Index: src/menu/UDisplay.pas
===================================================================
--- src/menu/UDisplay.pas	(revision 1702)
+++ src/menu/UDisplay.pas	(working copy)
@@ -42,8 +42,65 @@
   SysUtils;
 
 type
+  { this is a effect for screen fade that in fact does nothing
+    and should be used as parent for new fade effect.
+    It will also be used if fading is disabled }
+  TFadeEffect = class
+    private
+
+    public
+      constructor Create;
+
+      { this procedure is called when a screen change starts }
+      procedure StartFade;
+
+      { this function is called during a screen change, before screen
+        is drawn. screenchange is finished if this function returns
+        true. DoFadePostDraw will be called in every case after this
+        function was called, but fading will be finished regardless
+        what is returned DoFadePostDraw.}
+      function DoFadePreDraw: Boolean;
+
+      { this function is called during a screen change, after screen
+        was drawn. screenchange is finished if this function returns
+        true. }
+      function DoFadePostDraw: Boolean;
+
+
+
+      destructor Destroy;
+  end;
+
+  { class representing a kind of screen that is drawn over
+    one or more other screens. it has focus before the
+    screens that it is overlaying }
+  TOverlay = class(TMenu);
+
   TDisplay = class
     private
+      FadeInProgress: Boolean;
+      CurrentMenu: TMenu;
+
+      FadeEffect: TFadeEffect;
+    public
+      constructor Create(Caption: String);
+
+      { changes displayed screen, starts fading }
+      procedure ChangeMenu(NewScreen: TMenu);
+      property Menu: TMenu read CurrentMenu write ChangeMenu;
+
+
+
+
+
+      { calls draw procedures of Screen and overlays, it
+        returns false if application should be closed }
+      function Draw: Boolean;
+
+      destructor Destroy;
+
+  {TDisplay = class
+    private
       //fade-to-black-hack
       BlackScreen: boolean;
 
@@ -53,7 +110,7 @@
       LastFadeTime:  cardinal; // last fade update time
 
       FadeTex:       array[1..2] of GLuint;
- 
+
       FPSCounter:    cardinal;
       LastFPS:       cardinal;
       NextFPSSwap:   cardinal;
@@ -78,7 +135,7 @@
       procedure SaveScreenShot;
 
       function  Draw: boolean;
-  end;
+  end; }
 
 var
   Display:          TDisplay;