/data/refman/pasoursint/CMSSW_5_3_0/src/DataFormats/GeometryCommonDetAlgo/src/PerpendicularBoundPlaneBuilder.cc

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//#include "Utilities/Configuration/interface/Architecture.h"

#include "DataFormats/GeometryCommonDetAlgo/interface/PerpendicularBoundPlaneBuilder.h"

BoundPlane* 
PerpendicularBoundPlaneBuilder::operator()( const Surface::GlobalPoint& origin,
                                            const Surface::GlobalVector& perp) const
{
  // z axis coincides with perp
  GlobalVector zAxis = perp.unit();

  // x axis has no global Z component
  GlobalVector xAxis;
  if ( zAxis.x() != 0 || zAxis.y() != 0) {
    // precision is not an issue here, just protect against divizion by zero
    xAxis = GlobalVector( -zAxis.y(), zAxis.x(), 0).unit();
  }
  else { // perp coincides with global Z
    xAxis = GlobalVector( 1, 0, 0);
  }

  // y axis obtained by cross product
  GlobalVector yAxis( zAxis.cross( xAxis));

  Surface::RotationType rot( xAxis.x(), xAxis.y(), xAxis.z(),
                             yAxis.x(), yAxis.y(), yAxis.z(),
                             zAxis.x(), zAxis.y(), zAxis.z());

  return new BoundPlane( origin, rot);
}