The Scene Manager

The Scene Manager is the most important piece of the package. It is responsible for performing the scene operations in coordination with the Unity Scene Manager.

ISceneManager interface

The ISceneManager interface exposes a few methods and events to standardize the scene load operations:

public interface ISceneManager : IDisposable
{
  event Action<Scene, Scene> ActiveSceneChanged;
  event Action<Scene> SceneUnloaded;
  event Action<Scene> SceneLoaded;

  int LoadedSceneCount { get; }
  int TotalSceneCount { get; }

  void SetActiveScene(Scene scene);

  ValueTask<Scene[]> LoadScenesAsync(ILoadSceneInfo[] sceneInfos, int setIndexActive = -1, IProgress<float> progress = null, CancellationToken token = default);

  ValueTask<Scene> LoadSceneAsync(ILoadSceneInfo sceneInfo, bool setActive = false, IProgress<float> progress = null, CancellationToken token = default);

  ValueTask<Scene[]> UnloadSceneAsync(ILoadSceneInfo[] sceneInfos, CancellationToken token = default);

  ValueTask<Scene> UnloadSceneAsync(ILoadSceneInfo sceneInfo, CancellationToken token = default);

  Scene GetActiveScene();

  Scene GetLoadedSceneAt(int index);

  Scene GetLastLoadedScene();

  Scene GetLoadedSceneByName(string name);
}

You can find many similarities between Unity's SceneManager class, and that's both for maintaining an easy learning curve as well as because some of these operations will end up calling the Unity Scene Manager internally (like SetActiveScene for instance). The ILoadSceneInfo interface will be covered in the next section.

The package includes the AdvancedSceneManager that is capable of handling both addressable and non-addressable scene operations. You can use its implementation as a reference to build your own Scene Manager if you need.

The AdvancedSceneManager is expected to be used as a wrapper for the Unity SceneManager. When creating an AdvancedSceneManager you can decide whether you want it to manage scenes that have been loaded already or not.

The ISceneManager interface defines that both LoadSceneAsync and UnloadSceneAsync methods return a ValueTask<Scene>. This means you can await those methods if they are implemented with the async keyword, or you can also subscribe to the SceneLoaded or SceneUnloaded events to receive the same Scene you would via the async methods.

Both these methods also receive an ILoadSceneInfo object. So, instead of having multiple methods for receiving the scene's build index or the scene's name, we simply have an object.

Alternatively, you can also use the LoadScenesAsync and UnloadScenesAsync methods, to perform the operations on multiple scenes in parallel. These will return a ValueTask<Scene[]>.

You can create an AdvancedSceneManager using three constructors:

// Creates an advanced scene manager including all currently loaded scenes. Useful for most cases.
// Should not be called on `Awake()`, since it runs before the scene is loaded.
new AdvancedSceneManager(addLoadedScenes: true);

// Creates an empty advanced scene manager. Useful if you are doing this before any scene loads or in a bootstrap scene.
new AdvancedSceneManager();

// Creates an advanced scene manager including an array of scenes. Useful when you want to include only a specific set of scenes to it.
new AdvancedSceneManager(initializationScenes: new Scene[]);