0025950: Bad performance of intersection algorithm.

1. Test case has been created.

2. Minor correction in DrawTrSurf.cxx file.

src/DrawTrSurf/DrawTrSurf.cxx

@@ -284,7 +284,7 @@ static Standard_Integer drawpoles(Draw_Interpretor&,
     }
   }
 
-  if ( n<2) return 1;
+  if ( n<2) return 0;
 
   Handle(DrawTrSurf_BezierSurface) BZS;
   BZS = GetBezierSurface(a[1]);

tests/lowalgos/intss/begin

@@ -47,4 +47,28 @@ proc CheckIntersectionResult {theSurf1 theSurf2 theListOfCurves theNbPoints theT
     xdistcs aCurve s1 U1 U2 $theNbPoints $theTolerS1
     xdistcs aCurve s2 U1 U2 $theNbPoints $theTolerS2
   }
-}
+}
+
+# Check whether given list contain overlapped curves 
+help CheckOverlapIntCurves { theListOfCurves }
+proc CheckOverlapIntCurves { theListOfCurves {theTolerance 1.0e-7} } {
+  set NbEdges [expr [llength $theListOfCurves] - 1 ]
+  for { set i1 0 } { $i1 < $NbEdges } { incr i1 } {
+    for { set i2 [expr $i1 + 1] } { $i2 <= $NbEdges } { incr i2 } {
+      upvar #0 [ lindex $theListOfCurves $i1 ] aCurve1
+      upvar #0 [ lindex $theListOfCurves $i2 ] aCurve2
+
+      mkedge e1 aCurve1
+      mkedge e2 aCurve2
+      
+      set coe [ checkoverlapedges e1 e2 $theTolerance ]
+
+      if { [regexp "Edges is not overlaped" $coe] != 1 } {
+        set cIdx1 [ expr $i1 + 1 ]
+        set cIdx2 [ expr $i2 + 1 ]
+        
+        puts "Error: Curves $cIdx1 and $cIdx2 are overlapped"
+      }
+    }
+  }
+}

tests/lowalgos/intss/bug21494_2

@@ -1,10 +1,7 @@
 puts "========"
-puts "OCC21494"
+puts "OCC21494: Intersection between cone and sphere fails"
 puts "========"
 puts ""
-############################################
-# Intersection between cone and sphere fails
-############################################
 
 foreach a [directory res*] {unset $a}
 

tests/lowalgos/intss/bug25950

@@ -0,0 +1,88 @@
+puts "========="
+puts "0025950: Bad performance of intersection algorithm."
+puts "========="
+puts ""
+
+cpulimit 200
+
+puts "TODO 0025950 ALL: Error: 0 vertices are expected but 2 are found."
+puts "TODO 0025950 ALL: Error : The length of result shape is 18.8605"
+
+set aGoodNbCurves 3
+
+foreach a [directory res*] {unset $a}
+
+restore [locate_data_file bug25950_b1.brep] b1
+restore [locate_data_file bug25950_b2.brep] b2
+
+mksurface s1 b1
+mksurface s2 b2
+
+don s1 s2
+clpoles s1
+clpoles s2
+clknots
+
+dchrono z reset
+dchrono z start
+
+intersect res s1 s2 
+
+dchrono z stop counter Bug25950IntSS
+dchrono z show 
+
+smallview +Y+Z
+fit
+checkview -screenshot -2d -path ${imagedir}/${test_image}_2d.png
+
+set che [whatis res]
+set ind [string first "3d curve" $che]
+if {${ind} >= 0} {
+  #Only variable "res" exists
+  renamevar res res_1
+}
+
+bclearobjects
+bcleartools
+compound IntEdges
+
+set CurvesList {}
+
+set ic 1
+set AllowRepeat 1
+while { $AllowRepeat != 0 } {
+  set che [whatis res_$ic]
+  set ind [string first "3d curve" $che]
+  if {${ind} < 0} {
+    set AllowRepeat 0
+  } else {
+    lappend CurvesList res_$ic
+    mkedge ee res_$ic
+    baddobjects ee
+    incr ic
+  }
+}
+
+set ic [expr $ic - 1]
+
+if { $ic != $aGoodNbCurves } {
+  puts "Error: $aGoodNbCurves curves is expected but $ic ones are found"
+} else {
+  CheckIntersectionResult s1 s2 $CurvesList 100 7.0e-5 2.0e-4
+  CheckOverlapIntCurves $CurvesList
+  if {$ic > 1} {
+    bfillds
+    bbuild result    
+  } elseif {$ic > 0} {
+    mkedge result res_1
+  }
+  
+  # Check gaps between intersection curves
+  checksection result -r 0
+  checkmaxtol result -min_tol 2.0e-7
+
+  checknbshapes result -edge 3 -vertex 4
+  checkprops result -l 37.721
+}
+
+checkview -display result -2d -path ${imagedir}/${test_image}_3d.png