RodPlaneBuilderFromDet.cc

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#include "TrackingTools/DetLayers/interface/RodPlaneBuilderFromDet.h"
#include "DataFormats/GeometrySurface/interface/RectangularPlaneBounds.h"
#include "DataFormats/GeometrySurface/interface/BoundingBox.h"

#include <algorithm>

using namespace std;

// Warning, remember to assign this pointer to a ReferenceCountingPointer!
Plane* RodPlaneBuilderFromDet::operator()(const vector<const Det*>& dets) const {
  // find mean position
  typedef Surface::PositionType::BasicVectorType Vector;
  Vector posSum(0, 0, 0);
  for (vector<const Det*>::const_iterator i = dets.begin(); i != dets.end(); i++) {
    posSum += (**i).surface().position().basicVector();
  }
  Surface::PositionType meanPos(posSum / float(dets.size()));

  // temporary plane - for the computation of bounds
  Surface::RotationType rotation = computeRotation(dets, meanPos);
  Plane tmpPlane(meanPos, rotation);
  auto bo = computeBounds(dets, tmpPlane);

  //   LogDebug("DetLayers") << "Creating plane at position " << meanPos
  //        << " displaced by " << bo.second ;
  //   LogDebug("DetLayers") << "Bounds are (wid/len/thick) " << bo.first.width()
  //        << " / " <<  bo.first.length()
  //        << " / " <<  bo.first.thickness() ;

  return new Plane(meanPos + bo.second, rotation, bo.first);
}

pair<RectangularPlaneBounds*, GlobalVector> RodPlaneBuilderFromDet::computeBounds(const vector<const Det*>& dets,
                                                                                  const Plane& plane) const {
  // go over all corners and compute maximum deviations from mean pos.
  vector<GlobalPoint> corners;
  for (vector<const Det*>::const_iterator idet = dets.begin(); idet != dets.end(); idet++) {
    /* ---- original implementation. Is it obsolete?
    vector<const DetUnit*> detUnits = (**idet).basicComponents();
    for (vector<const DetUnit*>::const_iterator detu=detUnits.begin();
     detu!=detUnits.end(); detu++) {
      vector<GlobalPoint> dc = 
    BoundingBox().corners((**detu).specificSurface());
      corners.insert( corners.end(), dc.begin(), dc.end());
    }
    ---- */

    // temporary implementation (May be the final one if the GluedDet surface
    // really contains both the mono and the stereo surfaces
    vector<GlobalPoint> dc = BoundingBox().corners((**idet).specificSurface());
    corners.insert(corners.end(), dc.begin(), dc.end());
  }

  float xmin(0), xmax(0), ymin(0), ymax(0), zmin(0), zmax(0);
  for (vector<GlobalPoint>::const_iterator i = corners.begin(); i != corners.end(); i++) {
    LocalPoint p = plane.toLocal(*i);
    if (p.x() < xmin)
      xmin = p.x();
    if (p.x() > xmax)
      xmax = p.x();
    if (p.y() < ymin)
      ymin = p.y();
    if (p.y() > ymax)
      ymax = p.y();
    if (p.z() < zmin)
      zmin = p.z();
    if (p.z() > zmax)
      zmax = p.z();
  }

  LocalVector localOffset((xmin + xmax) / 2., (ymin + ymax) / 2., (zmin + zmax) / 2.);
  GlobalVector offset(plane.toGlobal(localOffset));

  pair<RectangularPlaneBounds*, GlobalVector> result(
      new RectangularPlaneBounds((xmax - xmin) / 2, (ymax - ymin) / 2, (zmax - zmin) / 2), offset);

  return result;
}

Surface::RotationType RodPlaneBuilderFromDet::computeRotation(const vector<const Det*>& dets,
                                                              const Surface::PositionType& meanPos) const {
  // choose first mono out-pointing rotation
  // the rotations of GluedDets coincide with the mono part
  // Simply take the x,y of the first Det if z points out,
  // or -x, y if it doesn't
  const Plane& plane = dynamic_cast<const Plane&>(dets.front()->surface());
  //GlobalVector n = plane.normalVector();

  GlobalVector xAxis;
  GlobalVector yAxis;
  GlobalVector planeYAxis = plane.toGlobal(LocalVector(0, 1, 0));
  if (planeYAxis.z() < 0)
    yAxis = -planeYAxis;
  else
    yAxis = planeYAxis;

  GlobalVector planeXAxis = plane.toGlobal(LocalVector(1, 0, 0));
  GlobalVector n = planeXAxis.cross(planeYAxis);

  if (n.x() * meanPos.x() + n.y() * meanPos.y() > 0) {
    xAxis = planeXAxis;
  } else {
    xAxis = -planeXAxis;
  }

  //   LogDebug("DetLayers") << "Creating rotation with x,y axis "
  //        << xAxis << ", " << yAxis ;

  return Surface::RotationType(xAxis, yAxis);
}