Hard Light Productions Forums
General FreeSpace => Multiplayer => Topic started by: JGZinv on October 19, 2010, 07:11:04 pm
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I know this has been talked about in the distant past (search yields nothing in the last 365 days)
but where is the development on the overhaul of the netcode sitting?
We could probably make a good list of projects that are going to ultimately need smoother
net play, and in particular hit detection before their release.
Last I heard, we didn't have someone experienced enough in that field to do anything significant
and there were other attached issues that were pressing at that time.
So I figure lets start some dialogue on that again, eh?
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On behalf of Stellar Assault, we fully advocate the furthering improvment of the FS2 netcode.
:nod:
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I also had a question on the data being sent:
What data is being sent over the 'net related to the player positions?
For example, X-Y-Z coordinates, direction angles, current velocity, acceleration, etc.
and:
How, in general, does the FS2 multiplayer work from the standpoints of the client computers and the server?
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Well the big problem with the net code is that I'm the only coder who touches it (Taylor does a lot of the PXO stuff but he rarely touches the game to game stuff).
I've been reading through the code whenever I have time in order to get a better understanding of how it works but basically the client reports what they are doing and the server is responsible for working out everything else (collisions, etc included). I've not looked that closely into exactly what data is sent though.
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So it boils down to we don't have someone versed in that area to make any major headway.
Ok, do we know what criteria we need to look for in a net code specific coder? (Besides the usual,
C/C++, lives off pb&j, etc) ;)
Do we also know if part of the problem is related to (or complicated by) Squadwar and the other sections of code getting
ripped out when FS2 got released, or is that more a non-issue / we don't know?
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It's a non-issue, really. The problem is more that the fsnetd code that replaced the SquadWar/PXO stuff was written to much the same specifications as the original code, which of course also meant that it has much the same limitations. Whoever takes this on will have to basically redesign the entire network backend in terms of client/server interaction and lag compensation.
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The FS2NetD code isn't even the issue here. Bear in mind that even with the PXO code gone you could still play multiplayer if you passed your friends your IP address.
PXO/FS2NetD are stat saving and game matchmaking services. I'm not familiar with it but I doubt that Taylor would have made too many big restrictions in the way it worked when he refactored the FS2NetD code.
The real problem is that the actual multiplayer code (the stuff that handles communication between the server and the client machines playing the same mission) is largely untouched since we first got hold of the source cause only a few coders (Taylor, myself and Kazan mainly) have ever bothered to do anything with it.
Without looking at the code I can think of a couple of major issues.
1) The game is set up with a bunch of basic assumptions (Maximum of 12 players, 2 TvT teams maximum, 1 wing per team) which have been defined as constants. Change any of those and you're going to break a lot of things cause the code wasn't designed to use anything beyond those assumptions and it shows in several places.
The loadout menu is an enormous example of this. It's based around 12 players and will completely break down if you tried to have more.
2) Something is lagging the game with larger number of players. I have no idea what. The result is that as soon as you have over 9-10 players the game lags out. Unfortunately I lack the kind of network coding experience to track down the exact cause and actually finding that number of people to help test is virtually impossible.
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Here's an interesting tangent - how does the interface code, which is also quite archaic and chock-full of constant values, relate to the netcode? In a sense, the interface is just another factor bogging down the expansion of multiplayer, no?
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Here's an interesting tangent - how does the interface code, which is also quite archaic and chock-full of constant values, relate to the netcode? In a sense, the interface is just another factor bogging down the expansion of multiplayer, no?
No. Those two areas of the code are pretty isolated from each other; While the interface needs to be updated for new features, it's not the main reason why changes are so hard.
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So looking at it from say a PCS2 type example, what are the criteria you want to see
in a net coder kara?
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Basically anyone with experience of debugging anything network related in C would be a step up. I have very little/none.
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Small changes tweaks and optimizations could probably help get to 16, maybe even 20 players. But reaching levels like 64 or 128 players in the same mission, the system probably isn't capable of handling that. Systems that can are designed with that in mind from the ground up, and even those often lag when that many players get close enough within a mission to actually matter to each other. You'd probably be talking about doing updates more often for nearby ships and not every entity in the map, the latter of which I'm guessing is what FSO currently does. I don't know anything about the netcode really, other than to know that to really modernize it you probably need a coder who has a lot of experience working with net code that can handle that many concurrent players to actually know what needs to be done. That or someone willing to put in the research hours and figure out how to apply some modern methods to FSO's code.
