recreate YUMFILE_1.BIN by issuing this command:

$ perl yum-unpack.pl YUMFILE_1


REPLACING FILES IN ARCHIVE
==========================

Recreating archive takes very long time (and after that that you'll have to upload it to your psp!), so if you did just a small modification to one file, you can just insert it into existing archive INSIDE existing iso file (on your psp connected to your computer), you can do this:

$ perl isoyum-inject.pl I:/ISO/imas-x.iso YUMFILE_1/script/1694.script

If you get a message that it's not possible then you have to recreate whole archive.


GAME SCRIPTS
============

Game scripts are stored in .script files. To get more or less human readable from of script, you have to do this:

$ perl script-decode.pl YUMFILE_1/script/1694.script

After that you will get have 1694.src and 1694.txt -- edit them to your heart's content. When you're done, do this:

$ perl script-encode.pl YUMFILE_1/script/1694.script

It will create new script with changes you made that you can insert into game archives. After you encode the scripts, some clever transformations are applied to characters, so don't try to decode it again.


WORKING WITH PICTURES
=====================
Pictures are stored inside .pom files. Program that converts them needs imagemagick installed: http://www.imagemagick.org/
You can convert a pom file with this command:

$ perl pom-unpack.pl 1694.pom

This will create a 1694.png file, or, if 1694.pom had many pictues inside it, 1694-1.png .. 1694-N.png files. You can edit them in your favorite editor now (photoshop). When you're done, do this:

$ perl pom-pack.pl 1694.pom

or, if there was many PNG files and you edited some other than the first one:

$ perl pom-pack.pl 1694.pom 1694-42.png

Be advised that .pom files have palettes in them -- they have only a limited set of colors, and this particular program does not change the palette. What this really means, though, is that if original .pom only had red color, even if you change PNG to green, it will turn up as red in game. When editing PNGs, try to preserve colors.

Some pom pictures have a lot of so-called subpictures in them. Look at 57849.pom, it has a lot of words in it -- 営業, 取材, etc. Game uses each word separately, and to locate where in the picture these words are scattered, it uses .mif files. A .mif (multi image file?) is just a plain text list of rectangles, so you can modify it by hand. But this is tedious, so another program - mif-unpack.pl can be used to represent them visually. Change directory to where your pom files are located and type this:

$ perl mif-unpack.pl 57848

(Notice that picture is 57849.pom, but we run mif-pack.pl with 57848, less by one. .mif files that are associated with .poms usually have number that is 1 less or 1 more than .pom)
This will create picture 57848.mif.png with lots of rectangles that are visual representations of the ones in .mif. Normally you wouldn't need all this, but in some cases, like 57849.pom's case, where 営業 translates as Promotion, and the word Promotion just doesn't fit, this is necessaty. Add .mif picture as layer to the pic you're editing, rearrange layout, save that modified layer, and generate .mif from it:

$ perl mif-pack.pl 57848

(see http://www.tsukuru.info/tlwiki/index.php?title=Idolmaster_SP:Pictures for some samples of modified .mifs)