upstream-man-pages/man2/glArrayElement.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glArrayElement">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glArrayElement</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glArrayElement</refname>
  17         <refpurpose>render a vertex using the specified vertex array element</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glArrayElement</function></funcdef>
  23                 <paramdef>GLint <parameter>i</parameter></paramdef>
  24             </funcprototype>
  25         </funcsynopsis>
  26     </refsynopsisdiv>
  27     <!-- eqn: ignoring delim $$ -->
  28     <refsect1 id="parameters"><title>Parameters</title>
  29         <variablelist>
  30         <varlistentry>
  31             <term><parameter>i</parameter></term>
  32             <listitem>
  33                 <para>
  34                     Specifies an index into the enabled vertex data arrays.
  35                 </para>
  36             </listitem>
  37         </varlistentry>
  38         </variablelist>
  39     </refsect1>
  40     <refsect1 id="description"><title>Description</title>
  41         <para>
  42             <function>glArrayElement</function> commands are used within <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>/<citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry> pairs to
  43             specify vertex and attribute data for point, line, and polygon
  44             primitives. If <constant>GL_VERTEX_ARRAY</constant> is enabled when <function>glArrayElement</function> is called, a
  45             single vertex is drawn, using
  46             vertex and attribute data taken from location <parameter>i</parameter> of the enabled
  47             arrays. If <constant>GL_VERTEX_ARRAY</constant> is not enabled, no drawing occurs but
  48             the attributes corresponding to the enabled arrays are modified.
  49         </para>
  50         <para>
  51             Use <function>glArrayElement</function> to construct primitives by indexing vertex data, rather than
  52             by streaming through arrays of data in first-to-last order. Because
  53             each call specifies only a single vertex, it is possible to explicitly
  54             specify per-primitive attributes such as a single normal for each
  55             triangle.
  56         </para>
  57         <para>
  58             Changes made to array data between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the
  59             corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry> may affect calls to <function>glArrayElement</function> that are made
  60             within the same <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>/<citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry> period in nonsequential ways.
  61             That is, a call to
  62             <function>glArrayElement</function> that precedes a change to array data may
  63             access the changed data, and a call that follows a change to array data
  64             may access original data.
  65         </para>
  66     </refsect1>
  67     <refsect1 id="notes"><title>Notes</title>
  68         <para>
  69             <function>glArrayElement</function> is available only if the GL version is 1.1 or greater.
  70         </para>
  71         <para>
  72             <function>glArrayElement</function> is included in display lists. If <function>glArrayElement</function> is entered into a
  73             display list, the necessary array data (determined by the array
  74             pointers and enables) is also entered into the display list. Because
  75             the array pointers and enables are client-side state, their values
  76             affect display lists when the lists are created, not when the lists
  77             are executed.
  78         </para>
  79     </refsect1>
  80     <refsect1 id="errors"><title>Errors</title>
  81         <para>
  82             <constant>GL_INVALID_VALUE</constant> may be generated if <parameter>i</parameter> is negative.
  83         </para>
  84         <para>
  85             <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to an
  86             enabled array and the buffer object's data store is currently mapped.
  87         </para>
  88     </refsect1>
  89     <refsect1 id="seealso"><title>See Also</title>
  90         <para>
  91             <citerefentry><refentrytitle>glClientActiveTexture</refentrytitle></citerefentry>,
  92             <citerefentry><refentrytitle>glColorPointer</refentrytitle></citerefentry>,
  93             <citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
  94             <citerefentry><refentrytitle>glEdgeFlagPointer</refentrytitle></citerefentry>,
  95             <citerefentry><refentrytitle>glFogCoordPointer</refentrytitle></citerefentry>,
  96             <citerefentry><refentrytitle>glGetPointerv</refentrytitle></citerefentry>,
  97             <citerefentry><refentrytitle>glIndexPointer</refentrytitle></citerefentry>,
  98             <citerefentry><refentrytitle>glInterleavedArrays</refentrytitle></citerefentry>,
  99             <citerefentry><refentrytitle>glNormalPointer</refentrytitle></citerefentry>,
 100             <citerefentry><refentrytitle>glSecondaryColorPointer</refentrytitle></citerefentry>,
 101             <citerefentry><refentrytitle>glTexCoordPointer</refentrytitle></citerefentry>,
 102             <citerefentry><refentrytitle>glVertexPointer</refentrytitle></citerefentry>
 103         </para>
 104     </refsect1>
 105     <refsect1 id="Copyright"><title>Copyright</title>
 106         <para>
 107             Copyright <trademark class="copyright"></trademark> 1991-2006
 108             Silicon Graphics, Inc. This document is licensed under the SGI
 109             Free Software B License. For details, see
 110             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 111         </para>
 112     </refsect1>
 113 </refentry>