Dogcows Code - chaz/yoink/blob - src/cml/mathlib/projection.h

   1 /* -*- C++ -*- ------------------------------------------------------------
   2
   3 Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
   4
   5 The Configurable Math Library (CML) is distributed under the terms of the
   6 Boost Software License, v1.0 (see cml/LICENSE for details).
   7
   8  *-----------------------------------------------------------------------*/
   9 /** @file
  10  *  @brief
  11  */
  12
  13 #ifndef projection_h
  14 #define projection_h
  15
  16 #include <cml/mathlib/matrix_concat.h>
  17 #include <cml/mathlib/vector_transform.h>
  18
  19 /* Functions for projection and 'unprojection' of points in 3D. */
  20
  21 namespace cml {
  22
  23 namespace detail {
  24
  25 template < typename E > void
  26 divide_by_w(vector< E,fixed<4> >& v) {
  27     v *= E(1) / v[3];
  28 }
  29
  30 } // namespace detail
  31
  32 /* Project a point to screen space using the given model, view, projection,
  33  * and viewport matrices. The z value of the returned point is a depth value
  34  * in the range specified by the viewport matrix.
  35  */
  36
  37 template <class MatT_1, class MatT_2, class MatT_3, class MatT_4, class VecT>
  38 vector< typename VecT::value_type, fixed<3> > project_point(
  39     const MatT_1& model,
  40     const MatT_2& view,
  41     const MatT_3& projection,
  42     const MatT_4& viewport,
  43     const VecT& p)
  44 {
  45     return project_point(
  46         detail::matrix_concat_transforms_4x4(model,view),
  47         projection,
  48         viewport,
  49         p
  50     );
  51 }
  52
  53 /* Project a point to screen space using the given modelview, projection, and
  54  * viewport matrices. The z value of the returned point is a depth value in
  55  * the range specified by the viewport matrix.
  56  */
  57
  58 template < class MatT_1, class MatT_2, class MatT_3, class VecT >
  59 vector< typename VecT::value_type, fixed<3> > project_point(
  60     const MatT_1& modelview,
  61     const MatT_2& projection,
  62     const MatT_3& viewport,
  63     const VecT& p)
  64 {
  65     typedef vector< typename VecT::value_type, fixed<3> > vector3_type;
  66     typedef vector< typename VecT::value_type, fixed<4> > vector4_type;
  67     typedef typename vector3_type::value_type value_type;
  68
  69     detail::CheckVec3(p);
  70
  71     vector4_type result = transform_vector_4D(
  72         detail::matrix_concat_transforms_4x4(
  73             modelview,
  74             detail::matrix_concat_transforms_4x4(
  75                 projection,
  76                 viewport
  77             )
  78         ),
  79         vector4_type(p[0],p[1],p[2],value_type(1))
  80     );
  81     detail::divide_by_w(result);
  82     return vector3_type(result[0],result[1],result[2]);
  83 }
  84
  85 /* 'Unproject' a point from screen space using the given model, view,
  86  * projection, and viewport matrices. The z value of the input point is a
  87  * depth value in the range specified by the viewport matrix.
  88  */
  89
  90 template <class MatT_1, class MatT_2, class MatT_3, class MatT_4, class VecT>
  91 vector< typename VecT::value_type, fixed<3> > unproject_point(
  92     const MatT_1& model,
  93     const MatT_2& view,
  94     const MatT_3& projection,
  95     const MatT_4& viewport,
  96     const VecT& p)
  97 {
  98     return unproject_point(
  99         detail::matrix_concat_transforms_4x4(model,view),
 100         projection,
 101         viewport,
 102         p
 103     );
 104 }
 105
 106 /* 'Unproject' a point from screen space using the given modelview,
 107  * projection, and viewport matrices. The z value of the input point is a
 108  * depth value in the range specified by the viewport matrix.
 109  */
 110
 111 template < class MatT_1, class MatT_2, class MatT_3, class VecT >
 112 vector< typename VecT::value_type, fixed<3> > unproject_point(
 113     const MatT_1& modelview,
 114     const MatT_2& projection,
 115     const MatT_3& viewport,
 116     const VecT& p)
 117 {
 118     typedef vector< typename VecT::value_type, fixed<3> > vector3_type;
 119     typedef vector< typename VecT::value_type, fixed<4> > vector4_type;
 120     typedef typename vector3_type::value_type value_type;
 121
 122     detail::CheckVec3(p);
 123
 124     vector4_type result = transform_vector_4D(
 125         inverse(
 126             detail::matrix_concat_transforms_4x4(
 127                 modelview,
 128                 detail::matrix_concat_transforms_4x4(
 129                     projection,
 130                     viewport
 131                 )
 132             )
 133         ),
 134         vector4_type(p[0],p[1],p[2],value_type(1))
 135     );
 136     detail::divide_by_w(result);
 137     return vector3_type(result[0],result[1],result[2]);
 138 }
 139
 140 } // namespace cml
 141
 142 #endif