インスペクターでシーン名をEnumで選択できるプロパティ拡張

SceneAttribute.cs

using UnityEngine;

public class SceneAttribute : PropertyAttribute
{
	public int selectedValue = 0;
	
	public SceneAttribute ()
	{
	}
}

SceneNameDrawer.cs

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

[CustomPropertyDrawer(typeof(SceneAttribute))]
public class SceneNameDrawer : PropertyDrawer
{
	
	public override void OnGUI (Rect position, SerializedProperty property, GUIContent label)
	{
		SceneAttribute sceneAttribute = (SceneAttribute)attribute;
		
		HashSet<string> sceneNames = GetSceneNames ();
		
		string[] sceneNamesArray = sceneNames.ToArray ();
		int[] sceneNumbers = new int[sceneNamesArray.Length];
		
		SetSceneNambers (sceneNumbers, sceneNamesArray);
		
		sceneAttribute.selectedValue = EditorGUI.IntPopup (position, label.text, sceneAttribute.selectedValue, sceneNamesArray, sceneNumbers);
		
		property.stringValue = sceneNamesArray [sceneAttribute.selectedValue];
	}

	HashSet<string> GetSceneNames ()
	{
		List<EditorBuildSettingsScene> scenes = EditorBuildSettings.scenes.Where (scene => scene.enabled).ToList ();
		
		HashSet<string> sceneNames = new HashSet<string> ();
		scenes.ForEach (scene => {
			sceneNames.Add (scene.path.Substring (scene.path.LastIndexOf ("/") + 1).Replace (".unity", string.Empty));
		});
		return sceneNames;
	}

	void SetSceneNambers (int[] sceneNumbers, string[] sceneNamesArray)
	{
		for (int i =0; i<sceneNamesArray.Length; i++) {
			sceneNumbers [i] = i;
		}
	}
}