<div class="refentry" lang="en" xml:lang="en"><a id="glEdgeFlag"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glEdgeFlag — flag edges as either boundary or nonboundary</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glEdgeFlag</b>(</code></td><td>GLboolean  </td><td><var class="pdparam">flag</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>flag</code></em></span></dt><dd><p>

Specifies the current edge flag value,

either <code class="constant">GL_TRUE</code> or <code class="constant">GL_FALSE</code>. The initial value is <code class="constant">GL_TRUE</code>.

</p></dd></dl></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glEdgeFlagv</b>(</code></td><td>const GLboolean *  </td><td><var class="pdparam">flag</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters2"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>flag</code></em></span></dt><dd><p>

Specifies a pointer to an array that contains a single boolean element,

which replaces the current edge flag value.

</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>

Each vertex of a polygon,

separate triangle,

or separate quadrilateral specified between a <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>/<a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a> pair

is marked as the start of either a boundary or nonboundary edge.

If the current edge flag is true when the vertex is specified,

the vertex is marked as the start of a boundary edge.

Otherwise, the vertex is marked as the start of a nonboundary edge.

<code class="function">glEdgeFlag</code> sets the edge flag bit to <code class="constant">GL_TRUE</code> if <em class="parameter"><code>flag</code></em> is <code class="constant">GL_TRUE</code>

and to <code class="constant">GL_FALSE</code> otherwise.

</p><p>

The vertices of connected triangles and connected quadrilaterals are always

marked as boundary,

regardless of the value of the edge flag.

</p><p>

Boundary and nonboundary edge flags on vertices are significant only if

<code class="constant">GL_POLYGON_MODE</code> is set to <code class="constant">GL_POINT</code> or <code class="constant">GL_LINE</code>.

See <a class="citerefentry" href="glPolygonMode"><span class="citerefentry"><span class="refentrytitle">glPolygonMode</span></span></a>.

</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>

The current edge flag can be updated at any time.

In particular,

<code class="function">glEdgeFlag</code> can be called between a call to <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding

call to <a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.

</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_EDGE_FLAG</code>

</p></div>

{$pipelinestall}{$examples}

<div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>

<a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>,

<code class="function">glEdgeFlagPointer</code>,

<a class="citerefentry" href="glPolygonMode"><span class="citerefentry"><span class="refentrytitle">glPolygonMode</span></span></a>

</p></div><div class="refsect1" lang="en" xml:lang="en"><div id="Copyright"><h2>Copyright</h2><p>

Copyright © 1991-2006

Silicon Graphics, Inc. This document is licensed under the SGI

Free Software B License. For details, see

<a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.

</p></div></div></div>