smesh/src/SMESHUtils/SMESH_ControlPnt.cxx
2021-03-23 17:44:29 +03:00

410 lines
14 KiB
C++

// Copyright (C) 2007-2021 CEA/DEN, EDF R&D, OPEN CASCADE
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
//
// Author : Lioka RAZAFINDRAZAKA (CEA)
#include "SMESH_ControlPnt.hxx"
#include <BRepBndLib.hxx>
#include <BRepMesh_IncrementalMesh.hxx>
#include <BRep_Tool.hxx>
#include <Bnd_Box.hxx>
#include <GCPnts_UniformAbscissa.hxx>
#include <GeomAdaptor_Curve.hxx>
#include <Geom_Curve.hxx>
#include <IntCurvesFace_Intersector.hxx>
#include <Poly_Array1OfTriangle.hxx>
#include <Poly_Triangle.hxx>
#include <Poly_Triangulation.hxx>
#include <Precision.hxx>
#include <TColgp_Array1OfPnt.hxx>
#include <TopExp_Explorer.hxx>
#include <TopLoc_Location.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Edge.hxx>
#include <TopoDS_Face.hxx>
#include <TopoDS_Iterator.hxx>
#include <TopoDS_Solid.hxx>
#include <gp_Ax3.hxx>
#include <gp_Dir.hxx>
#include <gp_Lin.hxx>
#include <gp_Trsf.hxx>
#include <gp_Vec.hxx>
#include <set>
namespace SMESHUtils
{
// Some functions for surface sampling
void subdivideTriangle( const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& p3,
const double& theSize,
std::vector<ControlPnt>& thePoints );
void computePointsForSplitting( const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& p3,
gp_Pnt midPoints[3]);
gp_Pnt tangencyPoint(const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& Center);
}
//================================================================================
/*!
* \brief Fills a vector of points from which a size map input file can be written
*/
//================================================================================
void SMESHUtils::createControlPoints( const TopoDS_Shape& theShape,
const double& theSize,
std::vector<ControlPnt>& thePoints )
{
if ( theShape.ShapeType() == TopAbs_VERTEX )
{
gp_Pnt aPnt = BRep_Tool::Pnt( TopoDS::Vertex(theShape) );
ControlPnt aControlPnt( aPnt, theSize );
thePoints.push_back( aControlPnt );
}
if ( theShape.ShapeType() == TopAbs_EDGE )
{
createPointsSampleFromEdge( TopoDS::Edge( theShape ), theSize, thePoints );
}
else if ( theShape.ShapeType() == TopAbs_WIRE )
{
TopExp_Explorer Ex;
for (Ex.Init(theShape,TopAbs_EDGE); Ex.More(); Ex.Next())
{
createPointsSampleFromEdge( TopoDS::Edge( Ex.Current() ), theSize, thePoints );
}
}
else if ( theShape.ShapeType() == TopAbs_FACE )
{
createPointsSampleFromFace( TopoDS::Face( theShape ), theSize, thePoints );
}
else if ( theShape.ShapeType() == TopAbs_SOLID )
{
createPointsSampleFromSolid( TopoDS::Solid( theShape ), theSize, thePoints );
}
else if ( theShape.ShapeType() == TopAbs_COMPOUND )
{
TopoDS_Iterator it( theShape );
for(; it.More(); it.Next())
{
createControlPoints( it.Value(), theSize, thePoints );
}
}
}
//================================================================================
/*!
* \brief Fills a vector of points with point samples approximately
* \brief spaced with a given size
*/
//================================================================================
void SMESHUtils::createPointsSampleFromEdge( const TopoDS_Edge& theEdge,
const double& theSize,
std::vector<ControlPnt>& thePoints )
{
double step = theSize;
double first, last;
Handle( Geom_Curve ) aCurve = BRep_Tool::Curve( theEdge, first, last );
GeomAdaptor_Curve C ( aCurve );
GCPnts_UniformAbscissa DiscretisationAlgo(C, step , first, last, Precision::Confusion());
int nbPoints = DiscretisationAlgo.NbPoints();
ControlPnt aPnt;
aPnt.SetSize(theSize);
for ( int i = 1; i <= nbPoints; i++ )
{
double param = DiscretisationAlgo.Parameter( i );
aCurve->D0( param, aPnt );
thePoints.push_back( aPnt );
}
}
//================================================================================
/*!
