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libsst/Lib/Include/CML/mathlib/projection.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 projection_h
#define projection_h
#include <cml/mathlib/matrix_concat.h>
#include <cml/mathlib/vector_transform.h>
/* Functions for projection and 'unprojection' of points in 3D. */
namespace cml {
namespace detail {
template < typename E > void
divide_by_w(vector< E,fixed<4> >& v) {
v *= E(1) / v[3];
}
} // namespace detail
/* Project a point to screen space using the given model, view, projection,
* and viewport matrices. The z value of the returned point is a depth value
* in the range specified by the viewport matrix.
*/
template <class MatT_1, class MatT_2, class MatT_3, class MatT_4, class VecT>
vector< typename VecT::value_type, fixed<3> > project_point(
const MatT_1& model,
const MatT_2& view,
const MatT_3& projection,
const MatT_4& viewport,
const VecT& p)
{
return project_point(
detail::matrix_concat_transforms_4x4(model,view),
projection,
viewport,
p
);
}
/* Project a point to screen space using the given modelview, projection, and
* viewport matrices. The z value of the returned point is a depth value in
* the range specified by the viewport matrix.
*/
template < class MatT_1, class MatT_2, class MatT_3, class VecT >
vector< typename VecT::value_type, fixed<3> > project_point(
const MatT_1& modelview,
const MatT_2& projection,
const MatT_3& viewport,
const VecT& p)
{
typedef vector< typename VecT::value_type, fixed<3> > vector3_type;
typedef vector< typename VecT::value_type, fixed<4> > vector4_type;
typedef typename vector3_type::value_type value_type;
detail::CheckVec3(p);
vector4_type result = transform_vector_4D(
detail::matrix_concat_transforms_4x4(
modelview,
detail::matrix_concat_transforms_4x4(
projection,
viewport
)
),
vector4_type(p[0],p[1],p[2],value_type(1))
);
detail::divide_by_w(result);
return vector3_type(result[0],result[1],result[2]);
}
/* 'Unproject' a point from screen space using the given model, view,
* projection, and viewport matrices. The z value of the input point is a
* depth value in the range specified by the viewport matrix.
*/
template <class MatT_1, class MatT_2, class MatT_3, class MatT_4, class VecT>
vector< typename VecT::value_type, fixed<3> > unproject_point(
const MatT_1& model,
const MatT_2& view,
const MatT_3& projection,
const MatT_4& viewport,
const VecT& p)
{
return unproject_point(
detail::matrix_concat_transforms_4x4(model,view),
projection,
viewport,
p
);
}
/* 'Unproject' a point from screen space using the given modelview,
* projection, and viewport matrices. The z value of the input point is a
* depth value in the range specified by the viewport matrix.
*/
template < class MatT_1, class MatT_2, class MatT_3, class VecT >
vector< typename VecT::value_type, fixed<3> > unproject_point(
const MatT_1& modelview,
const MatT_2& projection,
const MatT_3& viewport,
const VecT& p)
{
typedef vector< typename VecT::value_type, fixed<3> > vector3_type;
typedef vector< typename VecT::value_type, fixed<4> > vector4_type;
typedef typename vector3_type::value_type value_type;
detail::CheckVec3(p);
vector4_type result = transform_vector_4D(
inverse(
detail::matrix_concat_transforms_4x4(
modelview,
detail::matrix_concat_transforms_4x4(
projection,
viewport
)
)
),
vector4_type(p[0],p[1],p[2],value_type(1))
);
detail::divide_by_w(result);
return vector3_type(result[0],result[1],result[2]);
}
} // namespace cml
#endif