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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glTexParameter">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glTexParameter</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glTexParameter</refname>
        <refpurpose>set texture parameters</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glTexParameterf</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>GLfloat <parameter>param</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glTexParameteri</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>GLint <parameter>param</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>target</parameter></term>
            <listitem>
                <para>
                    Specifies the target texture,
                    which must be either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>,
                    <constant>GL_TEXTURE_3D</constant>, or <constant>GL_TEXTURE_CUBE_MAP</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>pname</parameter></term>
            <listitem>
                <para>
                    Specifies the symbolic name of a single-valued texture parameter.
                    <parameter>pname</parameter> can be one of the following:
                    <constant>GL_TEXTURE_MIN_FILTER</constant>,
                    <constant>GL_TEXTURE_MAG_FILTER</constant>,
                    <constant>GL_TEXTURE_MIN_LOD</constant>,
                    <constant>GL_TEXTURE_MAX_LOD</constant>,
                    <constant>GL_TEXTURE_BASE_LEVEL</constant>,
                    <constant>GL_TEXTURE_MAX_LEVEL</constant>,
                    <constant>GL_TEXTURE_WRAP_S</constant>,
                    <constant>GL_TEXTURE_WRAP_T</constant>,
                    <constant>GL_TEXTURE_WRAP_R</constant>,
                    <constant>GL_TEXTURE_PRIORITY</constant>,
                    <constant>GL_TEXTURE_COMPARE_MODE</constant>,
                    <constant>GL_TEXTURE_COMPARE_FUNC</constant>,
                    <constant>GL_DEPTH_TEXTURE_MODE</constant>, or
                    <constant>GL_GENERATE_MIPMAP</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>param</parameter></term>
            <listitem>
                <para>
                    Specifies the value of <parameter>pname</parameter>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glTexParameterfv</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>const GLfloat * <parameter>params</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glTexParameteriv</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>const GLint * <parameter>params</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters2"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>target</parameter></term>
            <listitem>
                <para>
                    Specifies the target texture,
                    which must be either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant> or
                    <constant>GL_TEXTURE_3D</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>pname</parameter></term>
            <listitem>
                <para>
                    Specifies the symbolic name of a texture parameter.
                    <parameter>pname</parameter> can be one of the following:
                    <constant>GL_TEXTURE_MIN_FILTER</constant>,
                    <constant>GL_TEXTURE_MAG_FILTER</constant>,
                    <constant>GL_TEXTURE_MIN_LOD</constant>,
                    <constant>GL_TEXTURE_MAX_LOD</constant>,
                    <constant>GL_TEXTURE_BASE_LEVEL</constant>,
                    <constant>GL_TEXTURE_MAX_LEVEL</constant>,
                    <constant>GL_TEXTURE_WRAP_S</constant>,
                    <constant>GL_TEXTURE_WRAP_T</constant>,
                    <constant>GL_TEXTURE_WRAP_R</constant>,
                    <constant>GL_TEXTURE_BORDER_COLOR</constant>,
                    <constant>GL_TEXTURE_PRIORITY</constant>,
                    <constant>GL_TEXTURE_COMPARE_MODE</constant>,
                    <constant>GL_TEXTURE_COMPARE_FUNC</constant>,
                    <constant>GL_DEPTH_TEXTURE_MODE</constant>, or
                    <constant>GL_GENERATE_MIPMAP</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>params</parameter></term>
            <listitem>
                <para>
                    Specifies a pointer to an array where the value or values of <parameter>pname</parameter>
                    are stored.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            Texture mapping is a technique that applies an image onto an object's surface
            as if the image were a decal or cellophane shrink-wrap.
            The image is created in texture space,
            with an 
            (<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>, 
            <inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>)
            coordinate system.
            A texture is a one- or two-dimensional image and a set of parameters
            that determine how samples are derived from the image.
        </para>
        <para>
            <function>glTexParameter</function> assigns the value or values in <parameter>params</parameter> to the texture parameter
            specified as <parameter>pname</parameter>.
