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OCCT/src/BRepMesh/BRepMesh_GeomTool.cxx
oan 7bd071edb1 0026106: BRepMesh - revision of data model 
Removed tight connections between data structures, auxiliary tools and algorithms in order to create extensible solution, easy for maintenance and improvements;
Code is separated on several functional units responsible for specific operation for the sake of simplification of debugging and readability;
Introduced new data structures enabling possibility to manipulate discrete model of particular entity (edge, wire, face) in order to perform computations locally instead of processing an entire model.

The workflow of updated component can be divided on six parts:
* Creation of model data structure: source TopoDS_Shape passed to algorithm is analyzed and exploded on faces and edges. For each topological entity corresponding reflection is created in data model. Note that underlying algorithms use data model as input and access it via common interface which allows user to create custom data model with necessary dependencies between particular entities;
* Discretize edges 3D & 2D curves: 3D curve as well as associated set of 2D curves of each model edge is discretized in order to create coherent skeleton used as a base in faces meshing process. In case if some edge of source shape already contains polygonal data which suites specified parameters, it is extracted from shape and stored to the model as is. Each edge is processed separately, adjacency is not taken into account;
* Heal discrete model: source TopoDS_Shape can contain problems, such as open-wire or self-intersections, introduced during design, exchange or modification of model. In addition, some problems like self-intersections can be introduced by roughly discretized edges. This stage is responsible for analysis of discrete model in order to detect and repair faced problems or refuse model’s part for further processing in case if problem cannot be solved;
* Preprocess discrete model: defines actions specific for implemented approach to be performed before meshing of faces. By default, iterates over model faces and checks consistency of existing triangulations. Cleans topological faces and its adjacent edges from polygonal data in case of inconsistency or marks face of discrete model as not required for computation;
* Discretize faces: represents core part performing mesh generation for particular face based on 2D discrete data related to processing face. Caches polygonal data associated with face’s edges in data model for further processing and stores generated mesh to TopoDS_Face;
* Postprocess discrete model: defines actions specific for implemented approach to be performed after meshing of faces. By default, stores polygonal data obtained on previous stage to TopoDS_Edge objects of source model.

Component is now spread over IMeshData, IMeshTools, BRepMeshData and BRepMesh units.

<!break>

1. Extend "tricheck" DRAW-command in order to find degenerated triangles.

2. Class BRepMesh_FastDiscret::Parameters has been declared as deprecated.

3. NURBS range splitter: do not split intervals without necessity. Intervals are split only in case if it is impossible to compute normals directly on intervals.

4. Default value of IMeshTools_Parameters::MinSize has been changed. New value is equal to 0.1*Deflection.

5. Correction of test scripts:

1) perf mesh bug27119: requested deflection is increased from 1e-6 to 1e-5 to keep reasonable performance (but still reproducing original issue)
2) bugs mesh bug26692_1, 2: make snapshot of triangulation instead of wireframe (irrelevant)

