OverlapCheckerModule.cc

/**************************************************************************
 * BASF2 (Belle Analysis Framework 2)                                     *
 * Copyright(C) 2011 - Belle II Collaboration                             *
 *                                                                        *
 * Author: The Belle II Collaboration                                     *
 * Contributors: Thomas Kuhr                                              *
 *                                                                        *
 * This software is provided "as is" without any warranty.                *
 **************************************************************************/
 
#include <geometry/modules/overlapchecker/OverlapCheckerModule.h>
#include <geometry/GeometryManager.h>
#include <framework/gearbox/Unit.h>
 
#include "G4VPhysicalVolume.hh"
#include "G4LogicalVolume.hh"
#include "G4UnitsTable.hh"
#include "G4VExceptionHandler.hh"
#include "G4StateManager.hh"
#include "G4AffineTransform.hh"
#include "G4VSolid.hh"
 
#include <regex>
#include <utility>
 
using namespace Belle2;
 
REG_MODULE(OverlapChecker);
 
namespace {
  class OverlapHandler: public G4VExceptionHandler {
  public:
    explicit OverlapHandler(std::function<void(const std::string&)> callback): m_callback(std::move(callback)) {}
    bool Notify(const char*, const char*, G4ExceptionSeverity, const char* description) override
    {
      m_callback(description);
      return false;
    }
  private:
    std::function<void(const std::string&)> m_callback;
  };
}
 
OverlapCheckerModule::OverlapCheckerModule()
{
  //Set module properties and the description
  setDescription("Checks the geometry for overlaps.");
 
  //Parameter definition
  addParam("points", m_points, R"DOC(
Number of test points we will generate on randomly on the surface of each geometry volume and then check for all of them that
             
1. The points are inside the mother volume
2. The points are not inside any neighbor volume
                     
The higher the number the more precise the check for overlaps becomes, and the slower it gets.
See also https://questions.belle2.org/question/7264/ )DOC",
           m_points);
  addParam("tolerance", m_tolerance, "Tolerance of overlap check.", m_tolerance);
  addParam("maxErrors", m_maxErrors, "Number of overlap errors per volume before continuing with next volume", m_maxErrors);
  addParam("maxDepth", m_maxDepth, "Maximum depth to go into the geometry tree, 0 means no maximum", m_maxDepth);
  addParam("prefix", m_prefix, "Prefix path, only volumes starting with the given path are checked", m_prefix);
}
 
void OverlapCheckerModule::initialize()
{
  m_displayData.registerInDataStore();
  if (m_maxErrors <= 0) m_maxErrors = m_points + 1;
}
 
void OverlapCheckerModule::event()
{
  if (!m_displayData.isValid()) m_displayData.create();
  //Check the geometry tree for overlaps
  G4UnitDefinition::BuildUnitsTable();
  G4VPhysicalVolume* volume = geometry::GeometryManager::getInstance().getTopVolume();
  if (!volume) {
    B2ERROR("No geometry found. => Add the Geometry module to the path before the OverlapChecker module.");
    return;
  }
  m_seen.clear();
  // reset the navigation history to be in the top level volume
  m_nav.Reset();
  // remember the existing G4Exception handler and set our own one to find the position of the intersection
  G4VExceptionHandler* old = G4StateManager::GetStateManager()->GetExceptionHandler();
  // set our own exception handler
  OverlapHandler handler([&](const std::string & message) { handleOverlap(message); });
  G4StateManager::GetStateManager()->SetExceptionHandler(&handler);
  // now check for overlaps
  checkVolume(volume, "");
  // and reset the exception handler
  G4StateManager::GetStateManager()->SetExceptionHandler(old);
 
