Preserving the value of parallelism before parametric branch

* 2D intersector takes into account the given tolerance when intersects line with circle.
* Extrema curve-curve executes parametric branch in case of analytical has given zero solutions.
* Command 'intersect' has been improved to show additional information about the area of tangency (start and end parameters on each curve).

src/Extrema/Extrema_ExtCC.cxx

@@ -249,6 +249,10 @@ void Extrema_ExtCC::Perform()
     }
     default: break;
     }
+    if (mypoints.Size() == 0)
+    {
+      myDone = Standard_False;
+    }
   } else if (type1 == GeomAbs_Circle && type2 == GeomAbs_Circle) {
     //analytical case - two circles
     Standard_Boolean bIsDone;
@@ -258,12 +262,14 @@ void Extrema_ExtCC::Perform()
       PrepareResults(CCXtrem, Standard_False, U11, U12, U21, U22);
     }
     else {
-      myECC.Perform();
-      PrepareResults(myECC, U11, U12, U21, U22);
+      myDone = Standard_False;
     }
-  } else {
+  } 
+  if(!myDone){
+    Standard_Boolean isParallel = myIsPar;
     myECC.Perform();
     PrepareResults(myECC, U11, U12, U21, U22);
+    myIsPar = myIsPar || isParallel;
   }
 }
 

src/GeomliteTest/GeomliteTest_API2dCommands.cxx

@@ -384,8 +384,10 @@ static Standard_Integer intersect(Draw_Interpretor& di, Standard_Integer n, cons
   Standard_Integer aNbSegments = Intersector.NbSegments();
   for (Standard_Integer i = 1; i <= aNbSegments; i++)
   {
-    di << "Segment #" << i << " found.\n";
     Intersector.Segment(i,S1,S2);
+    di << "Segment #" << i << " found.\n";
+    di << "Curve 1 first parameter: " << S1->FirstParameter() << " last parameter: " << S1->LastParameter() <<"\n";
+    di << "Curve 2 first parameter: " << S2->FirstParameter() << " last parameter: " << S2->LastParameter() <<"\n";
     CD = new DrawTrSurf_Curve2d(S1, Draw_bleu, 30);
     dout << CD;
     CD = new DrawTrSurf_Curve2d(S2, Draw_violet, 30);

src/IntCurve/IntCurve_IntConicConic_1.cxx

@@ -397,6 +397,7 @@ void LineCircleGeometricIntersection(const gp_Lin2d& Line,
   Standard_Real dO1O2=Line.Distance(Circle.Location());
   Standard_Real R=Circle.Radius();
   Standard_Real RmTol=R-Tol;
+  Standard_Real RpTol = R + Tol;
   Standard_Real binf1,binf2=0,bsup1,bsup2=0;
     
   //---------------------------------------------------------------- 
@@ -430,7 +431,7 @@ void LineCircleGeometricIntersection(const gp_Lin2d& Line,
     if(dO1O2 > RmTol && !b2Sol) { 
     //if(dO1O2 > RmTol) { 
       Standard_Real dx=dO1O2;
-      Standard_Real dy=0.0;     //(RpTol*RpTol-dx*dx); //Patch !!!
+      Standard_Real dy = RpTol*RpTol - dx*dx;;     //(RpTol*RpTol-dx*dx); //Patch !!!
       dy=(dy>=0.0)? Sqrt(dy) : 0.0;
       dAlpha1=ATan2(dy,dx);
       
@@ -444,7 +445,7 @@ void LineCircleGeometricIntersection(const gp_Lin2d& Line,
     else {
       //------------------- Intersection Line Circle+ --------------------------
       Standard_Real dx=dO1O2;
-      Standard_Real dy=R*R-dx*dx;    //(RpTol*RpTol-dx*dx); //Patch !!!
+      Standard_Real dy = RpTol*RpTol - dx*dx;  //(RpTol*RpTol-dx*dx); //Patch !!!
       dy=(dy>=0.0)? Sqrt(dy) : 0.0;
       
       dAlpha1=ATan2(dy,dx);

