EveVisBField.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
#include <framework/geometry/BFieldManager.h>
 
#include <TEveTrackPropagator.h>
 
namespace Belle2 {
  class EveVisBField : public TEveMagField {
  public:
    EveVisBField(): TEveMagField() { }
    virtual ~EveVisBField() { }
 
    virtual TEveVector GetField(Float_t x, Float_t y, Float_t z) const override
    {
      TEveVector v;
      ROOT::Math::XYZVector bfield = BFieldManager::getField(x, y, z) / Unit::T;
      v.Set(bfield.X(), bfield.Y(), bfield.Z());
      v.fZ *= -1; //Eve has inverted B field convention
      v.fZ -= 1e-6; //field must not be zero!
 
      return v;
    }
    virtual Float_t GetMaxFieldMag() const override { return 1.5; }
  };
}