Clean up logic for popup.

Assets/Cryville/Crtr/UI/PopupManager.cs

@@ -0,0 +1,25 @@
+using System;
+using UnityEngine;
+using UnityEngine.UI;
+
+namespace Cryville.Crtr.UI {
+	public class PopupManager : MonoBehaviour {
+		static PopupManager s_instance;
+		public static PopupManager Instance { get { return s_instance; } }
+
+		[SerializeField]
+		GameObject m_popupPrefab;
+
+		void Awake() {
+			if (s_instance != null) {
+				Destroy(gameObject);
+				throw new InvalidOperationException("Attempted to initialize a singleton twice.");
+			}
+			s_instance = this;
+		}
+
+		public void Create(string msg) {
+			Instantiate(m_popupPrefab, transform, false).GetComponent<Popup>().Message = msg;
+		}
+	}
+}