0029323: Intersection algorithm produces the curve with oscillation

Sometimes the algorithm of purging of extra points in the walking line makes enormous difference in distance between two neighbor segments of the line. This badly impacts the quality of approximation result. This patch balances the difference in distances by forbidding deletion of some points.

1. tests/bugs/modalg_6/bug27615

The reason of the correction is explained in the message ~0072580 (see issue #28557).

2. tests/bugs/modalg_7/bug28892*
   tests/bugs/modalg_7/bug28984

The reason of the correction is explained in the message ~0072583 (see issue #28984).

src/IntPatch/IntPatch_WLineTool.cxx

@@ -91,20 +91,80 @@ static void FillPointsHash(const Handle(IntPatch_WLine)         &theWLine,
 //            Static subfunction in ComputePurgedWLine and DeleteOuter.
 //=========================================================================
 static Handle(IntPatch_WLine) MakeNewWLine(const Handle(IntPatch_WLine)         &theWLine,
-                                           const NCollection_Array1<Standard_Integer> &thePointsHash)
+                                           NCollection_Array1<Standard_Integer> &thePointsHash,
+                                           const Standard_Boolean theIsOuter)
 {
   Standard_Integer i;
 
   Handle(IntSurf_LineOn2S) aPurgedLineOn2S = new IntSurf_LineOn2S();
   Handle(IntPatch_WLine) aLocalWLine = new IntPatch_WLine(aPurgedLineOn2S, Standard_False);
-  Standard_Integer anOldLineIdx = 1, aVertexIdx = 1;
+  Standard_Integer anOldLineIdx = 1, aVertexIdx = 1, anIndexPrev = -1, anIdxOld = -1;
+  gp_Pnt aPPrev, aPOld;
   for(i = 1; i <= thePointsHash.Upper(); i++)
   {
     if (thePointsHash(i) == 0)
     {
-      // Store this point.
-      aPurgedLineOn2S->Add(theWLine->Point(i));
-      anOldLineIdx++;
+      // Point has to be added
+
+      const gp_Pnt aP = theWLine->Point(i).Value();
+      const Standard_Real aSqDistPrev = aPPrev.SquareDistance(aPOld);
+      const Standard_Real aSqDist = aPPrev.SquareDistance(aP);
+
+      const Standard_Real aRatio = (aSqDistPrev < gp::Resolution()) ? 0.0 : 9.0*aSqDist / aSqDistPrev;
+
+      if(theIsOuter ||
+         (aRatio < gp::Resolution()) ||
+         ((1.0 < aRatio) && (aRatio < 81.0)) ||
+         (i - anIndexPrev <= 1) ||
+         (i - anIdxOld <= 1))
+      {
+        // difference in distances is satisfactory
+        // (1/9 < aSqDist/aSqDistPrev < 9)
+
+        // Store this point.
+        aPurgedLineOn2S->Add(theWLine->Point(i));
+        anOldLineIdx++;
+        aPOld = aPPrev;
+        aPPrev = aP;
+        anIdxOld = anIndexPrev;
+        anIndexPrev = i;
+      }
+      else if(aSqDist >= aSqDistPrev*9.0)
+      {
+        // current segment is much more longer
+        // (aSqDist/aSqDistPrev >= 9)
+
+        i = (i + anIndexPrev)/2;
+        thePointsHash(i) = 0;
+        i--;
+      }
+      else
+      {
+        //previous segment is much more longer
+        //(aSqDist/aSqDistPrev <= 1/9)
+
+        if(anIndexPrev - anIdxOld > 1)
+        {
+          //Delete aPPrev from WL
+          aPurgedLineOn2S->RemovePoint(aPurgedLineOn2S->NbPoints());
+          anOldLineIdx--;
+
+          // Insert point between aPOld and aPPrev 
+          i = (anIdxOld + anIndexPrev) / 2;
+          thePointsHash(i) = 0;
+
+          aPPrev = aPOld;
+          anIndexPrev = anIdxOld;
+        }
+        else
+        {
+          aPOld = aPPrev;
+          anIdxOld = anIndexPrev;
+        }
+
+        //Next iterations will start from this inserted point.
+        i--;
+      }
     }
     else if (thePointsHash(i) == -1)
     {
@@ -113,7 +173,11 @@ static Handle(IntPatch_WLine) MakeNewWLine(const Handle(IntPatch_WLine)
       aVertex.SetParameter(anOldLineIdx++);
       aLocalWLine->AddVertex(aVertex);
       aPurgedLineOn2S->Add(theWLine->Point(i));
+      aPPrev = aPOld = theWLine->Point(i).Value();
+      anIndexPrev = anIdxOld = i;
     }
+
+    //Other points will be rejected by purger.
   }
 
   return aLocalWLine;
@@ -241,7 +305,7 @@ static Handle(IntPatch_WLine)
   }
 
   // Build new line and modify geometry of necessary vertexes.
-  Handle(IntPatch_WLine) aLocalWLine = MakeNewWLine(theWLine, aDelOuterPointsHash);
+  Handle(IntPatch_WLine) aLocalWLine = MakeNewWLine(theWLine, aDelOuterPointsHash, Standard_True);
 
   if (aChangedFirst)
   {
@@ -483,7 +547,7 @@ static Handle(IntPatch_WLine)
     }
   }
 
