Verzögerungen in Online-Spielen durch Client-Side Prediction kompensieren (text is in German)
The author Christian Oeing explains the basics of online games whose simulated world is managed by a central, authoritative game server that clients can connect to. It is very well described how network latency affects basic implementations of such client-server setups, and how this causes the player to perceive the game as sluggish or lagged. As the key matter of the article, Christian explains how the "client prediction" can be used to compensate for the network lag. As "client prediction" can, quasi as a side effect, cause the client's idea of the world state and that of the server to disagree, the author also describes the techniques that can be use to overcome such divergencies: "reconciliation" (or "reprediction", in Cafu lingo) and interpolation.
What makes the article special and my definitive recommendation (for those among you who speak German), is that all this is written in a very readable manner that is easy to follow and understand – and the huge coincidence that everything that he describes is also implemented in the Cafu Engine since several years. (To be precise, Cafu implements the "client prediction" and the very important "reprediction" features, but deals with interpolation only in a slightly different manner than described in the article.) Thus, especially for those who want to familiarize themselves with the Cafu networking code but find the comments and internal documentation too terse, the article is a must read.
If you don't speak German, the article also provides links to English texts:
- Client-Side Prediction and Server Reconciliation by Gabriel Gambetta, and
- What every programmer needs to know about game-networking by Glen Fiedler
In the meanwhile, we're still very busy with finishing the details of our newly introduced Component Systems.
The basic work is all long done, but I would still like to fix a few more loose ties in the Map Editor before this very fundamental project can be declared done and ready for public consumption.