マルチシーン環境下でライトマップを焼く

LightmapBaker.cs

using UnityEngine;
using System.Collections;
using UnityEditor.SceneManagement;
using UnityEditor;
using System.Linq;

[CreateAssetMenu()]
public class LightmapBaker : ScriptableObject {

	[SerializeField] SceneAsset mainScene = null;
	[SerializeField] SceneAsset[] scenes = new SceneAsset[0];

	public void Bake()
	{
		if (EditorSceneManager.SaveCurrentModifiedScenesIfUserWantsTo () == false) {
			return;
		}
		string mainScenePath = AssetDatabase.GetAssetPath(mainScene);
		string[] giScenes = scenes.Select (c => AssetDatabase.GetAssetPath (c)).ToArray();

		LoadScenes (mainScenePath, giScenes);
		Lightmapping.Bake ();
	}

	static void LoadScenes (string mainScenePath, string[] giScenes)
	{
		EditorSceneManager.OpenScene (mainScenePath, OpenSceneMode.Single);
		foreach (var scene in giScenes) {
			EditorSceneManager.OpenScene (scene, OpenSceneMode.Additive);
		}
	}

	[CustomEditor(typeof(LightmapBaker))]
	class LightmapBakerEditor : Editor
	{
		public override void OnInspectorGUI ()
		{
			base.OnInspectorGUI ();

			var targetInstance = target as LightmapBaker;

			if (targetInstance.mainScene == null) {
				EditorGUILayout.HelpBox ("メインのシーンを登録してください", MessageType.Error);
				return;
			}

			if (targetInstance.scenes.Length == 0) {
				EditorGUILayout.HelpBox ("結合するシーンを登録してください", MessageType.Info);
			}

			if( GUILayout.Button("Bake")){
				targetInstance.Bake ();
			}
		}
	}
}