0022795: Make possible to display some presentable objects in overlay of others, groupped by display priority

src/PrsMgr/PrsMgr_PresentableObject.cdl

@@ -234,8 +234,22 @@ is
     
    UpdateLocation(me:mutable;P : mutable Presentation from Prs3d) is virtual;
     
+   SetZLayer ( me         : mutable;
+               thePrsMgr  : PresentationManager from PrsMgr;
+               theLayerId : Integer from Standard )
+     is virtual;
+   ---Purpose: Set Z layer ID and update all presentations of
+   -- the presentable object. The layer can be set only for displayed object.
+   -- If all object presentations are removed, the layer ID will be set to 
+   -- default value when computing presentation. The layers mechanism allows
+   -- drawing objects in higher layers in overlay of objects in lower layers.
     
-    
+   GetZLayer ( me;
+               thePrsMgr  : PresentationManager from PrsMgr )
+     returns Integer from Standard is static;
+   ---Purpose: Get ID of Z layer. If no presentations of object is displayed,
+   -- and layer ID is unavailable, the -1 value is returned.
+ 
 fields
     myPresentations: Presentations from PrsMgr is protected;
     myTypeOfPresentation3d: TypeOfPresentation3d from PrsMgr is protected;

src/PrsMgr/PrsMgr_PresentableObject.cxx

@@ -335,3 +335,28 @@ gp_Pnt  PrsMgr_PresentableObject::GetTransformPersistencePoint() const
 {
   return gp_Pnt( myTransformPersistence.Point.x, myTransformPersistence.Point.y, myTransformPersistence.Point.z );
 }
+
+//=======================================================================
+//function : SetZLayer
+//purpose  :
+//=======================================================================
+void PrsMgr_PresentableObject::SetZLayer 
+  (const Handle(PrsMgr_PresentationManager)& thePrsMgr,
+   const Standard_Integer theLayerId)
+{
+  if (!thePrsMgr.IsNull())
+    thePrsMgr->SetZLayer (this, theLayerId);
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  :
+//=======================================================================
+Standard_Integer PrsMgr_PresentableObject::GetZLayer 
+  (const Handle(PrsMgr_PresentationManager)& thePrsMgr) const
+{
+  if (!thePrsMgr.IsNull())
+    return thePrsMgr->GetZLayer (this);
+
+  return -1;
+}

src/PrsMgr/PrsMgr_Presentation.cdl

@@ -48,6 +48,15 @@ is
     SetDisplayPriority(me:mutable;aNewPrior:Integer from Standard)
     is deferred private;
 
+    SetZLayer ( me : mutable;
+                theLayerId : Integer from Standard )
+      is deferred private;
+    ---Purpose: Set Z layer ID for the presentation
+
+    GetZLayer ( me )
+      returns Integer from Standard is deferred private;
+    ---Purpose: Get Z layer ID for the presentation
+
     Clear(me: mutable) 
     is deferred private;
     

src/PrsMgr/PrsMgr_Presentation2d.cdl

@@ -51,6 +51,14 @@ is
     SetDisplayPriority(me:mutable;aNewPrior:Integer from Standard)
     is redefined static private;
    
+    SetZLayer ( me : mutable;
+                theLayerId : Integer from Standard )
+      is redefined static private;
+    ---Purpose: Set Z layer ID for the presentation
+
+    GetZLayer ( me )
+      returns Integer from Standard is redefined static private;
+    ---Purpose: Get Z layer ID for the presentation
 
     Clear(me:mutable)
     	---Purpose: removes the whole content of the presentation.

src/PrsMgr/PrsMgr_Presentation2d.cxx

@@ -78,3 +78,22 @@ Standard_Integer PrsMgr_Presentation2d::Offset () const {
 
 void PrsMgr_Presentation2d::Destroy () {
 }
+
+//=======================================================================
+//function : SetZLayer
+//purpose  :
+//=======================================================================
+
+void PrsMgr_Presentation2d::SetZLayer (Standard_Integer theLayer)
+{
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  :
+//=======================================================================
+
+Standard_Integer PrsMgr_Presentation2d::GetZLayer () const
+{
+  return 0;
+}

src/PrsMgr/PrsMgr_Presentation3d.cdl

@@ -58,6 +58,15 @@ is
     SetDisplayPriority(me:mutable;aNewPrior:Integer from Standard)
     is redefined static private;
 
