Thanks for the post Mark, that was fascinating! Being a very amateur programmer myself I actually understood it too!
2.1 Discussion on AI weapon spam "rate of fire" bug
- Thread starter Mengy
- Start date
Thanks for the post Mark, that was fascinating! Being a very amateur programmer myself I actually understood it too!
Huh, so it's possible that solo mode isn't affected by this bug at all? I might just grab my Python and play in solo until the update then...
I play almost exclusively in Solo and I have not been affected by this bug. Seems like a viable route to go until the rest of the bug gets patched out.
Haha, so now people are leaving Open for Solo because even the NPCs in Open are cheating gankers! 
(I'm kidding! I'm kidding! I love playing in Open, especially in a few days when the bug is fixed. Just thought it was funny )
(I'm kidding! I'm kidding! I love playing in Open, especially in a few days when the bug is fixed. Just thought it was funny
)
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Awesome read Mark! Thanks for sharing, i feel your pain!
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Only when transferring authority between machines. That must have been a fun one to pin down!
Thanks for the detail Mark. Always interesting to get insights into the internals. [smile]
On one hand, this is a nice look under the hood. Always fascinates me when developers can explain to a layman what went wrong. On the other hand, how long was the beta? How was this not caught?
If I had to guess... Low number of beta testers = Insufficient feedback
And/Or, low number of beta testers = low probability of getting the extreme manifestation of the bug. If the pointers were pointing to weapon types that are somewhat close, then it's possible players didn't notice, or chalked it up to "new feature" instead of a bug.
Likely. Especially given the bug only presented in certain circumstances.
I also feel that beta testers are less concerned about negative outcomes like this during beta. They're not supposed to be. That's the whole point of beta. Make everything cheap and easy to get so that you can experiment, and nothing affects your live account. It's amazing how much more effort you put into looking for answers to things that actually start to hurt. That's just a theory, of course. [wink]
Honestly when beta testers died to AI ships they probably just chalked it up to the new improved combat AI using strong engineer weapons. Seems like a plausible explanation to a quick death. It wasn't really until we started seeing AI ships from an outside view spewing plasmas like Gatling guns that we knew something was terribly, horrendously wrong. That prompted all of the closer examinations that led to discovering the bug.
Not to sound daft, but a longer beta testing period probably would have found this before it went live.
I'm just very happy it's now figured out and getting fixed. [yesnod]
In the books of the series War Against the Chtorr, by David Gerrold (inventor of tribbles[hehe]), there was a cool hand held weapon called a needler. It was a rapid fire gauss rifle (similar to rail gun) that fired about 1,000 tiny needles per second at a very high velocity.
If this weapon was converted to an ED ship based weapon, we would have a beam railgun [woah]
If this weapon was converted to an ED ship based weapon, we would have a beam railgun [woah]
Ouch doesn't even begin to cover it.
Let us assume that the dps on coriolis.io is correct at 26 MJ/s. Now the weapon fires each and every frame, not knowing if that means 30 shots or 60 shots per second, we have a multiplier of 30 or 60. That gives a grand total of 780 MJ or 1560 MJ per second. No wonder that commanders report seeing nothing but a bright light followed by the rebuy screen!
Cudos to Mark for the update and background info!
can i have a plasma shotgun can be a med - fixed no complains over here....
can be a med - fixed no complains over here.... 
Is is possible for this to affect non-weapons? In particular shields? I ask because sometimes we've seen small ships that seem to be able to outclass anacondas in shield strength.
Pity noone saw this happen with the ships that we sometimes see shooting at a station. It would have been a good way to fnd out if they ever put a damage model on a station.
Given the speculation about what might be causing this bug, and what it means for the game - I thought I'd clarify a few things on the technical side
So, to try and explain.
The data for a module in Elite is split up into a set of blocks: things like power consumption, vulnerability to overheating, health, and of particular interest in this case, Weapon data. Weapon data is about 40-50 values controlling everything from the more obvious rate of fire & range, to slightly obscure things like how fast the beam fades after you release the trigger. More or less any combination of values is allowed (you want a laser shotgun? sure, take a pulse laser and set the Rounds Per Shot value to 12). This flow is identical between players and npcs, even stations and skimmers actually.
Prior to 1.6/2.1 the cached pointer each weapon held to its data was a simple affair pointing at a bit of data loaded from resources, but as part of the changes to make items modifiable I had to change this so it could also be a pointer to a block of data constructed from a base item plus a set of modifiers - ideally without the code reading that data caring (or even knowing) where it actually came from and therefore not needing to be rewritten to cope. This all works great in theory, and then in practice, up until a few naughty NPC's got into the mix and decided to make a mess. I'll gloss over a few details here, but the important information is that a specific sequence of events relating to how NPCs transfer authority from one players' machine to another, combined with some performance optimisations and an otherwise minor misunderstanding on my part of one of the slightly obscure networking functions got the weapon into an odd state. The NPC's weapon which should have been a railgun and had all the correct data for a railgun, but the cached pointer to its weapon data was pointing somewhere else. Dangling pointers aren't all that uncommon (and other programmers may know the pains they can cause!) but in this case the slightly surprising thing was that it would always be a pointer to a valid WeaponData - It's correct enough that it'd never have tripped any of the sanity checks or asserts that something was wrong, and yet.. clearly it's not right either!
What did this do exactly? Well in that example the weapon would have thought it was a slugshot: it'd make decisions on ammo, when to fire, how much power to consume and heat to generate as if it were a slugshot. It then tells the game to fire 12 shots but now we're outside the areas that use the cached data, the weapon manager knows its a railgun and dutifully fires 12 railgun shots
Why does this never occur on players? Well AI and players aren't governed by different rules in combat - but one thing AI's do that players never do is transfer authority between machines (it's rather hard to move out of range of yourself after all), which is the trigger at the heart of this bug. Removing modified weapons from NPCs earlier in the week will have reduced the frequency of the problem as it's more-or-less tied to how many modified weapons are in the session, the fix included in the build Zac mentioned coming soon should stamp it the rest of the way out. With the usual caveat of programmers: I fixed the problem I found, can't promise it's the last one!
Much as I love the insane weapons, and part of me likes having the proof that actually the system is hugely flexible... lets add them when we mean to next time! er... Sorry
-Mark
As a developer i know your pain. Thank you for sharing
Had a good laugh until.... i realized that i am at work right now and need to fix my own code. Damnit
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