transform/detail/TransformTransformer.hh

0001 //------------------------------- -*- C++ -*- -------------------------------//
0002 // Copyright Celeritas contributors: see top-level COPYRIGHT file for details
0003 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0004 //---------------------------------------------------------------------------//
0005 //! \file orange/transform/detail/TransformTransformer.hh
0006 //---------------------------------------------------------------------------//
0007 #pragma once
0008
0009 #include "geocel/Types.hh"
0010 #include "orange/MatrixUtils.hh"
0011
0012 #include "../NoTransformation.hh"
0013 #include "../Transformation.hh"
0014 #include "../Translation.hh"
0015
0016 namespace celeritas
0017 {
0018 namespace detail
0019 {
0020 //---------------------------------------------------------------------------//
0021 /*!
0022  * Apply a transformation to another transformation.
0023  *
0024  * An instance of this class applies a daughter-to-parent translation to
0025  * another transformation: the translation needed to relocate a "lower"
0026  * universe to a new coordinate system in the "higher" universe.
0027  *
0028  * Given a transform operator \b T defined \f[
0029    \mathbf{T}x = \mathbf{R} x + t
0030  * \f]
0031  * this operation returns a new transform
0032  * \f[
0033    \mathbf{T}' = \mathbf{T}_A \mathbf{T}_B
0034  * \f]
0035  * where \f$\mathbf{T}_A\f$ is the constructor argument
0036  * (the operator itself), \f$\mathbf{T}_b\f$ is the argument passed to the call
0037  * operator, and the \f$\mathbf{T}'\f$ is the return value.
0038  * The new transform has rotation
0039  * \f[
0040    \mathbf{R}' = \mathbf{R}_A\mathbf{R}_B
0041  * \f]
0042  * and translation
0043  * \f[
0044    \mathbf{t}' = \mathbf{R}_A\mathbf{t}_B + \mathbf{t}_A
0045  * \f]
0046  */
0047 class TransformTransformer
0048 {
0049   public:
0050     //@{
0051     //! \name Type aliases
0052     using Mat3 = SquareMatrix<real_type, 3>;
0053     //@}
0054
0055   public:
0056     //! Construct with the new reference frame of the transformation
0057     explicit TransformTransformer(Transformation const& tr) : tr_{tr} {}
0058
0059     //! Transform an identity
0060     Transformation const& operator()(NoTransformation const&) const
0061     {
0062         return tr_;
0063     }
0064
0065     //!@{
0066     //! Transform a transformation
0067     inline Transformation operator()(Mat3 const&) const;
0068     inline Transformation operator()(Transformation const&) const;
0069     inline Transformation operator()(Translation const&) const;
0070     //!@}
0071
0072   private:
0073     Transformation tr_;
0074 };
0075
0076 //---------------------------------------------------------------------------//
0077 /*!
0078  * Apply a transformation to a rotation matrix.
0079  */
0080 Transformation TransformTransformer::operator()(Mat3 const& other) const
0081 {
0082     return Transformation{gemm(tr_.rotation(), other), tr_.translation()};
0083 }
0084
0085 //---------------------------------------------------------------------------//
0086 /*!
0087  * Apply a transformation to a transform.
0088  */
0089 Transformation
0090 TransformTransformer::operator()(Transformation const& other) const
0091 {
0092     return Transformation{gemm(tr_.rotation(), other.rotation()),
0093                           tr_.transform_up(other.translation())};
0094 }
0095
0096 //---------------------------------------------------------------------------//
0097 /*!
0098  * Apply a transformation to a translation.
0099  */
0100 Transformation TransformTransformer::operator()(Translation const& other) const
0101 {
0102     return Transformation{tr_.rotation(),
0103                           tr_.transform_up(other.translation())};
0104 }
0105
0106 //---------------------------------------------------------------------------//
0107 }  // namespace detail
0108 }  // namespace celeritas