Overlay system zorder

[aronze]

Hi, I've some questions about overlay.

See following pseudo code:

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Overlay
{
   assignZOrder()
   {
      loop
      {
         zorder = i->_notifyZOrder(zorder);
      }
   }
   
   void setZOrder()
   {
      assignZOrder();
   }
   
   void add2D(c)
   {
      push_back(c);
      assignZOrder();
   }
   
   void remove2D(c)
   {
      remove(c);
      assignZOrder();
   }
}

OverlayContainer
{
   ushort _notifyZOrder(ushort newZOrder)
   {
      mZOrder = newZOrder++;
      
      loop
      {
         newZOrder = getNextChild()->_notifyZOrder(newZOrder);
      }
      
      return newZOrder;
   }
   
   addChild(e)
   {
      insert(e);
      e->_notifyZOrder(mZOrder + 1);
   }
}

I'll assume the following situation:

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Overlay* Root = OverlayManager::getSingleton().create("Root");
Root->setZOrder(100);

And then, I'll create and attach new OverlayContainers.

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OverlayContainer* A = OverlayManager::getSingleton().createOverlayElement("Panel", "A");
Root->add2D(A);// A zorder is 100.

( Actually, Overlay use multiply 100 to zorder but It's not important for me, so I'll just omit that. )

Now, attach more Elements to use only addChild method.

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Root(100)
    A(100)
        B(101)
            C(102)
        D(101)

While B~D elements was added, assignZOrder was not called. But if you add "E" OverlayContainer to "Root" Overlay, assignZOrder will be called by add2D and all zordering is re assigned like this:

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Root(100)
    A(100)
        B(101)
            C(102)
        D(103)
    E(104) // <----- now we added this

!!! What is that? Before added E, C element is over D element, but now, D is over C. !!! Could you something explain this?

[bstone]

That's how the Overlay code seems to work. Not sure why but probably because precise z-ordering is seldom important there.