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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glReadBuffer">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2014</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glReadBuffer</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glReadBuffer</refname>
        <refpurpose>select a color buffer source for pixels</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glReadBuffer</function></funcdef>
                <paramdef>GLenum <parameter>mode</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>mode</parameter></term>
            <listitem>
                <para>
                    Specifies a color buffer.
                    Accepted values are
                    <constant>GL_BACK</constant>,
                    <constant>GL_NONE</constant>, and
                    <constant>GL_COLOR_ATTACHMENTi</constant>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glReadBuffer</function> specifies a color buffer as the source for subsequent
            <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>, , <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>, and
            <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry> commands.
            <parameter>mode</parameter> accepts one of the following values:
            <constant>GL_NONE</constant>,
            <constant>GL_BACK</constant> names the back buffer of the default framebuffer, and
            <constant>GL_COLOR_ATTACHMENTi</constant> names a color attachment of the current framebuffer,
        </para>
    </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is not <constant>GL_BACK</constant>,
                    <constant>GL_NONE</constant>, or <constant>GL_COLOR_ATTACHMENTi</constant>, where i is less than
                                        <constant>GL_MAX_COLOR_ATTACHMENTS</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the current framebuffer is the default framebufer and
                        <parameter>mode</parameter> is not <constant>GL_NONE</constant> or <constant>GL_BACK</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the current framebuffer is a named framebufer and
                        <parameter>mode</parameter> is not <constant>GL_NONE</constant> or <constant>GL_COLOR_ATTACHMENTi</constant>.
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_READ_BUFFER</constant>
        </para>
    </refsect1>
    <refsect1 xml:id="versions">
        <title>API Version Support</title>
        <informaltable>
            <tgroup cols="3" align="left">
                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
                <tbody>
                    <row>
                        <entry>glReadBuffer</entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es30']/*)"/>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawBuffers</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 xml:id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
            Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
            This document is licensed under the SGI Free Software B License.
            For details, see
            <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
        </para>
    </refsect1>
</refentry>