Correction in upgrade guide.
2018-11-02 17:06:40 +03:00

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// Created on: 1993-09-29
// Created by: Isabelle GRIGNON
// Copyright (c) 1993-1999 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.
#include <BRepMesh_GeomTool.hxx>
#include <BRepMesh_DefaultRangeSplitter.hxx>
#include <TopAbs_Orientation.hxx>
#include <CSLib.hxx>
#include <Precision.hxx>
#include <Adaptor3d_IsoCurve.hxx>
#include <Adaptor3d_HCurve.hxx>
#include <BRepAdaptor_Curve.hxx>
#include <BRepAdaptor_HSurface.hxx>
#include <Geom2d_Curve.hxx>
#include <BRep_Tool.hxx>
namespace
{
void ComputeErrFactors (const Standard_Real theDeflection,
const Handle(Adaptor3d_HSurface)& theFace,
Standard_Real& theErrFactorU,
Standard_Real& theErrFactorV)
{
theErrFactorU = theDeflection * 10.;
theErrFactorV = theDeflection * 10.;
switch (theFace->GetType ())
{
case GeomAbs_Cylinder:
case GeomAbs_Cone:
case GeomAbs_Sphere:
case GeomAbs_Torus:
break;
case GeomAbs_SurfaceOfExtrusion:
case GeomAbs_SurfaceOfRevolution:
{
Handle(Adaptor3d_HCurve) aCurve = theFace->BasisCurve ();
if (aCurve->GetType () == GeomAbs_BSplineCurve && aCurve->Degree () > 2)
{
theErrFactorV /= (aCurve->Degree () * aCurve->NbKnots ());
}
break;
}
case GeomAbs_BezierSurface:
{
if (theFace->UDegree () > 2)
{
theErrFactorU /= (theFace->UDegree ());
}
if (theFace->VDegree () > 2)
{
theErrFactorV /= (theFace->VDegree ());
}
break;
}
case GeomAbs_BSplineSurface:
{
if (theFace->UDegree () > 2)
{
theErrFactorU /= (theFace->UDegree () * theFace->NbUKnots ());
}
if (theFace->VDegree () > 2)
{
theErrFactorV /= (theFace->VDegree () * theFace->NbVKnots ());
}
break;
}
case GeomAbs_Plane:
default:
theErrFactorU = theErrFactorV = 1.;
}
}
void AdjustCellsCounts (const Handle(Adaptor3d_HSurface)& theFace,
const Standard_Integer theNbVertices,
Standard_Integer& theCellsCountU,
Standard_Integer& theCellsCountV)
{
const GeomAbs_SurfaceType aType = theFace->GetType ();
if (aType == GeomAbs_OtherSurface)
{
// fallback to the default behavior
theCellsCountU = theCellsCountV = -1;
return;
}
Standard_Real aSqNbVert = theNbVertices;
if (aType == GeomAbs_Plane)
{
theCellsCountU = theCellsCountV = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
else if (aType == GeomAbs_Cylinder || aType == GeomAbs_Cone)
{
theCellsCountV = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
else if (aType == GeomAbs_SurfaceOfExtrusion || aType == GeomAbs_SurfaceOfRevolution)
{
Handle (Adaptor3d_HCurve) aCurve = theFace->BasisCurve ();
if (aCurve->GetType () == GeomAbs_Line ||
(aCurve->GetType () == GeomAbs_BSplineCurve && aCurve->Degree () < 2))
{
// planar, cylindrical, conical cases
if (aType == GeomAbs_SurfaceOfExtrusion)
theCellsCountU = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
else
theCellsCountV = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
if (aType == GeomAbs_SurfaceOfExtrusion)
{
// V is always a line
theCellsCountV = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
}
else if (aType == GeomAbs_BezierSurface || aType == GeomAbs_BSplineSurface)
{
if (theFace->UDegree () < 2)
{
theCellsCountU = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
if (theFace->VDegree () < 2)
{
theCellsCountV = (Standard_Integer)Ceiling (Pow (2, Log10 (aSqNbVert)));
}
}
theCellsCountU = Max (theCellsCountU, 2);
theCellsCountV = Max (theCellsCountV, 2);
}
}
//=======================================================================
//function : Constructor
//purpose :
