_C_ License Applicability. Except to the extent portions of this file are
_C_ made subject to an alternative license as permitted in the SGI Free
_C_ Software License B, Version 1.1 (the "License"), the contents of this
_C_ file are subject only to the provisions of the License. You may not use
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_C_ http://oss.sgi.com/projects/FreeB
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_C_ Note that, as provided in the License, the Software is distributed on an
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_C_ 
_C_ Original Code. The Original Code is: OpenGL Sample Implementation,
_C_ Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
_C_ Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
_C_ Copyright in any portions created by third parties is as indicated
_C_ elsewhere herein. All Rights Reserved.
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_C_ Additional Notice Provisions: The application programming interfaces
_C_ established by SGI in conjunction with the Original Code are The
_C_ OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
_C_ April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
_C_ 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
_C_ Window System(R) (Version 1.3), released October 19, 1998. This software
_C_ was created using the OpenGL(R) version 1.2.1 Sample Implementation
_C_ published by SGI, but has not been independently verified as being
_C_ compliant with the OpenGL(R) version 1.2.1 Specification.
_C_
_C_ $Date: 2004/12/14 16:20:37 $ $Revision: 1.1.1.1 $
_C_ The first character in this file must be an '_'!
_C_ Anything on a line after _C_ is ignored
_define(_filters,eqn)_C_
_C_      eqn is automatically replaced with neqn for nroff
_header(Ortho2D, define a 2D orthographic projection matrix)
_names(Ortho2D)
.EQ
delim $$
.EN
.SH PARAMETERS
_phead(_param1 _param2)
Specify the coordinates for the left and right vertical clipping planes.
_phead(_param3 _param4)
Specify the coordinates for the bottom and top horizontal clipping planes.
.SH DESCRIPTION
_cmnd sets up a two-dimensional orthographic viewing region.  
This is equivalent to calling _glcmnd(Ortho) with $ near ~=~ -1 $ and 
$ far ~=~ 1 $.
.SH SEE ALSO
_glcmnd(Ortho), _cmnd(Perspective)

