0031798: Visualization, SelectMgr_ViewerSelector - fix comparing depth of direct and indirect triangle hits

Replaced bias approach to depth test criterion to instead use bool that marks if a hit was direct or not. The bool is used in processing elements and in matching methods.

src/Select3D/Select3D_SensitivePrimitiveArray.cxx

@@ -931,7 +931,7 @@ Standard_Boolean Select3D_SensitivePrimitiveArray::Matches (SelectBasics_Selecti
       {
         myDetectedNodeMap->ChangeMap().Unite (aChild->myDetectedNodeMap->Map());
       }
-      if (thePickResult.Depth() > aPickResult.Depth())
+      if (thePickResult.Depth() > aPickResult.Depth() && thePickResult.IsDirectHit())
       {
         myDetectedIdx = aGroupIter;
         thePickResult = aPickResult;

src/Select3D/Select3D_SensitiveSet.cxx

@@ -111,7 +111,7 @@ Standard_Boolean Select3D_SensitiveSet::processElements (SelectBasics_SelectingV
         continue;
       }
 
-      if (thePickResult.Depth() > aPickResult.Depth())
+      if ((thePickResult.Depth() > aPickResult.Depth()) && (aPickResult.IsDirectHit()))
       {
         thePickResult = aPickResult;
         myDetectedIdx = anIdx;

src/SelectBasics/SelectBasics_PickResult.hxx

@@ -35,7 +35,8 @@ public:
   SelectBasics_PickResult()
   : myObjPickedPnt (RealLast(), 0.0, 0.0),
     myDepth (RealLast()),
-    myDistToCenter (RealLast()) {}
+    myDistToCenter (RealLast()), 
+    myIsDirectHit(Standard_False) {}
 
   //! Constructor with initialization.
   SelectBasics_PickResult (Standard_Real theDepth,
@@ -43,7 +44,8 @@ public:
                            const gp_Pnt& theObjPickedPnt)
   : myObjPickedPnt (theObjPickedPnt),
     myDepth (theDepth),
-    myDistToCenter (theDistToCenter) {}
+    myDistToCenter (theDistToCenter),
+    myIsDirectHit(Standard_False) {}
 
 public:
 
@@ -56,6 +58,7 @@ public:
     myDepth = RealLast();
     myObjPickedPnt = gp_Pnt (RealLast(), 0.0, 0.0);
     myNormal.SetValues (0.0f, 0.0f, 0.0f);
+    myIsDirectHit = Standard_False;
   }
 
   //! Return depth along picking ray.
@@ -93,11 +96,18 @@ public:
     myNormal.SetValues ((float )theNormal.X(), (float )theNormal.Y(), (float )theNormal.Z());
   }
 
+  //! Set boolean value for pick result direct hit (true) or indirect hit (false) 
+  void SetDirectHit(Standard_Boolean theIsDirectHit) { myIsDirectHit = theIsDirectHit; }
+
+  //! Return value for direct hit test
+  Standard_Boolean IsDirectHit() const { return myIsDirectHit; }
+
 private:
   gp_Pnt                  myObjPickedPnt; //!< User-picked selection point onto object
   NCollection_Vec3<float> myNormal;       //!< surface normal
   Standard_Real           myDepth;        //!< Depth to detected point
   Standard_Real           myDistToCenter; //!< Distance from 3d projection user-picked selection point to entity's geometry center
+  Standard_Boolean        myIsDirectHit;  //!< Checks if the detected point was obtained from a direct hit
 };
 
 #endif // _SelectBasics_PickResult_HeaderFile

src/SelectMgr/SelectMgr_RectangularFrustum.cxx

@@ -503,6 +503,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsBox (const SelectMgr_Vec3
 
     aDepth = aNearestPnt.Distance (myNearPickedPnt);
     thePickResult.SetDepth (aDepth);
+    thePickResult.SetDirectHit(Standard_False);
     return !theClipRange.IsClipped (thePickResult.Depth());
   }
 