+    SetZLayer ( me : mutable;
+                theLayerId : Integer from Standard )
+      is redefined static private;
+    ---Purpose: Set Z layer ID for the presentation
+
+    GetZLayer ( me )
+      returns Integer from Standard is redefined static private;
+    ---Purpose: Get Z layer ID for the presentation
+
     Clear(me:mutable)
     ---Purpose: removes the whole content of the presentation.
     --          Does not remove the other connected presentations.

src/PrsMgr/PrsMgr_Presentation3d.cxx

@@ -308,3 +308,23 @@ void PrsMgr_Presentation3d::Destroy () {
     myStructure->Clear();
   myStructure.Nullify();
 }
+
+//=======================================================================
+//function : SetZLayer
+//purpose  :
+//=======================================================================
+
+void PrsMgr_Presentation3d::SetZLayer (Standard_Integer theLayerId)
+{
+  myStructure->SetZLayer (theLayerId);
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  :  
+//=======================================================================
+
+Standard_Integer PrsMgr_Presentation3d::GetZLayer () const
+{
+  return myStructure->GetZLayer ();
+}

src/PrsMgr/PrsMgr_PresentationManager.cdl

@@ -79,6 +79,19 @@ is
 	-- aPresentableObject in this framework with the
 	-- display mode aMode.
     
+    SetZLayer ( me                   : mutable;
+                thePresentableObject : PresentableObject from PrsMgr;
+                theLayerId           : Integer from Standard )
+      is static;
+    ---Purpose: Set Z layer ID for all presentations of the object.
+
+    GetZLayer ( me;
+                thePresentableObject : PresentableObject from PrsMgr )
+      returns Integer from Standard is static;
+    ---Purpose: Get Z layer ID assigned to all presentations of the object.
+    -- Method returns -1 value if object has no presentations and is
+    -- impossible to get layer index.
+    
     IsDisplayed(me;aPresentableObject: PresentableObject from PrsMgr;
                 aMode: Integer from Standard = 0) 
         ---Purpose: Returns true if the presentation of the presentable

src/PrsMgr/PrsMgr_PresentationManager.cxx

@@ -204,6 +204,12 @@ void PrsMgr_PresentationManager::AddPresentation
     Handle(PrsMgr_Presentation) P = newPresentation(aPresentableObject);
     aPresentableObject->Presentations().Append(PrsMgr_ModedPresentation(P,aMode));
     aPresentableObject->Fill(this,P,aMode);
+
+    // set layer index accordingly to object's presentations
+    Standard_Integer aZLayerId = GetZLayer (aPresentableObject);
+    if (aZLayerId >= 0)
+      P->SetZLayer (aZLayerId);
+
     P->SetUpdateStatus(Standard_False);
 }
 
@@ -222,3 +228,39 @@ void PrsMgr_PresentationManager::RemovePresentation(const Handle(PrsMgr_Presenta
   }
 }
 
+//=======================================================================
+//function : SetZLayer
+//purpose  :
+//=======================================================================
+
+void PrsMgr_PresentationManager::SetZLayer 
+  (const Handle(PrsMgr_PresentableObject)& thePresentableObject,
+   const Standard_Integer theLayerId)
+{
+  PrsMgr_Presentations& aPresentations = thePresentableObject->Presentations();
+  for (Standard_Integer aIdx = 1; aIdx <= aPresentations.Length (); aIdx++)
+  {
+    Handle(PrsMgr_Presentation) aPrs = aPresentations (aIdx).Presentation ();
+    if (aPrs->PresentationManager () == this)
+      aPrs->SetZLayer (theLayerId);
+  }
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  :
+//=======================================================================
+
+Standard_Integer PrsMgr_PresentationManager::GetZLayer 
+  (const Handle(PrsMgr_PresentableObject)& thePresentableObject) const
+{
+  PrsMgr_Presentations& aPresentations = thePresentableObject->Presentations();
+  for (Standard_Integer aIdx = 1; aIdx <= aPresentations.Length (); aIdx++)
+  {
+    Handle(PrsMgr_Presentation) aPrs = aPresentations (aIdx).Presentation ();
+    if (aPrs->PresentationManager () == this)
+      return aPrs->GetZLayer ();
+  }
+  
+  return -1;
+}