fglViewport(3G)

NAME
     fglViewport - set the viewport


FORTRAN SPECIFICATION
     SUBROUTINE fglViewport( INTEGER*4 x,
                             INTEGER*4 y,
                             INTEGER*4 width,
                             INTEGER*4 height )


PARAMETERS
     x, y Specify the lower left corner of the viewport rectangle, in pixels.
          The default is (0,0).

     width, height
          Specify the width and height, respectively, of the viewport.  When a
          GL context is first attached to a window, width and height are set
          to the dimensions of that window.

DESCRIPTION
     fglViewport specifies the affine transformation of x and y from
     normalized device coordinates to window coordinates.  Let (x  , y  ) be
                                                                 nd   nd
     normalized device coordinates.  Then the window coordinates (x , y ) are
                                                                   w   w
     computed as follows:

                           x  = (x  +1)*(width / 2) + x
                            w     nd

                           y  = (y  +1)*(height / 2) + y
                            w     nd

     Viewport width and height are silently clamped to a range that depends on
     the implementation.  This range is queried by calling fglGet with
     argument GL_MAX_VIEWPORT_DIMS.

ERRORS
     GL_INVALID_VALUE is generated if either width or height is negative.

     GL_INVALID_OPERATION is generated if fglViewport is executed between the
     execution of fglBegin and the corresponding execution of fglEnd.

ASSOCIATED GETS
     fglGet with argument GL_VIEWPORT
     fglGet with argument GL_MAX_VIEWPORT_DIMS


SEE ALSO
     fglDepthRange