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geant4/source/geometry/solids/BREPS/include/G4Ellipse.icc
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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: G4Ellipse.icc,v 1.6 2001/07/11 09:59:34 gunter Exp $
// GEANT4 tag $Name: geant4-05-00 $
//
// --------------------------------------------------------------------
// GEANT 4 inline definitions file
//
// G4Ellipse.icc
//
// Implementation of inline methods of G4Ellipse
// --------------------------------------------------------------------
inline
void G4Ellipse::Init(const G4Axis2Placement3D& position0,
G4double semiAxis10, G4double semiAxis20)
{
position= position0;
semiAxis1= semiAxis10;
semiAxis2= semiAxis20;
ratioAxis2Axis1= semiAxis2/semiAxis1;
SetBounds(0, 0);
// needed only for 2D ellipses
toUnitCircle = G4Scale3D(1/semiAxis1, 1/semiAxis2, 0)
* position.GetToPlacementCoordinates();
forTangent= -semiAxis1*semiAxis1/(semiAxis2*semiAxis2);
}
inline
G4double G4Ellipse::GetSemiAxis1() const
{
return semiAxis1;
}
inline
G4double G4Ellipse::GetSemiAxis2() const
{
return semiAxis2;
}
/////////////////////////////////////////////////////////////////////////////
inline
G4double G4Ellipse::GetPMax() const
{
return twopi;
}
inline
G4Point3D G4Ellipse::GetPoint(G4double param) const
{
param-= GetPShift();
return G4Point3D( position.GetLocation()
+ semiAxis1*cos(param)*position.GetPX()
+ semiAxis2*sin(param)*position.GetPY() );
}
inline
G4double G4Ellipse::GetPPoint(const G4Point3D& pt) const
{
G4Point3D ptLocal= position.GetToPlacementCoordinates()*pt;
G4double angle= atan2(ptLocal.y(), ptLocal.x()*ratioAxis2Axis1);
G4double r= (angle<0)? angle+twopi: angle;
return r+GetPShift();
}
/////////////////////////////////////////////////////////////////////////////
#include "G4CurveRayIntersection.hh"
/*
inline
void G4Ellipse::IntersectRay2D(const G4Ray& ray,
G4CurveRayIntersection& is)
{
is.Init(*this, ray);
// transform s.t. the ellipse becomes the unit circle
// with the center at the origin
// 2D operations would be faster
G4Point3D s= toUnitCircle*ray.GetStart();
G4Vector3D d= toUnitCircle*ray.GetDir();
// solve (s+i*t)^2 = 1 for i (the distance)
G4double sd= s*d;
G4double dd= d.mag2(); // never 0
G4double ss= s.mag2();
G4double discr= sd*sd-dd*(ss-1);
if (discr >= 0) {
// 2 intersections (maybe 1, but this case is rare)
G4double sqrtdiscr= sqrt(discr);
// find the smallest positive i
G4double i= -sd-sqrtdiscr;
if (i<kCarTolerance) {
i= -sd+sqrtdiscr;
if (i<kCarTolerance) {
return;
}
}
i/= dd;
G4CurveRayIntersection isTmp(*this, ray);
isTmp.ResetDistance(i);
is.Update(isTmp);
}
}
*/
inline
G4int G4Ellipse::IntersectRay2D(const G4Ray& ray)
{
// transform s.t. the ellipse becomes the unit circle
// with the center at the origin
// 2D operations would be faster
G4Point3D s= toUnitCircle*ray.GetStart();
G4Vector3D d= toUnitCircle*ray.GetDir();
// solve (s+i*t)^2 = 1 for i (the distance)
G4double sd= s*d;
G4double dd= d.mag2(); // never 0
G4double ss= s.mag2();
G4double discr= sd*sd-dd*(ss-1);
G4int nbinter = 0;
G4double i;
if (discr > 0)
{
// 2 intersections
G4double sqrtdiscr= sqrt(discr);
// if i is positive, we have an intersection
i= -sd-sqrtdiscr;
if (i > kCarTolerance)
nbinter++;
i= -sd+sqrtdiscr;
if (i > kCarTolerance)
nbinter++;
}
// if the ray is tangent on the circle
if (discr == 0)
nbinter = 1;
return nbinter;
}