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Well, the only thing I know of in the current gaming market that is capable of large player groups
is MAG on the PS3.
Not that I'm saying FringeSpace wants it, because I think it's unrealistic... but Tachyon back in '99
oringally came out with 128 player support. Somewhere shortly after release they found out it didn't
work and things were limited to 64 players using Novalogic hosted maps. Player hosted maps have
always had a hard limit of 32 players, even though from a map standpoint, the environments on many
were identical. Granted at the height of Tach's popularity the 64 and 32 player rooms were filled to the brim
and the game list stretched on for pages both public and private. 64 seems like a very unrealistic number to
shoot for though, 32 is pushing it some too. It's not impossible in the FPS world however to see 32 players.
kara - I've got a few coding related people I know (besides the one I mentioned earlier). Not sure if any have
any network experience, but I'll send out some feelers and see if I get someone that can at least tell us how big this monster is.
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Why not doing something like was done for the max to pcs2 support? cash price for netcode rewrite :p
I think before upgrading the max number of player in a game (a 8vs8 tvt would be already great)
it would be great to have a smoother moving ships in multiplayer because right now it's hard to shoot a shaking ship ^^
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Frankly, even if that ship isn't shaking and you see your weapons making contact but don't do anything at all, that's far worse.
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Yes, we know that lag compensation is bad. Which is why we need a coder who knows how to implement a better solution.
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I'm not disputing that. Just making a note that Thaeris and I are basically in the same
state.. which granted network differences aside... there shouldn't be a significant portion of "lag."
Short of being same city, same ISP, or same room... you can't get much better than that.
I'm probably going to end up testing Kali here in the near future to see how IPX mode
handles things differently from TCP/IP. Maybe it'll tell us something.
Still trying to contact the coders I know.. not having much success.
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I wonder too how is caculated ping cause sunday i was testing multiplayer with a friend, we are 2 streets away from each other (less than 1 km) and both have optic fiber connexion and the same isp, but fs2 gave us a ping of.... 500? i usually have in anygame somthing like 15/20
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I wonder too how is caculated ping cause sunday i was testing multiplayer with a friend, we are 2 streets away from each other (less than 1 km) and both have optic fiber connexion and the same isp, but fs2 gave us a ping of.... 500? i usually have in anygame somthing like 15/20
500 means something is wrong.
A note to Thaeris and JGZinv;
The client only renders hits on ships if shots hit the ships on the client.
If you see a ship or it's shields get hit, on your screen as a client, you missed.
Lag compensation isn't present at all, you see the ships however many fractions of a second after (*discerned via ping) their current position on the host box, if the host box registers you as having fired and you weren't lined up on their computations, you missed, simple as, end of discussion.
Now, from experience;
Anything under 200ms (.2 seconds) is easily playable.
Anything under 500ms (.5 seconds) is 'compensatable for' with a bit of thought and some determination but 200-500 is a bit less enjoyable.
Anything 1-150 can reasonable called 'live'.
Anything under 100 you cannot complain about 'lag' even if you have no prior experience of dealing with it, most brains can't distinguish the difference, even for gamers.
Now, packet loss is something different, if you have that something is wrong on a connection between host and client somewhere in the intarwerbs.
Packet loss has quite random effects on gameplay.. and is insanely hard to compensate for (it's doable up to a point but after about 40% packet loss you're pretty much only ever gonna be able to dodge incoming missiles and not do much else 'cept shoot things that don't move, even then you gotta pray your fire command got to the server...
Anyway, if the current model is to be used at all it simple needs drastically speeding up.
However, several (!) things to consider;
In most online games, you play with locals, or perhaps continental neighbors at worst.
Most games are built with modern architecture in mind, and take full advantage of it.
Most modern games especially, run on dedicated hardware and aren't hosted on your machine.
FreeSpace usually ends up with games where people are regularly playing from several hundred miles distance.
FreeSpace is built with 56kers in mind, being a niche game that was mostly, meant to be hosted by clients, it's netcode is very forgiving for people who do have high latency, while people who expect a host-experience from clients with modern standards in mind, are sorely disappointed because they're looking for the wrong things.
Most FreeSpace games are hosted on a persons computer while it's playing the game itself, any slow downs on that persons computer or in their network directly effects the game.
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A note to Thaeris and JGZinv;
The client only renders hits on ships if shots hit the ships on the client.
