screenspace(3G)						       screenspace(3G)

NAME    [Toc]    [Back]

     screenspace - map world space to absolute screen coordinates

C SPECIFICATION    [Toc]    [Back]

     void screenspace()

PARAMETERS    [Toc]    [Back]

     none

DESCRIPTION    [Toc]    [Back]

     screenspace sets the projection matrix and	viewport of the	current	window
     so	as to map world	space to absolute screen coordinates (instead of to
     the more usual window-relative screen coordinates).  This provides	a
     convenient	coordinate system for operations that are not constrained to a
     window, e.g. reading pixels.

     screenspace is equivalent to:

	  long xmin, ymin;

	  getorigin(&xmin, &ymin);
	  viewport(-xmin, getgdesc(GD_XPMAX)-xmin,
		   -ymin, getgdesc(GD_YPMAX)-ymin);
	  ortho2(-0.5, getgdesc(GD_XPMAX)+0.5,
		 -0.5, getgdesc(GD_YPMAX)+0.5);

SEE ALSO    [Toc]    [Back]

     fullscrn, getgdesc, getorigin, viewport, ortho2

NOTE    [Toc]    [Back]

     This routine is available only in immediate mode.


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