When is loot generated?

Dungeons, Raids and Scenarios
11/19/2012 02:03 PMPosted by Keeblik
Huh. If a blue said that's how they do it, I'll take their word for it, but I can't imagine why. Maybe they do it so that they can keep the whole instance in one contiguous block of memory, I guess.

(1) At least in vanilla, there were mobs who wore (some of) the gear they dropped. Not sure if these exist anymore.
(2) It allows you to have drops in an instance that are not limited to one mob, but where you don't want less/more than a certain minimum/maximum of drops. Or any other form of drop that's calculated on a per-instance rather than per-mob basis.
11/19/2012 11:27 AMPosted by Melhunt
What are the variables in the random generator's kernel, is it based on some attribute of the players in the raid, or the raid leader?

None of the above. Back in vanilla, Blizzard used IBAA [1], which is a cryptograpically secure random number generator. The RNG is initialized once at server start (presumably from /dev/random or some other source of random data) and then simply used to generate a sequence of pseudo-random [2] numbers. There is no way to predict or manipulate rolls without hacking the server (which has not stopped a lot of superstitious beliefs from arising).

[1] http://www.wowpedia.org/Random_loot
[2] You'll get to read a lot of nonsensical stuff that "pseudo-random" is not really random, but in reality a good PRNG's numbers are less predictable than what, say, a roulette wheel produces and would require more computing power to figure out -- even if you had a perfect record of past rolls, and you won't see 99.9% of them -- than you could muster outside of having your own personal Google-sized data center.
Yeah that question was actually just an excerpt from a blue post on the old forums (nuked when we switched over).
11/19/2012 05:58 PMPosted by Melhunt
Yeah that question was actually just an excerpt from a blue post on the old forums (nuked when we switched over).

Oops, my bad, I didn't make the connection.
Although a lot of it has been previously stated, here's some links to support what others have already said/


Daze: Is Loot determined when the monster dies or when we actually loot it?

Drysc: Loot is generated upon creation.

As soon as you step into an instance, or a mob is created in the world, the loot that's going to drop has already been determined.

Q u o t e: What are the variables in the random generator's kernel, is it based on some attribute of the players in the raid, or the raid leader?

Drysc: Heh, no.

I believe it uses a time stamp to seed the generator. So, there's nothing you can influence within the game that would alter or coerce the generator.

Q u o t e: So what you are saying is that we've killed Curator at the exact same second each week for the last 7 weeks, to account for the Champion gear? Or 14 out of the last 15 weeks? All we have to do is kill him a minute later? Huh...

Drysc: No, the time it uses to seed would have no real implication into the final outcome of what loot its given. On a long enough generation table, you may see some type of pattern based purely on a random generators inability to truly be random. But we're talking about astronomical numbers, something ridiculous like hundreds of billions of generations. Nothing you would or could see a pattern in during your time playing the game.

What you're seeing is pure and basic laws of probability. Have a few thousand people roll a pair of dice and you're bound to see hundreds of people able to roll snake-eyes 10 times in a row. (not that dice are truly random either)

Q u o t e: I believe loot is determined at the time the mob dies. How else would quest mobs drop quest items for people only on the quest? Does it register client side or is the quest item in the spawn only for people who are on the quest?

Drysc: Quest items are always there, they're just hidden if you don't have the quest.

Q u o t e: After stepping out of an instance or logging into an empty zone, I've often seen all the mobs throw up their buffs at the same time. Is this just my client, or does the server only create the mobs when someone's around to reduce load?

Drysc: The mobs aren't actually created until someone enters the area. Sometimes you'll see mobs sort of "fall" a bit to the ground, or groups of mobs all fan out from a single point. This is usually the creation happening. Ideally you don't notice it at all though.

And old EJ thread ([url]http://elitistjerks.com/f15/t23187-loot_generation_mechanics_finding_warglaives/[/url])discussed issues related to loot generation as well.

I think the last area that was covered with loot generation was whether the loot table was consistent if you were to wipe/rest/despawn a boss. When the mob specific tags were added to the game, it kind of settled that issue given the final posts in the EJ thread.
Here's a screenshot of Drysc laying it out:


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