<div class="refentry" lang="en" xml:lang="en"><a id="glArrayElement"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glArrayElement — render a vertex using the specified vertex array element</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glArrayElement</b>(</code></td><td>GLint  </td><td><var class="pdparam">i</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>i</code></em></span></dt><dd><p>

Specifies an index into the enabled vertex data arrays.

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

<code class="function">glArrayElement</code> commands are used within <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> pairs to

specify vertex and attribute data for point, line, and polygon

primitives. If <code class="constant">GL_VERTEX_ARRAY</code> is enabled when <code class="function">glArrayElement</code> is called, a

single vertex is drawn, using

vertex and attribute data taken from location <em class="parameter"><code>i</code></em> of the enabled

arrays. If <code class="constant">GL_VERTEX_ARRAY</code> is not enabled, no drawing occurs but

the attributes corresponding to the enabled arrays are modified.

</p><p>

Use <code class="function">glArrayElement</code> to construct primitives by indexing vertex data, rather than

by streaming through arrays of data in first-to-last order. Because

each call specifies only a single vertex, it is possible to explicitly

specify per-primitive attributes such as a single normal for each

triangle.

</p><p>

Changes made to array data between the execution of <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the

corresponding execution of <a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a> may affect calls to <code class="function">glArrayElement</code> that are made

within the same <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> period in nonsequential ways.

That is, a call to

<code class="function">glArrayElement</code> that precedes a change to array data may

access the changed data, and a call that follows a change to array data

may access original data.

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

<code class="function">glArrayElement</code> is available only if the GL version is 1.1 or greater.

</p><p>

<code class="function">glArrayElement</code> is included in display lists. If <code class="function">glArrayElement</code> is entered into a

display list, the necessary array data (determined by the array

pointers and enables) is also entered into the display list. Because

the array pointers and enables are client-side state, their values

affect display lists when the lists are created, not when the lists

are executed.

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

<code class="constant">GL_INVALID_VALUE</code> may be generated if <em class="parameter"><code>i</code></em> is negative.

</p><p>

<code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to an

enabled array and the buffer object's data store is currently mapped.

</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="glClientActiveTexture"><span class="citerefentry"><span class="refentrytitle">glClientActiveTexture</span></span></a>,

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

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

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

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

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

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

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

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

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

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

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