libcommon: Rebuild the game menu on engine reset

The game menu is now rebuilt following an engine reset. If the menu
was previously open it will be re-opened on the active page.

Todo: Remember the previously focused widget on the active page.

doomsday/plugins/common/include/hu_menu.h

@@ -111,7 +111,14 @@ void Hu_MenuTicker(timespan_t ticLength);
 /// @return  @c true if the menu is presently visible.
 dd_bool Hu_MenuIsVisible();
 
-menu::Page *Hu_MenuFindPageByName(char const *name);
+menu::Page *Hu_MenuFindPageByName(de::String name);
+
+/**
+ * Lookup the unique page identifier/name for the given @a page.
+ *
+ * @return  Unique identifier/name of the page; otherwise an empty string.
+ */
+de::String Hu_MenuFindPageName(menu::Page const *page);
 
 /**
  * @param name  Symbolic name.

doomsday/plugins/common/src/hu_menu.cpp

@@ -346,11 +346,11 @@ static menucommand_e chooseCloseMethod()
     return Con_GetInteger("con-transition-tics") == 0? MCMD_CLOSE : MCMD_CLOSEFAST;
 }
 
-Page *Hu_MenuFindPageByName(char const *name)
+Page *Hu_MenuFindPageByName(String name)
 {
-    if(name && name[0])
+    if(!name.isEmpty())
     {
-        Pages::iterator found = pages.find(String(name).toLower());
+        Pages::iterator found = pages.find(name.toLower());
         if(found != pages.end())
         {
             return *found;
@@ -359,6 +359,22 @@ Page *Hu_MenuFindPageByName(char const *name)
     return 0; // Not found.
 }
 
+String Hu_MenuFindPageName(Page const *page)
+{
+    if(page)
+    {
+        Pages::const_iterator i = pages.constBegin();
+        while(i != pages.constEnd())
+        {
+            if(i.value() == page)
+            {
+                return i.key();
+            }
+        }
+    }
+    return "";
+}
+
 /// @todo Make this state an object property flag.
 /// @return  @c true if the rotation of a cursor on this object should be animated.
 static dd_bool Hu_MenuHasCursorRotation(Widget *wi)
@@ -3558,8 +3574,18 @@ Page *Hu_MenuNewPage(char const *name, Point2Raw const *origin, int flags,
 void Hu_MenuInit()
 {
     cvarbutton_t *cvb;
+    bool wasOpen = false;
+    String activePageName;
+
+    if(inited)
+    {
+        // Remember the previously open menu page, if any.
+        /// @todo Remember the previously focused widget on said page -ds
+        wasOpen = Hu_MenuIsActive();
+        activePageName = Hu_MenuFindPageName(Hu_MenuActivePage());
 
-    if(inited) return;
+        Hu_MenuShutdown();
+    }
 
     mnAlpha = mnTargetAlpha = 0;
     menuActivePage    = 0;
@@ -3594,6 +3620,13 @@ void Hu_MenuInit()
     }
 #endif
 
+    // Are we re-opening?
+    if(wasOpen)
+    {
+        Hu_MenuCommand(MCMD_OPEN);
+    }
+    Hu_MenuSetActivePage(Hu_MenuFindPageByName(activePageName));
+
     inited = true;
 }
 
@@ -3686,7 +3719,7 @@ void Hu_MenuTicker(timespan_t ticLength)
 #undef MENUALPHA_FADE_STEP
 }
 
-Page* Hu_MenuActivePage()
+Page *Hu_MenuActivePage()
 {
     return menuActivePage;
 }