C SPECIFICATION

       void GLAPIENTRY glViewport( GLint x,
                                   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)(_e_q_n_p_a_r_a_m__)+x

                            yw=(ynd+1)(_e_q_n_p_a_r_a_m__)+GLint

Viewport  width and height are silently clamped to a range that depends on the

       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.





















                                                                GLVIEWPORT(3G)