glViewport(3G)

NAME
     glViewport - set the viewport


C SPECIFICATION
     void glViewport( GLint x,
                      GLint y,
                      GLsizei width,
                      GLsizei height )


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

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

                                           (_____)
                             x  = (x   + 1)        + x
                              w     nd     (  2  )

                                          (______)
                            y  = (y   + 1)         + y
                             w     nd     (  2   )

     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 width or height 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