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geant4/source/geometry/solids/BREPS/src/G4Parabola.cc
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2016-06-08 16:18:25 +02:00

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//
// ********************************************************************
// * DISCLAIMER *
// * *
// * The following disclaimer summarizes all the specific disclaimers *
// * of contributors to this software. The specific disclaimers,which *
// * govern, are listed with their locations in: *
// * http://cern.ch/geant4/license *
// * *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work make any representation or warranty, express or implied, *
// * regarding this software system or assume any liability for its *
// * use. *
// * *
// * This code implementation is the intellectual property of the *
// * GEANT4 collaboration. *
// * By copying, distributing or modifying the Program (or any work *
// * based on the Program) you indicate your acceptance of this *
// * statement, and all its terms. *
// ********************************************************************
//
//
// $Id: G4Parabola.cc,v 1.5 2001/07/11 09:59:45 gunter Exp $
// GEANT4 tag $Name: geant4-04-00 $
//
// ----------------------------------------------------------------------
// GEANT 4 class source file
//
// G4Parabola.cc
//
// ----------------------------------------------------------------------
#include "G4Parabola.hh"
#include "G4CurvePoint.hh"
G4Parabola::G4Parabola(){}
G4Parabola::~G4Parabola(){}
G4Parabola::G4Parabola(const G4Parabola& right)
: focalDist(right.focalDist), F(right.F), L0(right.L0)
{
pShift = right.pShift;
position = right.position;
bBox = right.bBox;
start = right.start;
end = right.end;
pStart = right.pStart;
pEnd = right.pEnd;
pRange = right.pRange;
bounded = right.bounded;
sameSense = right.sameSense;
}
G4Parabola& G4Parabola::operator=(const G4Parabola& right)
{
if (&right == this) return *this;
F = right.F;
L0 = right.L0;
focalDist = right.focalDist;
pShift = right.pShift;
position = right.position;
bBox = right.bBox;
start = right.start;
end = right.end;
pStart = right.pStart;
pEnd = right.pEnd;
pRange = right.pRange;
bounded = right.bounded;
sameSense = right.sameSense;
return *this;
}
G4Curve* G4Parabola::Project(const G4Transform3D& tr)
{
G4double axisZ= (tr*position.GetPZ()).unit().z();
if (abs(axisZ)<kAngTolerance)
return 0;
G4Vector3D newAxis(0, 0, axisZ>0? +1: -1);
G4Vector3D xPrime= tr*position.GetPX();
xPrime.setZ(0);
G4Vector3D yPrime= tr*position.GetPY();
yPrime.setZ(0);
G4double u= -(xPrime*yPrime)/xPrime.mag2();
G4Point3D newLocation= G4Point3D( tr*position.GetLocation()+
focalDist*(u*u*xPrime+2*u*yPrime) );
newLocation.setZ(0);
G4Vector3D newRefDirection= xPrime;
G4double newFocalDist= (focalDist*((2*u+1)*xPrime+2*yPrime)).mag()/sqrt(5.);
// create the new parabola
G4Axis2Placement3D newPosition;
newPosition.Init(newRefDirection, newAxis, newLocation);
G4Parabola* r= new G4Parabola;
r->Init(newPosition, newFocalDist);
// introduce the shift in the parametrization
// maybe the Sign must be changed?
r->SetPShift(u);
// set the bounds when necessary
if (IsBounded())
r->SetBounds(GetPStart(), GetPEnd());
return r;
}
void G4Parabola::InitBounded()
{
// the bbox must include the start and endpoints as well as the
// extreme points if they lie on the curve
bBox.Init(GetStart(), GetEnd());
// the parameter values
// belonging to the points with an extreme x, y and z coordinate
for (G4int i=0; i<3; i++)
{
G4double x_i= position.GetPX()(i);
if (abs(x_i) <= kAngTolerance)
{
G4double u= - position.GetPY()(i) / x_i;
if (IsPOn(u))
bBox.Extend(GetPoint(u));
}
}
}
G4bool G4Parabola::Tangent(G4CurvePoint& cp, G4Vector3D& v)
{
// The tangent is computed from the 3D point representation
// for all conics. An alternaive implementation (based on
// the parametric point) might be worthwhile adding
// for efficiency.
const G4Axis2Placement3D& pos= *(GetPosition());
G4Point3D p= pos.GetToPlacementCoordinates() * cp.GetPoint();
v= p.y()*pos.GetPX() + (2*focalDist)*pos.GetPY();
return true;
}