
<refentry id="glIndex">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glIndex</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glIndex</refname>
        <refpurpose>set the current color index</refpurpose>
    </refnamediv>
    <para>
    </para>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexs</function></funcdef>
                <paramdef>GLshort <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexi</function></funcdef>
                <paramdef>GLint <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexf</function></funcdef>
                <paramdef>GLfloat <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexd</function></funcdef>
                <paramdef>GLdouble <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexub</function></funcdef>
                <paramdef>GLubyte <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>c</parameter></term>
            <listitem>
                <para>
                    Specifies the new value for the current color index.
                </para>
                <para>
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexsv</function></funcdef>
                <paramdef>const GLshort * <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexiv</function></funcdef>
                <paramdef>const GLint * <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexfv</function></funcdef>
                <paramdef>const GLfloat * <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexdv</function></funcdef>
                <paramdef>const GLdouble * <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glIndexubv</function></funcdef>
                <paramdef>const GLubyte * <parameter>c</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters2"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>c</parameter></term>
            <listitem>
                <para>
                    Specifies a pointer to a one-element array that contains
                    the new value for the current color index.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>glIndex</function> updates the current (single-valued) color index.
            It takes one argument, the new value for the current color index.
        </para>
        <para>
            The current index is stored as a floating-point value.
            Integer values are converted directly to floating-point values,
            with no special mapping.
            The initial value is 1.
        </para>
        <para>
            Index values outside the representable range of the color index buffer
            are not clamped.
            However,
            before an index is dithered (if enabled) and written to the frame buffer,
            it is converted to fixed-point format.
            Any bits in the integer portion of the resulting fixed-point value
            that do not correspond to bits in the frame buffer are masked out.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>glIndexub</function> and <function>glIndexubv</function> are available only if the GL version is
            1.1 or greater.
        </para>
        <para>
            The current index can be updated at any time.
            In particular,
            <function>glIndex</function> can be called between a call to <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding
            call to <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_INDEX</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glColor</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glIndexPointer</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
