RPCs

Replication handles continuous state - properties that change over time like position, health or score. But games also need one-shot events: a player fires a weapon, sends a chat message or triggers an ability. Remote Procedure Calls (RPCs) fill this gap by letting one client invoke a function on other clients without storing anything in the sync buffer.

RPCs are fire-and-forget - they are delivered once and not retained. If a client joins after an RPC was sent, it will not receive that call. For state that must survive late joins, use replicated properties instead.

Overview

Fusion RPCs are sent using fusion.rpc(), either to a specific player or to all players. RPCs are received as events.

-- set target_player to 0 to broadcast to all players
local target_player = 0
local descriptor = hash("chathandler")
local event = hash("on_message")
local data = json.encode({ text = "Hello" })
fusion.rpc(target_player, descriptor, event, data)

fusion.on_event(function(self, event_id, data)
	if event_id == fusion.EVENT_RPC then
		print(data.descriptor_type)		-- "chathandler"
		print(data.event)				-- "on_message"
		
		local message = json.decode(data.bytes)
		print(message.text)				-- "Hello"
	end
end)