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GLVIEWPORT(3G)                                                                                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 win-dow window
       dow coordinates.  Let (xnd, ynd) be normalized device coordinates.  Then the window coordinates  (xw,
       yw) are computed as follows:

                                            xw = (xnd+1) (width/2) + x

                                            yw = (ynd+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
       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(3G)




                                                                                              GLVIEWPORT(3G)