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<?xml version="1.0" encoding="UTF-8"?>
<!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="glPixelStore">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glPixelStore</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glPixelStore</refname>
<refpurpose>set pixel storage modes</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPixelStoref</function></funcdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLfloat <parameter>param</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPixelStorei</function></funcdef>
<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>pname</parameter></term>
<listitem>
<para>
Specifies the symbolic name of the parameter to be set.
Six values affect the packing of pixel data into memory:
<constant>GL_PACK_SWAP_BYTES</constant>,
<constant>GL_PACK_LSB_FIRST</constant>,
<constant>GL_PACK_ROW_LENGTH</constant>,
<constant>GL_PACK_IMAGE_HEIGHT</constant>,
<constant>GL_PACK_SKIP_PIXELS</constant>,
<constant>GL_PACK_SKIP_ROWS</constant>,
<constant>GL_PACK_SKIP_IMAGES</constant>, and
<constant>GL_PACK_ALIGNMENT</constant>.
Six more affect the unpacking of pixel data <emphasis>from</emphasis> memory:
<constant>GL_UNPACK_SWAP_BYTES</constant>,
<constant>GL_UNPACK_LSB_FIRST</constant>,
<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 id="description"><title>Description</title>
<para>
<function>glPixelStore</function> sets pixel storage modes that affect the operation of subsequent
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> as well as the unpacking of
polygon stipple patterns (see <citerefentry><refentrytitle>glPolygonStipple</refentrytitle></citerefentry>), bitmaps (see
<citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>), texture patterns (see <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>).
Additionally, if the <code>ARB_imaging</code> extension is supported, pixel
storage modes affect convolution filters
(see <citerefentry><refentrytitle>glConvolutionFilter1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glConvolutionFilter2D</refentrytitle></citerefentry>, and
<citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry>, color table (see <citerefentry><refentrytitle>glColorTable</refentrytitle></citerefentry>, and
<citerefentry><refentrytitle>glColorSubTable</refentrytitle></citerefentry>, and unpacking histogram (See <citerefentry><refentrytitle>glHistogram</refentrytitle></citerefentry>),
and minmax (See <citerefentry><refentrytitle>glMinmax</refentrytitle></citerefentry>) data.
</para>
<para>
<parameter>pname</parameter> is a symbolic constant indicating the parameter to be set, and
<parameter>param</parameter> is the new value. Six of the twelve storage parameters affect
how pixel data is returned to client memory.
They are as follows:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_PACK_SWAP_BYTES</constant></term>
<listitem>
<para>
If true,
byte ordering for multibyte color components,
depth components,
color indices,
or stencil indices
is reversed.
That is,
if a four-byte component consists of bytes
<inlineequation><mml:math>
<!-- eqn: b sub 0:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>0</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 1:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 2:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 3:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>3</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
it is stored in memory as
<inlineequation><mml:math>
<!-- eqn: b sub 3:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>3</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 2:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 1:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 0:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>0</mml:mn>
</mml:msub>
</mml:math></inlineequation>
if <constant>GL_PACK_SWAP_BYTES</constant> is true.
<constant>GL_PACK_SWAP_BYTES</constant> has no effect on the memory order of components
within a pixel,
only on the order of bytes within components or indices.
For example,
the three components of a <constant>GL_RGB</constant> format pixel are always stored with
red first,
green second,
and blue third,
regardless of the value of <constant>GL_PACK_SWAP_BYTES</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_PACK_LSB_FIRST</constant></term>
<listitem>
<para>
If true,
bits are ordered within a byte from least significant to most significant;
otherwise,
the first bit in each byte is the most significant one.
This parameter is significant for bitmap data only.
