Joined: 3/31/2010
Posts: 1466
Location: Not playing Puyo Tetris
Monster Rancher uses discs to create monsters. I know that disc swapping is already emulated for PSX (See MGS). But, that run used game discs that were meant for that game. Monster Rancher, can use discs of music, games and even movies (?) to create in-game monsters the player can obtain and train.
A few questions I wanted to ask:
What data is being read from the disc by the game when a monster is being created?
Can that data be forged (fake ISO)?
Is that forged file (ISO) copyrighted?
Would a TAS be accepted if it used those forged files? What if the ISO files could be proven to work on a console (once burned)?
When TAS does Quake 1, SDA will declare war.
The Prince doth arrive he doth please.
I would assume that the game just reads some small portion of the disc, constructs a hash, and uses that hash as the seed to an RNG that determines which monster you get. As a result, you should be able to create discs with arbitrary data on them and have them work; no need to worry about copyright, and IMO making such "forged" discs would be perfectly acceptable.
Pyrel - an open-source rewrite of the Angband roguelike game in Python.
Monster Rancher uses discs to create monsters.
A few questions I wanted to ask:
Can that data be forged (fake ISO)?
If the game doesn't just hash the discs and compare to pre-stored hashes or something like that, it should be forgeable.
hegyak wrote:
Is that forged file (ISO) copyrighted?
Yes, however, if you make one from scratch, it is copyright by you.
Edit: Based on quick reading, it seems like there might be some pre-stored hashes (generating unique monsters), but mostly the game accepts any CD image.
Edit2: I consider it unlikely that one would have to have anything that would work on the CD. Maybe the structures needed to transfer control to entrypoint, but everything after can presumably be garbage (which would cause instant crash on real system).
Edit3: Since any game works and most PSX discs don't use CD-DA, the disc reading should at least partially work in PSXjin.
Joined: 3/31/2010
Posts: 1466
Location: Not playing Puyo Tetris
I don't think Monster Rancher hashes the whole disc. It doesn't take that long to check the disc in game.
But, what data is being read? The "get data and hash that," theory sounds right due to the time delay (which isn't long) for the game to get whatever it wants from the disc the player is using.
According to the Monster Rancher Wiki, the games use the disc inserted as a source of RNG and that determines the monster's stats (including breed/sex).
If the game is using the disc's data as an RNG source, will the exact same monster with the exact same stats come out of the same disc, every time?
When TAS does Quake 1, SDA will declare war.
The Prince doth arrive he doth please.
