RPCs

Overview

Fusion RPCs are sent through the FusionClient singleton. Routing is automatic — if the callable belongs to a node with a FusionReplicator child, it's an object-targeted RPC; otherwise it's a broadcast RPC.

All RPC methods live on FusionClient. Annotate receiving functions with @rpc as usual.

Three Calling Styles

rpc() — Send to All

GDScript

FusionClient.rpc(my_method, arg1, arg2)

Sends to every peer (equivalent to rpc_to(FusionClient.TARGET_ALL, ...)).

rpc_to() — Send to Enum Target

GDScript

FusionClient.rpc_to(FusionClient.TARGET_MASTER, my_method, arg1)
FusionClient.rpc_to(FusionClient.TARGET_OWNER, my_method, arg1)   # object RPCs only
FusionClient.rpc_to(FusionClient.TARGET_PLUGIN, my_method, arg1)

First argument is a FusionClient.RpcTarget enum value.

rpc_to_player() — Send to Specific Player

GDScript

FusionClient.rpc_to_player(player_id, my_method, arg1, arg2)

Targets a specific player by their numeric ID (must be > 0).

RpcTarget Enum

All constants are on FusionClient:

| Constant | Description |
|----------|-------------|
| TARGET_ALL | All peers (default) |
| TARGET_MASTER | Master client only |
| TARGET_PLUGIN | Server plugin only (custom Photon plugin) |
| TARGET_OWNER | Object owner only — object RPCs only, errors on broadcast |

Object vs Broadcast Routing

Routing is determined automatically by the callable:

• Object RPC: The callable's object has a FusionReplicator child → RPC is sent to that specific networked object on remote clients.
• Broadcast RPC: The callable's object is null or has no FusionReplicator → RPC is delivered to all registered broadcast receivers.

Object-Targeted RPCs

GDScript

@rpc("any_peer", "call_local")
func take_damage(amount: int):
    health -= amount

func attack():
    # Callable bound to this node → routes through our FusionReplicator
    FusionClient.rpc(take_damage, 10)

    # Send only to owner
    FusionClient.rpc_to(FusionClient.TARGET_OWNER, take_damage, 10)

Broadcast RPCs

Global calls not tied to any object. Register a receiver, then call via FusionClient.

GDScript

func _ready():
    FusionClient.register_broadcast_receiver(self)

func _exit_tree():
    if FusionClient:
        FusionClient.unregister_broadcast_receiver(self)

@rpc("any_peer", "call_local")
func chat_message(sender: String, text: String):
    print("[%s]: %s" % [sender, text])

func send_chat(text: String):
    FusionClient.rpc(chat_message, sender, text)

@rpc Annotation

GDScript

@rpc("any_peer", "call_local")    # Any peer can send, also executes locally
@rpc("authority")                  # Only authority can send (default)
@rpc("any_peer", "call_remote")   # Any peer, remotes only

• Mode: "authority" checks has_authority() before sending. "any_peer" allows anyone.
• Sync: "call_remote" (default) sends to remotes only. "call_local" also executes on the sender immediately after sending.

Supported Argument Types

bool, int, float, String, Vector2, Vector3, Vector4, Quaternion, Color, PackedByteArray, Array, Dictionary, and networked Node references (encoded as Fusion ObjectId).