            <parameter>target</parameter> defines the target texture,
            either <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, or <constant>GL_TEXTURE_3D</constant>.
            The following symbols are accepted in <parameter>pname</parameter>:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_MIN_FILTER</constant></term>
                <listitem>
                    <para>
                        The texture minifying function is used whenever the pixel being textured
                        maps to an area greater than one texture element.
                        There are six defined minifying functions.
                        Two of them use the nearest one or nearest four texture elements
                        to compute the texture value.
                        The other four use mipmaps.
                    </para>
                    <para>
                        A mipmap is an ordered set of arrays representing the same image
                        at progressively lower resolutions.
                        If the texture has dimensions 
                        <inlineequation><mml:math>
                            <!-- eqn: 2 sup n  times  2 sup m:-->
                            <mml:mrow>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">n</mml:mi>
                                </mml:msup>
                                <mml:mo>&times;</mml:mo>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">m</mml:mi>
                                </mml:msup>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        there are
                        <inlineequation><mml:math>
                            <!-- eqn: max ( n, m ) + 1:-->
                            <mml:mrow>
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">max</mml:mi>
                                    <mml:mo>&af;</mml:mo>
                                    <mml:mfenced open="(" close=")">
                                        <mml:mi mathvariant="italic">n</mml:mi>
                                        <mml:mi mathvariant="italic">m</mml:mi>
                                    </mml:mfenced>
                                </mml:mrow>
                                <mml:mo>+</mml:mo>
                                <mml:mn>1</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        mipmaps.
                        The first mipmap is the original texture,
                        with dimensions 
                        <inlineequation><mml:math>
                            <!-- eqn: 2 sup n  times  2 sup m:-->
                            <mml:mrow>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">n</mml:mi>
                                </mml:msup>
                                <mml:mo>&times;</mml:mo>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">m</mml:mi>
                                </mml:msup>
                            </mml:mrow>
                        </mml:math></inlineequation>.
                        Each subsequent mipmap has dimensions 
                        <inlineequation><mml:math>
                            <!-- eqn: 2 sup { k - 1 }  times  2 sup { l - 1 }:-->
                            <mml:mrow>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">k</mml:mi>
                                        <mml:mo>-</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mfenced>
                                </mml:msup>
                                <mml:mo>&times;</mml:mo>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">l</mml:mi>
                                        <mml:mo>-</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mfenced>
                                </mml:msup>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        where 
                        <inlineequation><mml:math>
                            <!-- eqn: 2 sup k  times  2 sup l:-->
                            <mml:mrow>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                </mml:msup>
                                <mml:mo>&times;</mml:mo>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mi mathvariant="italic">l</mml:mi>
                                </mml:msup>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        are the dimensions of the previous mipmap,
                        until either 
                        <inlineequation><mml:math>
                            <!-- eqn: k  =  0:-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mn>0</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        or 
                        <inlineequation><mml:math>
                            <!-- eqn: l = 0:-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">l</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mn>0</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>.
                        At that point,
                        subsequent mipmaps have dimension 
                        <inlineequation><mml:math>
                            <!-- eqn: 1  times  2 sup { l - 1 }:-->
                            <mml:mrow>
                                <mml:mn>1</mml:mn>
                                <mml:mo>&times;</mml:mo>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">l</mml:mi>
                                        <mml:mo>-</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mfenced>
                                </mml:msup>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        or 
                        <inlineequation><mml:math>
                            <!-- eqn: 2 sup { k - 1}  times  1:-->
                            <mml:mrow>
                                <mml:msup><mml:mn>2</mml:mn>
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">k</mml:mi>
                                        <mml:mo>-</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mfenced>
                                </mml:msup>
                                <mml:mo>&times;</mml:mo>
                                <mml:mn>1</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        until the final mipmap,
                        which has dimension 
                        <inlineequation><mml:math>
                            <!-- eqn: 1  times  1:-->
                            <mml:mrow>
                                <mml:mn>1</mml:mn>
                                <mml:mo>&times;</mml:mo>
                                <mml:mn>1</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>.
