4 ms·

World of Warcraft, for example, trusts the client to handle pathing and movement logic in order to create the illusion of low-latency, super smooth motion. The

by shasta 14y ago

World of Warcraft, for example, trusts the client to handle pathing and movement logic in order to create the illusion of low-latency, super smooth motion. There is a simple solution: Trust but verify. The main reasons not to check that your clients aren't cheating are code complexity and the server processing required.

kevingadd 14y ago
Well, there's a reason why there are games (DOTA 2, for one modern example I'm certain about) that don't do 'trust but verify': sometimes if you verify, you will find that the client is wrong, in a way that probably just means they are innocently desynced, but might mean they're cheating, and it's hard to tell the difference. Worse still, those minor desyncs end up causing major gameplay differences that make the player feel like your netcode is terrible. Textbook example of the latter: Playing a melee class in Diablo 3. Rubber-banding and teleporting everywhere, getting killed by things you can't see or that are on the other side of the screen, etc: http://www.youtube.com/watch?v=CFw6MYqUyKs#t=0m15s http://www.youtube.com/watch?v=CFw6MYqUyKs#t=0m15s I do wish 'trust but verify' worked at scale though. It feels like one of those brilliant technology solutions that lets you beat the competitor on server costs. :D
- shasta 14y ago
  AFAIK, the primary reasons are the ones that I gave. Synchronization of client and server can be achieved at scale -- just look at every multiplayer RTS -- it's just expensive to do on top of an FPS client-server architecture because you have to simulate every client on the server.
- Negitivefrags 14y ago
  Trust but verify is absolutely the way that games using client side movement prediction work, and games without client side movement prediction feel terrible to play. World of Warcraft has problems because they don't do much of the verify part. The kind of problems you are seeing in this Diablo 3 video are avoidable, and solving those kinds of problems are essential to making a networked game.

by shasta 14y ago

kevingadd 14y ago

Well, there's a reason why there are games (DOTA 2, for one modern example I'm certain about) that don't do 'trust but verify': sometimes if you verify, you will find that the client is wrong, in a way that probably just means they are innocently desynced, but might mean they're cheating, and it's hard to tell the difference. Worse still, those minor desyncs end up causing major gameplay differences that make the player feel like your netcode is terrible. Textbook example of the latter: Playing a melee class in Diablo 3. Rubber-banding and teleporting everywhere, getting killed by things you can't see or that are on the other side of the screen, etc: http://www.youtube.com/watch?v=CFw6MYqUyKs#t=0m15s http://www.youtube.com/watch?v=CFw6MYqUyKs#t=0m15s I do wish 'trust but verify' worked at scale though. It feels like one of those brilliant technology solutions that lets you beat the competitor on server costs. :D

shasta 14y ago
AFAIK, the primary reasons are the ones that I gave. Synchronization of client and server can be achieved at scale -- just look at every multiplayer RTS -- it's just expensive to do on top of an FPS client-server architecture because you have to simulate every client on the server.
Negitivefrags 14y ago
Trust but verify is absolutely the way that games using client side movement prediction work, and games without client side movement prediction feel terrible to play. World of Warcraft has problems because they don't do much of the verify part. The kind of problems you are seeing in this Diablo 3 video are avoidable, and solving those kinds of problems are essential to making a networked game.