Initial main menu impl

EvilSatellites/ScreenManager.cs

@@ -4,7 +4,6 @@ using System.Text;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Input;
 using SynthySound;
-using Synthizer;
 using Microsoft.Xna.Framework.Audio;
 using EvilSatellites.Screens;
 
@@ -14,6 +13,8 @@ namespace EvilSatellites
     public class ScreenManager : DrawableGameComponent
     {
         private List<IScreen> _Screens;
+        private List<IScreen> _ToRemove;
+        private List<IScreen> _ToAdd;
         private IScreen _CurrentScreen;
         private Game _Game;
         private bool _Running = false;
@@ -29,9 +30,11 @@ namespace EvilSatellites
             EnvironmentEffect.T60 = 1;
             EnvironmentEffect.Defusion = 1f;
             EnvironmentEffect.FreePath = 0.02;
-            
+            Sound.SetMaxDistance(150);
             _Game = instance;
             _Screens = new List<IScreen>();
+            _ToRemove = new List<IScreen>();
+            _ToAdd = new List<IScreen>();
             _CurrentScreen = null;
         }
 
@@ -48,8 +51,7 @@ namespace EvilSatellites
         public void AddScreen(IScreen screen)
         {
             screen.Manager = this;
-            if (_Running) screen.Activate();
-            _Screens.Add(screen);
+            _ToAdd.Add(screen);
         }
         public void RemoveScreen(IScreen screen)
         {
@@ -57,12 +59,29 @@ namespace EvilSatellites
             {
                 throw new Exception("Cannot remove a screen that isn't added to manager");
             }
-            screen.Deactivate();
-            _Screens.Remove(screen);
+            _ToRemove.Add(screen);
         }
 
         public void Update(GameTime gameTime)
         {
+            if (_ToAdd.Count > 0)
+            {
+                foreach (var screen in _ToAdd)
+                {
+                    screen.Activate();
+                    _Screens.Add(screen);
+                }
+                _ToAdd.Clear();
+            }
+            if (_ToRemove.Count > 0)
+            {
+                foreach (var screen in _ToRemove)
+                {
+                    screen.Deactivate();
+                    _Screens.Remove(screen);
+                }
+                _ToRemove.Clear();
+            }
             Sound.Update();
             var input = Keyboard.GetState();
             foreach (var screen in _Screens)