If you see a ship or it's shields get hit, on your screen as a client, you missed.
Lag compensation isn't present at all, you see the ships however many fractions of a second after (*discerned via ping) their current position on the host box, if the host box registers you as having fired and you weren't lined up on their computations, you missed, simple as, end of discussion.
Forgive me, but I don't understand. To me, if I'm seeing something hit, it ought to be hitting. If there's a discrepency and in actuality nothing's happening, that means there's a problem. The means to fix the problem is assumably unknown to you or I, but it's still a problem.
About the last part with FS being good as a 56K game, I think I'd have to contest that, as would JGZinv. We've had several discussions a while back about the 56K connection capabilities of several older games, and something like FS just doesn't stack up to a game like Tachyon, which could not only handle quite a few players over multi (more than FS), but could also run at very high speeds without substantial lag problems. As such, our general concensus is that FS never had a good net code, merely a passable one for the time. Unfortunately, fixing this problem would require a complete re-write of the net code, and that's probably not going to happen over night...
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He's not describing how things should be, he's describing how they are. Telling him there's a problem isn't gonna help with that.
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I understand where you're coming from Delta. I'm not a coder but I've been through
enough to realize packet loss, distance, and so forth has a role to play. 90% of the time
since Novalogic dropped their servers, the Tach community is doing the same client hosting
as the FS2 community is. Except in our case we've got one box in Europe and most players
are in the US.
I also realize that we're trying to force FS2 to work, when over the years it's been
updated and added on to significantly by FSU/SCP. We're throwing a lot more at the
engine than when it was originally setup. By the time our mod is done, I hope to be throwing
a lot more at the multiplayer end of things too.
The bottom line is just we need to find someone for the job. It needs to be inspected to
find out what it's condition really is, and then decide on fixing it. There's no doubt it's "broken"
as it stands.
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We could consider trying to move to client-side hit detection, instead of host-side. Half-Life did it way back when they released 1.1.0.0 (http://www.gamesurge.com/features/editorials/netcode.shtml). It may be a step backwards though. That article is very against the concept, but there are benefits for it too. I think it exaggerates the problems for low ping players, it really was closer to equaling out the playing field. There's another explanation of this here (http://www.sk-gaming.com/blog/Karvameduusa/20418-HalfLife_Netcode_Explained). There may be things we can do to expose more of the various timings to the player, assuming we have a similar set of timings, to allow them to make custom compensations depending on the situation. We could even thinking about making some timings dynamic, based on the ping and packet loss.
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I really wish that people would stop saying we need to rewrite the code without having actually looked at it. Quite frankly no one knows why the net code is so laggy. It could be that it's perfectly good code and there is a bug that is resulting in it running slowly.
I'm looking at it now but I'm not an expert. What we need is for someone with some actual skill in this area to look at the code and determine if this is in fact the case.
Deciding what we actually need to do to solve the problem is putting the cart before the horse. We need to figure out what the actual problem is before we try to solve it.
We could consider trying to move to client-side hit detection, instead of host-side.
:v: tried that too. It's all been commented out by them though so it looks like it didn't work.
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Clientside hit detection opens a bit of a scary can of worms for squadwars, I don't mind the idea but due to some of the quirks with some of the lag bugs clientside hit detection actually would seriously put a laggy player at a massive advantage.
Thaeris;
Again; FS2 is completely playable at about 200 ping, a local 56k connection (local meaning; national european sized countries) would register within this range to another 56k host.
A local (again, national), 1.5mbit host equates to anything between 10 and 80 ping, which is very very difficult to tell whether there is any actual lag or not.
A British 1.5mbit host to western america is about 150-200 ping, where people less able to cope will start finding problems.
To austrialia, probably close to 300, 400 ping.
the exaggerations of a great many people about the netcode really irks me.
For something like tach, or a FPS of the day (looking at you tribes) with many many players, no, FS2s netcode would not have been agreeable, however, considering the PXO community survived for 4 years? 5? with no memorable lag complaints for a patch on the network code - I personally think you are one of those crying about nothing.
Sure - compared to modern day games there is a massive difference, and sure, there is massive room for improvement, but honestly, having played this game for over 2 years on a 33.6k modem, and, normally for most of that on a .5mbit cable host in HAWAII, I honestly think most people can STFU. Simply in terms of global networking FS2's latency has improved and honestly so long as you get over your stupid predisposition about where **** should be instead of actually thinking about where it is the lag _doesn't_ effect you.