//=======================================================================
BRepMesh_GeomTool::BRepMesh_GeomTool(
const BRepAdaptor_Curve& theCurve,
const Standard_Real theFirstParam,
const Standard_Real theLastParam,
const Standard_Real theLinDeflection,
const Standard_Real theAngDeflection,
const Standard_Integer theMinPointsNb,
const Standard_Real theMinSize)
: myEdge(&theCurve.Edge()),
myIsoType(GeomAbs_NoneIso)
{
myDiscretTool.Initialize(theCurve, theFirstParam, theLastParam,
theAngDeflection, theLinDeflection, theMinPointsNb,
Precision::PConfusion(), theMinSize);
}
//=======================================================================
//function : Constructor
//purpose :
//=======================================================================
BRepMesh_GeomTool::BRepMesh_GeomTool(
const Handle(BRepAdaptor_HSurface)& theSurface,
const GeomAbs_IsoType theIsoType,
const Standard_Real theParamIso,
const Standard_Real theFirstParam,
const Standard_Real theLastParam,
const Standard_Real theLinDeflection,
const Standard_Real theAngDeflection,
const Standard_Integer theMinPointsNb,
const Standard_Real theMinSize)
: myEdge(NULL),
myIsoType(theIsoType)
{
Adaptor3d_IsoCurve aIso(theSurface, theIsoType, theParamIso,
theFirstParam, theLastParam);
myDiscretTool.Initialize(aIso, theFirstParam, theLastParam,
theAngDeflection, theLinDeflection, theMinPointsNb,
Precision::PConfusion(), theMinSize);
}
//=======================================================================
//function : Value
//purpose :
//=======================================================================
Standard_Boolean BRepMesh_GeomTool::Value(
const Standard_Integer theIndex,
const Handle(BRepAdaptor_HSurface)& theSurface,
Standard_Real& theParam,
gp_Pnt& thePoint,
gp_Pnt2d& theUV) const
{
if (theIndex < 1 || theIndex > NbPoints())
return Standard_False;
if (myEdge == NULL)
return Standard_False;
thePoint = myDiscretTool.Value(theIndex);
theParam = myDiscretTool.Parameter(theIndex);
const TopoDS_Face& aFace = ((BRepAdaptor_Surface*)&(theSurface->Surface()))->Face();
Standard_Real aFirst, aLast;
Handle(Geom2d_Curve) aCurve =
BRep_Tool::CurveOnSurface(*myEdge, aFace, aFirst, aLast);
aCurve->D0(theParam, theUV);
return Standard_True;
}
//=======================================================================
//function : Value
//purpose :
//=======================================================================
Standard_Boolean BRepMesh_GeomTool::Value(
const Standard_Integer theIndex,
const Standard_Real theIsoParam,
Standard_Real& theParam,
gp_Pnt& thePoint,
gp_Pnt2d& theUV) const
{
if (theIndex < 1 || theIndex > NbPoints())
return Standard_False;
thePoint = myDiscretTool.Value(theIndex);
theParam = myDiscretTool.Parameter(theIndex);
if (myIsoType == GeomAbs_IsoU)
theUV.SetCoord(theIsoParam, theParam);
else
theUV.SetCoord(theParam, theIsoParam);
return Standard_True;
}
//=======================================================================
//function : Normal
//purpose :
//=======================================================================
Standard_Boolean BRepMesh_GeomTool::Normal(
const Handle(BRepAdaptor_HSurface)& theSurface,
const Standard_Real theParamU,
const Standard_Real theParamV,
gp_Pnt& thePoint,
gp_Dir& theNormal)
{
Standard_Boolean isOK = Standard_True;
gp_Vec aD1U, aD1V;
theSurface->D1(theParamU, theParamV, thePoint, aD1U, aD1V);
CSLib_DerivativeStatus aStatus;
CSLib::Normal(aD1U, aD1V, Precision::Angular(), aStatus, theNormal);
if (aStatus != CSLib_Done)
{
