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

src/AIS/AIS_InteractiveContext.cdl

@@ -406,6 +406,26 @@ is
     ---Purpose: Sets the display priority aPriority of the seen parts
 -- presentation of the entity anIobj.
 
+    SetZLayer( me         : mutable;
+               theIObj    : InteractiveObject from AIS;
+               theLayerId : Integer from Standard );
+    ---Purpose: Set Z layer id for interactive object. The layer can be
+    -- specified for displayed object only. The Z layers can be used to display
+    -- temporarily presentations of some object in front of the other objects
+    -- in the scene. The ids for Z layers are generated by V3d_Viewer.
+    -- Note that Z layers differ from under-/overlayer in V3d_View:
+    -- under-/overlayer are intended for specific 2D drawings that appear
+    -- behind/in front of all 3D presentations, while SetZLayer() method
+    -- applies to regular 3D presentations and does not imply any specific
+    -- drawing methods.
+
+    GetZLayer( me;
+               theIObj : InteractiveObject from AIS )
+      returns Integer from Standard;
+    ---Purpose: Get Z layer id set for displayed interactive object.
+    -- If the object doesn't exists in context or has no computed presentations,
+    -- the method returns -1.
+
     Redisplay(me     : mutable;
     	      aniobj : InteractiveObject from AIS;
 	      updateviewer : Boolean from Standard = Standard_True;

src/AIS/AIS_InteractiveContext.cxx

@@ -3147,3 +3147,54 @@ Standard_Boolean AIS_InteractiveContext::GetAutoActivateSelection() const
 {
   return myIsAutoActivateSelMode;
 }
+
+//=======================================================================
+//function : SetZLayer
+//purpose  : 
+//=======================================================================
+
+void AIS_InteractiveContext::SetZLayer (const Handle(AIS_InteractiveObject)& theIObj,
+                                        const Standard_Integer theLayerId)
+{
+  if (theIObj.IsNull ())
+    return;
+
+  if (myObjects.IsBound (theIObj))
+  {
+    switch (myObjects (theIObj)->GraphicStatus ())
+    {
+      case AIS_DS_Displayed:
+      {
+        theIObj->SetZLayer (myMainPM, theLayerId);
+        break;
+      }
+      case AIS_DS_Erased:
+      {
+        theIObj->SetZLayer (myCollectorPM, theLayerId);
+        break;
+      }
+      default:
+        break;
+    }
+  }
+  else if (HasOpenedContext ())
+  {
+    myLocalContexts (myCurLocalIndex)->SetZLayer (theIObj, theLayerId);
+  }
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  : 
+//=======================================================================
+
+Standard_Integer AIS_InteractiveContext::GetZLayer (const Handle(AIS_InteractiveObject)& theIObj) const
+{
+  if (theIObj.IsNull ())
+    return -1;
+
+  if (myObjects.IsBound (theIObj))
+    return theIObj->GetZLayer (myMainPM);
+
+  return myLocalContexts (myCurLocalIndex)->GetZLayer (theIObj);
+}

src/AIS/AIS_LocalContext.cdl

@@ -373,6 +373,26 @@ is
                        anObject: InteractiveObject from AIS;
                        Prior   : Integer from Standard);
 
+    SetZLayer( me         : mutable;
+               theIObj    : InteractiveObject from AIS;
+               theLayerId : Integer from Standard );
+    ---Purpose: Set Z layer id for interactive object. The layer can be
+    -- specified for displayed object only. The Z layers can be used to display
+    -- temporarily presentations of some object in front of the other objects
+    -- in the scene. The ids for Z layers are generated by V3d_Viewer.
+    -- Note that Z layers differ from under-/overlayer in V3d_View:
+    -- under-/overlayer are intended for specific 2D drawings that appear
+    -- behind/in front of all 3D presentations, while SetZLayer() method
+    -- applies to regular 3D presentations and does not imply any specific
+    -- drawing methods.
+
+    GetZLayer( me;
+               theIObj : InteractiveObject from AIS )
+      returns Integer from Standard;
+    ---Purpose: Get Z layer id set for displayed interactive object.
+    -- If the object doesn't exists in context or has no computed presentations,
+    -- the method returns -1.
+
     DisplayedObjects(me;theMapToFill : in out MapOfTransient from TColStd)
     returns Integer from Standard;
 

src/AIS/AIS_LocalContext.cxx

@@ -881,7 +881,6 @@ void AIS_LocalContext::SetDisplayPriority(const Handle(AIS_InteractiveObject)& a
   
 }
 
-
 //=======================================================================
 //function : DisplayedObjects
 //purpose  : 
@@ -1220,3 +1219,34 @@ void AIS_LocalContext::SetSensitivity(const Standard_Integer aPrecision) {
   myMainVS->Set(aPrecision);
 }
 #endif
+
+//=======================================================================
+//function : SetZLayer
+//purpose  :
+//=======================================================================
+
+void AIS_LocalContext::SetZLayer (const Handle(AIS_InteractiveObject)& theIObj,
+                                  const Standard_Integer theLayerId)
+{
+  if (!myActiveObjects.IsBound (theIObj)) 
+    return;
+
+  const Handle(AIS_LocalStatus)& aStatus = myActiveObjects (theIObj);
+  if (aStatus->DisplayMode () == -1)
+    return;
+
+  theIObj->SetZLayer (myMainPM, theLayerId);
+}
+
+//=======================================================================
+//function : GetZLayer
+//purpose  : 
+//=======================================================================
+
+Standard_Integer AIS_LocalContext::GetZLayer (const Handle(AIS_InteractiveObject)& theIObj) const
+{
+  if (!myActiveObjects.IsBound (theIObj)) 
+    return -1;
+
+  return theIObj->GetZLayer (myMainPM);
+}