                        To define the mipmaps, call <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>
                        with the <emphasis>level</emphasis> argument indicating the order of the mipmaps.
                        Level 0 is the original texture;
                        level 
                        <inlineequation><mml:math>
                            <!-- eqn: max ( n, m ):-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">max</mml:mi>
                                <mml:mo>&af;</mml:mo>
                                <mml:mfenced open="(" close=")">
                                    <mml:mi mathvariant="italic">n</mml:mi>
                                    <mml:mi mathvariant="italic">m</mml:mi>
                                </mml:mfenced>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        is the final 
                        <inlineequation><mml:math>
                            <!-- eqn: 1  times  1:-->
                            <mml:mrow>
                                <mml:mn>1</mml:mn>
                                <mml:mo>&times;</mml:mo>
                                <mml:mn>1</mml:mn>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        mipmap.
                    </para>
                    <para>
                        <parameter>params</parameter> supplies a function for minifying the texture as one of the
                        following:
                        <variablelist>
                            <varlistentry>
                                <term><constant>GL_NEAREST</constant></term>
                                <listitem>
                                    <para>
                                        Returns the value of the texture element that is nearest
                                        (in Manhattan distance)
                                        to the center of the pixel being textured.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_LINEAR</constant></term>
                                <listitem>
                                    <para>
                                        Returns the weighted average of the four texture elements
                                        that are closest to the center of the pixel being textured.
                                        These can include border texture elements,
                                        depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,
                                        and on the exact mapping.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_NEAREST_MIPMAP_NEAREST</constant></term>
                                <listitem>
                                    <para>
                                        Chooses the mipmap that most closely matches the size of the pixel
                                        being textured and uses the <constant>GL_NEAREST</constant> criterion
                                        (the texture element nearest to the center of the pixel)
                                        to produce a texture value.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_LINEAR_MIPMAP_NEAREST</constant></term>
                                <listitem>
                                    <para>
                                        Chooses the mipmap that most closely matches the size of the pixel
                                        being textured and uses the <constant>GL_LINEAR</constant> criterion
                                        (a weighted average of the four texture elements that are closest
                                        to the center of the pixel)
                                        to produce a texture value.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_NEAREST_MIPMAP_LINEAR</constant></term>
                                <listitem>
                                    <para>
                                        Chooses the two mipmaps that most closely match the size of the pixel
                                        being textured and uses the <constant>GL_NEAREST</constant> criterion
                                        (the texture element nearest to the center of the pixel)
                                        to produce a texture value from each mipmap.
                                        The final texture value is a weighted average of those two values.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_LINEAR_MIPMAP_LINEAR</constant></term>
                                <listitem>
                                    <para>
                                        Chooses the two mipmaps that most closely match the size of the pixel
                                        being textured and uses the <constant>GL_LINEAR</constant> criterion
                                        (a weighted average of the four texture elements that are closest
                                        to the center of the pixel)
                                        to produce a texture value from each mipmap.
                                        The final texture value is a weighted average of those two values.
                                    </para>
                                </listitem>
                            </varlistentry>
                        </variablelist>
                    </para>
                    <para>
                        As more texture elements are sampled in the minification process,
                        fewer aliasing artifacts will be apparent.
                        While the <constant>GL_NEAREST</constant> and <constant>GL_LINEAR</constant> minification functions can be
                        faster than the other four,
                        they sample only one or four texture elements to determine the texture value
                        of the pixel being rendered and can produce moire patterns
                        or ragged transitions.
                        The initial value of <constant>GL_TEXTURE_MIN_FILTER</constant> is
                        <constant>GL_NEAREST_MIPMAP_LINEAR</constant>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_MAG_FILTER</constant></term>
                <listitem>
                    <para>
                        The texture magnification function is used when the pixel being textured
                        maps to an area less than or equal to one texture element.
