Patch: Wilder Randomness

If i remember correctly, the Auction House is a event. As long I know, no event opcode reads the coordinates of another NPCs. Please, can you give more information about how the NPCs movement interfere with the Auction House?

If i understood the script, it use flags to determinate if an item/esper is available. If the item is available, its uses the BD opcode to determinate if the item will be used in the auction. It is a 50% chance to skip the item for another one. I don't see where the NPCs movement/coordinates are used.

You are correct. The random number generator doesn't use NPCs to determine random numbers. What I'm saying is that the NPCs use the same random number generator as the Auction House to determine how they move. Thus, the NPCs in Jidoor affect the state of the RNG. For this reason, speedrunners are able to predict the items in the Auction House by looking at the NPCs in Jidoor.

The issue I was concerned about is, there are about 9 NPCs that walk around randomly in Jidoor, and they all take steps at approximately the same time. That means the RNG will get called approximately 9 times per step (more if an NPC walks into an obstacle) and will skip over many values. When players are searching for espers, they won't spend much time on the main Jidoor map... they'll probably re-enter the auction house as soon as they leave it. Thus, the state changes in the RNG are very predictable, and are likely to get trapped in a loop. If you advance the RNG 9 times every attempt and there are only 256 possible RNG states, then the shortest loop might be only 29 RNG states long. Since there's a 12.5% chance of getting an esper in the worst case scenario, if you randomize the RNG table, there's a 2% chance that the esper won't appear anywhere in that 29-state loop.

I know it sounds crazy but you actually encounter these kinds of patterns when you try to do RNG manipulation for a speedrun. Another example is the Lete River. For certain NPC RNG values, you can get only 2 battles on the river and save a lot of time. But for many of those RNG values, they're impossible or very difficult to get because the way the NPCs move, the generator will skip right over them.

I will test the Auction House when i have free time.

Don't worry about it, it was just an example of why you would want a balanced random number generator. FF6 isn't that complicated it's pretty unlikely that something like that would happen. Even if your RNG isn't perfectly random, it can't be worse than the RNG that FF6 already uses.