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

<!-- Converted by db4-upgrade version 1.1 -->

<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glPixelStorei">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2016</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glPixelStorei</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glPixelStorei</refname>
        <refpurpose>set pixel storage modes</refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glPixelStorei</function></funcdef>
                <paramdef>GLenum <parameter>pname</parameter></paramdef>
                <paramdef>GLint <parameter>param</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>pname</parameter></term>
            <listitem>
                <para>
                    Specifies the symbolic name of the parameter to be set.
                    Four values affect the packing of pixel data into memory:
                    <constant>GL_PACK_ROW_LENGTH</constant>,
                    <constant>GL_PACK_SKIP_PIXELS</constant>,
                    <constant>GL_PACK_SKIP_ROWS</constant>, and
                    <constant>GL_PACK_ALIGNMENT</constant>.
                    Six more affect the unpacking of pixel data <emphasis>from</emphasis> memory:
                    <constant>GL_UNPACK_ROW_LENGTH</constant>,
                    <constant>GL_UNPACK_IMAGE_HEIGHT</constant>,
                    <constant>GL_UNPACK_SKIP_PIXELS</constant>,
                    <constant>GL_UNPACK_SKIP_ROWS</constant>,
                    <constant>GL_UNPACK_SKIP_IMAGES</constant>, and
                    <constant>GL_UNPACK_ALIGNMENT</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>param</parameter></term>
            <listitem>
                <para>
                    Specifies the value that <parameter>pname</parameter> is set to.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glPixelStorei</function> sets pixel storage modes that affect the operation of subsequent
            <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> as well as the unpacking of
            texture patterns (see <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>).
        </para>
        <para>
            <parameter>pname</parameter> is a symbolic constant indicating the parameter to be set, and
            <parameter>param</parameter> is the new value.  Four of the ten storage parameters affect
            how pixel data is returned to client memory.
            They are as follows:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_PACK_ROW_LENGTH</constant></term>
                <listitem>
                    <para>
                        If greater than 0,
                        <constant>GL_PACK_ROW_LENGTH</constant> defines the number of pixels in a row.
                        If the first pixel of a row is placed at location
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">p</mml:mi></mml:math></inlineequation>
                        in memory,
                        then the location of the first pixel of the next row is obtained by skipping
                    </para>
                    <para>
                        <informalequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k  =   left {      lpile { n l above {a over s} left ceiling { s n l } over a right ceiling}         lpile {s  >=  a above s  <  a }: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mfenced open="{" close="">
                                    <mml:mrow>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mfenced open="" close="">
                                                        <mml:mfrac>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                            <mml:mi mathvariant="italic">s</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mfenced open="&lceil;" close="&rceil;">
                                                        <mml:mfrac>
                                                            <mml:mfenced open="" close="">
                                                                <mml:mrow>
                                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                                </mml:mrow>
                                                            </mml:mfenced>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                        <mml:mo>&it;</mml:mo>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&gt;=</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&lt;</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                    </mml:mrow>
                                </mml:mfenced>
                            </mml:mrow>
                        </mml:math></informalequation>
                    </para>
                    <para>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
                        is the number of components or indices in a pixel,
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">l</mml:mi></mml:math></inlineequation>
                        is the number of pixels in a row
                        (<constant>GL_PACK_ROW_LENGTH</constant> if it is greater than 0,
                        the
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
                        argument to the pixel routine otherwise),
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
                        is the value of <constant>GL_PACK_ALIGNMENT</constant>, and
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        is the size, in bytes, of a single component
                        (if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a < s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>&lt;</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        then it is as if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a  =  s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>).
                        In the case of 1-bit values,
                        the location of the next row is obtained by skipping
                    </para>
                    <para>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k  =  8 a left ceiling { n l } over { 8 a } right ceiling: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
                                    <mml:mn>8</mml:mn>
                                    <mml:mo>&it;</mml:mo>
                                    <mml:mi mathvariant="italic">a</mml:mi>
                                    <mml:mo>&it;</mml:mo>
                                    <mml:mfenced open="&lceil;" close="&rceil;">
                                        <mml:mfrac>
                                            <mml:mfenced open="" close="">
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                </mml:mrow>
                                            </mml:mfenced>
                                            <mml:mfenced open="" close="">
                                                <mml:mrow>
                                                    <mml:mn>8</mml:mn>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mfenced>
                                        </mml:mfrac>
                                    </mml:mfenced>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></inlineequation>
                    </para>
                    <para>
                        components or indices.
