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Author Topic: FFTA's Text Data: LZSS Compression assistance  (Read 1 times)
Edea
Guest
« on: October 08, 2011, 05:16:53 pm »
Code:
158\t85\t\t\t9E\t55\t\t\tProbably start of string\t
128\t195\t\t\t80\tC3\t\t\tT\t
128\t209\t\t\t80\tD1\t\t\th\t
128\t210\t\t\t80\tD2\t\t\ti\t
128\t220\t\t\t80\tDC\t\t\ts\t
64\t115\t\t\t40\t73\t\t\tSpace\t
128\t224\t\t\t80\tE0\t\t\tw\t
128\t216\t\t\t80\tD8\t\t\to\t
128\t214\t\t\t80\tD6\t\t\tm\t
128\t206\t\t\t80\tCE\t\t\te\t
128\t215\t\t\t80\tD7\t\t\tn\t
128\t244\t\t\t80\tF4\t\t\t'\t
144\t15\t\t\t90\t0F\t\t\tgo to compression, s + Space\t
64\t219\t\t\t40\tDB\t\t\tr\t
128\t23\t\t\t80\t17\t\t\ti\t
64\t203\t\t\t40\tCB\t\t\tb\t
128\t1\t\t\t80\t01\t\t\tb\t
66\t216\t\t\t42\tD8\t\t\treturn to uncompressed text, o\t
128\t215\t\t\t80\tD7\t\t\tn\t
144\t29\t\t\t90\t1D\t\t\tgo to compression, Space + w\t
64\t202\t\t\t40\tCA\t\t\ta\t
128\t17\t\t\t80\t11\t\t\tr\t
64\t205\t\t\t40\tCD\t\t\td\t
128\t41\t\t\t80\t29\t\t\ts\t
64\t110\t\t\t40\t6E\t\t\tNewline\t
128\t39\t\t\t80\t27\t\t\to\t
66\t207\t\t\t42\tCF\t\t\treturn to uncompressed text, f\t
128\t207\t\t\t80\tCF\t\t\tf\t
128\t49\t\t\t80\t31\t\t\tSpace\t
68\t202\t\t\t44\tCA\t\t\ta\t
128\t213\t\t\t80\tD5\t\t\tl\t
128\t213\t\t\t80\tD5\t\t\tl\t
144\t7\t\t\t90\t07\t\t\tgo to compression, Space + a\t
64\t210\t\t\t40\tD2\t\t\ti\t
128\t9\t\t\t80\t09\t\t\tl\t
152\t59\t\t\t98\t3B\t\t\t\t
72\t221\t\t\t48\tDD\t\t\treturn to uncompressed text, t\t
128\t228\t\t\t80\tE4\t\t\t.\t
64\t112\t\t\t40\t70\t\t\tDisplay "next page" button and wait for button press.\t
64\t99\t\t\t40\t63\t\t\tClear dialog box. \t
128\t193\t\t\t80\tC1\t\t\tR\t
192\t61\t\t\tC0\t3D\t\t\tCompressed, retrieves six characters, "ibbon "\t
66\t110\t\t\t42\t6E\t\t\tReturn to uncompressed text, Newline\t
128\t251\t\t\t80\tFB\t\t\t[\t
128\t85\t\t\t80\t55\t\t\t\t
64\t222\t\t\t40\tDE\t\t\tu\t
136\t45\t67\t\t88\t2D\t43\t\t\t
128\t252\t\t\t80\tFC\t\t\t]\t
128\t176\t\t\t80\tB0\t\t\tA\t
160\t53\t\t\tA0\t35\t\t\t\t
64\t220\t\t\t40\tDC\t\t\ts\t
128\t43\t\t\t80\t2B\t\t\tt\t
64\t202\t\t\t40\tCA\t\t\ta\t
128\t47\t\t\t80\t2F\t\t\tt\t
64\t222\t\t\t40\tDE\t\t\tu\t
144\t125\t\t\t90\t7D\t\t\t\t
216\t67\t\t\tD8\t43\t\t\t\t
68\t220\t\t\t44\tDC\t\t\ts\t
64\t97\t\t\t40\t61\t\t\tWait for button press.\t
64\t99\t\t\t40\t63\t\t\tClear dialog box.\t
32\t128\t\t\t20\t80\t\t\t\t
40\t24\t\t\t\t\t28\t18\t\t\t\t

