_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
_C_ this file except in compliance with the License. You may obtain a copy
_C_ of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
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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
_C_ "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
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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(PolygonMode,select a polygon rasterization mode)
_names(PolygonMode)
.SH PARAMETERS
_phead(_param1)
Specifies the polygons that _param2 applies to.
Must be
_const(FRONT) for front-facing polygons,
_const(BACK) for back-facing polygons,
or _const(FRONT_AND_BACK) for front- and back-facing polygons.
_phead(_param2)
Specifies how polygons will be rasterized.
Accepted values are
_const(POINT),
_const(LINE), and
_const(FILL).
The initial value is _const(FILL) for both front- and back-facing polygons.
.SH DESCRIPTION
_cmnd controls the interpretation of polygons for rasterization.
_param1 describes which polygons _param2 applies to:
front-facing polygons (_const(FRONT)),
back-facing polygons (_const(BACK)),
or both (_const(FRONT_AND_BACK)).
The polygon mode affects only the final rasterization of polygons.
In particular,
a polygon's vertices are lit and
the polygon is clipped and possibly culled before these modes are applied.
.P
Three modes are defined and can be specified in _param2:
.TP 14
_const(POINT)
Polygon vertices that are marked as the start of a boundary edge
are drawn as points.
Point attributes such as
_const(POINT_SIZE) and
_const(POINT_SMOOTH) control
the rasterization of the points.
Polygon rasterization attributes other than _const(POLYGON_MODE) have no effect.
.TP
_const(LINE)
Boundary edges of the polygon are drawn as line segments.
They are treated as connected line segments for line stippling;
the line stipple counter and pattern are not reset between segments
(see _cmnd(LineStipple)).
Line attributes such as
_const(LINE_WIDTH) and
_const(LINE_SMOOTH) control
the rasterization of the lines.
Polygon rasterization attributes other than _const(POLYGON_MODE) have no effect.
.TP
_const(FILL)
The interior of the polygon is filled.
Polygon attributes such as
_const(POLYGON_STIPPLE) and
_const(POLYGON_SMOOTH) control the rasterization of the polygon.
.SH EXAMPLES
To draw a surface with filled back-facing polygons
and outlined front-facing polygons,
call
.Ex 1
glPolygonMode(_const(FRONT), _const(LINE));
.Ee
.SH NOTES
Vertices are marked as boundary or nonboundary with an edge flag.
Edge flags are generated internally by the GL when it decomposes
polygons; they can be set explicitly using _cmnd(EdgeFlag).
.SH ERRORS
_const(INVALID_ENUM) is generated if either _param1 or _param2 is not
an accepted value.
.P
_const(INVALID_OPERATION) is generated if _cmnd
is executed between the execution of _cmnd(Begin)
and the corresponding execution of _cmnd(End).
.SH ASSOCIATED GETS
_cmnd(Get) with argument _const(POLYGON_MODE)
.SH SEE ALSO
_cmnd(Begin),
_cmnd(EdgeFlag),
_cmnd(LineStipple),
_cmnd(LineWidth),
_cmnd(PointSize),
_cmnd(PolygonStipple)