                    </para>
                    <para>
                        The word <emphasis>component</emphasis> in this description refers to the nonindex values
                        red,
                        green,
                        blue,
                        alpha,
                        and depth.
                        Storage format <constant>GL_RGB</constant>,
                        for example,
                        has three components per pixel:
                        first red,
                        then green,
                        and finally blue.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_PACK_SKIP_PIXELS</constant> and <constant>GL_PACK_SKIP_ROWS</constant></term>
                <listitem>
                    <para>
                        These values are provided as a convenience to the programmer;
                        they provide no functionality that cannot be duplicated simply by
                        incrementing the pointer passed to <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>.
                        Setting <constant>GL_PACK_SKIP_PIXELS</constant> to
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
                        is equivalent to incrementing
                        the pointer by
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: i n: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">i</mml:mi>
                                <mml:mo>&it;</mml:mo>
                                <mml:mi mathvariant="italic">n</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
                        is the number of components or indices in each pixel.
                        Setting <constant>GL_PACK_SKIP_ROWS</constant> to
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>
                        is equivalent to incrementing
                        the pointer by
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: j m: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">j</mml:mi>
                                <mml:mo>&it;</mml:mo>
                                <mml:mi mathvariant="italic">m</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">m</mml:mi></mml:math></inlineequation>
                        is the number of components or indices per row,
                        as just computed in the <constant>GL_PACK_ROW_LENGTH</constant> section.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_PACK_ALIGNMENT</constant></term>
                <listitem>
                    <para>
                        Specifies the alignment requirements for the start of each pixel row in memory.
                        The allowable values are
                        1 (byte-alignment),
                        2 (rows aligned to even-numbered bytes),
                        4 (word-alignment), and
                        8 (rows start on double-word boundaries).
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            The other six of the ten storage parameters affect how pixel data is
            read from client memory.
            These values are significant for
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>, and
            <citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>
        </para>
        <para>
            They are as follows:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_UNPACK_ROW_LENGTH</constant></term>
                <listitem>
                    <para>
                        If greater than 0,
                        <constant>GL_UNPACK_ROW_LENGTH</constant> defines the number of pixels in a row.
                        If the first pixel of a row is placed at location
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">p</mml:mi></mml:math></inlineequation>
                        in memory,
                        then the location of the first pixel of the next row is obtained by skipping
                    </para>
                    <para>
                        <informalequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k  =   left {       lpile { n l above {a over s} left ceiling { s n l } over a right ceiling }        lpile { s  >=  a above s  <  a }: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mfenced open="{" close="">
                                    <mml:mrow>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mfenced open="" close="">
                                                        <mml:mfrac>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                            <mml:mi mathvariant="italic">s</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mfenced open="&lceil;" close="&rceil;">
                                                        <mml:mfrac>
                                                            <mml:mfenced open="" close="">
                                                                <mml:mrow>
                                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                                </mml:mrow>
                                                            </mml:mfenced>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                        <mml:mo>&it;</mml:mo>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&gt;=</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&lt;</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                    </mml:mrow>
                                </mml:mfenced>
                            </mml:mrow>
                        </mml:math></informalequation>
                    </para>
                    <para>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
                        is the number of components or indices in a pixel,
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">l</mml:mi></mml:math></inlineequation>
                        is the number of pixels in a row
                        (<constant>GL_UNPACK_ROW_LENGTH</constant> if it is greater than 0,
                        the
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
                        argument to the pixel routine otherwise),
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
                        is the value of <constant>GL_UNPACK_ALIGNMENT</constant>, and
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        is the size, in bytes, of a single component
                        (if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a < s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>&lt;</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        then it is as if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a = s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>).
                        In the case of 1-bit values,
                        the location of the next row is obtained by skipping
                    </para>
                    <para>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k  =  8 a left ceiling { n l } over { 8 a } right ceiling: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
                                    <mml:mn>8</mml:mn>
                                    <mml:mo>&it;</mml:mo>
                                    <mml:mi mathvariant="italic">a</mml:mi>
                                    <mml:mo>&it;</mml:mo>
                                    <mml:mfenced open="&lceil;" close="&rceil;">
                                        <mml:mfrac>
                                            <mml:mfenced open="" close="">
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                </mml:mrow>
                                            </mml:mfenced>
                                            <mml:mfenced open="" close="">
                                                <mml:mrow>
                                                    <mml:mn>8</mml:mn>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mfenced>
                                        </mml:mfrac>
                                    </mml:mfenced>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></inlineequation>
                    </para>
                    <para>
                        components or indices.
