GeometryTransformer.cxx

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
 
#include "MIDBase/GeometryTransformer.h"
 
#include <fstream>
#include <string>
#include "TMath.h"
#include "TGeoVolume.h"
#include "TGeoManager.h"
#include "Math/GenVector/RotationX.h"
#include "Math/GenVector/RotationY.h"
#include "MIDBase/GeometryParameters.h"
 
namespace o2
{
namespace mid
{
 
void GeometryTransformer::setMatrix(int deId, const ROOT::Math::Transform3D& matrix)
{
  detparams::assertDEId(deId);
  mTransformations[deId] = matrix;
}
 
ROOT::Math::Transform3D getDefaultChamberTransform(int ichamber)
{
  const double degToRad = TMath::DegToRad();
  ROOT::Math::Rotation3D planeRot(ROOT::Math::RotationX(geoparams::BeamAngle * degToRad));
  ROOT::Math::Translation3D planeTrans(0., 0., geoparams::DefaultChamberZ[ichamber]);
  return planeTrans * planeRot;
}
 
ROOT::Math::Transform3D getDefaultRPCTransform(bool isRight, int chamber, int rpc)
{
  const double degToRad = TMath::DegToRad();
  double angle = isRight ? 0. : 180.;
  ROOT::Math::Rotation3D rot(ROOT::Math::RotationY(angle * degToRad));
  double xSign = isRight ? 1. : -1.;
  double xPos = xSign * geoparams::getRPCCenterPosX(chamber, rpc);
  double sign = (rpc % 2 == 0) ? 1. : -1;
  if (!isRight) {
    sign *= -1.;
  }
  double zPos = sign * geoparams::RPCZShift;
  double newZ = geoparams::DefaultChamberZ[0] + zPos;
  double oldZ = geoparams::DefaultChamberZ[0] - zPos;
  double yPos = geoparams::getRPCHalfHeight(chamber) * (rpc - 4) * (1. + newZ / oldZ);
  ROOT::Math::Translation3D trans(xPos, yPos, zPos);
  return trans * rot;
}
 
GeometryTransformer createDefaultTransformer()
{
  GeometryTransformer geoTrans;
  for (int ich = 0; ich < detparams::NChambers; ++ich) {
    for (int iside = 0; iside < 2; ++iside) {
      bool isRight = (iside == 0);
      for (int irpc = 0; irpc < detparams::NRPCLines; ++irpc) {
        int deId = detparams::getDEId(isRight, ich, irpc);
        ROOT::Math::Transform3D matrix = getDefaultChamberTransform(ich) * getDefaultRPCTransform(isRight, ich, irpc);
        geoTrans.setMatrix(deId, matrix);
      }
    }
  }
  return geoTrans;
}
 
GeometryTransformer createTransformationFromManager(const TGeoManager* geoManager)
{
  GeometryTransformer geoTrans;
  TGeoNavigator* navig = geoManager->GetCurrentNavigator();
  for (int ide = 0; ide < detparams::NDetectionElements; ++ide) {
    int ichamber = detparams::getChamber(ide);
    std::stringstream volPath;
    volPath << geoManager->GetTopVolume()->GetName() << "/";
    if (geoManager->GetVolume("YOUT2")) {
      volPath << "YOUT2_1/";
    }
    volPath << geoparams::getChamberVolumeName(ichamber) << "_1/" << geoparams::getRPCVolumeName(geoparams::getRPCType(ide), ichamber) << "_" << std::to_string(ide);
    if (!navig->cd(volPath.str().c_str())) {
      throw std::runtime_error("Could not get to volPathName=" + volPath.str());
    }
    geoTrans.setMatrix(ide, o2::math_utils::Transform3D{*(navig->GetCurrentMatrix())});
  }
  return geoTrans;
}
 
} // namespace mid
} // namespace o2