</para>
</listitem>
</varlistentry>
<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><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>
<!-- 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>⁢</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>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mtable>
<mml:mtr><mml:mtd>
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>>=</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><</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><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
is the number of components or indices in a pixel,
<inlineequation><mml:math><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><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
argument to the pixel routine otherwise),
<inlineequation><mml:math><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
is the value of <constant>GL_PACK_ALIGNMENT</constant>, and
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
is the size, in bytes, of a single component
(if
<inlineequation><mml:math>
<!-- 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>,
then it is as if
<inlineequation><mml:math>
<!-- 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>
<!-- 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>⁢</mml:mo>
<mml:mi mathvariant="italic">a</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</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>⁢</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_IMAGE_HEIGHT</constant></term>
<listitem>
<para>
If greater than 0,
<constant>GL_PACK_IMAGE_HEIGHT</constant> defines the number of pixels in an image
three-dimensional texture volume, where ``image'' is defined by all pixels
sharing the same third dimension index.
If the first pixel of a row is placed at location
<inlineequation><mml:math><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>
<!-- 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>⁢</mml:mo>
<mml:mi mathvariant="italic">l</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">l</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mtable>
<mml:mtr><mml:mtd>
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>>=</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><</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><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
is the number of components or indices
in a pixel,
<inlineequation><mml:math><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><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
argument to <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> otherwise),
<inlineequation><mml:math><mml:mi mathvariant="italic">h</mml:mi></mml:math></inlineequation>
is the number of
rows in a pixel image (<constant>GL_PACK_IMAGE_HEIGHT</constant> if it is greater than
0, the
<inlineequation><mml:math><mml:mi mathvariant="italic">height</mml:mi></mml:math></inlineequation>
argument to the <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> routine otherwise),
<inlineequation><mml:math><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
is the value of
<constant>GL_PACK_ALIGNMENT</constant>, and
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
is the size, in bytes, of a single
component (if
<inlineequation><mml:math>
<!-- 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>,
then it is as if
<inlineequation><mml:math>
<!-- 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_PACK_SKIP_PIXELS</constant>, <constant>GL_PACK_SKIP_ROWS</constant>, and <constant>GL_PACK_SKIP_IMAGES</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><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
is equivalent to incrementing
the pointer by
<inlineequation><mml:math>
<!-- eqn: i n:-->
<mml:mrow>
<mml:mi mathvariant="italic">i</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
</mml:mrow>
</mml:math></inlineequation>
components or indices,
where
<inlineequation><mml:math><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><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>
is equivalent to incrementing
the pointer by
<inlineequation><mml:math>
<!-- eqn: j m:-->
<mml:mrow>
<mml:mi mathvariant="italic">j</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">m</mml:mi>
</mml:mrow>
</mml:math></inlineequation>
components or indices,
where
<inlineequation><mml:math><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.
Setting <constant>GL_PACK_SKIP_IMAGES</constant> to
<inlineequation><mml:math><mml:mi mathvariant="italic">k</mml:mi></mml:math></inlineequation>
is equivalent to incrementing
the pointer by
<inlineequation><mml:math>
<!-- eqn: k p:-->
<mml:mrow>
<mml:mi mathvariant="italic">k</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">p</mml:mi>
</mml:mrow>
</mml:math></inlineequation>,
where
<inlineequation><mml:math><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_PACK_IMAGE_HEIGHT</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 twelve storage parameters affect how pixel data is
read from client memory.
These values are significant for <citerefentry><refentrytitle>glDrawPixels</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>,
<citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>, and
<citerefentry><refentrytitle>glPolygonStipple</refentrytitle></citerefentry>.
</para>
<para>
Additionally, if the <code>ARB_imaging</code> extension is supported,
<citerefentry><refentrytitle>glColorTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glColorSubTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter2D</refentrytitle></citerefentry>, and
<citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry>.
They are as follows:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_UNPACK_SWAP_BYTES</constant></term>
<listitem>
<para>
If true,
byte ordering for multibyte color components,
depth components,
color indices,
or stencil indices
is reversed.
That is,
if a four-byte component consists of bytes
<inlineequation><mml:math>
<!-- eqn: b sub 0:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>0</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 1:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 2:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 3:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>3</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
it is taken from memory as
<inlineequation><mml:math>
<!-- eqn: b sub 3:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>3</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 2:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>2</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 1:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>1</mml:mn>
</mml:msub>
</mml:math></inlineequation>,
<inlineequation><mml:math>
<!-- eqn: b sub 0:-->
<mml:msub><mml:mi mathvariant="italic">b</mml:mi>
<mml:mn>0</mml:mn>
</mml:msub>
</mml:math></inlineequation>
if <constant>GL_UNPACK_SWAP_BYTES</constant> is true.
