What Game Mechanics would you like to know?

Any information you would like to share or ask in regards to the hacking of Legend of Legaia
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meth962
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Re: What Game Mechanics would you like to know?

Post by meth962 » Tue Mar 03, 2015 11:25 am

Glad to hear it was actually useful! You are very welcome. Besides the fact that it was fun to dive into the guts of Legaia and figure out questions, the rest of it is just numbers and most people wouldn't care :)
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Re: What Game Mechanics would you like to know?

Post by Nightshade » Thu Mar 12, 2015 10:53 pm

Here's one big thing: Do you have any information on the exact specifications of the random number generator - what increments it, does it start on a constant value when soft/hard reset, etc.? Do you think there's any possibility that the RNG could be manipulated somehow to ensure favorable outcomes?
Do not question yourself with the why or the how. I simply am, and that is all you need to know.

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Re: What Game Mechanics would you like to know?

Post by meth962 » Fri Mar 13, 2015 9:24 am

I do know exactly how it works and yes&no about manipulating it. Since it is very time sensitive, there is no way a human could get it to execute at the exact right time. Not just talking about the frames per second because it changes the rng more than once per frame. It's essentially every time it is used and it is called many times during one frame. You can see this by load stating say, in a battle right before "Begin!" of a round, and try to hit confirm at the same time every time. I.E. load state, count 1 second, hit ok. See how much damage you do. Load state and try to wait that 1 second again and hit ok, to see if you get the same damage result.
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Re: What Game Mechanics would you like to know?

Post by Nightshade » Fri Mar 13, 2015 8:11 pm

Do you happen to know what gets used as a seed for the RNG? Even if it isn't possible to manipulate it with human skills, it might be possible for a TAS to do so with frame advance.

This certainly seems to be one of the most difficult games to try to manipulate. At least that suggests that actually routing intricacies isn't necessary since it can't be done.
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Re: What Game Mechanics would you like to know?

Post by meth962 » Mon Mar 16, 2015 9:36 am

It would be easier to just force the seed value into the playstation's memory. Although as to which value to put there would have to be calculated following all my crazy assembly notes O_o Not sure I know the rules or views on what is considered cheating on tool assisted speed runs but if they're already using something other than the game to manipulate what happens, they're already cheating in my mind and it makes no difference if you just overwrite the memory?

And no I don't know the starting seed. Suppose it could be easily solved by break pointing that memory address from launch of the game. I might get a chance to run home for lunch break at work and try it. Otherwise I won't be home until Thursday. :(
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Re: What Game Mechanics would you like to know?

Post by Nightshade » Tue Mar 17, 2015 5:31 pm

Anything that messes with the game's internal memory through methods outside of the game itself are forbidden. Glitches that are internal to the game that may lead to memory corruption / rewriting are acceptable, such as 1 minute Pokemon Red.

It wouldn't be legit to force to a particular string of the RNG, even with tool-assistance. Everything they do must be theoretically possible by a normal human playing the game on a console, and while a TAS is allowed to always pick the right frames for inputs, they can't also be messing with memory addresses through external mechanisms.
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Re: What Game Mechanics would you like to know?

Post by meth962 » Wed Mar 18, 2015 3:12 pm

Hrm interesting. So what would you intend for this tool on rng? Seru capturing or the slot machine reels?

Also, sorry I didn't actually get time to try it like I thought I would. I might be able to today quick after work before I meet some friends.
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Re: What Game Mechanics would you like to know?

Post by Nightshade » Thu Mar 19, 2015 9:46 am

Seru capturing is the big one; slot machines can be timed, albeit imperfectly except with tool-assistance.
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Re: What Game Mechanics would you like to know?

Post by meth962 » Thu Mar 19, 2015 12:28 pm

So yep, the seed is started on the playstation startup screen actually.

Initial value is hardcoded to 0x24040001
then during the playstation logo, it is called many times and ends at 0x351ff07b.
Btw, to get to this number, it calls the RNG 142 times during the playstation logo.

It stays on this value in the Media Playing screen as well as starting up Legaia. As soon as I went to 'New Game' it started being called and changed. So yes it may be possible to have a tool that watches it. I didn't look to see when it changes on a loaded save.

I'm going to go dump the assembly code in the tutorial section now :)
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Re: What Game Mechanics would you like to know?

Post by Nightshade » Tue Apr 14, 2015 8:55 pm

I was wanting to get confirmation on something; I have noticed that JuggerCort doesn't seem to use Doomsday until he is below around 30,000 health - after some twenty turns of setup with him at full HP, he used Ultra Charge / Final Crisis plenty of times, but never once used Doomsday; the speedrun route is predicated on this fact (and therefore takes Cort from full HP to dead in one turn), but I'd like to get some sort of confirmation that this is actually correct - I don't want to have a great run that I just lose because JuggerCort decides to use Doomsday on the very first turn.
Do not question yourself with the why or the how. I simply am, and that is all you need to know.

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