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libsst/Lib/Include/CML/mathlib/vector_transform.h
2026-04-03 00:22:39 -05:00

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/* -*- C++ -*- ------------------------------------------------------------
Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
The Configurable Math Library (CML) is distributed under the terms of the
Boost Software License, v1.0 (see cml/LICENSE for details).
*-----------------------------------------------------------------------*/
/** @file
* @brief
*/
#ifndef vector_transform_h
#define vector_transform_h
#include <cml/mathlib/checking.h>
/* Functions for transforming a vector, representing a geometric point or
* or vector, by an affine transfom.
*
* Note: This functionality may be provisional, depending on what architecture
* we settle on for the higher-level math functions. If we do keep these
* functions, then this code may ending up being a placeholder for expression
* template code.
*/
namespace cml {
/** A fixed-size temporary 4D vector */
#define TEMP_VEC4 vector< \
typename et::ScalarPromote< \
typename MatT::value_type, \
typename VecT::value_type \
>::type, \
fixed<4> \
>
/** A fixed-size temporary 3D vector */
#define TEMP_VEC3 vector< \
typename et::ScalarPromote< \
typename MatT::value_type, \
typename VecT::value_type \
>::type, \
fixed<3> \
>
/** A fixed-size temporary 2D vector */
#define TEMP_VEC2 vector< \
typename et::ScalarPromote< \
typename MatT::value_type, \
typename VecT::value_type \
>::type, \
fixed<2> \
>
namespace detail {
template < class MatT, class VecT > TEMP_VEC4
transform_vector_4D(const MatT& m, const VecT& v, row_basis) {
return v*m;
}
template < class MatT, class VecT > TEMP_VEC4
transform_vector_4D(const MatT& m, const VecT& v, col_basis) {
return m*v;
}
} // namespace detail
/** Apply a 4x4 homogeneous transform matrix to a 4D vector */
template < class MatT, class VecT > TEMP_VEC4
transform_vector_4D(const MatT& m, const VecT& v) {
return detail::transform_vector_4D(m,v,typename MatT::basis_orient());
}
/** Apply a homogeneous (e.g. perspective) transform to a 3D point. */
template < class MatT, class VecT > TEMP_VEC3
transform_point_4D(const MatT& m, const VecT& v)
{
typedef TEMP_VEC3 vector_type;
typedef typename TEMP_VEC3::coordinate_type coordinate_type;
/* Checking */
detail::CheckMatHomogeneous3D(m);
detail::CheckVec3(v);
/* Compute the 4D point: */
TEMP_VEC4 v4 = transform_vector_4D(
m, TEMP_VEC4(v[0], v[1], v[2], coordinate_type(1)));
/* Return the projected point: */
coordinate_type w = v4[3];
return vector_type(v4[0]/w, v4[1]/w, v4[2]/w);
}
/** Apply a 3D affine transform to a 3D point */
template < class MatT, class VecT > TEMP_VEC3
transform_point(const MatT& m, const VecT& v)
{
typedef TEMP_VEC3 vector_type;
/* Checking */
detail::CheckMatAffine3D(m);
detail::CheckVec3(v);
return vector_type(
m.basis_element(0,0)*v[0]+m.basis_element(1,0)*v[1]+
m.basis_element(2,0)*v[2]+m.basis_element(3,0),
m.basis_element(0,1)*v[0]+m.basis_element(1,1)*v[1]+
m.basis_element(2,1)*v[2]+m.basis_element(3,1),
m.basis_element(0,2)*v[0]+m.basis_element(1,2)*v[1]+
m.basis_element(2,2)*v[2]+m.basis_element(3,2)
);
}
/** Apply a 3D affine transform to a 3D vector */
template < class MatT, class VecT > TEMP_VEC3
transform_vector(const MatT& m, const VecT& v)
{
typedef TEMP_VEC3 vector_type;
/* Checking */
detail::CheckMatLinear3D(m);
detail::CheckVec3(v);
return vector_type(
m.basis_element(0,0)*v[0]+m.basis_element(1,0)*v[1]+
m.basis_element(2,0)*v[2],
m.basis_element(0,1)*v[0]+m.basis_element(1,1)*v[1]+
m.basis_element(2,1)*v[2],
m.basis_element(0,2)*v[0]+m.basis_element(1,2)*v[1]+
m.basis_element(2,2)*v[2]
);
}
/** Apply a 2D affine transform to a 2D point */
template < class MatT, class VecT > TEMP_VEC2
transform_point_2D(const MatT& m, const VecT& v)
{
typedef TEMP_VEC2 vector_type;
/* Checking */
detail::CheckMatAffine2D(m);
detail::CheckVec2(v);
return vector_type(
m.basis_element(0,0)*v[0]+m.basis_element(1,0)*v[1]+
m.basis_element(2,0),
m.basis_element(0,1)*v[0]+m.basis_element(1,1)*v[1]+
m.basis_element(2,1)
);
}
/** Apply a 2D affine transform to a 2D vector */
template < class MatT, class VecT > TEMP_VEC2
transform_vector_2D(const MatT& m, const VecT& v)
{
typedef TEMP_VEC2 vector_type;
/* Checking */
detail::CheckMatLinear2D(m);
detail::CheckVec2(v);
return vector_type(
m.basis_element(0,0)*v[0] + m.basis_element(1,0)*v[1],
m.basis_element(0,1)*v[0] + m.basis_element(1,1)*v[1]
);
}
#undef TEMP_VEC4
#undef TEMP_VEC3
#undef TEMP_VEC2
} // namespace cml
#endif