G4UPolyhedra.cc

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//
//
// $Id:$
//
// Implementation of G4UPolycone wrapper class
// --------------------------------------------------------------------

#include "G4Polyhedra.hh"
#include "G4UPolyhedra.hh"
#include "G4Polyhedron.hh"
#include "G4VPVParameterisation.hh"

using CLHEP::twopi;

//
// Constructor (GEANT3 style parameters)
//
// GEANT3 PGON radii are specified in the distance to the norm of each face.
//  
G4UPolyhedra::G4UPolyhedra(const G4String& name, 
                                 G4double phiStart,
                                 G4double phiTotal,
                                 G4int numSide,  
                                 G4int numZPlanes,
                           const G4double zPlane[],
                           const G4double rInner[],
                           const G4double rOuter[]  )
  : G4USolid(name, new UPolyhedra(name,phiStart, phiTotal, numSide,
                                  numZPlanes, zPlane, rInner, rOuter))
{
}


//
// Constructor (generic parameters)
//
G4UPolyhedra::G4UPolyhedra(const G4String& name, 
                                 G4double phiStart,
                                 G4double phiTotal,
                                 G4int    numSide,  
                                 G4int    numRZ,
                           const G4double r[],
                           const G4double z[]   )
  : G4USolid(name, new UPolyhedra(name, phiStart, phiTotal, numSide,
                                  numRZ, r, z))
{ 
}


//
// Fake default constructor - sets only member data and allocates memory
//                            for usage restricted to object persistency.
//
G4UPolyhedra::G4UPolyhedra( __void__& a )
  : G4USolid(a)
{
}


//
// Destructor
//
G4UPolyhedra::~G4UPolyhedra()
{
}


//
// Copy constructor
//
G4UPolyhedra::G4UPolyhedra( const G4UPolyhedra &source )
  : G4USolid( source )
{
}


//
// Assignment operator
//
G4UPolyhedra& G4UPolyhedra::operator=( const G4UPolyhedra &source )
{
  if (this == &source) return *this;

  G4USolid::operator=( source );
    
  return *this;
}


//
// Dispatch to parameterisation for replication mechanism dimension
// computation & modification.
//
void G4UPolyhedra::ComputeDimensions(G4VPVParameterisation* p,
                                     const G4int n,
                                     const G4VPhysicalVolume* pRep)
{
  p->ComputeDimensions(*(G4Polyhedra*)this,n,pRep);
}


//
// CreatePolyhedron
//
G4Polyhedron* G4UPolyhedra::CreatePolyhedron() const
{
  if (!IsGeneric())
  {
    G4PolyhedraHistorical* original_parameters = GetOriginalParameters();
    G4PolyhedronPgon*
      polyhedron = new G4PolyhedronPgon( GetOriginalParameters()->Start_angle,
                                 GetOriginalParameters()->Opening_angle,
                                 GetOriginalParameters()->numSide,
                                 GetOriginalParameters()->Num_z_planes,
                                 GetOriginalParameters()->Z_values,
                                 GetOriginalParameters()->Rmin,
                                 GetOriginalParameters()->Rmax);
    delete original_parameters;  // delete local copy 
    return polyhedron;
  }
  else
  {
    // The following code prepares for:
    // HepPolyhedron::createPolyhedron(int Nnodes, int Nfaces,
    //                                 const double xyz[][3],
    //                                 const int faces_vec[][4])
    // Here is an extract from the header file HepPolyhedron.h:
    G4int nNodes;
    G4int nFaces;
    typedef G4double double3[3];
    double3* xyz;
    typedef G4int int4[4];
    int4* faces_vec;
    if (IsOpen())
    {
      // Triangulate open ends.  Simple ear-chopping algorithm...
      // I'm not sure how robust this algorithm is (J.Allison).
      //
      std::vector<G4bool> chopped(GetNumRZCorner(), false);
      std::vector<G4int*> triQuads;
      G4int remaining = GetNumRZCorner();
      G4int iStarter = 0;
      while (remaining >= 3)
      {
        // Find unchopped corners...
        //
        G4int A = -1, B = -1, C = -1;
        G4int iStepper = iStarter;
        do
        {
          if (A < 0)      { A = iStepper; }
          else if (B < 0) { B = iStepper; }
          else if (C < 0) { C = iStepper; }
          do
          {
            if (++iStepper >= GetNumRZCorner()) iStepper = 0;
          }
          while (chopped[iStepper]);
        }
        while (C < 0 && iStepper != iStarter);

