NAME    [Toc]    [Back]

       glViewport - set the viewport

SYNOPSIS    [Toc]    [Back]

       void glViewport(
               GLint x,
               GLint y,
               GLsizei width,
               GLsizei height );

PARAMETERS    [Toc]    [Back]

       Specify  the  lower left corner of the viewport rectangle,
       in pixels.  The initial value is (0,0).  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    [Toc]    [Back]

       glViewport()  specifies the affine transformation of x and
       y from normalized device  coordinates  to  window  coordinates.
  Let  (x[n]d,  y[n]d)  be normalized device coordinates.
 Then the window coordinates (x[w], y[w])  are  computed
  as  follows:  x[w] = (x[nd] + 1) width/2 + x y[w] =
       (y[nd] + 1) height/2 + y

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       glGet() with argument GL_VIEWPORT
       glGet() with argument GL_MAX_VIEWPORT_DIMS

SEE ALSO    [Toc]    [Back]

       glDepthRange(3)



                                                   glViewport(3G)