* \brief Fills a vector of points with point samples approximately
* \brief spaced with a given size
*/
//================================================================================
void SMESHUtils::createPointsSampleFromFace( const TopoDS_Face& theFace,
const double& theSize,
std::vector<ControlPnt>& thePoints )
{
BRepMesh_IncrementalMesh M(theFace, 0.01, Standard_True);
TopLoc_Location aLocation;
// Triangulate the face
Handle(Poly_Triangulation) aTri = BRep_Tool::Triangulation (theFace, aLocation);
// Get the transformation associated to the face location
gp_Trsf aTrsf = aLocation.Transformation();
// Get triangles
int nbTriangles = aTri->NbTriangles();
const Poly_Array1OfTriangle& triangles = aTri->Triangles();
// GetNodes
int nbNodes = aTri->NbNodes();
TColgp_Array1OfPnt nodes(1,nbNodes);
nodes = aTri->Nodes();
// Iterate on triangles and subdivide them
thePoints.reserve( thePoints.size() + nbTriangles );
for ( int i = 1; i <= nbTriangles; i++ )
{
const Poly_Triangle& aTriangle = triangles.Value(i);
gp_Pnt p1 = nodes.Value(aTriangle.Value(1));
gp_Pnt p2 = nodes.Value(aTriangle.Value(2));
gp_Pnt p3 = nodes.Value(aTriangle.Value(3));
p1.Transform(aTrsf);
p2.Transform(aTrsf);
p3.Transform(aTrsf);
subdivideTriangle( p1, p2, p3, theSize, thePoints );
}
}
//================================================================================
/*!
* \brief Fills a vector of points with point samples approximately
* \brief spaced with a given size
*/
//================================================================================
void SMESHUtils::createPointsSampleFromSolid( const TopoDS_Solid& theSolid,
const double& theSize,
std::vector<ControlPnt>& thePoints )
{
// Compute the bounding box
double Xmin, Ymin, Zmin, Xmax, Ymax, Zmax;
Bnd_Box B;
BRepBndLib::Add(theSolid, B);
B.Get(Xmin, Ymin, Zmin, Xmax, Ymax, Zmax);
// Create the points
double step = theSize;
for ( double x=Xmin; x-Xmax<Precision::Confusion(); x=x+step )
{
for ( double y=Ymin; y-Ymax<Precision::Confusion(); y=y+step )
{
// Step1 : generate the Zmin -> Zmax line
gp_Pnt startPnt(x, y, Zmin);
gp_Pnt endPnt(x, y, Zmax);
gp_Vec aVec(startPnt, endPnt);
gp_Lin aLine(startPnt, aVec);
double endParam = Zmax - Zmin;
// Step2 : for each face of theSolid:
std::set<double> intersections;
for ( TopExp_Explorer Ex( theSolid, TopAbs_FACE ); Ex.More(); Ex.Next() )
{
// check if there is an intersection
IntCurvesFace_Intersector anIntersector(TopoDS::Face(Ex.Current()), Precision::Confusion());
anIntersector.Perform(aLine, 0, endParam);
// get the intersection's parameter and store it
int nbPoints = anIntersector.NbPnt();
for ( int i = 0 ; i < nbPoints; i++ )
{
intersections.insert( anIntersector.WParameter(i+1) );
}
}
// Step3 : go through the line chunk by chunk
if ( intersections.size() > 1 )
{
std::set<double>::iterator intersectionsIterator=intersections.begin();
double first = *intersectionsIterator;
intersectionsIterator++;
bool innerPoints = true;
for ( ; intersectionsIterator!=intersections.end() ; intersectionsIterator++ )
{
double second = *intersectionsIterator;
if ( innerPoints )
{
// If the last chunk was outside of the shape or this is the first chunk
// add the points in the range [first, second] to the points vector
double localStep = (second -first) / ceil( (second - first) / step );
for ( double z = Zmin + first; z < Zmin + second; z = z + localStep )
{
thePoints.emplace_back( x, y, z, theSize );
}
thePoints.emplace_back( x, y, Zmin + second, theSize );
}
first = second;
innerPoints = !innerPoints;
}
}
}
}
}
//================================================================================
/*!
* \brief Subdivides a triangle until it reaches a certain size (recursive function)
*/
//================================================================================
void SMESHUtils::subdivideTriangle( const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& p3,
const double& theSize,
std::vector<ControlPnt>& thePoints)
{
// Size threshold to stop subdividing
// This value ensures that two control points are distant no more than 2*theSize
// as shown below
//
// The greater distance D of the mass center M to each Edge is 1/3 * Median
// and Median < sqrt(3/4) * a where a is the greater side (by using Apollonius' thorem).
