Comments on: Networked physics with Farseer & Lidgren https://undertowgames.com/blog/networked-physics-with-farseer-lidgren/ Sat, 28 Mar 2026 17:33:05 +0000 hourly 1 https://wordpress.org/?v=4.2.39 By: Regalis https://undertowgames.com/blog/networked-physics-with-farseer-lidgren/#comment-48 Mon, 02 Feb 2015 23:08:41 +0000 http://undertowgames.com/?p=195#comment-48 I’m actually already using it for those “important packets”, but it seems that some packets are still lost if packet loss is very high (= if I set Lidgren’s SimulatedPacketLoss config to something like 0.4). Or it could be that it’s just some bug in my code, I’ll have to look into it more closely.

]]> By: juanjpro https://undertowgames.com/blog/networked-physics-with-farseer-lidgren/#comment-47 Mon, 02 Feb 2015 22:42:58 +0000 http://undertowgames.com/?p=195#comment-47 I read that Lidgren supports optional packet reliability, maybe you can make pickup-packets reliable to guarantee that players will pick up items if they try.

]]> By: Regalis https://undertowgames.com/blog/networked-physics-with-farseer-lidgren/#comment-46 Mon, 02 Feb 2015 21:33:03 +0000 http://undertowgames.com/?p=195#comment-46 Currently I don’t handle packet loss in any way. The clients just periodically send their state to server and if a packet is lost, the server will use the next packet to update the player. This isn’t a problem when it comes to moving the characters, but losing a packet that notifies about someone picking up an item definitely is.

I have a couple of ideas on how it could be fixed though. At the moment when someone picks up an item for example or does anything else that the other clients should know about, they send a message to the server and the server passes it to each client. If the client who picked the item up doesn’t receive their message back, it must’ve been lost at some point and the client resends it.

That obviously doesn’t help if the packet is lost between the server and one of the other clients it’s been passed to. Something that might work would be for the server to keep track of maybe a dozen of the last “important events” that have occurred, along the lines of “this button was pushed | this item was picked up | this door was closed” and sending that data to the clients every few seconds. That way the clients can see if they’ve missed any important packets and ask for them to be resent.

And yeah, the server trusts the players, another thing that I hope “will be good enough”. Because it’s essentially a co-op game, where it’s easy to grief even without hacking (open an airlock, break a window or something), I hope it won’t be a major problem considering that the host can just kick hackers out of the server.

]]> By: juanjpro https://undertowgames.com/blog/networked-physics-with-farseer-lidgren/#comment-45 Mon, 02 Feb 2015 20:30:21 +0000 http://undertowgames.com/?p=195#comment-45 How do you handle packet loss? Does the server trust the players (i.e. allow them to apply arbitrary forces to themselves) or does it perform actions based on keypresses?

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