ShowSceneButtons.cs

using UnityEngine;
using UnityEditor;
using UnityEditor.SceneManagement;
using System.Collections.Generic;
using System.Text;

namespace Helios
{
    [InitializeOnLoad]
    public class ShowSceneButtons : EditorWindow
    {
        // Stored Settings
        static bool m_show = EditorPrefs.GetBool(string.Format("ShowSceneButtons.{0}_Show", PlayerSettings.productName), true);
        static int m_buttonWidth = EditorPrefs.GetInt(string.Format("ShowSceneButtons.{0}_ButtonWidth", PlayerSettings.productName), 100);

        // Internal variables
        static Dictionary<string, string> sceneLookup;
        static float lastCheck = 0;

        #region Settings Window
        [MenuItem("Helios/SceneButtons/Configure", false, 1)]
        static void Init()
        {
            // Get existing open window or if none, make a new one:
            ShowSceneButtons window = (ShowSceneButtons)GetWindow(typeof(ShowSceneButtons));
            window.Show();
        }

        void OnGUI()
        {
            GUI.changed = false;
            EditorGUILayout.BeginHorizontal();
            m_show = EditorGUILayout.Toggle("Show Scene Buttons", m_show);
            EditorGUILayout.EndHorizontal();

            EditorGUILayout.BeginHorizontal();
            m_buttonWidth = EditorGUILayout.IntField("Button Width", m_buttonWidth);
            EditorGUILayout.EndHorizontal();

            if (GUI.changed)
            {
                EditorPrefs.SetBool(string.Format("ShowSceneButtons.{0}_Show", PlayerSettings.productName), m_show);
                EditorPrefs.SetInt(string.Format("ShowSceneButtons.{0}_ButtonWidth", PlayerSettings.productName), m_buttonWidth);
            }
        }
        #endregion

        static ShowSceneButtons()
        {
            SceneView.onSceneGUIDelegate += OnScene;
            EditorApplication.update += Update;

            RefreshLookup();
        }

        private static void OnScene(SceneView sceneView)
        {
            if (m_show)
            {
                Handles.BeginGUI();
                GUILayout.BeginArea(new Rect(5, 5, m_buttonWidth, 20 * sceneLookup.Count));
                foreach (var item in sceneLookup)
                {
                    if (GUILayout.Button(item.Key))
                    {
                        SafeLoad(item);
                    }
                }
                GUILayout.EndArea();
                Handles.EndGUI();
            }
        }

        public static void SafeLoad(KeyValuePair<string, string> item)
        {
            if (Application.isPlaying)
            {
                // Load Scene By name
                UnityEngine.SceneManagement.SceneManager.LoadScene(item.Key);
            }
            else
            {
                // Offer to save first
                EditorSceneManager.SaveCurrentModifiedScenesIfUserWantsTo();

                // Load Scene by path
                EditorSceneManager.OpenScene(item.Value);
            }
        }

        public void OnDestroy()
        {
            EditorApplication.update -= Update;
        }

        static void Update()
        {
            // Refresh Listing every 5 seconds
            if (lastCheck == 0 || Time.realtimeSinceStartup - lastCheck > 5)
            {
                RefreshLookup();
                lastCheck = Time.realtimeSinceStartup;
            }
        }

        [MenuItem("Helios/SceneButtons/Refresh", false, 2)]
        static void RefreshLookup()
        {
            if(sceneLookup != null)
            {
                sceneLookup.Clear();
            }
            else
            {
                sceneLookup = new Dictionary<string, string>();
            }
            foreach (UnityEditor.EditorBuildSettingsScene S in UnityEditor.EditorBuildSettings.scenes)
            {
                if (S.enabled)
                {
                    string name = S.path.Substring(S.path.LastIndexOf('/') + 1);
                    name = name.Substring(0, name.Length - 6);
                    if (!sceneLookup.ContainsKey(name))
                    {
                        sceneLookup.Add(name, S.path);
                    }
                    else
                    {
                        Debug.LogErrorFormat("You have two scenes called {0}, skipping a button for the second one.", name);
                    }
                }
            }

        }

        [MenuItem("Helios/SceneButtons/GenerateMenuItems", false, 3)]
        static void GenerateMenuItems()
        {
            if(sceneLookup != null)
            {
                string scriptFile = Application.dataPath + "/[Vendor]/Helios/Editor/SceneMenuItems.cs";

                StringBuilder sb = new StringBuilder();
                sb.AppendLine("// This class is Auto-Generated");
                sb.AppendLine("using UnityEngine;");
                sb.AppendLine("using UnityEditor;");
                sb.AppendLine("using System.Collections.Generic;");
                sb.AppendLine("");
                sb.AppendLine("namespace Helios {");
                sb.AppendLine("  public static class SceneMenuItems {");
                sb.AppendLine("");

                foreach (var item in sceneLookup)
                {
                    sb.AppendLine("    [MenuItem(\"Helios/Scenes/" + item.Key + "\")]");
                    sb.AppendLine("    private static void LoadScene" + item.Key + "() {");
                    sb.AppendLine(string.Format("    ShowSceneButtons.SafeLoad(new KeyValuePair<string, string>(\"{0}\", \"{1}\"));", item.Key, item.Value));
                    sb.AppendLine("    }");
                    sb.AppendLine("");
                }

                sb.AppendLine("");
                sb.AppendLine("}");
                sb.AppendLine("}");

                // writes the class and imports it so it is visible in the Project window
                System.IO.File.Delete(scriptFile);
                System.IO.File.WriteAllText(scriptFile, sb.ToString(), System.Text.Encoding.UTF8);
                AssetDatabase.ImportAsset("Assets/[Vendor]/Helios/Editor/SceneMenuItems.cs");
            }
            else
            {
                Debug.LogError("Can't create menu items without any scenes. Try adding scenes to your Build Settings or Refreshing.");
            }
        }

    }
}