        // Check triangle at B is pointing outward (an "ear").
        // Sign of z cross product determines...

        G4double BAr = GetCorner(A).r - GetCorner(B).r;
        G4double BAz = GetCorner(A).z - GetCorner(B).z;
        G4double BCr = GetCorner(C).r - GetCorner(B).r;
        G4double BCz = GetCorner(C).z - GetCorner(B).z;
        if (BAr * BCz - BAz * BCr < kCarTolerance)
        {
          G4int* tq = new G4int[3];
          tq[0] = A + 1;
          tq[1] = B + 1;
          tq[2] = C + 1;
          triQuads.push_back(tq);
          chopped[B] = true;
          --remaining;
        }
        else
        {
          do
          {
            if (++iStarter >= GetNumRZCorner()) { iStarter = 0; }
          }
          while (chopped[iStarter]);
        }
      }

      // Transfer to faces...
      G4int numSide=GetNumSide();
      nNodes = (numSide + 1) * GetNumRZCorner();
      nFaces = numSide * GetNumRZCorner() + 2 * triQuads.size();
      faces_vec = new int4[nFaces];
      G4int iface = 0;
      G4int addition = GetNumRZCorner() * numSide;
      G4int d = GetNumRZCorner() - 1;
      for (G4int iEnd = 0; iEnd < 2; ++iEnd)
      {
        for (size_t i = 0; i < triQuads.size(); ++i)
        {
          // Negative for soft/auxiliary/normally invisible edges...
          //
          G4int a, b, c;
          if (iEnd == 0)
          {
            a = triQuads[i][0];
            b = triQuads[i][1];
            c = triQuads[i][2];
          }
          else
          {
            a = triQuads[i][0] + addition;
            b = triQuads[i][2] + addition;
            c = triQuads[i][1] + addition;
          }
          G4int ab = std::abs(b - a);
          G4int bc = std::abs(c - b);
          G4int ca = std::abs(a - c);
          faces_vec[iface][0] = (ab == 1 || ab == d)? a: -a;
          faces_vec[iface][1] = (bc == 1 || bc == d)? b: -b;
          faces_vec[iface][2] = (ca == 1 || ca == d)? c: -c;
          faces_vec[iface][3] = 0;
          ++iface;
        }
      }

      // Continue with sides...

      xyz = new double3[nNodes];
      const G4double dPhi = (GetEndPhi() - GetStartPhi()) / numSide;
      G4double phi = GetStartPhi();
      G4int ixyz = 0;
      for (G4int iSide = 0; iSide < numSide; ++iSide)
      {
        for (G4int iCorner = 0; iCorner < GetNumRZCorner(); ++iCorner)
        {
          xyz[ixyz][0] = GetCorner(iCorner).r * std::cos(phi);
          xyz[ixyz][1] = GetCorner(iCorner).r * std::sin(phi);
          xyz[ixyz][2] = GetCorner(iCorner).z;
          if (iCorner < GetNumRZCorner() - 1)
          {
            faces_vec[iface][0] = ixyz + 1;
            faces_vec[iface][1] = ixyz + GetNumRZCorner() + 1;
            faces_vec[iface][2] = ixyz + GetNumRZCorner() + 2;
            faces_vec[iface][3] = ixyz + 2;
          }
          else
          {
            faces_vec[iface][0] = ixyz + 1;
            faces_vec[iface][1] = ixyz + GetNumRZCorner() + 1;
            faces_vec[iface][2] = ixyz + 2;
            faces_vec[iface][3] = ixyz - GetNumRZCorner() + 2;
          }
          ++iface;
          ++ixyz;
        }
        phi += dPhi;
      }