                    </para>
                    <para>
                        The word <emphasis>component</emphasis> in this description refers to the nonindex values
                        red,
                        green,
                        blue,
                        alpha,
                        and depth.
                        Storage format <constant>GL_RGB</constant>,
                        for example,
                        has three components per pixel:
                        first red,
                        then green,
                        and finally blue.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_UNPACK_IMAGE_HEIGHT</constant></term>
                <listitem>
                    <para>
                        If greater than 0,
                        <constant>GL_UNPACK_IMAGE_HEIGHT</constant> defines the number of pixels in an image of
                        a three-dimensional texture volume.  Where ``image'' is defined by all
                        pixel sharing the same third dimension index.
                        If the first pixel of a row is placed at location
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">p</mml:mi></mml:math></inlineequation>
                        in memory,
                        then the location of the first pixel of the next row is obtained by skipping
                    </para>
                    <para>
                        <informalequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k  =   left {       lpile { n l h above {a over s} left ceiling { s n l h } over a right ceiling }        lpile { s   >=  a above s  <  a }: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mfenced open="{" close="">
                                    <mml:mrow>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mi mathvariant="italic">h</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mfenced open="" close="">
                                                        <mml:mfrac>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                            <mml:mi mathvariant="italic">s</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                    <mml:mo>&it;</mml:mo>
                                                    <mml:mfenced open="&lceil;" close="&rceil;">
                                                        <mml:mfrac>
                                                            <mml:mfenced open="" close="">
                                                                <mml:mrow>
                                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">n</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">l</mml:mi>
                                                                    <mml:mo>&it;</mml:mo>
                                                                    <mml:mi mathvariant="italic">h</mml:mi>
                                                                </mml:mrow>
                                                            </mml:mfenced>
                                                            <mml:mi mathvariant="italic">a</mml:mi>
                                                        </mml:mfrac>
                                                    </mml:mfenced>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                        <mml:mo>&it;</mml:mo>
                                        <mml:mtable>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&gt;=</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                            <mml:mtr><mml:mtd>
                                                <mml:mrow>
                                                    <mml:mi mathvariant="italic">s</mml:mi>
                                                    <mml:mo>&lt;</mml:mo>
                                                    <mml:mi mathvariant="italic">a</mml:mi>
                                                </mml:mrow>
                                            </mml:mtd></mml:mtr>
                                        </mml:mtable>
                                    </mml:mrow>
                                </mml:mfenced>
                            </mml:mrow>
                        </mml:math></informalequation>
                    </para>
                    <para>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
                        is the number of components or indices in a pixel,
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">l</mml:mi></mml:math></inlineequation>
                        is the number of pixels in a row
                        (<constant>GL_UNPACK_ROW_LENGTH</constant> if it is greater than 0,
                        the
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
                        argument to <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> otherwise),
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math></inlineequation>
                        is the number of rows in an image (<constant>GL_UNPACK_IMAGE_HEIGHT</constant> if
                        it is greater than 0, the
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">height</mml:mi></mml:math></inlineequation>
                        argument to <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> otherwise),
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
                        is the value of <constant>GL_UNPACK_ALIGNMENT</constant>, and
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
                        is the size, in bytes, of a single component
                        (if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a < s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>&lt;</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        then it is as if
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: a  =  s: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">a</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mi mathvariant="italic">s</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>).
                    </para>
                    <para>
                        The word <emphasis>component</emphasis> in this description refers to the nonindex values
                        red,
                        green,
                        blue,
                        alpha,
                        and depth.
                        Storage format <constant>GL_RGB</constant>,
                        for example,
                        has three components per pixel:
                        first red,
                        then green,
                        and finally blue.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_UNPACK_SKIP_PIXELS</constant>, <constant>GL_UNPACK_SKIP_ROWS</constant> and <constant>GL_UNPACK_SKIP_IMAGES</constant></term>
                <listitem>
                    <para>
                        These values are provided as a convenience to the programmer;
                        they provide no functionality that cannot be duplicated by
                        incrementing the pointer passed to
                        <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
                        <citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry> or
                        <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>.
