[MUD-Dev] Client side prediction

[Ola Fosheim Grøstad <olag@ifi.uio.no>]

"Dr. Cat" wrote:
> have a bunch of overhead issues tile based worlds don't.  (Though I wonder
> how many of them do things like conserving bandwidth by using dead
> reckoning and only sending a packet when the client's expected prediction
> will be too far form the actual correct position.)

Are you by "dead reckoning" suggesting implementing all the physics in
the client? I've spent too much time thinking about this, and I've
reached the conclusion that the problems that are associated with this
approach are too many and the benefits are too few.

- Hacked clients will benefit tremendously, they will all have access to
"intelligent firearms" and "spiderman danger sensing".  
- What are you going to do with intercepted events (like when somebody
prevents you from jumping off a cliff)? 
- How much more difficult will extending the world become and how
complicated will the protocol become if you want a flexible system?
- How dynamic can you allow your world to be without offsetting the
assumed advantage. It is no use if the physics has a chaotic element
(such as spheres and an inaccurate root solver), as all objects will
start to drift more or less instantaneously.
- My gut feeling is that lag will have more impact due to the cascading
problems associated with dropped packages...

Basically, when you start to think in that direction you will be driven
towards activities that are disjoint, that doesn't require syncing, that
doesn't depend on what other people do. That's no good if user-user
interaction is the main goal.

> of like ICQ and Napster.  I had an idea last year for a voice-chat startup
> based on this and some other thoughts, but I decided I didn't have the
> heart to play that whole cheesy venture capital game, mainly because it

Competing with the big telecoms is not a good idea. They have the
skills, the technology, the money and own the infrastructure. Currently
they just don't have the motivation. They deploy the technology when
somebody else try to get into their market segment (at least in Norway),
and they'll make it free if they have to. Which happened to be the case
with internet access, it is free now..

Ola.




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