PlayMainScene_PrevSceneAutoLoader.cs

#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;

namespace Custom.Scripts
{
[InitializeOnLoad]
static class PlayMainScene_PrevSceneAutoLoader
{
	static PlayMainScene_PrevSceneAutoLoader() // [InitializeOnLoad] above makes sure this gets executed.
	{
		EditorApplication.playModeStateChanged += OnPlayModeChanged;
	}

	private static string PrevScenePath
	{
		get { return EditorPrefs.GetString("cEditorPrefPreviousScene", EditorSceneManager.GetActiveScene().path); }
		set { EditorPrefs.SetString("cEditorPrefPreviousScene", value); }
	}

	private static void OnPlayModeChanged(PlayModeStateChange state)
	{
		if (!EditorApplication.isPlaying
			&& !EditorApplication.isPlayingOrWillChangePlaymode // User pressed stop -- reload previous scene.
			&& !string.IsNullOrEmpty(PrevScenePath) )
		{
			// Debug.Log( PrevScenePath );
			try
			{
				EditorSceneManager.OpenScene(PrevScenePath);
			}
			catch
			{
				Debug.LogError(string.Format("error: scene not found: {0}", PrevScenePath));
			}
			finally
			{
				PrevScenePath = "";
			}
		}
	}

	[MenuItem("Custom/Play Main Scene #F8")]
	private static void Play()
	{
		if ( EditorApplication.isPlaying )
		{
			EditorApplication.isPaused = !EditorApplication.isPaused;
			return;
		}
		var proceed = EditorSceneManager.SaveCurrentModifiedScenesIfUserWantsTo();
		if ( proceed )
		{
			PrevScenePath = EditorSceneManager.GetActiveScene().path;
			EditorSceneManager.OpenScene(EditorBuildSettings.scenes[0].path);
			EditorApplication.isPlaying = true;
		}
	}
}
}
#endif