Above is the code inside $4db1fd-$4db279 from a Final Fantasy Tactics Advance ROM (GBA, header).  It's an in-menu text description of the Ribbon item (which I've since turned into a gender-neutral accessory):

"This women's ribbon wards
off all ailment. (Page Button)
Ribbon
[null]All status ailments"

The problem here seems simple enough: the description has 'women' in it, and that's not how the item behaves anymore, so it needs to come out.  Since that part of the string is (blessedly) uncompressed, it was relatively simple to put in another 10-byte string (in this case I used the word 'saint').  However, now other parts of the description are incorrect, because the compressed portions of the data are retrieving information from the uncompressed portions (Example: the word 'ailment' is compressed, and retrieves 'men' from 'women'.  Since 'women' is now 'saint', 'ailment' becomes 'ailintt').

Now for the problem: working with these compressed bytes.  I've been trying to use the information on Data Crystal to figure out what the heck the 'commands' are, but every time I attempt to change one of these compressed bytes the whole text box goes haywire.  I'm not really sure where to go at this point; I've tried using Lunar Decompress and gbalzss to...well, decompress...but LD didn't understand LZ77 format and gbalzss requires pcs files (no idea what that is, Google says it's a PICT File Animation o_O).  So I just need some assistance from people who are used to working with that kind of compression so I can get this text edited >_<.  If more info is required to assist I'll try to provide it.

Also, I guess there's an FFTA modding community somewhere on the intarbutts?  I have no idea where they might be or how to find them, but if anyone has info on that I'd greatly appreciate knowing about it (as such a group's probably hacked the text already).  Thank you in advance for any assistance provided.  Also, the notes in the Code section at the top of the page are not 100% verified, quite the opposite.  Feel free to correct.
« Last Edit: October 09, 2011, 08:19:50 pm by DarkSol »
Darthatron
Guest
« Reply #1 on: October 09, 2011, 01:57:14 am »
After some research, it appears that strings are just using the LZSS compression that's already been documented. Item's description strings are located by the offsets located by the pointer at 0036D6CC in the ROM. This pointer is 084D276C in the default ROM. From this pointer, you can get the offset-pointer halfword by using the equation [0x0036D6CC] + ((ItemID - 1) * 2);

So, for example the offset for the Ribbon is:
Code:
[0x0036D6CC] + ((0x114 - 1) * 2) = 0x084D276C + (0x113* 2) = 0x084D276C + 0x226 = 0x084D2992

So the offset 084D2992 contains a halfword (2 bytes), which we then add to [0x0036D6CC]; so...

Code:
[0x0036D6CC] + [[0x0036D6CC] + ((0x114 - 1) * 2)] = 0x084D276C + 8A8C = [b]0x084DB1F8[/b]
//This this offset for our compressed string.

Here, there is a halfword (no idea what it's for), a big-endian word (maybe the length of something) and our compressed string/data.

