0028390: Visualization, AIS_InteractiveContext - add topmost-only picking strategy

AIS_InteractiveContext::PickingStrategy(), added new property
defining picking strategy SelectMgr_PickingStrategy.
Strategy SelectMgr_PickingStrategy_OnlyTopmost allows picking only
topmost detected entity not rejected by Selection Filters.

src/AIS/AIS_InteractiveContext.cxx

@@ -95,6 +95,7 @@ myCurLocalIndex(0),
 myCurDetected(0),
 myCurHighlighted(0),
 myZDetectionFlag(0),
+myPickingStrategy (SelectMgr_PickingStrategy_FirstAcceptable),
 myIsAutoActivateSelMode(Standard_True)
 { 
   InitAttributes();

src/AIS/AIS_InteractiveContext.hxx

@@ -17,33 +17,32 @@
 #ifndef _AIS_InteractiveContext_HeaderFile
 #define _AIS_InteractiveContext_HeaderFile
 
-#include <Standard.hxx>
-#include <Standard_Type.hxx>
-
-#include <AIS_DataMapOfIOStatus.hxx>
-#include <PrsMgr_PresentationManager3d.hxx>
-#include <StdSelect_ViewerSelector3d.hxx>
-#include <TCollection_AsciiString.hxx>
-#include <Standard_Boolean.hxx>
-#include <Prs3d_Drawer.hxx>
-#include <Quantity_NameOfColor.hxx>
-#include <Standard_Integer.hxx>
 #include <AIS_DataMapOfILC.hxx>
+#include <AIS_DataMapOfIOStatus.hxx>
+#include <AIS_DisplayMode.hxx>
 #include <AIS_DisplayStatus.hxx>
+#include <AIS_ClearMode.hxx>
 #include <AIS_KindOfInteractive.hxx>
-#include <Standard_Real.hxx>
+#include <AIS_ListOfInteractive.hxx>
+#include <AIS_Selection.hxx>
+#include <AIS_StatusOfDetection.hxx>
+#include <AIS_StatusOfPick.hxx>
+#include <AIS_TypeOfIso.hxx>
 #include <Aspect_TypeOfFacingModel.hxx>
 #include <Graphic3d_HighlightStyle.hxx>
 #include <Graphic3d_NameOfMaterial.hxx>
-#include <Standard_ShortReal.hxx>
-#include <TColStd_ListOfInteger.hxx>
-#include <AIS_DisplayMode.hxx>
-#include <AIS_TypeOfIso.hxx>
-#include <AIS_StatusOfDetection.hxx>
-#include <AIS_StatusOfPick.hxx>
-#include <TColgp_Array1OfPnt2d.hxx>
+#include <Prs3d_Drawer.hxx>
+#include <Graphic3d_HighlightStyle.hxx>
+#include <PrsMgr_PresentationManager3d.hxx>
 #include <SelectMgr_IndexedMapOfOwner.hxx>
-#include <AIS_ClearMode.hxx>
+#include <SelectMgr_ListOfFilter.hxx>
+#include <SelectMgr_PickingStrategy.hxx>
+#include <Standard.hxx>
+#include <Standard_Type.hxx>
+#include <StdSelect_ViewerSelector3d.hxx>
+#include <TCollection_AsciiString.hxx>
+#include <TColgp_Array1OfPnt2d.hxx>
+#include <TColStd_ListOfInteger.hxx>
 #include <TopAbs_ShapeEnum.hxx>
 #include <SelectMgr_ListOfFilter.hxx>
 #include <AIS_ListOfInteractive.hxx>
@@ -144,6 +143,26 @@ public:
   
   Standard_EXPORT Standard_Boolean GetAutoActivateSelection() const;
   
+  //! Setup picking strategy - which entities detected by picking line will be accepted, considering Selection Filters.
+  //! By default (SelectMgr_PickingStrategy_FirstAcceptable), Selection Filters reduce the list of entities
+  //! so that the context accepts topmost in remaining.
+  //!
+  //! This means that entities behind non-selectable (by filters) parts can be picked by user.
+  //! If this behavior is undesirable, and user wants that non-selectable (by filters) parts
+  //! should remain an obstacle for picking, SelectMgr_PickingStrategy_OnlyTopmost can be set instead.
+  //!
+  //! Notice, that since Selection Manager operates only objects registered in it,
+  //! SelectMgr_PickingStrategy_OnlyTopmost will NOT prevent picking entities behind
+  //! visible by unregistered in Selection Manager presentations (e.g. deactivated).
+  //! Hence, SelectMgr_PickingStrategy_OnlyTopmost changes behavior only with Selection Filters enabled.
+  void SetPickingStrategy (const SelectMgr_PickingStrategy theStrategy)
+  {
+    myPickingStrategy = theStrategy;
+  }
+
+  //! Return picking strategy; SelectMgr_PickingStrategy_FirstAcceptable by default.
+  SelectMgr_PickingStrategy PickingStrategy() const { return myPickingStrategy; }
+
   //! Controls the choice between the using the display
   //! and selection modes of open local context which you
   //! have defined and activating those available by default.
@@ -1719,6 +1738,7 @@ protected:
   Standard_Integer myCurDetected;
   Standard_Integer myCurHighlighted;
   Standard_Boolean myZDetectionFlag;
+  SelectMgr_PickingStrategy myPickingStrategy; //!< picking strategy to be applied within MoveTo()
   Standard_Boolean myIsAutoActivateSelMode;
 
