Acts/Surfaces/SurfacePlacementBase.hpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 CERN for the benefit of the ACTS project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
0008
0009 #pragma once
0010
0011 #include "Acts/Definitions/Algebra.hpp"
0012 #include "Acts/Geometry/GeometryContext.hpp"
0013
0014 namespace Acts {
0015 class Surface;
0016 /// @brief The `SurfacePlacementBase` is an API proxy to model the dynamic
0017 ///        movement of the `Acts::Surface` representing e.g. the experiment's
0018 ///        sensor planes.
0019 ///
0020 ///        If the user wants to let the sensor surface float, he has to
0021 ///        implement an experiment-specifc class inheriting from
0022 ///        SurfacePlacementBase and to instantiate the surface with such an
0023 ///        instance.
0024 ///
0025 ///        In every call for the Surface's current position the GeometryContext
0026 ///        which is also contextualized by the experiment is piped through the
0027 ///        entire call stack until its piped back to the experiment specific
0028 ///        implementation via the call of the
0029 ///        `SurfacePlacementBase::localToGlobalTransform`. There the user needs
0030 ///        to unpack the GeometryContext, look-up the appropriate cached
0031 ///        transform and return it back to the Acts library
0032 class SurfacePlacementBase {
0033  public:
0034   /// @brief Virtual default constructor
0035   virtual ~SurfacePlacementBase() = default;
0036
0037   /// @brief Return the transform for the Element proxy mechanism
0038   ///
0039   /// @param gctx The current geometry context object, e.g. alignment
0040   /// @return reference to the transform to switch from the element's
0041   ///         coordinates to the experiment's global coordinate system
0042   virtual const Transform3& localToGlobalTransform(
0043       const GeometryContext& gctx) const = 0;
0044
0045   /// @brief Get a reference to the surface that is associated
0046   ///        with this placement element.
0047   /// @note It is expected that the surface returned will have it's @ref
0048   ///       Acts::Surface::surfacePlacement method return a pointer to
0049   ///       this object.
0050   /// @return Reference to a surface that represents this detector element
0051   virtual const Surface& surface() const = 0;
0052
0053   /// @copydoc surface
0054   /// @return Reference to a surface that represents this detector element
0055   virtual Surface& surface() = 0;
0056
0057   /// @brief Returns whether the placement corresponds to a surface on which
0058   ///        the measurements from the experiment are represented, i.e. it is
0059   //         a detector surface
0060   /// @return True if this is a sensitive surface
0061   virtual bool isSensitive() const = 0;
0062 };
0063 }  // namespace Acts