Code:
182A
0000009E
55          ""; 0b01XXXXXX; Next compressed byte is after X+1 (22) bytes.
80 C3       "T"
80 D1       "Th"
80 D2       "Thi"
80 DC       "This"
40 73       "This "
80 E0       "This w"
80 D8       "This wo"
80 D6       "This wom"
80 CE       "This wome"
80 D7       "This women"
80 F4       "This women'"
90 0F       "This women's "; 0b1XXXXYYY 0bYYYYYYYY;\tTrack back Y (15) bytes and copy X+3 (5) bytes.
40          "This women's "; 0b01XXXXXX; Next compressed byte is after X+1 (1) bytes.
DB          "This women's r"; This is because the 0x80 was copied to the decompressed data already.
80 17       "This women's ri"; 0b1XXXXYYY 0bYYYYYYYY; Track back Y (23) bytes and copy X+3 (3) bytes.
40          "This women's ri"; 0b01XXXXXX; Next compressed byte is after X+1 (1) bytes.
CB          "This women's rib"; This is because the 0x80 was copied to the decompressed data already.
80 01       "This women's ribb"; 0b1XXXXYYY 0bYYYYYYYY; Track back Y (1) byte and copy X+3 (3) bytes.
42          "This women's ribb"; 0b01XXXXXX; Next compressed byte is after X+1 (3) bytes.
D8          "This women's ribbo"; This is because the 0x80 was copied to the decompressed data already.
80 D7       "This women's ribbon";
90 1D       "This women's ribbon w";
40          "This women's ribbon w"; 0b01XXXXXX; Next compressed byte is after X+1 (1) bytes.
CA          "This women's ribbon wa"
80 11       "This women's ribbon war"; 0b1XXXXYYY 0bYYYYYYYY; Track back Y (17) bytes and copy X+3 (3) bytes.
40          "This women's ribbon war"; 0b01XXXXXX; Next compressed byte is after X+1 (1) bytes.
CD          "This women's ribbon ward"
80 29       "This women's ribbon wards"; 0b1XXXXYYY 0bYYYYYYYY; Track back Y (41) bytes and copy X+3 (3) bytes.

etc...

Hope this helped.

It may be hard to comprehend since the text is just data until it's decompressed. It'd be best to have some tool to do the work for you.
Edea
Guest
« Reply #2 on: October 09, 2011, 02:15:28 am »
It does, I'll mess with it some as the week progresses and report results here.  Thanks for the reply!
October 09, 2011, 07:35:01 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
Praise the gods.  Finally capable of editing the text (for the equipment descriptions at least).







Pointers for item descriptions start at $4d276c in the ROM (I think this is what was meant by 084d276c?).  Simply add $4d276c to the listed pointer to get the start of the address for the string it corresponds to (or subtract 4d276c from the string address to get the pointer values).  Here's the kicker (for these strings at least); all of them begin with a 2 byte operation.  If $02 00 is set, that string is marked for compression and will be succeeded by a big-endian like Darthatron indicated.  This operation looks like "$2a 18."  However, if $02 00 is NOT set, the whole string is considered free of compression (and you will be unable to use compression code in the string), and this looks like "$28 18."

So if you want to edit a compressed string (at least as far as item dialogue is concerned)?  Change $2A to $28, and get rid of any 'opcodes' that are not $80 or $40 (used to indicate characters ($80) and calls for things like spaces, dialog clear, etc. ($40)).  Then remove the big-endian (I just treated it as free space).  Voila, the string is no longer compressed.  Make sure to end any decompressed string with at least one $00 (more is fine and allows for filler); otherwise, the game will hang once you're finished scrolling through the text.

Haven't looked at other text types yet; I'm just happy I got Ribbon edited, to be honest.  Thanks again for the help, if anyone finds out more about how to effectively handle compressed text in this game please post it here.
« Last Edit: October 09, 2011, 07:35:01 pm by Edea »
Darthatron
Guest
« Reply #3 on: October 10, 2011, 05:43:30 am »
The pointer just after that pointer (0x084DDD28) is for Job Descriptions. But it's based on the halfword that is the NameID for the Job. (1C for Sage, 1D for Soldier, etc) It takes the same steps other than that. Smiley

I assume the other pointers around there point to other long texts. Dunno if that's any help to you?
itoikenza
Guest
« Reply #4 on: October 11, 2011, 10:11:19 am »
Quote from: Edea on October 08, 2011, 05:16:53 pm

Also, I guess there's an FFTA modding community somewhere on the intarbutts?  I have no idea where they might be or how to find them, but if anyone has info on that I'd greatly appreciate knowing about it (as such a group's probably hacked the text already).  Thank you in advance for any assistance provided.  Also, the notes in the Code section at the top of the page are not 100% verified, quite the opposite.  Feel free to correct.

Ask Darthatron for the ffta forum he frequents.. i'm a member there it's really good...
« Last Edit: October 11, 2011, 10:30:28 am by itoikenza »
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