Author Topic: How do I edit damage formulas? [FFVIII] (Read 41087 times)

SunnyD · « **on:** 2016-04-27 23:52:21 »

I'm quite new to modding FFVIII and I'm curious about one thing. How would I exactly edit damage formulas for both party members and allies? In particular I'd like to make some magic spells more useful whilst also nerfing other attacks. I'm using HxD as my editor but admittedly don't know where I should start looking.

Thanks in advance and sorry for what's probably a really simple question.

Tirlititi · « **Reply #1 on:** 2016-04-28 07:00:49 »

I don't know about FF VIII, but for IX, that's far from the most simple thing to modify ^^"
Spell formulas are written in MIPS code in the PSX version.

nfitc1 · « **Reply #2 on:** 2016-04-28 11:07:34 »

As far as FFVII goes, if you change formulae for allies, you change it for enemies too. FFVIII probably uses the same data for magics for all PCs and enemies.

But do you actually want to change the math behind the calculations or just change some strengths of individual actions? Those are two pretty different requests.

JWP · « **Reply #3 on:** 2016-04-28 11:17:50 »

Is this for the PC or Playstation version of FF8?

SunnyD · « **Reply #4 on:** 2016-04-28 17:35:01 »

Quote from: NFITC1 on 2016-04-28 11:07:34

As far as FFVII goes, if you change formulae for allies, you change it for enemies too. FFVIII probably uses the same data for magics for all PCs and enemies.

But do you actually want to change the math behind the calculations or just change some strengths of individual actions? Those are two pretty different requests.

Just some strengths of individual actions.

Quote from: JWP on 2016-04-28 11:17:50

Is this for the PC or Playstation version of FF8?

PC version sorry. Steam version specifically.

JWP · « **Reply #5 on:** 2016-04-28 20:37:07 »

It's probably in the exe, you'll probably need a disassembler and debugger to modify them.

There's a function at 0x48D200 (in memory) that takes 7 args which might lead to where the values are stored:
arg1: caster id (0-2 for Seeds, 3+ for monsters - each person in a battle has an id)
arg2: either something like 2 (for magic) or a large value that might be some sort of offset/pointer
arg3: integer representing magic type e.g. 0x0C for Bio, 0x23 for haste
arg4: some pointer?
arg5: some dinput call or null (I've not actually investigated it, it might just be an assumption by my debugger)
arg6: target bitmask
arg7: some d3d call or null (I've not actually investigated it, it might just be an assumption by my debugger)

EDIT: Couple of other things:
function at 0x47E970 gets the name of magic from an ID
all the magic is listed in structs of 60 bytes from 0x1CF4064, no idea what these values are or if they're static/loaded from a file. I only know that the first word is an offset for locating the name and the second word is an offset for the description - the rest are a mystery and may relate to damage, status etc. or they could be completely useless for what you want.
The bytes that are usually 0x64 are probably for status/elemental stuff - could also be for junctions.
for example: bio has an id of 0x0C, so all the bio stuff is the 60 bytes at address 0x1CF4334
There's probably magic info stored elsewhere too, I'll see if I can dig out any more information at a later date.
Hope that helps!

list of magic can be found in this post:
http://forums.qhimm.com/index.php?topic=11137.msg166280#msg166280

JWP · « **Reply #6 on:** 2016-04-30 09:33:13 »

So after a bit more investigation, I've found that the magic data I mentioned in the previous post is loaded from the kernel.bin file and the magic stuff starts at offset 0x21C in kernel.bin and ends at 0xF78 - so you can use HxD to edit it (kernel.bin is in the main.fi archive and you'll need an archive extractor to remove it - see http://wiki.qhimm.com/view/FF8/Tools - in my case, main.fi is located at: "C:\Program Files (x86)\Steam\steamapps\common\FINAL FANTASY VIII\Data\lang-en\main.fi").
!!!--- Don't forget to make a backup of main.fi, main.fs and main.fl files before you edit it ---!!!
the 60 byte structures starting at 0x21C are comprised roughly as follows:

see: http://finalfantasy.wikia.com/wiki/Magic_(Final_Fantasy_VIII) for more information on magic,
see also: http://www.gamefaqs.com/ps/197343-final-fantasy-viii/faqs/58936

2 bytes - offset to spell name
2 bytes - offset to spell description
4 bytes - unknown
1 byte - spell power (basically relates to how much damage it does)
3 bytes - unknown
1 byte - draw resist (how hard it is to draw - higher = harder)
10 bytes - unknown
1 byte - HP junction value
1 byte - str junction value
1 byte - vit junction value
1 byte - mag junction value
1 byte - spr junction value
1 byte - spd junction value
1 byte - eva junction value
1 byte - hit junction value
1 byte - luck junction value
28 bytes - unknown

so modifying the spell damage is simple enough but this will also modify it for enemies.
If you wanted to modify the actual equation (the one listed on the wiki), then you'd need to know x86 ASM, there's a bunch of sub functions called from 0x4922B0:
arg1 - think this is 0x02 for magic but can be other values depending on attack type (e.g. attacking with gunblade is 0x0A)
arg2 - caster_id
arg3 - target_id
arg4 - spell_power
and one of those probably deals with that but I'd not recommend doing that.

EDIT:
function 0x491DA0 is probably the main damage calculation function:
arg1 - caster_id
arg2 - target_id
arg3 - spell_power (I made haste deal damage by changing this on the fly with a debugger

)
arg4 - 0 = magic damage?, 2 = GF?

The main magic damage calculation is in this section of code (note that it's elsewhere for different damage types) - I'd recommend modifying the spell power listed above instead, since it's a lot easier:
note you can see the formula listed at section 4.2 of http://www.gamefaqs.com/ps/197343-final-fantasy-viii/faqs/58936 listed in the code