Custom SyncVar Serialization

Unity Engine
1

Hi,

I’m interested in writing Serialization functionality so that I can have an object in one of my classes sync automatically. However, when trying to write an example with the example given on the state synchronization page, I can’t seem to replicate the example without compile errors. Specifically base.get_syncVarDirtyBits() doesn’t seem to exist.

http://docs.unity3d.com/Manual/UNetStateSync.html

Thanks,

2

base.get_syncVarDirtyBits() is the accessor function for the property base.syncVarDirtyBits, so replace it with “base.syncVarDirtyBits”.

3

Ok thanks for that. Seems to fix the compile errors.

        if ((base.syncVarDirtyBits & 1u) != 0u)
        {
            if (!wroteSyncVar)
            {
                // write dirty bits if this is the first SyncVar written
                writer.WritePackedUInt32(base.syncVarDirtyBits);
                wroteSyncVar = true;
            }
            writer.WritePackedUInt32((uint)this.int1);
        }

Can I get a little more explanation about the if statement. I noticed in the example, there being multiple checks with 1u/2u/4u. What are these values and where are they being calculated from and how would I work it out with an example of my own?

Thanks.

4

the constants 1u/2u/4u are bit masks that correspond to index positions into the array of dirty bits. These are used for telling the client which syncvars on the script have changed.

So:

the first sync var at position 0 uses the mask 1u.
the second sync var at position 1 uses the mask 2u.

The sync var dirty mask for the script is a binary OR of the masks of the dirty bits that are set.
The dirty bit mask is included in the update packet.
The client can then do a binary AND against that dirty mask for each position and tell which syncvars change, and only read values for those from the NetworkReader stream.

5

So as long as I know how many variables I’m sending over, I just have to keep going i.e. 1u, 2u, 4u, 8u and so on?