0027954: Create topology-preserving offset computation algorithm

[occt.git] / src / TopClass / TopClass_FaceClassifier.gxx

// Created on: 1992-11-18
// Created by: Remi LEQUETTE
// Copyright (c) 1992-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

//  Modified by skv - Thu Jul 13 18:00:34 2006 OCC12627
// The method Perform is totally rewroted.

#include <IntRes2d_IntersectionSegment.hxx>
#include <IntRes2d_IntersectionPoint.hxx>

//=======================================================================
//function : TopClass_FaceClassifier
//purpose  : 
//=======================================================================

TopClass_FaceClassifier::TopClass_FaceClassifier()
{
}

//=======================================================================
//function : TopClass_FaceClassifier
//purpose  : 
//=======================================================================

TopClass_FaceClassifier::TopClass_FaceClassifier(TheFaceExplorer& FExp,
						 const gp_Pnt2d& P,
						 const Standard_Real Tol)
{
  Perform(FExp,P,Tol);
}

//=======================================================================
//function : Perform
//purpose  : 
//=======================================================================

void TopClass_FaceClassifier::Perform(TheFaceExplorer& Fexp,
				      const gp_Pnt2d& P,
				      const Standard_Real Tol)
{
  // Test for rejection.
  rejected = Fexp.Reject(P);

  if (rejected)
    return;

  gp_Lin2d                   aLine;
  Standard_Real              aParam;
  Standard_Boolean           IsValidSegment = Fexp.Segment(P, aLine, aParam);
  TheEdge                    anEdge;
  TopAbs_Orientation         anEdgeOri;
  Standard_Integer           aClosestInd;
  IntRes2d_IntersectionPoint aPInter;
  TopAbs_State               aState = TopAbs_UNKNOWN;
  Standard_Boolean           IsWReject;
  Standard_Boolean           IsEReject;

  nowires = Standard_True;

  while (IsValidSegment) {
    myClassifier.Reset(aLine, aParam, Tol);

    for (Fexp.InitWires(); Fexp.MoreWires(); Fexp.NextWire()) {
      nowires   = Standard_False;
      IsWReject = Fexp.RejectWire(aLine, myClassifier.Parameter());

      if (!IsWReject) {
	// test this wire
	for (Fexp.InitEdges(); Fexp.MoreEdges(); Fexp.NextEdge()) {
	  IsEReject = Fexp.RejectEdge(aLine, myClassifier.Parameter());

	  if (!IsEReject) {
	    // test this edge
	    Fexp.CurrentEdge(anEdge, anEdgeOri);

	    if (anEdgeOri == TopAbs_FORWARD || anEdgeOri == TopAbs_REVERSED) {
	      myClassifier.Compare(anEdge, anEdgeOri);
	      aClosestInd = myClassifier.ClosestIntersection();

	      if (aClosestInd != 0) {
		// save the closest edge
		TheIntersection2d &anIntersector = myClassifier.Intersector();
		Standard_Integer   aNbPnts       = anIntersector.NbPoints();

		myEdge = anEdge;

		if (aClosestInd <= aNbPnts) {
		  aPInter = anIntersector.Point(aClosestInd);
		} else {
		  aClosestInd -= aNbPnts;

		  if (aClosestInd&1) {
		    aPInter =  anIntersector.
		      Segment((aClosestInd + 1)/2).FirstPoint();
		  } else {
		    aPInter =  anIntersector.
		      Segment((aClosestInd + 1)/2).LastPoint();
		  }
		}

		myPosition      = aPInter.
		                  TransitionOfSecond().PositionOnCurve();
		myEdgeParameter = aPInter.ParamOnSecond();
	      }
	      // if we are ON, we stop
	      aState = myClassifier.State();
	    
	      if (aState == TopAbs_ON)
		return;
	    }
	  }
	}

	// if we are out of the wire we stop
	aState = myClassifier.State();

	if (aState == TopAbs_OUT)
	  return;
      }
    }

    if (!myClassifier.IsHeadOrEnd() && aState != TopAbs_UNKNOWN)
      break;

    // Bad case for classification. Trying to get another segment.
    IsValidSegment = Fexp.OtherSegment(P, aLine, aParam);
  }
}

//=======================================================================
//function : State
//purpose  : 
//=======================================================================

TopAbs_State TopClass_FaceClassifier::State() const
{
  if (rejected)     return TopAbs_OUT;
  else if (nowires) return TopAbs_IN;
  else              return  myClassifier.State();
}

//=======================================================================
//function : Edge
//purpose  : 
//=======================================================================

const TheEdge& TopClass_FaceClassifier::Edge() const
{
  Standard_DomainError_Raise_if(rejected,
				"TopClass_FaceClassifier::Edge:rejected");
  return myEdge;
}


//=======================================================================
//function : EdgeParameter
//purpose  : 
//=======================================================================

Standard_Real TopClass_FaceClassifier::EdgeParameter() const
{
  Standard_DomainError_Raise_if(rejected,
				"TopClass_FaceClassifier::EdgeParameter:rejected");
  return myEdgeParameter;
}