 };

src/AIS/AIS_InteractiveContext_1.cxx

@@ -329,16 +329,22 @@ AIS_StatusOfDetection AIS_InteractiveContext::MoveTo (const Standard_Integer  th
   // (the objects must be AIS_Shapes)
   const Standard_Integer aDetectedNb = myMainSel->NbPicked();
   Standard_Integer aNewDetected = 0;
+  Standard_Boolean toIgnoreDetTop = Standard_False;
   for (Standard_Integer aDetIter = 1; aDetIter <= aDetectedNb; ++aDetIter)
   {
     Handle(SelectMgr_EntityOwner) anOwner = myMainSel->Picked (aDetIter);
     if (anOwner.IsNull()
      || !myFilters->IsOk (anOwner))
     {
+      if (myPickingStrategy == SelectMgr_PickingStrategy_OnlyTopmost)
+      {
+        toIgnoreDetTop = Standard_True;
+      }
       continue;
     }
 
-    if (aNewDetected < 1)
+    if (aNewDetected < 1
+    && !toIgnoreDetTop)
     {
       aNewDetected = aDetIter;
     }

src/SelectMgr/FILES

@@ -22,6 +22,7 @@ SelectMgr_ListIteratorOfListOfFilter.hxx
 SelectMgr_ListOfFilter.hxx
 SelectMgr_OrFilter.cxx
 SelectMgr_OrFilter.hxx
+SelectMgr_PickingStrategy.hxx
 SelectMgr_RectangularFrustum.cxx
 SelectMgr_RectangularFrustum.hxx
 SelectMgr_SelectableObject.cxx

src/SelectMgr/SelectMgr_PickingStrategy.hxx

@@ -0,0 +1,24 @@
+// Copyright (c) 2017 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#ifndef _SelectMgr_PickingStrategy_HeaderFile
+#define _SelectMgr_PickingStrategy_HeaderFile
+
+//! Enumeration defines picking strategy - which entities detected by picking line will be accepted, considering selection filters.
+enum SelectMgr_PickingStrategy
+{
+  SelectMgr_PickingStrategy_FirstAcceptable, //!< the first detected entity passing selection filter is accepted (e.g. any)
+  SelectMgr_PickingStrategy_OnlyTopmost      //!< only topmost detected entity passing selection filter is accepted
+};
+
+#endif // _SelectMgr_PickingStrategy_HeaderFile

src/ViewerTest/ViewerTest_ViewerCommands.cxx

@@ -10059,6 +10059,30 @@ static int VSelectionProperties (Draw_Interpretor& theDi,
   {
     aHiStyle->SetTransparency (aCmd.ArgFloat ("hiTransp"));
   }
+  if (aCmd.HasOption ("pickStrategy"))
+  {
+    SelectMgr_PickingStrategy aStrategy = SelectMgr_PickingStrategy_FirstAcceptable;
+    TCollection_AsciiString aVal (aCmd.Arg ("pickStrategy", 0).c_str());
+    aVal.LowerCase();
+    if (aVal == "first"
+     || aVal == "firstaccepted"
+     || aVal == "firstacceptable")
+    {
+      aStrategy = SelectMgr_PickingStrategy_FirstAcceptable;
+    }
+    else if (aVal == "topmost"
+          || aVal == "onlyTopmost")
+    {
+      aStrategy = SelectMgr_PickingStrategy_OnlyTopmost;
+    }
+    else
+    {
+      std::cout << "Syntax error: unknwon picking strategy '" << aVal << "'\n";
+      return 1;
+    }
+
+    aCtx->SetPickingStrategy (aStrategy);
+  }
 
   if (aCmd.HasOption ("print") || theArgsNb == 1)
   {
@@ -10687,6 +10711,9 @@ void ViewerTest::ViewerCommands(Draw_Interpretor& theCommands)
     "\n    vselprops [options]"
     "\n    Customizes selection and dynamic highlight parameters for the whole interactive context:"
     "\n    -autoActivate {0|1}     : disables|enables default computation and activation of global selection mode"
+    "\n    -pickStrategy {first|topmost} : defines picking strategy"
+    "\n                            'first'   to pick first acceptable (default)"
+    "\n                            'topmost' to pick only topmost (and nothing, if topmost is rejected by filters)"
     "\n    -pixTol    value        : sets up pixel tolerance"
     "\n    -selColor  {name|r g b} : sets selection color"
     "\n    -hiColor   {name|r g b} : sets dynamic highlight color"