Networking

Lumina uses a server-authoritative model. The server owns the simulation; clients receive replicated state and send input to the entities they own. World.Net tells a script which side it is on and who owns what.

Roles and ownership

if World.Net:IsServer() then
    -- authoritative logic
end

-- Only the peer that controls this entity should run input and camera code:
if World.Net:IsLocallyOwned(self.Entity) then
    self:EnableInput()
end

Method	Returns
`World.Net:IsServer()` / `IsClient()` / `IsStandalone()`	Which side this is
`World.Net:IsNetworked()` / `IsConnected()`	Connection state
`World.Net:HasAuthority(e)`	This peer is the authority for `e`
`World.Net:IsLocallyOwned(e)`	This peer controls `e`
`World.Net:GetOwner(e)` / `SetOwner(e, conn)`	Owning connection (`SetOwner` is server-only)
`World.Net:GetLocalRole(e)` / `GetRemoteRole(e)`	The `ENetRole` for `e`
`World.Net:GetUniqueId()`	This peer’s id (0 on the server)
`World.Net:GetLocallyOwnedEntity()`	The entity this client controls, or null
`World.Net:GetConnectionCount()` / `GetConnectionAt(i)`	Iterate clients (server)
`World.Net:MarkDirty(e)`	Server-only: force a replicated resend

Hosting and joining

World.Net:Host("/Game/Maps/Arena", 7777)   -- listen server; the server picks the level
World.Net:Connect("127.0.0.1", 7777)        -- join a server

Replicated properties

Mark a script field with --@replicated and the server’s value is sent to clients. Define an OnRep_<Field> function to react on the client:

--@replicated
Script.Health = 100

--@replicated(OwnerOnly)
Script.Ammo = 30

function Script:OnRep_Health(old: number)   -- runs on clients when Health changes
    print("health is now", self.Health)
end

The server changes the value, then calls World.Net:MarkDirty(self.Entity) to have it collected and sent. Conditions refine who receives it: OwnerOnly, SkipOwner, InitialOnly, or the default Always.

Remote procedure calls

Mark a function with --@rpc and calling it dispatches over the network instead of running locally:

--@rpc(multicast, reliable)
function Script:SetLabel(text: string)
    self.LabelText = text
end

The direction is server (client to server), client (server to a client), or multicast (server to everyone). Reliability is reliable or unreliable.