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 pix-
	    els. 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 normal-
       ized 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   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)