0029807: [Regression to 7.0.0] Impossible to cut cone from prism

The algorithm has been improved for the cases when the intersection line goes through the cone apex.

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1. All special points are put to the ALine forcefully (if they are true intersection point). Currently this step has not been implemented yet.

2. Now the tolerance of IntPatch_Point (put into ALine) is computed in order to cover the distance between it and the correspond ALine.

3. Test cases have been created.

4. Procedure of trimming IntAna_Curve has been improved.

5. Criterion when the discriminant of IntAna_Curve can be considered to be equal to 0 has been improved.

6. Methods IntAna_Curve::FindParameter(...) (and IntPatch_ALine::FindParameter(...)) currently returns list of all parameters corresponding the given point (IntAna_Curve can be self-interfered curve). Before the fix, this method always returned only one (randomly chosen) parameter.

7. Interfaces of the following methods have been changed: IntAna_Curve::FindParameter(...), IntPatch_ALine::FindParameter(...), IntPatch_ALine::ChangeVertex(...), IntPatch_SpecialPoints::AddPointOnUorVIso(...), IntPatch_SpecialPoints::AddSingularPole(...), IntPatch_WLineTool::ExtendTwoWLines().

8. Following methods have been added: IntAna_Quadric::SpecialPoints(...), IntPatch_ALineToWLine::GetSectionRadius(...), IntPatch_SpecialPoints::ProcessSphere(...), IntPatch_SpecialPoints::ProcessCone(...), IntPatch_SpecialPoints::GetTangentToIntLineForCone(...).

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1) tests/boolean/volumemaker/C5
   tests/boolean/volumemaker/C6
   tests/boolean/volumemaker/E7

They are real IMPROVEMENTS. In the FIX (in compare with MASTER), section result between pairs of faces f2&f6 (C5), f3&f7 (C6) and f1&f5 (E7) is closed. Separated test cases have been created in order to focus on the problem with section. Bug #28503 has been fixed.

Correction in test cases.

src/gp/gp_Cone.hxx

@@ -35,7 +35,7 @@ class gp_Vec;
 
 
 //! Defines an infinite conical surface.
-//! A cone is defined by its half-angle at the apex and
+//! A cone is defined by its half-angle (can be negative) at the apex and
 //! positioned in space with a coordinate system (a gp_Ax3
 //! object) and a "reference radius" where:
 //! -   the "main Axis" of the coordinate system is the axis of   revolution of the cone,
@@ -76,12 +76,13 @@ public:
 
   //! Creates an infinite conical surface. A3 locates the cone
   //! in the space and defines the reference plane of the surface.
-  //! Ang is the conical surface semi-angle between 0 and PI/2 radians.
+  //! Ang is the conical surface semi-angle. Its absolute value is in range
+  //! ]0, PI/2[.
   //! Radius is the radius of the circle in the reference plane of
   //! the cone.
   //! Raises ConstructionError
-  //! . if Radius is lower than 0.0
-  //! . Ang < Resolution from gp  or Ang >= (PI/2) - Resolution.
+  //! * if Radius is lower than 0.0
+  //! * Abs(Ang) < Resolution from gp  or Abs(Ang) >= (PI/2) - Resolution.
     gp_Cone(const gp_Ax3& A3, const Standard_Real Ang, const Standard_Real Radius);
   
   //! Changes the symmetry axis of the cone.  Raises ConstructionError
@@ -105,8 +106,9 @@ public:
   
 
   //! Changes the semi-angle of the cone.
-  //! Ang is the conical surface semi-angle  ]0,PI/2[.
-  //! Raises ConstructionError if Ang < Resolution from gp or Ang >= PI/2 - Resolution
+  //! Semi-angle can be negative. Its absolute value
+  //! Abs(Ang) is in range ]0,PI/2[.
+  //! Raises ConstructionError if Abs(Ang) < Resolution from gp or Abs(Ang) >= PI/2 - Resolution
     void SetSemiAngle (const Standard_Real Ang);
   
 
@@ -146,6 +148,7 @@ public:
     Standard_Real RefRadius() const;
   
   //! Returns the half-angle at the apex of this cone.
+  //! Attention! Semi-angle can be negative.
     Standard_Real SemiAngle() const;
   
   //! Returns the XAxis of the reference plane.