Replicated Objects

These are the special objects that are available on the server and the client. They share data and provide a remote procedure call (RPC) interface.

General structure

As explained in the setup tutorial these must be declared in a special directory called net_objects. You may only declare one object per file, the object is created for you and you just have to describe it. The name is the same in every file and will always be OBJECT.

For example the following code is a valid replicated object declaration.

OBJECT.Properties = { 
    NotReplicatedProperty = "Hi I am not replicated !",
    ReplicatedStringWithCallback = { Replicates = true, Default = "toto", 
        OnRep = function (self) 
            print("ReplicatedStringWithCallback was modified !")
        end
    },
    ReplicatedBool = { Replicates = true, Default = true },
    ReplicatedInt = { Replicates = true, Default = 45 },
    ReplicatedFloat = { Replicates = true, Default = 12.345 }
}

OBJECT.NetRPCs = {
    TestRpc = {
        OnMaster = function(self, a, b, c) 
            print("master received TestRpc(" .. a .. ", " .. b .. ", " .. c .. ")")
            return true
        end,
        OnProxy = function(self, a, b, c) 
            print("proxy received TestRpc(" .. a .. ", " .. b .. ", " .. c .. ")")
        end
    }
}

function OBJECT:OnActivate()
    self.NetRPCs.TestRpc(12, 24, "test")
end

Special fields

Properties

This is the only place where you should declare variables, everything outside of Properties will be removed from the object. Properties can be replicated or not, as you can see in the sample above a property can be declared directly with a value which is equivalent to { Default = value }, the following fields are allowed :

• Default: Sets the default value when an object is created, the allowed types are number, string and boolean, anything else will not work for now.
• Replicates: Set to true if you want the property to replicate on clients, otherwise every instance controls the value.
• OnRep: Can be bound to a function(self) and will be called automatically when the property is updated.

Note: A property has a static type, meaning if you set a number as a default, you can only set a number to the value.

You access a property exactly the same way you declared it, for example if the declared type is

OBJECT.Properties = {
   Test = { Default = 42, Replicates = true }
}

It can be accessed like so

myInstance.Properties.Test = 54
print(myInstance.Properties.Test) -- prints 54

NetRPCs

Remote Procedure Calls act as any function you would call in Lua except they are executed on the server first and then can be replicated to clients. When declaring a RPC you actually declare two functions OnMaster (required) and OnProxy (optional). OnMaster will execute on the server only and returns a boolean, if it returns true the OnProxy function will be called on all connected clients with the same parameters, if it returns false nothing more happens.

Note: The parameter types are limited to numbers, strings and booleans for now.

You call a RPC exactly the same way you declared it, for example if the declared type is

OBJECT.NetRPCs= {
   DisplaySomeValues = {
        OnMaster = function(self, a, b, c) 
            print("master received TestRpc(" .. a .. ", " .. b .. ", " .. c .. ")")
            return true
        end,
        OnProxy = function(self, a, b, c) 
            print("proxy received TestRpc(" .. a .. ", " .. b .. ", " .. c .. ")")
        end
    }
}

It can be accessed like so

myInstance.NetRPCs.DisplaySomeValues(123, "hello", true)

Callbacks

Some member functions are special and will be called automatically :

function OBJECT:OnActive()
    -- Called when an instance comes alive, server only
end

function OBJECT:OnDeactive()
    -- Called when an instance is destroyed, server only
end

function OBJECT:Tick(delta)
    -- Called every frame with the delta time in seconds, server & client
end