Network Binding Properties

Open 3D Engine (O3DE), the successor to Lumberyard, is now available in Developer Preview. Download O3DE or visit the AWS Game Tech blog to learn more.

For network binding features to function, you must have a Creating a NetBindable Component.

Properties

You can configure networking binding for properties by adding the netSynched table to the description of the variable inside of the Properties table.

local ExampleScript = {
    Properties = {
        Speed = {
            default = 0,   -- Supports numbers, strings, booleans, and nils for net bindings.
            min = 0,
            max = 100,
            step = 1,
            description = "Speed in m/s for the ...",
 
            -- If this table is missing, it is assumed the value is not networked.
            netSynched =
            {
                -- Optional fields
                OnNewValue = <function> -- OnNewValue is called whenever the property has a
                                        -- new value. OnNewValue accepts one parameter,which
                                        -- is the entity table for the instance that changed.
 
                -- The following flags are mainly here for debugging and profiling convenience.
                Enabled = true          -- Controls whether the field is network enabled. If 
                                        -- missing, assumes true.
                ForceIndex = [1..32]    -- Profiling helper tool to force a property to use a
                                        -- specific DataSet to make understanding what data is 
                                        -- being used where easier.
            }``
        }
    }
}
return ExampleScript

After you add networking to a property, any changes to the property are reflected across the network.

RPCs

Exposing RPCs to scripts involves creating a new table inside of the component table, but outside of the properties table, as shown in the following example.

local ExampleScript = {
    Properties = {
        -- ...
    },
  
    -- Table of remote procedure calls (RPCs) that the script wants to implement.
    NetRPCs =
    {
        RPCNoParam = {
            OnMaster = <function> -- The function to be called on the Primary Script.
                                  -- The function should return a bool value that 
                                  -- indicates whether or not proxy components can 
                                  -- execute the RPC on themselves. Required.
            OnProxy = <function>  -- The function to be called on the Proxy Script. 
                                  -- This function is optional and can be excluded if 
                                  -- the master never allows proxies to execute the function call.
        }
    }
}
 
return ExampleScript

You can invoke the RPC just like any other function. There is no need to specify the OnMaster/OnProxy from the calling script. For example, you can call RPCs as in the following example.

self.NetRPCs.RPCNoParam()
self.NetRPCs.RPCParam(1.0)