@@ -515,6 +516,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsBox (const SelectMgr_Vec3
   }
 
   thePickResult.SetDepth (aDepth);
+  thePickResult.SetDirectHit(Standard_True);
 
   return Standard_True;
 }
@@ -538,6 +540,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsPoint (const gp_Pnt& theP
 
   thePickResult.SetDepth (Abs (aDepth) * myScale);
   thePickResult.SetPickedPoint (thePnt);
+  thePickResult.SetDirectHit(Standard_True);
 
   return !theClipRange.IsClipped (thePickResult.Depth());
 }
@@ -570,6 +573,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsSegment (const gp_Pnt& th
     return Standard_False;
 
   segmentSegmentDistance (thePnt1, thePnt2, thePickResult);
+  thePickResult.SetDirectHit(Standard_True);
 
   return !theClipRange.IsClipped (thePickResult.Depth());
 }
@@ -605,6 +609,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsPolygon (const TColgp_Arr
         aMatchingSegmentsNb++;
         segmentSegmentDistance (aStartPnt, aEndPnt, aPickResult);
         thePickResult = SelectBasics_PickResult::Min (thePickResult, aPickResult);
+        thePickResult.SetDirectHit(Standard_True);
       }
     }
 
@@ -710,9 +715,10 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsTriangle (const gp_Pnt& t
       thePickResult.SetDepth (myNearPickedPnt.Distance (aPtOnPlane) * myScale);
       thePickResult.SetPickedPoint (aPtOnPlane);
       thePickResult.SetSurfaceNormal (aTriangleNormal);
+      thePickResult.SetDirectHit(Standard_True);
       return !theClipRange.IsClipped (thePickResult.Depth());
     }
-
+    
     Standard_Real aMinDist = RealLast();
     Standard_Integer aNearestEdgeIdx1 = -1;
     for (Standard_Integer anEdgeIdx = 0; anEdgeIdx < 3; ++anEdgeIdx)
@@ -733,8 +739,9 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsTriangle (const gp_Pnt& t
     {
       aNearestEdgeIdx2 = aNearestEdgeIdx1 == 0 ? 2 : aNearestEdgeIdx1 - 1;
     }
-    segmentSegmentDistance (aPnts[aNearestEdgeIdx1], aPnts[aNearestEdgeIdx2], thePickResult);
     thePickResult.SetSurfaceNormal (aTriangleNormal);
+    segmentSegmentDistance (aPnts[aNearestEdgeIdx1], aPnts[aNearestEdgeIdx2], thePickResult);
+    thePickResult.SetDirectHit(Standard_False);
   }
 
   return !theClipRange.IsClipped (thePickResult.Depth());
@@ -785,6 +792,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsCylinder (const Standard_
     thePickResult.SetSurfaceNormal (gp_Vec (aPntOnCylinder.X(), aPntOnCylinder.Y(), 0.0).Transformed (theTrsf));
   }
   thePickResult.SetPickedPoint (aPntOnCylinder.Transformed (theTrsf));
+  thePickResult.SetDirectHit(Standard_True);
   return !theClipRange.IsClipped (thePickResult.Depth());
 }
 
@@ -821,6 +829,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsCircle (const Standard_Re
   }
 
   thePickResult.SetDepth (aTime * myScale);
+  thePickResult.SetDirectHit(Standard_True);
   if (theClipRange.IsClipped (thePickResult.Depth()))
   {
     thePickResult.SetDepth (aTime * myScale);
@@ -1010,6 +1019,7 @@ Standard_Boolean SelectMgr_RectangularFrustum::OverlapsSphere (const gp_Pnt& the
   }
 
   thePickResult.SetDepth (aTimeEnter * myScale);
+  thePickResult.SetDirectHit(Standard_True);
   if (theClipRange.IsClipped (thePickResult.Depth()))
   {
     thePickResult.SetDepth (aTimeLeave * myScale);