<constant>GL_UNPACK_SWAP_BYTES</constant> has no effect on the memory order of components
within a pixel,
only on the order of bytes within components or indices.
For example,
the three components of a <constant>GL_RGB</constant> format pixel are always stored with
red first,
green second,
and blue third,
regardless of the value of <constant>GL_UNPACK_SWAP_BYTES</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_UNPACK_LSB_FIRST</constant></term>
<listitem>
<para>
If true,
bits are ordered within a byte from least significant to most significant;
otherwise,
the first bit in each byte is the most significant one.
This is relevant only for bitmap data.
</para>
</listitem>
</varlistentry>
<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><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>
<!-- 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>⁢</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>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mtable>
<mml:mtr><mml:mtd>
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>>=</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><</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><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
is the number of components or indices in a pixel,
<inlineequation><mml:math><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><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
argument to the pixel routine otherwise),
<inlineequation><mml:math><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
is the value of <constant>GL_UNPACK_ALIGNMENT</constant>, and
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
is the size, in bytes, of a single component
(if
<inlineequation><mml:math>
<!-- 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>,
then it is as if
<inlineequation><mml:math>
<!-- 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>
<!-- 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>⁢</mml:mo>
<mml:mi mathvariant="italic">a</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</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>⁢</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><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>
<!-- 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>⁢</mml:mo>
<mml:mi mathvariant="italic">l</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mfenced open="⌈" close="⌉">
<mml:mfrac>
<mml:mfenced open="" close="">
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">l</mml:mi>
<mml:mo>⁢</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>⁢</mml:mo>
<mml:mtable>
<mml:mtr><mml:mtd>
<mml:mrow>
<mml:mi mathvariant="italic">s</mml:mi>
<mml:mo>>=</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><</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><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
is the number of components or indices in a pixel,
<inlineequation><mml:math><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><mml:mi mathvariant="italic">width</mml:mi></mml:math></inlineequation>
argument to <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> otherwise),
<inlineequation><mml:math><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><mml:mi mathvariant="italic">height</mml:mi></mml:math></inlineequation>
argument to <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry> otherwise),
<inlineequation><mml:math><mml:mi mathvariant="italic">a</mml:mi></mml:math></inlineequation>
is the value of <constant>GL_UNPACK_ALIGNMENT</constant>, and
<inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>
is the size, in bytes, of a single component
(if
<inlineequation><mml:math>
<!-- 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>,
then it is as if
<inlineequation><mml:math>
<!-- 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> and <constant>GL_UNPACK_SKIP_ROWS</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>glDrawPixels</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>, or
<citerefentry><refentrytitle>glPolygonStipple</refentrytitle></citerefentry>.
Setting <constant>GL_UNPACK_SKIP_PIXELS</constant> to
<inlineequation><mml:math><mml:mi mathvariant="italic">i</mml:mi></mml:math></inlineequation>
is equivalent to incrementing
the pointer by
<inlineequation><mml:math>
<!-- eqn: i n:-->
<mml:mrow>
<mml:mi mathvariant="italic">i</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">n</mml:mi>
</mml:mrow>
</mml:math></inlineequation>
components or indices,
where
<inlineequation><mml:math><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><mml:mi mathvariant="italic">j</mml:mi></mml:math></inlineequation>
is equivalent to incrementing
the pointer by
<inlineequation><mml:math>
<!-- eqn: j k:-->
<mml:mrow>
<mml:mi mathvariant="italic">j</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">k</mml:mi>
</mml:mrow>
</mml:math></inlineequation>
components or indices,
where
<inlineequation><mml:math><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.
</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>glPixelStore</function>.
