Question

I need to transfer .NET objects (with hierarchy) over network (multiplayer game). To save bandwidth, I’d like to transfer only fields (and/or properties) that changes, so fields that won’t change won’t transfer.

I also need some mechanism to match proper objects on the other client side (global object identifier…something like object ID?)

I need some suggestions how to do it.
Would you use reflection? (performance is critical)
I also need mechanism to transfer IList deltas (added objects, removed objects).

How is MMO networking done, do they transfer whole objects?
(maybe my idea of per field transfer is stupid)

EDIT:
To make it clear: I’ve already got mechanism to track changes (lets say every field has property, setter adds field to some sort of list or dictionary, which contains changes – structure is not final now).

I don’t know how to serialize this list and then deserialize it on other client. And mostly how to do it effectively and how to update proper objects.

There’s about one hundred of objects, so I’m trying avoid situation when I would write special function for each object. Decorating fields or properties with attributes would be ok (for example to specify serializer, field id or something similar).

More about objects: Each object has 5 fields in average. Some object are inherited from other.

Thank you for all answeres.

Answer 1

Another approach; don’t try to serialize complex data changes: instead, send just the actual commands to apply (in a terse form), for example:

move 12432 134, 146
remove 25727

(which would move 1 object and remove another).

You would then apply the commands at the receiver, allowing for a full resync if they get out of sync.

I don’t propose you would actually use text for this – that is just to make the example clearer.

One nice thing about this: it also provides “replay” functionality for free.