                        It sets the texture magnification function to either <constant>GL_NEAREST</constant>
                        or <constant>GL_LINEAR</constant> (see below). <constant>GL_NEAREST</constant> is generally faster
                        than <constant>GL_LINEAR</constant>,
                        but it can produce textured images with sharper edges
                        because the transition between texture elements is not as smooth.
                        The initial value of <constant>GL_TEXTURE_MAG_FILTER</constant> is <constant>GL_LINEAR</constant>.
                        <variablelist>
                            <varlistentry>
                                <term><constant>GL_NEAREST</constant></term>
                                <listitem>
                                    <para>
                                        Returns the value of the texture element that is nearest
                                        (in Manhattan distance)
                                        to the center of the pixel being textured.
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_LINEAR</constant></term>
                                <listitem>
                                    <para>
                                        Returns the weighted average of the four texture elements
                                        that are closest to the center of the pixel being textured.
                                        These can include border texture elements,
                                        depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,
                                        and on the exact mapping.
                                    </para>
                                </listitem>
                            </varlistentry>
                        </variablelist>
                        <para>
                        </para>
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_MIN_LOD</constant></term>
                <listitem>
                    <para>
                        Sets the minimum level-of-detail parameter.  This floating-point value
                        limits the selection of highest resolution mipmap (lowest mipmap
                        level). The initial value is -1000.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_MAX_LOD</constant></term>
                <listitem>
                    <para>
                        Sets the maximum level-of-detail parameter.  This floating-point value
                        limits the selection of the lowest resolution mipmap (highest mipmap
                        level). The initial value is 1000.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_BASE_LEVEL</constant></term>
                <listitem>
                    <para>
                        Specifies the index of the lowest defined mipmap level. This is an
                        integer value. The initial value is 0.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_MAX_LEVEL</constant></term>
                <listitem>
                    <para>
                        Sets the index of the highest defined mipmap level. This is an integer
                        value. The initial value is 1000.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_WRAP_S</constant></term>
                <listitem>
                    <para>
                        Sets the wrap parameter for texture coordinate 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        to either <constant>GL_CLAMP</constant>,
                        <constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
                        <constant>GL_REPEAT</constant>.  <constant>GL_CLAMP</constant> causes 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        coordinates to be clamped to the
                        range [0,1] and is useful for preventing wrapping artifacts when mapping a
                        single image onto an object.  <constant>GL_CLAMP_TO_BORDER</constant> causes the 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        coordinate to be clamped to the range
                        <inlineequation><mml:math>
                            <!-- eqn: left [ {-1 over 2N}, 1 + {1 over 2N} right ]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mfrac>
                                            <mml:mn>-1</mml:mn>
                                            <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
                                        </mml:mfrac>
                                    </mml:mrow>
                                </mml:mfenced>
                                <mml:mrow>
                                    <mml:mn>1</mml:mn>
                                    <mml:mo>+</mml:mo>
                                    <mml:mfenced open="" close="">
                                        <mml:mrow>
                                            <mml:mfrac>
                                                <mml:mn>1</mml:mn>
                                                <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
                                            </mml:mfrac>
                                        </mml:mrow>
                                    </mml:mfenced>
                                </mml:mrow>
                            </mml:mfenced>
                        </mml:math></inlineequation>,
                        where 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
                        is the size of the texture in the direction of
                        clamping.<constant>GL_CLAMP_TO_EDGE</constant> causes 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        coordinates to be clamped to the
                        range 
                        <inlineequation><mml:math>
                            <!-- eqn: left [ {1 over 2N}, 1 - {1 over 2N} right ]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mfenced open="" close="">
                                    <mml:mrow>
                                        <mml:mfrac>
                                            <mml:mn>1</mml:mn>
                                            <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
                                        </mml:mfrac>
                                    </mml:mrow>
                                </mml:mfenced>
                                <mml:mrow>
                                    <mml:mn>1</mml:mn>
                                    <mml:mo>-</mml:mo>
                                    <mml:mfenced open="" close="">
                                        <mml:mrow>
                                            <mml:mfrac>
                                                <mml:mn>1</mml:mn>
                                                <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
                                            </mml:mfrac>
                                        </mml:mrow>
                                    </mml:mfenced>
                                </mml:mrow>
                            </mml:mfenced>
                        </mml:math></inlineequation>,
                        where 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>
                        is the size
                        of the texture in the direction of clamping.  <constant>GL_REPEAT</constant> causes the
                        integer part of the 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        coordinate to be ignored; the GL uses only the
                        fractional part, thereby creating a repeating pattern.
