Great Net Engine! Have some questions though :)

Hi,
first of all, thanks for Photon, it's awesome to work (and play!) with. I have worked with some other network engines for different gameengines before, but photon for unity is by far the most easiest to use. Writing netcode is actually fun now
Also, free Photon Cloud access is a real timesaver and makes it almost way to easy to get started.

After toying around with it for some days, i have some questions though:

1.)
I'm basically using the supplied code from the PUN Documentation for the PhotonView Component to pass data around between clients

void OnPhotonSerializeView(PhotonStream stream, PhotonMessageInfo info) {
    if (stream.isWriting) { //We own this player: send the others our data
        stream.SendNext((int)controllerScript._characterState);
        stream.SendNext(transform.position);
        stream.SendNext(transform.rotation);
    } else { //Network player, receive data 
        controllerScript._characterState = (CharacterState)(int)stream.ReceiveNext();
        correctPlayerPos = (Vector3)stream.ReceiveNext(); 
        correctPlayerRot = (Quaternion)stream.ReceiveNext(); 
    }
}

This is for very basic player movement and obviously doesn't create too much net overhead.
Now what if i want to add additional interaction methods for the player, like attack, casting spells, trading, whatever? The streamsize would increase. As far as i understand it, if ONE value of the stream changes (player position/rotation, isShooting, isCasting) the whole stream has to be sent over the net to update the changed value on all clients. Depending on the number of playerattributes/values, this could cause much unnecessary stream overhead.
My question is, would it be a good idea to use some kind of bitmasking when sending streams? Like so:

void OnPhotonSerializeView(PhotonStream stream, PhotonMessageInfo info) {
    if (stream.isWriting) { //We own this player: send the others our data
        - create a bitmask depending on changed player attributes/values which should be send to the other clients
        - send bitmask
        - for each entity in the bitmask, send it's coressponding data
    } else { //Network player, receive data 
        - get bitmask
        - get data according to bitmask
    }
}

Is this a good method for reducing stream/net overhead, or are there better ways? Is this even needed at all or does Photon handle unchanged values internally and doesn't even send them at all?


2.)
Let's say there a 2 gamerooms. Room A has 2 players, room B has 3. If a client sends data in room A via PhotonView Observers, do clients in room B internally recieve it, but simply don't use it? Same for RPCs. I'm asking because of this:

5.3.2 Groups and Scoping
The PhotonNetwork plugin does not support real network groups and no scoping yet.
While Unity‟s “scope” feature is not implemented, the network groups are currently implemented purely client side: Any RPC that should be ignored due to grouping, will be discarded after it‟s received. This way, groups are working but won‟t save bandwidth.

The way i get it, this only applies to client to client communication inside one room, but i want to be sure.


3.)
I'm currently coding everything within Unity/Mono for rapid prototyping, haven't touched servercode once. Somewhen in the future (we are talking about years here) i might need to port parts of the code to the Photon Server for security reasons (which is, i guess, pretty lousy right now due to the pure client side implementation?). If i want to move code from unity to photon server, i would have to port the function in question from unity to photon server, then make a call from unity to the server calling the function and pass the result (if there is any) back to unity. An example would be attacking: Only send player input to the server, then let the server decide if the player was 1.) able to shoot 2.) did hit something. How would i do the function-calling-on-the-server-via-unity-and-passing-back-some-data part (I'm not talking about porting from unity/mono to photon server here)?
If it's too much of a hassle to explain, don't worry. I'm far from porting code to photon server and only asked out of curiosity

4.)
I know this topic has been discussed before, but i want to make sure:
There will be lots of NPCs/Enemies in the game. What's the best way to send npc data to the clients?
1.) Attach a PhotonView to each NPC. I guess this is a bad idea.
2.) Extend the bitmask idea from above and send an ID first, then the bitmask, then the actual data. ID will be used to determine which object the bitmask and data belongs to. Then use a SINGLE PhotonView Component for all NPCs. This might be better than 1.), but sending over the ID and bitmask alone everytime would create quite some net overhead...i guess (again! ). Also, sending data from two or more NPC at once isn't that trivial anymore, which isn't all THAT bad as you could then simply pass the data one after another and forget about the small lag. If there are LOTS of NPCs at once on the screen though, you might get in trouble.
3.) Let the photon server handle all the NPCs. If a player creates a new room, server will create all the NPCs. Also, no problems if the master client changes. Might be the best choice ... Apart from handling all the other stuff like for example physics and world interaction in general plus reduced workflow as one would have to code in unity and server simultaneously. This might be the best choice (from a technical view).

Well, thats it for now. But don't expect me to not ask other questions once these are answered


On my next trip to Hamburg, i'll bring along some cake for you guys.