redhat man page for glviewport

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 dimen-
	    sions of that window.

DESCRIPTION
       glViewport specifies the affine transformation of x and y from normalized 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)(_____)+x

								  yw=(ynd+1)(______)+y

       Viewport  width	and height are silently clamped to a range that depends on the implementation.	To query this range, call glGet with argu-
       ment 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)