                        <constant>GL_MIRRORED_REPEAT</constant> causes the 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        coordinate to be set to the
                        fractional part of the texture coordinate if the integer part of 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        is
                        even; if the integer part of 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        is odd, then the 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        texture coordinate is
                        set to 
                        <inlineequation><mml:math>
                            <!-- eqn: 1 - frac(s):-->
                            <mml:mrow>
                                <mml:mn>1</mml:mn>
                                <mml:mo>-</mml:mo>
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">frac</mml:mi>
                                    <mml:mo>&af;</mml:mo>
                                    <mml:mfenced open="(" close=")">
                                        <mml:mi mathvariant="italic">s</mml:mi>
                                    </mml:mfenced>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        where 
                        <inlineequation><mml:math>
                            <!-- eqn: frac(s):-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">frac</mml:mi>
                                <mml:mo>&af;</mml:mo>
                                <mml:mfenced open="(" close=")">
                                    <mml:mi mathvariant="italic">s</mml:mi>
                                </mml:mfenced>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        represents the fractional part of
                        <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>.
                        Border texture
                        elements are accessed only if wrapping is set to <constant>GL_CLAMP</constant> or <constant>GL_CLAMP_TO_BORDER</constant>.  Initially,
                        <constant>GL_TEXTURE_WRAP_S</constant> is set to <constant>GL_REPEAT</constant>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_TEXTURE_WRAP_T</constant></term>
                <listitem>
                    <para>
                        Sets the wrap parameter for texture coordinate 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>
                        to either <constant>GL_CLAMP</constant>,
                        <constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
                        <constant>GL_REPEAT</constant>.  See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.
                        Initially, <constant>GL_TEXTURE_WRAP_T</constant> is set to <constant>GL_REPEAT</constant>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_WRAP_R</constant></term>
                <listitem>
                    <para>
                        Sets the wrap parameter for texture coordinate 
                        <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
                        to either <constant>GL_CLAMP</constant>,
                        <constant>GL_CLAMP_TO_BORDER</constant>, <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or
                        <constant>GL_REPEAT</constant>.  See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.
                        Initially, <constant>GL_TEXTURE_WRAP_R</constant> is set to <constant>GL_REPEAT</constant>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_BORDER_COLOR</constant></term>
                <listitem>
                    <para>
                        Sets a border color.  <parameter>params</parameter> contains four values that comprise the RGBA
                        color of the texture border.  Integer color components are interpreted
                        linearly such that the most positive integer maps to 1.0, and the most
                        negative integer maps to -1.0.  The values are clamped to the range [0,1]
                        when they are specified.  Initially, the border color is (0, 0, 0, 0).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_PRIORITY</constant></term>
                <listitem>
                    <para>
                        Specifies the texture residence priority of the currently bound texture.
                        Permissible values are in the range 
                        <inlineequation><mml:math>
                            <!-- eqn: [0,1]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mn>0</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>.
                        See <citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glBindTexture</refentrytitle></citerefentry> for more information.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_COMPARE_MODE</constant></term>
                <listitem>
                    <para>
                        Specifies the texture comparison mode for currently bound depth textures.