gp_Vec aD2U,aD2V,aD2UV;
theSurface->D2(theParamU, theParamV, thePoint, aD1U, aD1V, aD2U, aD2V, aD2UV);
CSLib_NormalStatus aNormalStatus;
CSLib::Normal(aD1U, aD1V, aD2U, aD2V, aD2UV, Precision::Angular(),
isOK, aNormalStatus, theNormal);
}
if (!isOK)
return Standard_False;
const TopoDS_Face& aFace = ((BRepAdaptor_Surface*)&(theSurface->Surface()))->Face();
TopAbs_Orientation aOri = aFace.Orientation();
if (aOri == TopAbs_REVERSED)
theNormal.Reverse();
return Standard_True;
}
//=============================================================================
//function : IntLinLin
//purpose :
//=============================================================================
BRepMesh_GeomTool::IntFlag BRepMesh_GeomTool::IntLinLin(
const gp_XY& theStartPnt1,
const gp_XY& theEndPnt1,
const gp_XY& theStartPnt2,
const gp_XY& theEndPnt2,
gp_XY& theIntPnt,
Standard_Real (&theParamOnSegment)[2])
{
gp_XY aVec1 = theEndPnt1 - theStartPnt1;
gp_XY aVec2 = theEndPnt2 - theStartPnt2;
gp_XY aVecO1O2 = theStartPnt2 - theStartPnt1;
Standard_Real aCrossD1D2 = aVec1 ^ aVec2;
Standard_Real aCrossD1D3 = aVecO1O2 ^ aVec2;
const Standard_Real aPrec = gp::Resolution();
// Are edgegs codirectional
if ( Abs( aCrossD1D2 ) < aPrec )
{
// Just a parallel case?
if( Abs( aCrossD1D3 ) < aPrec )
return BRepMesh_GeomTool::Same;
else
return BRepMesh_GeomTool::NoIntersection;
}
theParamOnSegment[0] = aCrossD1D3 / aCrossD1D2;
theIntPnt = theStartPnt1 + theParamOnSegment[0] * aVec1;
Standard_Real aCrossD2D3 = aVecO1O2 ^ aVec1;
theParamOnSegment[1] = aCrossD2D3 / aCrossD1D2;
return BRepMesh_GeomTool::Cross;
}
//=============================================================================
//function : IntSegSeg
//purpose :
//=============================================================================
BRepMesh_GeomTool::IntFlag BRepMesh_GeomTool::IntSegSeg(
const gp_XY& theStartPnt1,
const gp_XY& theEndPnt1,
const gp_XY& theStartPnt2,
const gp_XY& theEndPnt2,
const Standard_Boolean isConsiderEndPointTouch,
const Standard_Boolean isConsiderPointOnSegment,
gp_Pnt2d& theIntPnt)
{
Standard_Integer aPointHash[] = {
classifyPoint(theStartPnt1, theEndPnt1, theStartPnt2),
classifyPoint(theStartPnt1, theEndPnt1, theEndPnt2 ),
classifyPoint(theStartPnt2, theEndPnt2, theStartPnt1),
classifyPoint(theStartPnt2, theEndPnt2, theEndPnt1 )
};
// Consider case when edges have shared vertex
if ( aPointHash[0] < 0 || aPointHash[1] < 0 )
{
if ( isConsiderEndPointTouch )
return BRepMesh_GeomTool::EndPointTouch;
return BRepMesh_GeomTool::NoIntersection;
}
Standard_Integer aPosHash =
aPointHash[0] + aPointHash[1] + aPointHash[2] + aPointHash[3];
/*=========================================*/
/* 1) hash code == 1:
0+
/
0 1/ 0
+======+==========+
2) hash code == 2:
0 1 1 0
a) +----+========+---+
0 1 1 0
b) +-------+===+=====+
*/
/*=========================================*/
if ( aPosHash == 1 )
{
if (isConsiderPointOnSegment)
{
if (aPointHash[0] == 1)
theIntPnt = theStartPnt1;
else if (aPointHash[1] == 1)
theIntPnt = theEndPnt1;
else if (aPointHash[2] == 1)
theIntPnt = theStartPnt2;
else
theIntPnt = theEndPnt2;
return BRepMesh_GeomTool::PointOnSegment;
}
return BRepMesh_GeomTool::NoIntersection;
}
else if ( aPosHash == 2 )
return BRepMesh_GeomTool::Glued;
Standard_Real aParam[2];
IntFlag aIntFlag = IntLinLin(theStartPnt1, theEndPnt1,
theStartPnt2, theEndPnt2, theIntPnt.ChangeCoord(), aParam);
if (aIntFlag == BRepMesh_GeomTool::NoIntersection)
return BRepMesh_GeomTool::NoIntersection;
if (aIntFlag == BRepMesh_GeomTool::Same)