There is no "host advantage" (well....with two notable exceptions, hosts are the only ones that can /effectively/ shoot down bombs (I can sometimes on american hosts..most of the time on european hosts.. but no one else seems to be able to, and for me it's basically only because I move into a position where I'm actually shooting down the bombs path, if it's arcing I can't hit it at all)), and debris/spiny bits on ships don't work client side at all... debris is on the host and is invisible to the clients, clients debris is not on the host and intangible.
Other than that, in terms of **** moving around, and being hit by projectiles, is it so damn hard to think "well actually, where will this ship be in .2 seconds time?" - or if your ping is less than that, unless you're aiming at a subsystem on a fighter you just don't need to care.
to quote the second link on chiefs' post;
Why does it feel so smooth on my client even with high ping?
If you have played on a server with very high ping you feel that the weapons still are dead instant, when you hit that fire button the weapon reacts immediately and is being fired. In the new engine much of the multiplayer information is calculated on the client for visual effects. The client estimates were players are, it adds blood when you hit and also adds those bullet holes and marks on walls. But those are not true, they are only estimations and you never know if they are real. Only the server knows, and when you receive the correct update from the server the player that you aimed at will eventually die. And then you know for sure.
FS is the same.
Really, exactly the same.
While I do agree that something needs to be done to see if we can improve it (naturally, improvement is always good), the people who complain about it right now, are honestly just whining of the sake of it, and it grates on me because it puts people who would other wise have a fine time in multi, off playing it.
No, the netcode isn't perfect, but it's far from unplayable, so stop suggesting it is.
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Clientside hit detection opens a bit of a scary can of worms for squadwars, I don't mind the idea but due to some of the quirks with some of the lag bugs clientside hit detection actually would seriously put a laggy player at a massive advantage.
Yep, that's one of my objections to it too. Along with the one I gave above.
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Are there any files/functions of interest if one wanted to start looking at this themselves? I keep getting lost just looking for what happens with the net code.
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That's exactly my problem with it. Which is why I'm reading through the whole thing at the moment and trying to get a better idea of what happens where.
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The bottom line is just we need to find someone for the job. It needs to be inspected to
find out what it's condition really is, and then decide on fixing it.
Let's not have the thread fall apart on disagreements for the moment shall we?
It would appear at least, that everyone can agree on the quote above since we don't know
to what depths this rabbit hole goes. We can all agree that for some it may be sufficient, others
it is insufficient, and some don't know of that which they speak. All bases are covered.
So we need to find someone first off.... any constructive thoughts on where we might find
such a person? (I know that's borderline stupid obvious, if we knew already...)
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Quantum Delta, Good Sir, there's something you ought to keep in mind:
FS2 speeds are most of the time below 100m/s. Stellar Assault often plays at speeds in excess of 400m/s, FringeSpace is a little less, and something like Diaspora will probably come in third in terms of speed. Any bit of lag which was easily predicable before going at 65m/s is an entirely different story now. If your sole concern is multi in standard FS Open (FS2), then of course the current system isn't as great an issue. But, for every other game that doesn't fly at a snail's pace on the engine, there is a problem and it does make multi often less-than-enjoyable.
That said, if you'd ever be willing to test any of the other projects (and I assume you'd be well recieved) that perform in such a manner, I think you'd begin to see why we're making such a deal out of this.
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Yeah, not only that, but FotG has speeds approaching that, as well as ships that are only about 12-15 m long. Virtually impossible to hit even in single player without assistance for a normal person. I'm worried that multi in its current state just won't be able to handle it. We have computer-assisted targeting right now as it is, but in multi, hitting the ship every time, as has been stated, could result in an actual guaranteed miss every time. BtRL also had somewhat smaller than FS2 ships and faster times, were similar lead tactics required in many matches to score an effective hit?
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BtRL I can't speak much of, but the multi I did play, I went head to head against several foes
and even though I was hearing the "hit" sound... it took "a lot" of rounds to hurt anyone.
We'd run out of ammo in some cases... but that was a long while ago.
Lag was an understatement. But who knows what all the conditions were at the time.
I'd rather not get into more speculation.
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BtRL games were more likely than not capped to low object update.
As I said on IRC everyone always plays on low updates and then complains that they have problems caused by low updates.
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You two drive me around the bend, seriously,
I even went to bed to avoid exploding at you after that post thaeris.
