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GLULOOKAT()                                                        GLULOOKAT()

NAME
       gluLookAt - define a viewing transformation

C SPECIFICATION
       void gluLookAt( GLdouble eyeX,
                       GLdouble eyeY,
                       GLdouble eyeZ,
                       GLdouble centerX,
                       GLdouble centerY,
                       GLdouble centerZ,
                       GLdouble upX,
                       GLdouble upY,
                       GLdouble upZ )

PARAMETERS
       eyeX, eyeY, eyeZ
                       Specifies the position of the eye point.

       centerX, centerY, centerZ
                       Specifies the position of the reference point.

       upX, upY, upZ   Specifies the direction of the up vector.

DESCRIPTION
       gluLookAt creates a viewing matrix derived from an eye point, a
       reference point indicating the center of the scene, and an UP vector.

       The matrix maps the reference point to the negative z axis and the eye
       point to the origin.  When a typical projection matrix is used, the
       center of the scene therefore maps to the center of the viewport.
       Similarly, the direction described by the UP vector projected onto the
       viewing plane is mapped to the positive y axis so that it points upward
       in the viewport.  The UP vector must not be parallel to the line of
       sight from the eye point to the reference point.

       Let

       F = (((centerX centerY centerZ) (---) (eyeX eyeY eyeZ)))

       Let UP be the vector (upX, upY, upZ).

       Then normalize as follows: f = F/(|| F ||)

       UP^' = UP/(|| UP ||)

       Finally, let s = f x UP^', and u = s x f.

       M is then constructed as follows: M = (((s [0])(u [0])(-f [0]) 0) ((s
       [1])(u [1])(-f [1]) 0) ((s [2])(u [2])(-f [2]) 0) (0 0 0 1))

       and gluLookAt is equivalent to glMultMatrixf(M); glTranslated (-eyex,
       -eyey, -eyez);

SEE ALSO
       glFrustum, gluPerspective

                                                                   GLULOOKAT()