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man gluLookAt(3)
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gluLookAt(3)                                                    gluLookAt(3)


       gluLookAt - define a viewing transformation


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


       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.


       gluLookAt  creates a viewing matrix derived from an eye point, a refer-
       ence 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.  Sim-
       ilarly,  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.


            centerX - eyeX
        F = centerY - eyeY
            centerZ - 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:

             s[0]    s[1]    s[2]    0
             u[0]    u[1]    u[2]    0
        M = -f[0]   -f[1]   -f[2]    0
              0       0       0      1

       and gluLookAt is equivalent to


       glTranslated (-eyeX, -eyeY, -eyeZ);


       glFrustum, gluPerspective


Mac OS X 10.8 - Generated Sat Aug 25 18:27:18 CDT 2012
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