// So D < 1/3 * sqrt(3/4) * a and if a < sqrt(3) * S then D < S/2
// and the distance between two mass centers of two neighbouring triangles
// sharing an edge is < 2 * 1/2 * S = S
// If the traingles share a Vertex and no Edge the distance of the mass centers
// to the Vertices is 2*D < S so the mass centers are distant of less than 2*S
double threshold = sqrt( 3. ) * theSize;
if ( p1.Distance(p2) > threshold ||
p2.Distance(p3) > threshold ||
p3.Distance(p1) > threshold )
try
{
gp_Pnt midPoints[3];
computePointsForSplitting( p1, p2, p3, midPoints );
subdivideTriangle( midPoints[0], midPoints[1], midPoints[2], theSize, thePoints );
subdivideTriangle( midPoints[0], p2, midPoints[1], theSize, thePoints );
subdivideTriangle( midPoints[2], midPoints[1], p3, theSize, thePoints );
subdivideTriangle( p1, midPoints[0], midPoints[2], theSize, thePoints );
return;
}
catch (...)
{
}
gp_Pnt massCenter = ( p1.XYZ() + p2.XYZ() + p3.XYZ() ) / 3.;
thePoints.emplace_back( massCenter, theSize );
}
//================================================================================
/*!
* \brief Returns the appropriate points for splitting a triangle
* the tangency points of the incircle are used in order to have mostly
* well-shaped sub-triangles
*/
//================================================================================
void SMESHUtils::computePointsForSplitting( const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& p3,
gp_Pnt midPoints[3])
{
//Change coordinates
gp_Trsf Trsf_1; // Identity transformation
gp_Ax3 reference_system(gp::Origin(), gp::DZ(), gp::DX()); // OXY
gp_Vec Vx(p1, p3);
gp_Vec Vaux(p1, p2);
gp_Dir Dx(Vx);
gp_Dir Daux(Vaux);
gp_Dir Dz = Dx.Crossed(Daux);
gp_Ax3 current_system(p1, Dz, Dx);
Trsf_1.SetTransformation( reference_system, current_system );
gp_Pnt A = p1.Transformed(Trsf_1);
gp_Pnt B = p2.Transformed(Trsf_1);
gp_Pnt C = p3.Transformed(Trsf_1);
double a = B.Distance(C) ;
double b = A.Distance(C) ;
double c = B.Distance(A) ;
// Incenter coordinates
// see http://mathworld.wolfram.com/Incenter.html
double Xi = ( b*B.X() + c*C.X() ) / ( a + b + c );
double Yi = ( b*B.Y() ) / ( a + b + c );
gp_Pnt Center(Xi, Yi, 0);
// Calculate the tangency points of the incircle
gp_Pnt T1 = tangencyPoint( A, B, Center);
gp_Pnt T2 = tangencyPoint( B, C, Center);
gp_Pnt T3 = tangencyPoint( C, A, Center);
midPoints[0] = T1.Transformed(Trsf_1.Inverted());
midPoints[1] = T2.Transformed(Trsf_1.Inverted());
midPoints[2] = T3.Transformed(Trsf_1.Inverted());
return;
}
//================================================================================
/*!
* \brief Computes the tangency points of the circle of center Center with
* \brief the straight line (p1 p2)
*/
//================================================================================
gp_Pnt SMESHUtils::tangencyPoint(const gp_Pnt& p1,
const gp_Pnt& p2,
const gp_Pnt& Center)
{
double Xt = 0;
double Yt = 0;
// The tangency point is the intersection of the straight line (p1 p2)
// and the straight line (Center T) which is orthogonal to (p1 p2)
if ( fabs(p1.X() - p2.X()) <= Precision::Confusion() )
{
Xt=p1.X(); // T is on (p1 p2)
Yt=Center.Y(); // (Center T) is orthogonal to (p1 p2)
}
else if ( fabs(p1.Y() - p2.Y()) <= Precision::Confusion() )
{
Yt=p1.Y(); // T is on (p1 p2)
Xt=Center.X(); // (Center T) is orthogonal to (p1 p2)
}
else
{
// First straight line coefficients (equation y=a*x+b)
double a = (p2.Y() - p1.Y()) / (p2.X() - p1.X()) ;
double b = p1.Y() - a*p1.X(); // p1 is on this straight line
// Second straight line coefficients (equation y=c*x+d)
double c = -1 / a; // The 2 lines are orthogonal
double d = Center.Y() - c*Center.X(); // Center is on this straight line
Xt = (d - b) / (a - c);
Yt = a*Xt + b;
}
return gp_Pnt( Xt, Yt, 0 );
}