                        Setting <constant>GL_UNPACK_SKIP_PIXELS</constant> to
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
                        is equivalent to incrementing
                        the pointer by
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: i n: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">i</mml:mi>
                                <mml:mo>&it;</mml:mo>
                                <mml:mi mathvariant="italic">n</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
                        is the number of components or indices in each pixel.
                        Setting <constant>GL_UNPACK_SKIP_ROWS</constant> to
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>
                        is equivalent to incrementing
                        the pointer by
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: j k: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">j</mml:mi>
                                <mml:mo>&it;</mml:mo>
                                <mml:mi mathvariant="italic">k</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>
                        components or indices,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">k</mml:mi></mml:math></inlineequation>
                        is the number of components or indices per row,
                        as just computed in the <constant>GL_UNPACK_ROW_LENGTH</constant> section.
                                                Setting <constant>GL_UNPACK_SKIP_IMAGES</constant> to
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">k</mml:mi></mml:math></inlineequation>
                        is equivalent to incrementing
                        the pointer by
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: k p: -->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">k</mml:mi>
                                <mml:mo>&it;</mml:mo>
                                <mml:mi mathvariant="italic">p</mml:mi>
                            </mml:mrow>
                        </mml:math></inlineequation>,
                        where
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">p</mml:mi></mml:math></inlineequation>
                        is the number of components or indices
                        per image, as computed in the <constant>GL_UNPACK_IMAGE_HEIGHT</constant> section.
                                                </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_UNPACK_ALIGNMENT</constant></term>
                <listitem>
                    <para>
                        Specifies the alignment requirements for the start of each pixel row in memory.
                        The allowable values are
                        1 (byte-alignment),
                        2 (rows aligned to even-numbered bytes),
                        4 (word-alignment), and
                        8 (rows start on double-word boundaries).
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            The following table gives the type,
            initial value,
            and range of valid values for each storage parameter
            that can be set with <function>glPixelStorei</function>.
        </para>
        <para>
        </para>
        <informaltable>
            <tgroup cols="5" align="left">
                <colspec colwidth="2.5*"/>
                <colspec colwidth="1*" align="center"/>
                <colspec colwidth="1*" align="center"/>
                <colspec colwidth="2*" align="center"/>
                <thead>
                    <row>
                        <entry>
                            <emphasis role="bold"> <parameter>pname</parameter> </emphasis>
                        </entry>
                        <entry>
                            <emphasis role="bold"> Type </emphasis>
                        </entry>
                        <entry>
                            <emphasis role="bold"> Initial Value </emphasis>
                        </entry>
                        <entry>
                            <emphasis role="bold"> Valid Range </emphasis>
                        </entry>
                    </row>
                </thead>
                <tbody>
                    <row>
                        <entry>
                        <constant>GL_PACK_ROW_LENGTH</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_PACK_SKIP_ROWS</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_PACK_SKIP_PIXELS</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_PACK_ALIGNMENT</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        4
                        </entry>
                        <entry>
                        1, 2, 4, or 8
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_ROW_LENGTH</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_IMAGE_HEIGHT</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_SKIP_ROWS</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_SKIP_PIXELS</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_SKIP_IMAGES</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        0
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- eqn: left [ 0,\(if right ): -->
                            <mml:mfenced open="[" close=")">
                                <mml:mn>0</mml:mn>
                                <mml:infinity definitionURL="" encoding=""/>
                            </mml:mfenced>
                        </mml:math></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_UNPACK_ALIGNMENT</constant>
                        </entry>
                        <entry>
                        integer
                        </entry>
                        <entry>
                        4
                        </entry>
                        <entry>
                        1, 2, 4, or 8
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>pname</parameter> is not an accepted value.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if a negative row length,
            pixel skip,
            or row skip value is specified,
            or if alignment is specified as other than 1, 2, 4, or 8.
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_ROW_LENGTH</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_SKIP_ROWS</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_SKIP_PIXELS</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_ALIGNMENT</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_ROW_LENGTH</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_IMAGE_HEIGHT</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_SKIP_ROWS</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_SKIP_PIXELS</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_SKIP_IMAGES</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_ALIGNMENT</constant>
        </para>
    </refsect1>
    <refsect1 xml:id="versions">
        <title>API Version Support</title>
        <informaltable>
            <tgroup cols="5" align="left">
                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
                <tbody>
                    <row>
                        <entry>glPixelStorei</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>glReadPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage3D</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"/> 2010-2016 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>
