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<refentry id="glDepthRangeIndexed">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>2010</year>
                <holder>Khronos Group</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glDepthRangeIndexed</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glDepthRangeIndexed</refname>
        <refpurpose>specify mapping of depth values from normalized device coordinates to window coordinates for a specified viewport</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glDepthRangeIndexed</function></funcdef>
                <paramdef>GLuint <parameter>index</parameter></paramdef>
                <paramdef>GLdouble <parameter>nearVal</parameter></paramdef>
                <paramdef>GLdouble <parameter>farVal</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>index</parameter></term>
            <listitem>
                <para>
                    Specifies the index of the viewport whose depth range to update.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>nearVal</parameter></term>
            <listitem>
                <para>
                    Specifies the mapping of the near clipping plane to window coordinates.
                    The initial value is 0.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>farVal</parameter></term>
            <listitem>
                <para>
                    Specifies the mapping of the far clipping plane to window coordinates.
                    The initial value is 1.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            After clipping and division by <emphasis>w</emphasis>,
            depth coordinates range from 
            <inlineequation><mml:math>
                <!-- eqn: -1: -->
                <mml:mn>-1</mml:mn>
            </mml:math></inlineequation>
            to 1,
            corresponding to the near and far clipping planes.
            Each viewport has an independent depth range specified as a linear mapping of the normalized
            depth coordinates in this range to window depth coordinates.
            Regardless of the actual depth buffer implementation,
            window coordinate depth values are treated as though they range
            from 0 through 1 (like color components).
            <function>glDepthRangeIndexed</function> specifies a linear mapping of the normalized depth coordinates
            in this range to window depth coordinates for a specified viewport.
            Thus,
            the values accepted by <function>glDepthRangeIndexed</function> are both clamped to this range
            before they are accepted.
        </para>
        <para>
            The <parameter>index</parameter> parameter specifies the index of first viewport whose depth
            range to modify and must be less than the value of <constant>GL_MAX_VIEWPORTS</constant>.
            <parameter>nearVal</parameter> and <parameter>farVal</parameter> specify near and far values of the
            depth range for the specified viewport, respectively.
        </para>
        <para>
            The setting of (0,1) maps the near plane to 0 and
            the far plane to 1.
            With this mapping,
            the depth buffer range is fully utilized.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            It is not necessary that the near plane distance be less than the far plane distance.
            Reverse mappings such as 
            <inlineequation><mml:math>
                <!-- eqn: nearVal  =  1: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">nearVal</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            and 
            <inlineequation><mml:math>
                <!-- eqn: farVal  =  0: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">farVal</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mn>0</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>
            are acceptable.
        </para>
        <para>
            The type of the <parameter>nearVal</parameter> and
            <parameter>farVal</parameter> parameters was changed from
            GLclampd to GLdouble. This change is transparent to user
            code and is described in detail on the
            <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
            page.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>index</parameter> is greater than or equal to
            the value of <constant>GL_MAX_VIEWPORTS</constant>.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_DEPTH_RANGE</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glDepthFunc</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDepthRange</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDepthRangeArray</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPolygonOffset</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glViewportArray</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glViewport</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>removedTypes</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. 
            This material may be distributed subject to the terms and conditions set forth in 
            the Open Publication License, v 1.0, 8 June 1999.
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
        </para>
    </refsect1>
</refentry>