  //Print the list of found overlaps
  for (const auto& m_overlap : m_overlaps) {
    B2ERROR("Overlaps detected for " << m_overlap);
  }
}
 
void OverlapCheckerModule::handleOverlap(const std::string& geant4Message)
{
  // ok, let's handle the Overlap message
  G4VPhysicalVolume* volume = m_nav.GetTopVolume();
  m_nav.BackLevel();
  B2ERROR(geant4Message);
  std::regex r(R"((mother)?\s*local point \(([-+0-9eE.]+),([-+0-9eE.]+),([-+0-9eE.]+)\))");
  std::smatch m;
  if (std::regex_search(geant4Message, m, r)) {
    G4ThreeVector posLocal(std::atof(m[2].str().c_str()), std::atof(m[3].str().c_str()), std::atof(m[4].str().c_str()));
    if (m[1].length() == 0) {
      // Damn you Geant4, giving me the coordinates in the coordinate system of
      // the sister volume which I don't know exactly is almost useless. Aaah
      // darn it, let's check all sisters, see if they have the correct name
      // and if so check if the point transformed to the mother system is
      // inside the one were checking. So let's remember the transformation
      // relative to the top volume of our current volume.
      G4AffineTransform trans_volume(volume->GetRotation(), volume->GetTranslation());
      trans_volume.Invert();
      // And the solid
      G4VSolid* solid = volume->GetLogicalVolume()->GetSolid();
      // Now look for the name of the intersecting volume in the exception message (jaaaay)
      std::regex nameRegex("with (.*) volume's");
      std::smatch nameMatch;
      // And if we can find the name we can draw the intersection
      if (std::regex_search(geant4Message, nameMatch, nameRegex)) {
        const std::string& name = nameMatch[1].str();
        // By looping over all sisters
        for (int i = 0; i < volume->GetMotherLogical()->GetNoDaughters(); ++i) {
          G4VPhysicalVolume* sister = volume->GetMotherLogical()->GetDaughter(i);
          // ignoring the ones which don't match the name
          if (name != sister->GetName()) continue;
          // now transform the point into the coordinate system of the volume we actually look at
          G4AffineTransform trans_sister(sister->GetRotation(), sister->GetTranslation());
          G4ThreeVector posMother = trans_sister.TransformPoint(posLocal);
          G4ThreeVector posSister = trans_volume.TransformPoint(posMother);
          // and check if the point is inside our volume
          if (solid->Inside(posSister) != kOutside) {
            // if so this is the right volume which is intersecting.
            B2INFO("Found intersecting volume " << sister->GetName() << "." << sister->GetCopyNo());
            // so add the point to the display data
            G4AffineTransform t = m_nav.GetTopTransform().Inverse();
            G4ThreeVector global = t.TransformPoint(posMother);
            m_displayData->addPoint(geant4Message, TVector3(global[0], global[1], global[2]) * Unit::mm);
          }
        }
      } else {
        B2ERROR("Could not find name of intersecting volume");
      }
    } else {
      // in case of overlap with mother the life is so much simpler: just convert the point to global and save it.
      G4AffineTransform t = m_nav.GetTopTransform().Inverse();
      G4ThreeVector global = t.TransformPoint(posLocal);
      m_displayData->addPoint(geant4Message, TVector3(global[0], global[1], global[2]) * Unit::mm);
    }
  }
  m_nav.NewLevel(volume);
}
 
bool OverlapCheckerModule::checkVolume(G4VPhysicalVolume* volume, const std::string& path, int depth)
{
  // check if we exceeded maximum recursion depth
  if (m_maxDepth > 0 && depth >= m_maxDepth) return false;
  // add the volume to the navigation history
  m_nav.NewLevel(volume);
  // remember the path to the volume
  std::string volumePath = path + "/" + volume->GetName();
  bool result{false};
  // check if we have a prefix we have to match. if not prefix or prefix matches, check for overlaps
  if (m_prefix.empty() || volumePath.substr(0, m_prefix.size()) == m_prefix) {
    result = volume->CheckOverlaps(m_points, m_tolerance, true, m_maxErrors);
    if (result) {
      m_overlaps.push_back(volumePath);
    }
  }
 
  //Check the daughter volumes for overlaps
  G4LogicalVolume* logicalVolume = volume->GetLogicalVolume();
  for (int iDaughter = 0; iDaughter < logicalVolume->GetNoDaughters(); iDaughter++) {
    G4VPhysicalVolume* daughter = logicalVolume->GetDaughter(iDaughter);
    // check if we already checked this particular volume, if so skip it
    auto it = m_seen.insert(daughter);
    if (!it.second) continue;
    result |= checkVolume(daughter, volumePath, depth + 1);
  }
  m_nav.BackLevel();
  return result;
}