      // Last GetCorner...

      for (G4int iCorner = 0; iCorner < GetNumRZCorner(); ++iCorner)
      {
        xyz[ixyz][0] = GetCorner(iCorner).r * std::cos(phi);
        xyz[ixyz][1] = GetCorner(iCorner).r * std::sin(phi);
        xyz[ixyz][2] = GetCorner(iCorner).z;
        ++ixyz;
      }
    }
    else  // !phiIsOpen - i.e., a complete 360 degrees.
    {
      nNodes = GetNumSide() * GetNumRZCorner();
      nFaces = GetNumSide() * GetNumRZCorner();;
      xyz = new double3[nNodes];
      faces_vec = new int4[nFaces];
      // const G4double dPhi = (endPhi - startPhi) / numSide;
      const G4double dPhi = twopi / GetNumSide(); // !phiIsOpen endPhi-startPhi = 360 degrees.
      G4double phi = GetStartPhi();
      G4int ixyz = 0, iface = 0;
      for (G4int iSide = 0; iSide < GetNumSide(); ++iSide)
      {
        for (G4int iCorner = 0; iCorner < GetNumRZCorner(); ++iCorner)
        {
          xyz[ixyz][0] = GetCorner(iCorner).r * std::cos(phi);
          xyz[ixyz][1] = GetCorner(iCorner).r * std::sin(phi);
          xyz[ixyz][2] = GetCorner(iCorner).z;
          if (iSide < GetNumSide() - 1)
          {
            if (iCorner < GetNumRZCorner() - 1)
            {
              faces_vec[iface][0] = ixyz + 1;
              faces_vec[iface][1] = ixyz + GetNumRZCorner() + 1;
              faces_vec[iface][2] = ixyz + GetNumRZCorner() + 2;
              faces_vec[iface][3] = ixyz + 2;
            }
            else
            {
              faces_vec[iface][0] = ixyz + 1;
              faces_vec[iface][1] = ixyz + GetNumRZCorner() + 1;
              faces_vec[iface][2] = ixyz + 2;
              faces_vec[iface][3] = ixyz - GetNumRZCorner() + 2;
            }
          }
          else   // Last side joins ends...
          {
            if (iCorner < GetNumRZCorner() - 1)
            {
              faces_vec[iface][0] = ixyz + 1;
              faces_vec[iface][1] = ixyz + GetNumRZCorner() - nFaces + 1;
              faces_vec[iface][2] = ixyz + GetNumRZCorner() - nFaces + 2;
              faces_vec[iface][3] = ixyz + 2;
            }
            else
            {
              faces_vec[iface][0] = ixyz + 1;
              faces_vec[iface][1] = ixyz - nFaces + GetNumRZCorner() + 1;
              faces_vec[iface][2] = ixyz - nFaces + 2;
              faces_vec[iface][3] = ixyz - GetNumRZCorner() + 2;
            }
          }
          ++ixyz;
          ++iface;
        }
        phi += dPhi;
      }
    }
    G4Polyhedron* polyhedron = new G4Polyhedron;
    G4int problem = polyhedron->createPolyhedron(nNodes, nFaces, xyz, faces_vec);
    delete [] faces_vec;
    delete [] xyz;
    if (problem)
    {
      std::ostringstream message;
      message << "Problem creating G4Polyhedron for: " << GetName();
      G4Exception("G4Polyhedra::CreatePolyhedron()", "GeomSolids1002",
                  JustWarning, message);
      delete polyhedron;
      return 0;
    }
    else
    {
      return polyhedron;
    }
  }
}