-  return MakeNewWLine(theWLine, aNewPointsHash);
+  return MakeNewWLine(theWLine, aNewPointsHash, Standard_False);
 }
 
 //=======================================================================

tests/bugs/modalg_6/bug27615

@@ -22,9 +22,13 @@ whatis result
 explode result
 whatis result_1
 
+if { [regexp "This shape seems to be OK" [bopcheck result] ] != 1 } {
+    puts "Error : The result of General Fuse operation is self-interfered shape"
+}
+
 checkshape result_1
 
-checkprops result_1 -v 15041.2 -s 8245.4
+checkprops result_1 -v 15287.7 -s 8383.16
 
 checkview -display result_1 -2d -path ${imagedir}/${test_image}.png
 

tests/bugs/modalg_7/bug28557

@@ -0,0 +1,33 @@
+puts "========"
+puts "OCC28557"
+puts "========"
+puts ""
+#################################################
+# Test case bugs modalg_6 bug27615 works differently on VC10 and VC12
+#################################################
+
+set MaxTolReached 5.0e-6
+set GoodNbCurv 1
+
+brestore [locate_data_file bug27615.brep] b
+explode b f
+copy b_1 f1; copy b_19 f2;
+don f1 f2
+set log [bopcurves f1 f2 -2d -p 2.2023968513463648  29.150590232723459 2. 0.085664915040461045 -p 2.2023968513457164 31.082210390953925 2.9507808705284453 0.085823752287563393]
+
+smallview
+donly c_1
+fit
+disp f1 f2
+
+checkview -screenshot -2d -path ${imagedir}/${test_image}_1.png
+
+regexp {Tolerance Reached=+([-0-9.+eE]+)\n+([-0-9.+eE]+)} ${log} full Toler NbCurv
+
+if {$Toler > $MaxTolReached} {
+  puts "Error: Big tolerance is returned by intersector"
+}
+
+if {$NbCurv != $GoodNbCurv} {
+  puts "Error: Please check NbCurves for intersector"
+}

tests/bugs/modalg_7/bug28892_2

@@ -1,5 +1,3 @@
-puts "TODO OCC28989 ALL: Error: result is self-interfered"
-
 puts "======="
 puts "OCC28892"
 puts "======="

tests/bugs/modalg_7/bug28892_3

@@ -1,5 +1,3 @@
-puts "TODO OCC28989 ALL: Error: result is self-interfered"
-
 puts "======="
 puts "OCC28892"
 puts "======="

tests/bugs/modalg_7/bug28984

@@ -1,5 +1,3 @@
-puts "TODO OCC28984 ALL: Error: Too big intersection tolerance"
-
 puts "======="
 puts "0028984"
 puts "======="
@@ -20,6 +18,6 @@ if {$nb_curves != 2} {
   puts "Error: Invalid number of curves"
 }
 
-if {$tol_reached > 0.1} {
+if {$tol_reached > 0.01} {
   puts "Error: Too big intersection tolerance"
 }

tests/bugs/modalg_7/bug29323

@@ -0,0 +1,35 @@
+puts "========"
+puts "OCC29323"
+puts "========"
+puts ""
+#################################################
+# Intersection algorithm produces the curve with oscillation
+#################################################
+
+set MaxTolReached 0.15
+set GoodNbCurv 1
+set ExpLength 96.268040111795571
+
+restore [locate_data_file bug29323_hb.brep] h
+plane p 0 0 4 0 0 1
+mkface f p -200 200 -200 200
+explode h f
+
+set log [bopcurves h_4 f -2d]
+
+smallview
+donly c_1
+fit
+
+checkview -screenshot -2d -path ${imagedir}/${test_image}_1.png
+checklength c_1 -l $ExpLength
+
+regexp {Tolerance Reached=+([-0-9.+eE]+)\n+([-0-9.+eE]+)} ${log} full Toler NbCurv
+
+if {$Toler > $MaxTolReached} {
+  puts "Error: Big tolerance is returned by intersector"
+}
+
+if {$NbCurv != $GoodNbCurv} {
+  puts "Error: Please check NbCurves for intersector"
+}