NetworkIDObject¶

NetworkIDObject provides a way to assign unique identifiers to objects that all systems can reference.

Purpose¶

In multiplayer games, you need a way to refer to the same object across different machines. NetworkIDObject solves this by:

Assigning unique IDs to objects
Allowing lookup of objects by ID
Managing object ID allocation

Basic Usage¶

Inherit from NetworkIDObject¶

#include "mafianet/NetworkIDObject.h"

class Player : public MafiaNet::NetworkIDObject {
public:
    float x, y, z;
    int health;
    std::string name;
};

Creating and Registering Objects¶

The authority (usually server) creates objects and assigns IDs:

MafiaNet::NetworkIDManager networkIdManager;

// Create a player
Player* player = new Player();
player->SetNetworkIDManager(&networkIdManager);

// ID is automatically assigned
MafiaNet::NetworkID id = player->GetNetworkID();

// Send the ID to clients
MafiaNet::BitStream bs;
bs.Write((MafiaNet::MessageID)ID_SPAWN_PLAYER);
bs.Write(id);
bs.Write(player->x);
bs.Write(player->y);
bs.Write(player->z);
peer->Send(&bs, HIGH_PRIORITY, RELIABLE_ORDERED, 0, addr, true);

Receiving and Looking Up Objects¶

case ID_SPAWN_PLAYER: {
    MafiaNet::NetworkID id;
    float x, y, z;
    bs.Read(id);
    bs.Read(x);
    bs.Read(y);
    bs.Read(z);

    // Create local representation
    Player* player = new Player();
    player->SetNetworkIDManager(&networkIdManager);
    player->SetNetworkID(id);  // Use the same ID as server
    player->x = x;
    player->y = y;
    player->z = z;
    break;
}

case ID_PLAYER_POSITION: {
    MafiaNet::NetworkID id;
    float x, y, z;
    bs.Read(id);
    bs.Read(x);
    bs.Read(y);
    bs.Read(z);

    // Look up the player
    Player* player = (Player*)networkIdManager.GET_OBJECT_FROM_ID<Player*>(id);
    if (player) {
        player->x = x;
        player->y = y;
        player->z = z;
    }
    break;
}

NetworkIDManager¶

The NetworkIDManager maintains the mapping between IDs and objects.

MafiaNet::NetworkIDManager networkIdManager;

// Set whether this instance is the authority (assigns IDs)
networkIdManager.SetIsNetworkIDAuthority(isServer);

// Look up object by ID
void* obj = networkIdManager.GET_BASE_OBJECT_FROM_ID(id);

// Typed lookup
Player* player = networkIdManager.GET_OBJECT_FROM_ID<Player*>(id);

Authority vs Client¶

Authority (Server):

Creates NetworkIDs
SetIsNetworkIDAuthority(true)
IDs are automatically assigned

Client:

Receives NetworkIDs from server
SetIsNetworkIDAuthority(false)
Uses SetNetworkID() to assign received IDs

Object Deletion¶

When destroying networked objects:

// On authority (server)
void DestroyPlayer(Player* player) {
    MafiaNet::NetworkID id = player->GetNetworkID();

    // Notify clients
    MafiaNet::BitStream bs;
    bs.Write((MafiaNet::MessageID)ID_DESTROY_PLAYER);
    bs.Write(id);
    peer->Send(&bs, HIGH_PRIORITY, RELIABLE_ORDERED, 0, addr, true);

    delete player;  // Automatically unregisters from manager
}

// On client
case ID_DESTROY_PLAYER: {
    MafiaNet::NetworkID id;
    bs.Read(id);

    Player* player = networkIdManager.GET_OBJECT_FROM_ID<Player*>(id);
    if (player) {
        delete player;
    }
    break;
}

Integration with ReplicaManager3¶

For more advanced object replication, consider using ReplicaManager3, which builds on NetworkIDObject and provides:

Automatic object creation/destruction across network
Serialization management
Scoping (which clients see which objects)
Reference pointer serialization