{
if ( aPosHash < -2 )
return BRepMesh_GeomTool::Same;
else if ( aPosHash == -1 )
return BRepMesh_GeomTool::Glued;
return BRepMesh_GeomTool::NoIntersection;
}
// Cross
// Intersection is out of segments ranges
const Standard_Real aPrec = Precision::PConfusion();
const Standard_Real aEndPrec = 1 - aPrec;
for (Standard_Integer i = 0; i < 2; ++i)
{
if(aParam[i] < aPrec || aParam[i] > aEndPrec )
return BRepMesh_GeomTool::NoIntersection;
}
return BRepMesh_GeomTool::Cross;
}
//=============================================================================
//function : CellsCount
//purpose :
//=============================================================================
std::pair<Standard_Integer, Standard_Integer> BRepMesh_GeomTool::CellsCount (
const Handle (Adaptor3d_HSurface)& theSurface,
const Standard_Integer theVerticesNb,
const Standard_Real theDeflection,
const BRepMesh_DefaultRangeSplitter* theRangeSplitter)
{
if (theRangeSplitter == NULL)
return std::pair<Standard_Integer, Standard_Integer>(-1, -1);
const GeomAbs_SurfaceType aType = theSurface->GetType ();
Standard_Real anErrFactorU, anErrFactorV;
ComputeErrFactors(theDeflection, theSurface, anErrFactorU, anErrFactorV);
const std::pair<Standard_Real, Standard_Real>& aRangeU = theRangeSplitter->GetRangeU();
const std::pair<Standard_Real, Standard_Real>& aRangeV = theRangeSplitter->GetRangeV();
const std::pair<Standard_Real, Standard_Real>& aDelta = theRangeSplitter->GetDelta ();
Standard_Integer aCellsCountU, aCellsCountV;
if (aType == GeomAbs_Torus)
{
aCellsCountU = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeU.second - aRangeU.first) / aDelta.first)));
aCellsCountV = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeV.second - aRangeV.first) / aDelta.second)));
}
else if (aType == GeomAbs_Cylinder)
{
aCellsCountU = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeU.second - aRangeU.first) / aDelta.first /
(aRangeV.second - aRangeV.first))));
aCellsCountV = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeV.second - aRangeV.first) / anErrFactorV)));
}
else
{
aCellsCountU = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeU.second - aRangeU.first) / aDelta.first / anErrFactorU)));
aCellsCountV = (Standard_Integer)Ceiling(Pow(2, Log10(
(aRangeV.second - aRangeV.first) / aDelta.second / anErrFactorV)));
}
AdjustCellsCounts(theSurface, theVerticesNb, aCellsCountU, aCellsCountV);
return std::pair<Standard_Integer, Standard_Integer>(aCellsCountU, aCellsCountV);
}
//=============================================================================
//function : classifyPoint
//purpose :
//=============================================================================
Standard_Integer BRepMesh_GeomTool::classifyPoint(
const gp_XY& thePoint1,
const gp_XY& thePoint2,
const gp_XY& thePointToCheck)
{
gp_XY aP1 = thePoint2 - thePoint1;
gp_XY aP2 = thePointToCheck - thePoint1;
const Standard_Real aPrec = Precision::PConfusion();
const Standard_Real aSqPrec = aPrec * aPrec;
Standard_Real aDist = Abs(aP1 ^ aP2);
if (aDist > aPrec)
{
aDist = (aDist * aDist) / aP1.SquareModulus();
if (aDist > aSqPrec)
return 0; //out
}
gp_XY aMult = aP1.Multiplied(aP2);
if ( aMult.X() < 0.0 || aMult.Y() < 0.0 )
return 0; //out
if (aP1.SquareModulus() < aP2.SquareModulus())
return 0; //out
if (thePointToCheck.IsEqual(thePoint1, aPrec) ||
thePointToCheck.IsEqual(thePoint2, aPrec))
{
return -1; //coinsides with an end point
}
return 1;
}
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