Online Services

Online Services

Unified online platform integration with pluggable backends for authentication, matchmaking, leaderboards, achievements, cloud saves, and friends/presence.

Source: SparkEngine/Source/Engine/OnlineServices/OnlineServices.h

Overview

The Online Services system provides a single abstract interface (IOnlinePlatform) that encapsulates all platform-specific online functionality. Games code against this interface and never reference Steam, Epic, or console APIs directly. At runtime, the OnlineServiceManager singleton holds one active platform implementation.

The default platform is NullOnlinePlatform, which is fully functional offline -- it stores leaderboards in memory, achievements as a set, and cloud saves to local storage. This means single-player games work out of the box without any SDK dependencies, and developers can test online flows without network connectivity.

Adding a new platform requires implementing the IOnlinePlatform interface and passing it to OnlineServiceManager::SetPlatform(). Stub classes for Steam, Epic, and Console are included with detailed integration guides in their documentation comments.

Architecture

OnlineServiceManager (singleton)
  +-- IOnlinePlatform* (active platform pointer)
        |-- NullOnlinePlatform   (default -- fully functional offline)
        |-- SteamPlatform        (stub -- requires Steamworks SDK)
        |-- EpicPlatform         (stub -- requires EOS SDK)
        +-- ConsolePlatform      (stub -- requires NDA + dev kits)

Key Classes

Class	Description
IOnlinePlatform	Abstract interface defining all online service methods
NullOnlinePlatform	Fully functional offline implementation (default)
SteamPlatform	Stub for Steamworks SDK integration
EpicPlatform	Stub for Epic Online Services (EOS) SDK integration
ConsolePlatform	Stub for PlayStation/Xbox/Switch (NDA-protected SDKs)
OnlineServiceManager	Singleton that owns and routes to the active platform

Data Structures

Struct	Description
OnlinePlayerInfo	Player ID, display name, online status
SessionInfo	Multiplayer session metadata (host, map, mode, player count)
LeaderboardEntry	Player score with rank
AchievementInfo	Achievement ID, progress, unlock state
CloudSaveInfo	Save slot name, size, timestamp
FriendInfo	Friend ID, display name, online status, presence text

Usage

// Initialize with default offline platform
auto& online = Spark::OnlineServices::OnlineServiceManager::GetInstance();
online.Initialize();

// Use the platform interface
auto* platform = online.GetPlatform();
platform->Login("player1", "");
platform->SubmitScore("HighScores", 9999);
platform->UnlockAchievement("first_kill");
platform->SaveToCloud("save1", saveData);

// Switch to a custom platform at runtime
online.SetPlatform(std::make_unique<MySteamPlatform>());

Adding a New Platform

class MySteamPlatform : public Spark::OnlineServices::IOnlinePlatform
{
public:
    std::string GetPlatformName() const override { return "Steam"; }
    bool Login(const std::string& username, const std::string& token) override
    {
        // Initialize Steamworks SDK, authenticate user
        return SteamAPI_Init();
    }
    // ... implement all IOnlinePlatform methods
};

API Reference

OnlineServiceManager

Method	Description
GetInstance()	Get the singleton instance
Initialize()	Initialize with NullOnlinePlatform
Shutdown()	Log out and release all platforms
Update(float dt)	Per-frame update for async callbacks
GetPlatform()	Get the active IOnlinePlatform*
SetPlatform(unique_ptr)	Switch to a custom platform (takes ownership)
ResetToNullPlatform()	Revert to the offline platform

IOnlinePlatform

Method	Description
Login() / Logout()	Authentication
FindSessions() / CreateSession() / JoinSession()	Matchmaking
SubmitScore() / QueryScores()	Leaderboards
UnlockAchievement() / SetAchievementProgress()	Achievements
SaveToCloud() / LoadFromCloud()	Cloud saves
GetFriendsList() / SetPresence() / InviteToSession()	Social features

Configuration

Setting	Description
-DENABLE_STEAM=ON	Enable Steam SDK (requires ThirdParty/Steamworks/)
-DENABLE_EOS=ON	Enable Epic Online Services SDK (requires ThirdParty/EOS/)

Related Systems

• Networking -- UDP transport for gameplay networking
• Save System -- Local save/load persistence
• Gameplay Systems -- Inventory, quests, achievements