Network Session

The plNetworkSession provides high-level session management for multiplayer games. It wraps the lower-level connection APIs and adds session concepts: lobby states, ready checks, player tracking, and lifecycle callbacks.

Overview

A network session represents a multiplayer game from creation through gameplay to conclusion. The session manages:

Lifecycle states-- Lobby, Loading, InGame, PostGame.
Player tracking-- Who is connected and their ready state.
Game flow-- The host starts the game when all players are ready, which triggers level loading.

Accessing the Session

plNetworkSession* pSession = pNetModule->GetSession();

Session States

State	Description
`None`	No session active
`Lobby`	Waiting for players, setting up the game
`Loading`	A level is being loaded across all machines
`InGame`	Gameplay is active
`PostGame`	Game is over (scoreboards, replays)
`Migrating`	Host migration in progress (reserved for future)

Creating and Joining

As Host

plNetworkConfig config;
config.m_uiServerPort = 7777;
config.m_uiConnectionLimit = 8;

pSession->SetMaxPlayers(8);
pSession->CreateSession(config);  // Starts server and enters Lobby state

As Client

plNetworkConfig config;
config.m_sServerAddress = "192.168.1.100";
config.m_uiServerPort = 7777;

pSession->JoinSession(config);  // Connects to server

Leaving

pSession->LeaveSession();

Ready State

Players can signal they are ready to start:

// Set local player's ready state
pSession->SetLocalReady(true);

// Check if a specific player is ready
bool bReady = pSession->IsPlayerReady(clientID);

// Check if all players are ready
bool bAllReady = pSession->AreAllPlayersReady();

The host tracks all ready states. On clients, SetLocalReady() sends the state to the server.

Starting the Game

Only the session leader (the host) can start the game:

if (pSession->IsSessionLeader() && pSession->AreAllPlayersReady())
{
  pSession->StartGame("Levels/Mission01.plScene");
}

StartGame() transitions the session from Lobby to Loading and triggers level loading through the Level Manager. If no level path is provided, it simply transitions the state.

Player Tracking

// Get all connected player client IDs
const plDynamicArray<plUInt32>& players = pSession->GetPlayerList();

// Get the player count
plUInt32 count = pSession->GetPlayerCount();

// Check if this machine is the host
bool bIsLeader = pSession->IsSessionLeader();

Session Properties

pSession->SetMaxPlayers(16);
plUInt32 max = pSession->GetMaxPlayers();

pSession->SetSessionVisibility(true);   // Public session (for future matchmaking)
bool bPublic = pSession->IsPublicSession();

Message Handlers

Session events are delivered as plMessage types to all registered plNetworkComponent subclasses. Override the virtual handlers in your component:

class MyLobbyComponent : public plNetworkComponent
{
  PL_DECLARE_COMPONENT_TYPE(MyLobbyComponent, plNetworkComponent, MyLobbyComponentManager);

  void OnNetworkPlayerJoined(plMsgNetworkPlayerJoined& ref_msg) override
  {
    plLog::Info("Player {} joined the session", ref_msg.m_uiClientID);
  }

  void OnNetworkPlayerLeft(plMsgNetworkPlayerLeft& ref_msg) override
  {
    plLog::Info("Player {} left the session", ref_msg.m_uiClientID);
  }

  void OnNetworkSessionStateChanged(plMsgNetworkSessionStateChanged& ref_msg) override
  {
    if (ref_msg.m_NewState == plNetworkSessionState::InGame)
    {
      // Start gameplay logic
    }
  }

  void OnNetworkAllPlayersReady(plMsgNetworkAllPlayersReady& ref_msg) override
  {
    plLog::Info("All players ready! Host can start the game.");
  }
};

These handlers are registered in the plNetworkComponent base class via PL_MESSAGE_HANDLER, so any subclass can override them without additional setup.

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