GLint GLint )

PARAMETERS
       x, GLint Specify  the  lower  left  corner of the viewport rectangle, in
                pixels. The initial value is (0,0).

       _param3, _param4
                Specify the width and height of the viewport.  When a  GL  con‐
                text is first attached to a window, _param3 and _param4 are set
                to the dimensions of that window.

DESCRIPTION
       glViewport specifies the affine transformation of x and y  from  normal‐
       ized  device  coordinates to window coordinates.  Let (xnd, ynd) be nor‐
       malized device coordinates.  Then the window coordinates  (xw,  yw)  are
       computed as follows:

                               xw=(xnd+1)⎝__________⎠+x

                             yw=(ynd+1)⎝__________⎠+GLint

       Viewport  width  and height are silently clamped to a range that depends
       on the implementation.  To query this range, call  glGet  with  argument
       GL_MAX_VIEWPORT_DIMS.

ERRORS
       GL_INVALID_VALUE is generated if either _param3 or _param4 is negative.

       GL_INVALID_OPERATION  is generated if glViewport is executed between the
       execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS
       glGet with argument GL_VIEWPORT
       glGet with argument GL_MAX_VIEWPORT_DIMS

SEE ALSO
       glDepthRange

                                                                 GLVIEWPORT(3G)