                        That is, a texture whose internal format is <constant>GL_DEPTH_COMPONENT_*</constant>; see
                        <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>)
                        Permissible values are:
                        <variablelist>
                            <varlistentry>
                                <term><constant>GL_COMPARE_R_TO_TEXTURE</constant></term>
                                <listitem>
                                    <para>
                                        Specifies that the interpolated and clamped 
                                        <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
                                        texture coordinate should
                                        be compared to the value in the currently bound depth texture.  See the
                                        discussion of <constant>GL_TEXTURE_COMPARE_FUNC</constant> for details of how the comparison
                                        is evaluated.  The result of the comparison is assigned to luminance,
                                        intensity, or alpha (as specified by <constant>GL_DEPTH_TEXTURE_MODE</constant>).
                                    </para>
                                </listitem>
                            </varlistentry>
                            <varlistentry>
                                <term><constant>GL_NONE</constant></term>
                                <listitem>
                                    <para>
                                        Specifies that the luminance, intensity, or alpha (as specified by
                                        <constant>GL_DEPTH_TEXTURE_MODE</constant>) should be assigned the
                                        appropriate value from the currently bound depth texture.
                                    </para>
                                </listitem>
                            </varlistentry>
                        </variablelist>
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_TEXTURE_COMPARE_FUNC</constant></term>
                <listitem>
                    <para>
                        Specifies the comparison operator used when <constant>GL_TEXTURE_COMPARE_MODE</constant> is
                        set to <constant>GL_COMPARE_R_TO_TEXTURE</constant>.  Permissible values are:
                        <informaltable frame="topbot">
                            <tgroup cols="2" align="left">
                                <colspec/>
                                <colspec/>
                                <thead>
                                    <row>
                                        <entry rowsep="1" align="left"><emphasis role="bold">
                                        Texture Comparison Function
                                        </emphasis></entry>
                                        <entry rowsep="1" align="left"><emphasis role="bold">
                                        Computed result 
                                        </emphasis></entry>
                                    </row>
                                </thead>
                                <tbody>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_LEQUAL</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&lt;=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&gt;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_GEQUAL</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&gt;=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&lt;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_LESS</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&lt;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&gt;=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_GREATER</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&gt;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&lt;=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_EQUAL</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&ne;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_NOTEQUAL</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation><mml:math>
                                                <!-- eqn: result  =  left {   cpile {1.0 above 0.0}        lpile {r <= {D sub t} above r > {D sub t}}:-->
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mfenced open="{" close="">
                                                        <mml:mrow>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>1.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mn>0.0</mml:mn>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                            <mml:mo>&it;&nbsp;&nbsp;</mml:mo>
                                                            <mml:mtable>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>&ne;</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                                <mml:mtr><mml:mtd>
                                                                    <mml:mrow>
                                                                        <mml:mi mathvariant="italic">r</mml:mi>
                                                                        <mml:mo>=</mml:mo>
                                                                        <mml:mfenced open="" close="">
                                                                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                                                                            <mml:mi mathvariant="italic">t</mml:mi>
                                                                            </mml:msub>
                                                                        </mml:mfenced>
                                                                    </mml:mrow>
                                                                </mml:mtd></mml:mtr>
                                                            </mml:mtable>
                                                        </mml:mrow>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:math></informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_ALWAYS</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation>
                                                <mml:math>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mi>1.0</mml:mi>
                                                </mml:mrow>
                                                </mml:math>
                                            </informalequation>
                                        </entry>
                                    </row>
                                    <row>
                                        <entry align="left">
                                        <constant>GL_NEVER</constant>
                                        </entry>
                                        <entry align="left">
                                            <informalequation>
                                                <mml:math>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">result</mml:mi>
                                                    <mml:mo>=</mml:mo>
                                                    <mml:mi>0.0</mml:mi>
                                                </mml:mrow>
                                                </mml:math>
                                            </informalequation>
                                        </entry>
                                    </row>
                                </tbody>
                            </tgroup>
                        </informaltable>
                        where <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>
                        is the current interpolated texture coordinate, and 
                        <inlineequation><mml:math>
                            <!-- eqn: D sub t:-->
                            <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
                            <mml:mi mathvariant="italic">t</mml:mi>
                            </mml:msub>
                        </mml:math></inlineequation>
                        is the depth texture value sampled from the currently bound depth texture.
