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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> |