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GLUUNPROJECT()                                                  GLUUNPROJECT()

NAME
       gluUnProject - map window coordinates to object coordinates

C SPECIFICATION
       GLint gluUnProject( GLdouble winX,
                           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
       coordinates 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
       multiplies the normalized device coordinates by the inverse of
       model*proj as follows:

       ((objX objY objZ W)) = INV (P M) ((((2 (winX - view [0]))/(view [2]) -
       1) ((2 (winY - view [1]))/(view [3]) - 1) (2 (winZ) - 1) 1))

       INV () denotes matrix inversion.  W is an unused variable, included for
       consistent matrix notation.

SEE ALSO
       glGet, gluProject

                                                                GLUUNPROJECT()