GLdouble winY,
                                      GLdouble winZ,
                                      const GLdouble *model,
                                      const GLdouble *proj,
                                      const GLint *view,
                                      GLdouble* objX,
                                      GLdouble* objY,
                                      GLdouble* objZ )

PARAMETERS
       winX, winY, winZ
                       Specify the window coordinates to be mapped.

       model           Specifies  the  modelview matrix (as from a glGetDoublev
                       call).

       proj            Specifies the projection matrix (as from a  glGetDoublev
                       call).

       view            Specifies the viewport (as from a glGetIntegerv call).

       objX, objY, objZ
                       Returns the computed object coordinates.

DESCRIPTION
       gluUnProject  maps  the specified window coordinates into object coordi‐
       nates using model, proj, and view.  The result is stored in objX,  objY,
       and objZ. A return value of GL_TRUE indicates success; a return value of
       GL_FALSE indicates failure.

       To compute the coordinates (objX, objY, and objZ),  gluUnProject  multi‐
       plies  the normalized device coordinates by the inverse of model*proj as
       follows:

                           objX
                          ⎝objY⎠=INV(PM)⎝_______________−1⎠
                           objZ          _______________−1
                            W                2(winZ)−1
                                                 1
       INV() denotes matrix inversion.  W is an unused variable,  included  for
       consistent matrix notation.

SEE ALSO
       glGet, gluProject

                                                               GLUUNPROJECT(3G)