ルートオブジェクト一覧を取得する

GetRootInstancePrepared.cs

using UnityEngine;
using System.Collections;
using System;
using System.Collections.Generic;

#if UNITY_EDITOR
using UnityEditor;
#endif

public class GetRootInstancePrepared : MonoBehaviour {

	public List<Transform> transformList = new List<Transform>();

#if UNITY_EDITOR

	[ContextMenu("collection")]
	private void Collection()
	{
		var transforms = Resources.FindObjectsOfTypeAll<Transform>();
		var rootTransforms = Array.FindAll<Transform>( transforms, (item) => item.parent == null && item.hideFlags == HideFlags.None);
		
		transformList.Clear();
		transformList.AddRange(rootTransforms);
	}

	static GetRootInstancePrepared()
	{
		EditorApplication.playmodeStateChanged += () =>
		{
			if (!EditorApplication.isPlaying && EditorApplication.isPlayingOrWillChangePlaymode) {

				var instance = GameObject.FindObjectOfType<GetRootInstancePrepared>();
				if( instance == null)
					return;

				instance.Collection();
			}
		};
	}
#endif
}