tests/bugs/modalg_7/bug30217_1

@@ -0,0 +1,29 @@
+puts "============"
+puts "OCC30217_1"
+puts "============"
+puts ""
+#########################################################################
+# Intersection between a circle and a line not detected (2d)
+#########################################################################
+
+2ddrseg s2 -80.461134694338 53.07587187722 -31.501464018476 67.029737602069
+circle c2 -18.339655323916 20.849340929486 48.019394466707
+# Set tolerance.
+set tol_abs 1.0e-7 
+set tol_rel 1.0e-2
+
+# Set reference data.
+set param11 1.8484218380721342
+set param12 1.8484627151687805
+set param21 50.908401295062035
+set param22 50.909328431594709
+
+set info [2dintersect c2 s2 -tol 1e-8]
+regexp {Curve 1 first parameter: +([-0-9.+eE]+) last parameter: +([-0-9.+eE]+)} ${info} full curve1p1 curve1p2
+regexp {Curve 2 first parameter: +([-0-9.+eE]+) last parameter: +([-0-9.+eE]+)} ${info} full curve2p1 curve2p2
+
+checkreal "Curve 1 param 1" ${curve1p1} ${param11} ${tol_abs} ${tol_rel}
+checkreal "Curve 1 param 2" ${curve1p2} ${param12} ${tol_abs} ${tol_rel}
+
+checkreal "Curve 2 param 1" ${curve2p1} ${param21} ${tol_abs} ${tol_rel}
+checkreal "Curve 2 param 2" ${curve2p2} ${param22} ${tol_abs} ${tol_rel}

tests/bugs/modalg_7/bug30217_2

@@ -0,0 +1,26 @@
+puts "============"
+puts "OCC30217_2"
+puts "============"
+puts ""
+#########################################################################
+# Intersection between a circle and a line not detected (3d)
+#########################################################################
+set tol_abs 2.e-7
+
+drseg s -80.461134694338 53.07587187722 0.0 -31.501464018476 67.029737602069 0.0
+circle c -18.339655323916 20.849340929486 0.0 48.019394466707
+set info1 [extrema c s]
+if {[regexp "ext" ${info1}] != 1} {
+  puts "Error : No intersection detected"
+} else {
+  puts "OK: Intersection are detected"
+}
+
+# Distance check
+set info2 [dump ext_1]
+regexp "Parameters : 0 +(\[-0-9*\.+eE\]+)" $info2 full extLength
+if { ${extLength} > $tol_abs } {
+  puts "Error: bad distance poins obtained"
+} else {
+  puts "OK: good distance between obtained points"
+}

tests/bugs/modalg_7/bug30217_3

@@ -0,0 +1,28 @@
+puts "============"
+puts "OCC30217_3"
+puts "============"
+puts ""
+#########################################################################
+# Intersection between a circle and a line not detected (3d)
+#########################################################################
+set tol_abs 2.e-7
+
+drseg s -31.501464018476 67.029737602069 -10.0 -31.501464018476 67.029737602069 0.0
+circle c -18.339655323916 20.849340929486 0.0 48.019394466707
+set info1 [extrema c s]       
+if {[regexp "ext" ${info1}] != 1} {
+  puts "Error : No intersection detected"
+} else {
+  puts "OK: Intersection are detected"
+}
+
+# Distance check
+set infoext1 [dump ext_1]
+
+
+regexp "Parameters : 0 +(\[-0-9*\.+eE\]+)" $infoext1 full  ext1Length ext2Length 
+if { $ext1Length > $tol_abs || $ext2Length > $tol_abs } {
+  puts "Error: bad distance poins obtained"
+} else {
+  puts "OK: good distance between obtained points"
+}                                                                 

tests/bugs/modalg_7/bug30217_4

@@ -0,0 +1,20 @@
+puts "============"
+puts "OCC30217_4"
+puts "============"
+puts ""
+#########################################################################
+# Intersection between a circle and a line not detected (3d)
+#########################################################################
+
+set ExpDist 5
+
+circle c1 0 0 0 0 0 1 5
+line c2 0 0 0 0 0 1
+trim c2 c2 -1 -5e-8
+
+regexp {Infinite number of extremas, distance = +([-0-9.+eE]+)} [extrema c1 c2] full aDist1
+checkreal Distance $aDist1 $ExpDist 1.0e-7 0.0
+
+regexp {Infinite number of extremas, distance = +([-0-9.+eE]+)} [extrema c2 c1] full aDist2
+checkreal Distance $aDist2 $ExpDist 1.0e-7 0.0
+