Just because your crappy mods are faster doesn't mean it's harder.
Just because your crappy ships are smaller, doesn't mean it's harder.
Kay?
Kay.
Thanks.
The speed and size of the Dragon isn't what makes it so hard to deal with.
The speeds and physics models of those mods make them much, much easier (read;boring) to predict where the opponent is going to be a few seconds after current, I feel sorry for you if you're unable to adjust your aim a few dozen meters.
JGZinv; You......really don't get it do you? If you're 'hearing the hit sound' you're probably doing it wrong.
*grumbles*.
I might kill someone soon :I
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If this takes one more step in the way it's going I'm gonna splitlock.
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Thaeris, have you actually tried your mod on multiplayer mode already?
At such speeds i don't think we'll be seeing many maneuvers different from zoom and boom, and if you get tangled in a circle fight, well... the speed doesn't help you much there, so that wont be an issue.
But seriously, don't get concerned ahead of time, try it and see what happens first.
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Disclosure: Thaeris hasn't played FringeSpace, he's helping us with models.
That said, the Stellar Assault team plays multi to test their mod on a regular basis
(as in a couple to a few times a week / day). I've been in a couple games with them.
FringeSpace has played amongst it's own team with multi.
I would note that Chief also mentioned FotG.
In the interest of keeping things chilled, I won't go back over what we observed in our own
tests/games for the time being. Whether or not the netcode is at fault, or sufficient, we don't
have a SCP coder that understands it fully. So it "still" boils down to we need someone new.
Delta - if you want to vent, the you're welcome to do so at me over PM. I might have a couple
questions anyway.
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We may or may not need someone new, but we do need to put a focus on seeing if there is something wrong, which is what Karajorma started doing last night. We may need to get a large group together for investigating the net code to see if there's a bug causing it to become unplayable with larger numbers of people or high updates, as high updates shouldn't be crashing games and should make a low ping group have a very playable experience, eliminating the ghost shots you've been having. But we're hopefully capable of fixing a bug at this point, if that's indeed what it is. However, more help is always nice, but I wouldn't say we _need_ it at this point.
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More coders are always welcome of course. :)
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i remember there's a packet tracking app that some dudes used for hacking games ( i don't remember which game, but i think it was an mmo), maybe start tracking the packages and test it during intense multi sessions could help?
I'm pretty sure there must other programs that could help as well, tho...
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Wireshark (http://www.wireshark.org/)?
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I've used Wireshark a few times in the past (mainly to get to the bottom of why servers weren't appearing on the list). It's a nice program. It may or may not be useful for this issue. As I said before, I want t complete my code review before I start looking into the problem or else I'd probably end up wasting everyone's time.
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Roger that.
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Stellar Assault has done a number of Multiplayer tests. The largest having 5 players simultaneously.
Setting the game up to have high update rate helped a little considering we are all on broadband. But for weapons in the game with "instant hit" status, such as the Particle Beam Weapon (PBW), the lag guaranteed a miss every time; while in single player it was a very formidable weapon, in Multi it was worthless.
I am merely posting here to counter the idea that "there isn't a problem". Because there is indeed a problem. A problem that needs to be addressed. I can't offer much to this thread beyond that. But the point Thaeris made is perfectly valid and should be strongly considered, the faster the game is, the better the netcode needs to be.
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Speaking of which, Kara, any luck so far?
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What does instant hit mean?
If those are in any way like the beam-ish weapons/beam weapons in TBP, then they aren't useless... just lead like any other primary to compensate for lag... ideally it would be better to see it hit and actually register, but right now we don't have this. I don't say there isn't a problem, just that it isn't much of a huge game stopping deal, imho...
Anyway, any improvement is welcomed, i guess, i hope kara or someone else come along that can do something about it, and i'm sure i would be glad to lend a hand when testing comes around since i can't do much more than that :b
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What he's talking about is a weapon like a railgun or single fire slug with a very high velocity so
it is an "instant hit."
That said, probably going to try and do some more tests soonish.
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It doesn't really matter that it's not a beam - effectively from a players POV, it's exactly the same.
Muras explanation still stands, same as several other experienced multi pilots, and most of the coders have tried to explain in this thread, including indepth links to other games with similar netcode.
I'm starting to feel like giving up, considering I've had these complaints off bad players for over a decade can anyone actually blame me for being annoyed earlier? -.-
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Thread locked. Keep the drama out, people.