ZOA Platform Steam

SteamPlatformProvider implements IPlatformProvider and every one of the thirteen platform service interfaces on itself, forwarding each call to an ISteamClientBridge. It owns a PlatformEventHub, hooks the bridge's events into it once, and tracks the PlatformProviderState transitions that StateChanged reports.

Capabilities and Availability are both read straight off the bridge, so the provider reports what is reachable instead of advertising the full Steam surface and failing later.

Constructing it takes a SteamPlatformOptions and, optionally, a bridge. The single-argument constructor builds a SteamNativeClientBridge. Tests and custom native integrations use the two-argument one.

ISteamClientBridge is the whole Steam surface expressed in provider-neutral types. It takes SteamPlatformOptions on Initialize, exposes Shutdown and Tick, and then mirrors each platform service as a method returning a PlatformResult. It also declares the thirteen change events the provider republishes onto its hub.

SteamworksNetClientBridge is the real implementation. It references Steamworks.NET directly, registers typed Callback handlers for GameOverlayActivated_t, PersonaStateChange_t, LobbyChatUpdate_t, LobbyDataUpdate_t, LobbyInvite_t, and DlcInstalled_t, and reports the full capability set from Auth and Profile through Achievements, Leaderboards, Stats, Friends, RichPresence, Overlay, CloudSave, Commerce, InventoryItems, Workshop, Dlc, Lobbies, and Matchmaking.

SteamNativeClientBridge is the fallback. It reaches Steamworks.NET entirely through reflection, reports Availability with a reason when the assembly is missing, and declares only Auth and Profile as capabilities. Its events are declared as empty add and remove accessors, because it cannot register real Steam callbacks without the typed API. Operations that need the typed bridge return Unavailable with a message that names the installer menu path rather than failing obscurely.

ZOA.Platform.Steam.SteamworksNet carries a versionDefine on com.rlabrecque.steamworks.net that emits ZOA_STEAMWORKS_NET_AVAILABLE, and a defineConstraint requiring that same define. When the Steamworks.NET package is not in the project the define is never emitted, the assembly is skipped entirely, and SteamworksNetClientBridge does not exist in the build at all despite its unguarded using Steamworks statement.

SteamPlatformRuntime resolves the typed bridge by name through Type.GetType, looking for ZOA.Platform.Steam.SteamworksNetClientBridge in ZOA.Platform.Steam.SteamworksNet. When the type is present it constructs it; when it is absent, or when construction throws, it logs and falls back to SteamNativeClientBridge.

The gating shape differs from the one the networking backends use. Steamworks.NET ships as a UPM package with a real id, so a versionDefine can target it and no user opt-in toggle is needed. FishNet ships as an Asset Store package with no UPM id, which is why that integration needs two hand-managed defines instead.

SteamPlatformOptions carries the App ID plus three behavioural settings. RequireSteamClient, on by default, makes initialization fail with Unavailable when the Steam client is not running rather than proceeding into an undefined state. ServerAuthIdentity is the identity or audience string passed to native auth-ticket calls. AuthTicketTtl, ten minutes by default, is the provider-neutral local expiry stamped onto a minted ticket.

SteamPlatformRuntime solves a practical local-development problem before any of that runs. A build or editor session launched outside Steam has no App ID context, so the component writes steam_appid.txt next to the project root in the editor, or next to the player executable in a standalone build, before SteamAPI initialization. It skips the write when the file already contains the right value, and it warns rather than throwing when the directory is not writable.

The default App ID is 480, the Spacewar test app. That is correct for local integration testing and wrong for anything you ship, which is the first field to change in a real project.

SteamPlatformRuntime runs at execution order minus 9700 so the provider is registered before gameplay systems resolve anything in Start. Every lifecycle decision is a serialized flag: register on Awake, initialize on Start, make active after registration, keep alive across scene loads, unregister on destroy, and tick the provider from Update.

Initialize on Start defaults to off. A title that wants an explicit boot or login flow calls InitializeProviderAsync itself and drives its progress UI from the component's IsInitializing and LastInitializeResult.

EnsureRegistered is idempotent and cooperative. When a Steam provider is already registered and no bridge override was set, it adopts that instance and records that it does not own it. HandleDestroy then unregisters only a provider this component actually created, and only when it is still the registered one, so two bootstrap objects in a scene cannot tear down each other's provider.

SetBridgeOverride must be called before EnsureRegistered and throws if a provider already exists. The ordering is enforced in code, because a bridge swapped in after construction would silently go unused.

When the Steam provider is the active one, SteamPlatformRuntime can install two pieces of UI. PlatformLobbyMenuController comes from com.zoa.platform and is entirely provider-neutral: it binds to PlatformLobbySessionService, which binds to whichever provider is active. Steam only switches it on.

SteamProfileAvatarHudPresenter is the Steam-specific half. It supplies the signed-in user's Steam avatar image into the profile HUD region that PlatformProfileHudPresenter renders, refreshing on an interval.

Both installations are gated on the active provider actually being Steam, so a scene that carries the runtime component but resolves to another provider does not get Steam UI grafted onto it.

RequestAuthTicketAsync mints a Steam session ticket for a stated PlatformAuthTicketPurpose and returns a PlatformAuthTicket carrying the payload and a handle. ReleaseAuthTicket gives the handle back, which matters because Steam caps outstanding tickets per session.

The networking package's Steam auth adapter validates that ticket before admitting a joining peer. The two packages never reference each other: platform mints the ticket, the connect token carries an opaque payload, and the auth adapter validates it. The shape is provider-neutral, so another store's adapter slots into the same admission flow.

ServerAuthIdentity in the options is the audience string threaded through to the native call, so a dedicated server can require tickets minted for it specifically rather than accepting any ticket the client happens to hold.