View Full Version : FFiv GBA algorithms\RNG

05-01-2010, 05:53 PM
Is there any in-depth info on the algorithms\random number generator for this game? I want to know if i can manipulate rare item drops in any way, grinding Wicked Masks for the Glass Mask is getting tiresome.

EDIT:Some relevant info>

FF4TAY RNG guide, maybe the FF4 gba RNG is similar? GameFAQs: Final Fantasy IV: The After Years (WII) RNG Guaranteed Drop FAQ by The Mystical One (http://www.gamefaqs.com/console/wii/file/958463/57179)

TAS of FF2us, some RNG related info a bit down. TASVideos: #2033: Deign's SNES Final Fantasy IV in 2:53:14.37 (http://tasvideos.org/2033S.html)

More info on TAY RNG. RNG/Random Battle Observation - Final Fantasy IV: The After Years Message Board for Wii - GameFAQs (http://www.gamefaqs.com/boards/genmessage.php?board=958463&topic=51341898)

05-08-2010, 03:54 AM

I've got 2 crystal rings but no Glass Mask. I've noticed that I got the crystal rings after around 100 battles for each ring, resetting in between each attempt. I'm at lv99 for everyone.

05-09-2010, 06:18 PM
Do you know how a random generator works and what affects it? This is important to know before attempting something like this.

05-10-2010, 01:23 AM
I know what an RNG is, but I don't know what affects the RNG used by FFIV in particular.

05-10-2010, 01:20 PM
I have some experience with this and I'm very sure that only commands taken in battle affect the RNG.

- taking damage (exact amount)
- dealing damage (exact amount)
- which commands you use
- which enemy you target

All of this can be controlled, even the exact amount of damage dealt and taken. I suggest following this strategy:

Walking around the area where this item you want is dropped and get into battles. When you get into a fight just dispatch the enemies but remember the exact commands you used for each character, which enemy they targetted which foes you fought and the formation in which they appeared. Write this down if it is too complicated to rememeber. Try keeping it simple, use only attack and magic commands and no items.

If you keep using the exact same commands during each battle you get stuck in a "loop". After you fought a random number of enemies you encounter the exact same enemy group you fought at the very beginning. Meaning that it is possible to encounter the a specific enemy that appeared in this "loop" over and over again as many times as you like, even the rare ones.

If you get stuck in a loop, what happens during the battles and the outcome of it is always the same.

Now, keep doing this until you encounter the enemy you want and he drops the item. If this doesn't happen just try using different commands. This is a very easy method.

05-10-2010, 06:16 PM
Thanks, that's mostly helpful. The Wicked Mask however is the most common encounter on B1 of the Lunar Core, so finding him isn't a problem.

I've noticed after loading a save\quicksaving that the first enemy fought in the core is a Behemoth, after running away, the next 20ish fights are consistently Wicked Masks. After about 30+ fights, the most common encounter is Red Dragons and occasional Behemoths. Quicksaving resets the encounters of course.

dealing damage (exact amount)
Would you suggest using attacks that only deal 9999 dmg then? Would using the defend command affect anything?

Hope this info helps anyone else searching for the Glass Mask.

05-10-2010, 06:56 PM
I think defending would affect the RNG so I would suggest not to use it.

As for damage, it doesn't matter which weapon you use as long as you never change it. You don't have to deal the exact same damage in every battle. But you have to deal the exact same damage in a specific fight within the loop. If you notice you don't deal the same damage - with a specific character on a specific enemy - as the previous time you fought the battle in the previous loop then there is something wrong and the loop will most likely change. An oversimplified example:

[loop begins]

- 1 Goblin is encountered
- Cecil kills it and deals 1 damage with a random weapon.

*other battles are fought*

[loop is reset]

Now you should encounter the same goblin and Cecil should still deal 1 damage to him. If that isn't the case then something went wrong.


I should tell you that it's possible that you suddenly encounter completely different enemies from the ones you should have encountered while in a loop. If this is the case, then your not doing anything wrong and the game is merely trying to "correct" itself. If this happens just try and make the same loop happen again.

I hope this is all understandable.

edit: You can't affect how much damage a character inflicts on a specific enemy but you don't have to worry about this as the battles in the loop will always happent the same way as they did in the previous one as long as you use the right commands.

05-10-2010, 09:17 PM
So if I fight a Wicked Mask and hit it for 9546 damage the first time I meet it in a loop of encounters, the next time I encounter that specific Wicked Mask once the encounters reset my attack should do 9456 dmg?

Also, just thought I'd mention, I got 11 pairs of Dragon Gloves while trying to get the Glass Mask :P

05-12-2010, 07:55 PM
More relevant material, I've been learning ASM, maybe there's a way to predict what causes item drops to guarantee getting rare items.

Tutorial: using a debugger to figure out game mechanics - Zophar's Message Domain (http://www.zophar.net/forums/showthread.php?t=13521)

05-14-2010, 10:08 AM
Didn't my method work? :( It works for me, at least in Final Fantasy II.

05-14-2010, 06:54 PM
I'm playing the GBA version, I've heard the RNG works a bit differently(and badly), but I have recieved rare items(soma drop, ribbon, bomb summon) so I'm going to keep trying to get it.

Funny thing is, whenever I got a rare drop, I wasn't even trying to get them :P I got the Bomb summon on the way back to the lunar subterrane from the Lunar Whale.