</para>
<para>
</para>
<informaltable frame="topbot">
<tgroup cols="4" align="left">
<colspec colwidth="2.5*" />
<colspec colwidth="1*" align="center"/>
<colspec colwidth="1*" align="center"/>
<colspec colwidth="2*" align="center"/>
<thead>
<row>
<entry rowsep="1" align="left"><emphasis role="bold">
<parameter>pname</parameter>
</emphasis></entry>
<entry rowsep="1" align="center"><emphasis role="bold">
Type
</emphasis></entry>
<entry rowsep="1" align="center"><emphasis role="bold">
Initial Value
</emphasis></entry>
<entry rowsep="1" align="center"><emphasis role="bold">
Valid Range
</emphasis></entry>
</row>
</thead>
<tbody>
<row>
<entry align="left">
<constant>GL_PACK_SWAP_BYTES</constant>
</entry>
<entry align="center">
boolean
</entry>
<entry align="center">
false
</entry>
<entry align="center">
true or false
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_LSB_FIRST</constant>
</entry>
<entry align="center">
boolean
</entry>
<entry align="center">
false
</entry>
<entry align="center">
true or false
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_ROW_LENGTH</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_IMAGE_HEIGHT</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0, \(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_SKIP_ROWS</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_SKIP_PIXELS</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_SKIP_IMAGES</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_PACK_ALIGNMENT</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
4
</entry>
<entry align="center">
1, 2, 4, or 8
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_SWAP_BYTES</constant>
</entry>
<entry align="center">
boolean
</entry>
<entry align="center">
false
</entry>
<entry align="center">
true or false
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_LSB_FIRST</constant>
</entry>
<entry align="center">
boolean
</entry>
<entry align="center">
false
</entry>
<entry align="center">
true or false
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_ROW_LENGTH</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_IMAGE_HEIGHT</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_SKIP_ROWS</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_SKIP_PIXELS</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_SKIP_IMAGES</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
0
</entry>
<entry align="center">
<inlineequation><mml:math>
<!-- eqn: left [ 0,\(if right ):-->
<mml:mfenced open="[" close=")">
<mml:mn>0</mml:mn>
<mml:infinity/>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_UNPACK_ALIGNMENT</constant>
</entry>
<entry align="center">
integer
</entry>
<entry align="center">
4
</entry>
<entry align="center">
1, 2, 4, or 8
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
<function>glPixelStoref</function> can be used to set any pixel store parameter.
If the parameter type is boolean,
then if <parameter>param</parameter> is 0,
the parameter is false;
otherwise it is set to true.
If <parameter>pname</parameter> is a integer type parameter,
<parameter>param</parameter> is rounded to the nearest integer.
</para>
<para>
Likewise, <function>glPixelStorei</function> can also be used to set any of the
pixel store parameters.
Boolean parameters are set to false if <parameter>param</parameter> is 0 and true otherwise.
</para>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para>
The pixel storage modes in effect when
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glReadPixels</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>,
<citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>,
or <citerefentry><refentrytitle>glPolygonStipple</refentrytitle></citerefentry> is placed in a display list control the interpretation
of memory data.
Likewise, if the <code>ARB_imaging</code> extension is supported, the pixel
storage modes in effect when
<citerefentry><refentrytitle>glColorTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glColorSubTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter2D</refentrytitle></citerefentry>, of
<citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry> is placed in a display list control the
interpretation of memory data.
The pixel storage modes in effect when a display list is executed are
not significant.
</para>
<para>
Pixel storage modes are client state and must be pushed and restored
using
<citerefentry><refentrytitle>glPushClientAttrib</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glPopClientAttrib</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 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>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glPixelStore</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>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_SWAP_BYTES</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PACK_LSB_FIRST</constant>
</para>
<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_IMAGE_HEIGHT</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_SKIP_IMAGES</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_SWAP_BYTES</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_UNPACK_LSB_FIRST</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 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glColorTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glColorSubTable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter1D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glConvolutionFilter2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glHistogram</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMinmax</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelMap</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelTransfer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelZoom</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPolygonStipple</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPushClientAttrib</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glReadPixels</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>