The Scene Loader

The Scene Loader is an interface that you will use to load scenes in your game, as it works like a wrapper layer to the Scene Manager, but adds the Scene Transition operations. There are two base interfaces for Scene Loaders: one with a reference to the ISceneManager that will be used, and an async interface to be able to await the load operations.

ISceneLoader interfaces

The ISceneLoader interface defines:

public interface ISceneLoader : IDisposable
{
  ISceneManager Manager { get; }

  void TransitionToScenes(ILoadSceneInfo[] targetScenes, int setIndexActive, ILoadSceneInfo intermediateSceneInfo = null);

  void TransitionToScene(ILoadSceneInfo targetSceneInfo, ILoadSceneInfo intermediateSceneInfo = null);

  void UnloadScenes(ILoadSceneInfo[] sceneInfos);

  void UnloadScene(ILoadSceneInfo sceneInfo);

  void LoadScenes(ILoadSceneInfo[] sceneInfos, int setIndexActive = -1);

  void LoadScene(ILoadSceneInfo sceneInfo, bool setActive = false);
}

And the ISceneLoaderAsync:

public interface ISceneLoaderAsync<TAsyncScene, TAsyncSceneArray> : ISceneLoader
{
  TAsyncSceneArray TransitionToScenesAsync(ILoadSceneInfo[] targetScenes, int setIndexActive, ILoadSceneInfo intermediateSceneReference = default, CancellationToken token = default);
  
  TAsyncScene TransitionToSceneAsync(ILoadSceneInfo targetSceneReference, ILoadSceneInfo intermediateSceneReference = default, CancellationToken token = default);

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

  TAsyncScene LoadSceneAsync(ILoadSceneInfo sceneReference, bool setActive = false, IProgress<float> progress = null, CancellationToken token = default);

  TAsyncSceneArray UnloadScenesAsync(ILoadSceneInfo[] sceneReferences, CancellationToken token = default);

  TAsyncScene UnloadSceneAsync(ILoadSceneInfo sceneReference, CancellationToken token = default);
}

Note that the ISceneLoaderAsync interface inherits from ISceneLoader. The TAsyncScene type should return a Scene instance, and can be anything you mean to await, for example, Task<Scene>, ValueTask<Scene> or UniTask<Scene>, while the TAsyncSceneArray should return a Scene[] instance, such as Task<Scene[]>, ValueTask<Scene[]> or UniTask<Scene[]>.

Scene Loader Implementations

The package comes with one base implementations and two wrappers:

• The SceneLoaderAsync, that just like the ISceneManager implementations, will return ValueTask values.
• The SceneLoaderCoroutine, that uses the SceneLoaderAsync but returns a WaitTask that can be used in coroutines.
• The SceneLoaderUniTask, that uses the SceneLoaderAsync but returns UniTask values.

All of them have interfaces to simplify your code:

public interface ISceneLoaderCoroutine : ISceneLoaderAsync<WaitTask<Scene>, WaitTask<Scene[]>> { }

public interface ISceneLoaderAsync : ISceneLoaderAsync<ValueTask<Scene>, ValueTask<Scene[]>> { }

public interface ISceneLoaderUniTask : ISceneLoaderAsync<UniTask<Scene>, UniTask<Scene[]>> { }

The Manager property can be used to listen to the SceneLoaded, SceneUnloaded, and ActiveSceneChanged events. Both LoadSceneAsync and UnloadSceneAsync methods will simply call the ISceneManager equivalents, while the LoadScene and UnloadScene will do the same but without await. It's important to understand that LoadScene, UnloadScene, and TransitionToScene will still invoke asynchronous operations, instead of blocking the execution until they are done. You can use the ISceneManager events to react to the completion of those methods.