_C_ License Applicability. Except to the extent portions of this file are
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_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
_C_ this file except in compliance with the License. You may obtain a copy
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_C_ 
_C_ http://oss.sgi.com/projects/FreeB
_C_ 
_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.
_C_ 
_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_ 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(Scissor, define the scissor box)
_names(Scissor)
.SH PARAMETERS
_phead(_param1 _param2) 
Specify the lower left corner of the scissor box.
Initially (0, 0).
_phead(_param3 _param4)
Specify the width and height of the scissor box.
When a GL context is first attached to a window,
_param3 and _param4 are set to the dimensions of that window.
.SH DESCRIPTION
_cmnd defines a rectangle, called the scissor box,
in window coordinates.
The first two arguments,
_param1 and _param2,
specify the lower left corner of the box.
_param3 and _param4 specify the width and height of the box. 
.P
To enable and disable the scissor test, call
_cmnd(Enable) and _cmnd(Disable) with argument
_const(SCISSOR_TEST). The test is initially disabled. 
While the test is enabled, only pixels that lie within the scissor box
can be modified by drawing commands.
Window coordinates have integer values at the shared corners of
frame buffer pixels.
\f7glScissor(0,0,1,1)\fP allows modification of only the lower left
pixel in the window, and \f7glScissor(0,0,0,0)\fP doesn't allow
modification of any pixels in the window.  
.P
When the scissor test is disabled,
it is as though the scissor box includes the entire window.
.SH ERRORS
_const(INVALID_VALUE) is generated if either _param3 or _param4 is negative.
.P
_const(INVALID_OPERATION) is generated if _cmnd
is executed between the execution of _cmnd(Begin)
and the corresponding execution of _cmnd(End).
.bp
.SH ASSOCIATED GETS
_cmnd(Get) with argument _const(SCISSOR_BOX)
.br
_cmnd(IsEnabled) with argument _const(SCISSOR_TEST)
.SH SEE ALSO
_cmnd(Enable),
_cmnd(Viewport)