                        <inlineequation><mml:math><mml:mi mathvariant="italic">result</mml:mi></mml:math></inlineequation>
                        is assigned to the either the luminance, intensity, or alpha (as
                        specified by <constant>GL_DEPTH_TEXTURE_MODE</constant>.)
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_DEPTH_TEXTURE_MODE</constant></term>
                <listitem>
                    <para>
                        Specifies a single symbolic constant indicating how depth values should be
                        treated during filtering and texture application.  Accepted values are
                        <constant>GL_LUMINANCE</constant>, <constant>GL_INTENSITY</constant>, and <constant>GL_ALPHA</constant>.  The initial value
                        is <constant>GL_LUMINANCE</constant>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_GENERATE_MIPMAP</constant></term>
                <listitem>
                    <para>
                        Specifies a boolean value that indicates if all levels of a mipmap array
                        should be automatically updated when any modification to the base level
                        mipmap is done.  The initial value is <constant>GL_FALSE</constant>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <constant>GL_TEXTURE_3D</constant>, <constant>GL_TEXTURE_MIN_LOD</constant>, <constant>GL_TEXTURE_MAX_LOD</constant>,
            <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_TEXTURE_BASE_LEVEL</constant>, and <constant>GL_TEXTURE_MAX_LEVEL</constant> are
            available only if the GL version is 1.2 or greater.
        </para>
        <para>
            <constant>GL_CLAMP_TO_BORDER</constant> is available only if the GL version is 1.3 or greater.
        </para>
        <para>
            <constant>GL_MIRRORED_REPEAT</constant>, <constant>GL_TEXTURE_COMPARE_MODE</constant>,
            <constant>GL_TEXTURE_COMPARE_FUNC</constant>, <constant>GL_DEPTH_TEXTURE_MODE</constant>, and
            <constant>GL_GENERATE_MIPMAP</constant> are available only if the GL version is 1.4 or
            greater.
        </para>
        <para>
            <constant>GL_TEXTURE_COMPARE_FUNC</constant> allows the following additional comparison modes only
            if the GL version is 1.5 or greater:
            <constant>GL_LESS</constant>, <constant>GL_GREATER</constant>,
            <constant>GL_EQUAL</constant>, <constant>GL_NOTEQUAL</constant>,
            <constant>GL_ALWAYS</constant>, and <constant>GL_NEVER</constant>.
        </para>
        <para>
            Suppose that a program has enabled texturing (by calling <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> with
            argument <constant>GL_TEXTURE_1D</constant>, <constant>GL_TEXTURE_2D</constant>, or <constant>GL_TEXTURE_3D</constant>) and
            has set <constant>GL_TEXTURE_MIN_FILTER</constant> to one of the functions that requires a
            mipmap.  If either the dimensions of the texture images currently defined
            (with previous calls to <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>) do not
            follow the proper sequence for mipmaps (described above), or there are
            fewer texture images defined than are needed, or the set of texture images
            have differing numbers of texture components, then it is as if texture
            mapping were disabled.
        </para>
        <para>
            Linear filtering accesses the four nearest texture elements only in 2D
            textures.  In 1D textures, linear filtering accesses the two nearest
            texture elements.
        </para>
        <para>
            For OpenGL versions 1.3 and greater, or when the <code>ARB_multitexture</code> extension is supported, <function>glTexParameter</function>
            specifies the texture parameters for the active texture unit, specified
            by calling <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not
            one of the accepted defined values.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>params</parameter> should have a defined
            constant value (based on the value of <parameter>pname</parameter>) and does not.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <function>glTexParameter</function> is executed between the
            execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGetTexParameter</refentrytitle></citerefentry>
        </para>
        <para>
            <citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glBindTexture</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPixelTransfer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPrioritizeTextures</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexEnv</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage3D</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>
