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<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
<!-- Converted by db4-upgrade version 1.1 -->
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glPolygonMode">
<info>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
<copyright>
<year>2010-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glPolygonMode</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glPolygonMode</refname>
<refpurpose>select a polygon rasterization mode</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPolygonMode</function></funcdef>
<paramdef>GLenum <parameter>face</parameter></paramdef>
<paramdef>GLenum <parameter>mode</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>face</parameter></term>
<listitem>
<para>
Specifies the polygons that <parameter>mode</parameter> applies to.
Must be <constant>GL_FRONT_AND_BACK</constant> for front- and back-facing polygons.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mode</parameter></term>
<listitem>
<para>
Specifies how polygons will be rasterized.
Accepted values are
<constant>GL_POINT</constant>,
<constant>GL_LINE</constant>, and
<constant>GL_FILL</constant>.
The initial value is <constant>GL_FILL</constant> for both front- and back-facing polygons.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description"><title>Description</title>
<para>
<function>glPolygonMode</function> controls the interpretation of polygons for rasterization.
<parameter>face</parameter> describes which polygons <parameter>mode</parameter> applies to:
both front and back-facing polygons (<constant>GL_FRONT_AND_BACK</constant>).
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.
</para>
<para>
Three modes are defined and can be specified in <parameter>mode</parameter>:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_POINT</constant></term>
<listitem>
<para>
Polygon vertices that are marked as the start of a boundary edge
are drawn as points.
Point attributes such as
<constant>GL_POINT_SIZE</constant> and
<constant>GL_POINT_SMOOTH</constant> control
the rasterization of the points.
Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_LINE</constant></term>
<listitem>
<para>
Boundary edges of the polygon are drawn as line segments.
Line attributes such as
<constant>GL_LINE_WIDTH</constant> and
<constant>GL_LINE_SMOOTH</constant> control
the rasterization of the lines.
Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_FILL</constant></term>
<listitem>
<para>
The interior of the polygon is filled.
Polygon attributes such as <constant>GL_POLYGON_SMOOTH</constant> control the rasterization of the polygon.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="examples"><title>Examples</title>
<para>
To draw a surface with outlined polygons,
call
<programlisting>
glPolygonMode(<constant>GL_FRONT_AND_BACK</constant>, <constant>GL_LINE</constant>);
</programlisting>
</para>
</refsect1>
<refsect1 xml:id="notes"><title>Notes</title>
<para>
Vertices are marked as boundary or nonboundary with an edge flag.
Edge flags are generated internally by the GL when it decomposes
triangle stips and fans.
</para>
</refsect1>
<refsect1 xml:id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if either <parameter>face</parameter> or <parameter>mode</parameter> is not
an accepted value.
</para>
</refsect1>
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POLYGON_MODE</constant>
</para>
</refsect1>
<refsect1 xml:id="versions"><title>Version Support</title>
<informaltable>
<tgroup cols="13" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry><function>glPolygonMode</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glLineWidth</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPointSize</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
This document is licensed under the SGI Free Software B License.
For details, see
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
</para>
</refsect1>
</refentry>
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