<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>

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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glDepthRangef">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2018</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glDepthRangef</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glDepthRangef</refname>
        <refpurpose>specify mapping of depth values from normalized device coordinates to window coordinates</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glDepthRangef</function></funcdef>
                <paramdef>GLfloat <parameter>n</parameter></paramdef>
                <paramdef>GLfloat <parameter>f</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>n</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>f</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 xml:id="description"><title>Description</title>
        <para>
            After clipping and division by <emphasis>w</emphasis>,
            depth coordinates range from
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: -1: -->
                <mml:mn>-1</mml:mn>
            </mml:math></inlineequation>
            to 1,
            corresponding to the near and far clipping planes.
            <function>glDepthRangef</function> specifies a linear mapping of the normalized depth coordinates
            in this range to window depth coordinates.
            If a fixed-point depth representation is used, the parameters
            <parameter>n</parameter> and <parameter>f</parameter> are
            clamped to the range [0, 1] when specified.
       </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 xml:id="notes"><title>Notes</title>
        <para>
            It is not necessary that <parameter>n</parameter> be less than <parameter>f</parameter>.
            Reverse mappings such as
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: n  =  1: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">n</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            and
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: f  =  0: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">f</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mn>0</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>
            are acceptable.
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_DEPTH_RANGE</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>glDepthRangef</entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es20']/*)"/>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glDepthFunc</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPolygonOffset</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glViewport</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>
