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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glTexSubImage2D">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2013</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glTexSubImage2D</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glTexSubImage2D</refname>
        <refpurpose>specify a two-dimensional texture subimage</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glTexSubImage2D</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLint <parameter>level</parameter></paramdef>
                <paramdef>GLint <parameter>xoffset</parameter></paramdef>
                <paramdef>GLint <parameter>yoffset</parameter></paramdef>
                <paramdef>GLsizei <parameter>width</parameter></paramdef>
                <paramdef>GLsizei <parameter>height</parameter></paramdef>
                <paramdef>GLenum <parameter>format</parameter></paramdef>
                <paramdef>GLenum <parameter>type</parameter></paramdef>
                <paramdef>const GLvoid * <parameter>data</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>target</parameter></term>
            <listitem>
                <para>
                    Specifies the target texture.
                    Must be <constant>GL_TEXTURE_2D</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
                    <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>,
                    or <constant>GL_TEXTURE_1D_ARRAY</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>level</parameter></term>
            <listitem>
                <para>
                    Specifies the level-of-detail number.
                    Level 0 is the base image level.
                    Level <emphasis>n</emphasis> is the <emphasis>n</emphasis>th mipmap reduction image.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>xoffset</parameter></term>
            <listitem>
                <para>
                    Specifies a texel offset in the x direction within the texture array.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>yoffset</parameter></term>
            <listitem>
                <para>
                    Specifies a texel offset in the y direction within the texture array.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>width</parameter></term>
            <listitem>
                <para>
                    Specifies the width of the texture subimage.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>height</parameter></term>
            <listitem>
                <para>
                    Specifies the height of the texture subimage.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>format</parameter></term>
            <listitem>
                <para>
                    Specifies the format of the pixel data.
                    The following symbolic values are accepted:
                    <constant>GL_RED</constant>,
                    <constant>GL_RG</constant>,
                    <constant>GL_RGB</constant>,
                    <constant>GL_BGR</constant>,
                    <constant>GL_RGBA</constant>,
                    <constant>GL_BGRA</constant>,
                    <constant>GL_DEPTH_COMPONENT</constant>, and
                    <constant>GL_STENCIL_INDEX</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>type</parameter></term>
            <listitem>
                <para>
                    Specifies the data type of the pixel data.
                    The following symbolic values are accepted:
                    <constant>GL_UNSIGNED_BYTE</constant>,
                    <constant>GL_BYTE</constant>,
                    <constant>GL_UNSIGNED_SHORT</constant>,
                    <constant>GL_SHORT</constant>,
                    <constant>GL_UNSIGNED_INT</constant>,
                    <constant>GL_INT</constant>,
                    <constant>GL_FLOAT</constant>,
                    <constant>GL_UNSIGNED_BYTE_3_3_2</constant>,
                    <constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>,
                    <constant>GL_UNSIGNED_SHORT_5_6_5</constant>,
                    <constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>,
                    <constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
                    <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
                    <constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
                    <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
                    <constant>GL_UNSIGNED_INT_8_8_8_8</constant>,
                    <constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>,
                    <constant>GL_UNSIGNED_INT_10_10_10_2</constant>, and
                    <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>data</parameter></term>
            <listitem>
                <para>
                    Specifies a pointer to the image data in memory.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            Texturing maps a portion of a specified texture image
            onto each graphical primitive for which texturing is enabled.
        </para>
        <para>
            <function>glTexSubImage2D</function> redefines a contiguous subregion of an existing two-dimensional
            or one-dimensional arary texture image.
            The texels referenced by <parameter>data</parameter> replace the portion of the
            existing texture array with x indices <parameter>xoffset</parameter> and
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: xoffset + width - 1: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">xoffset</mml:mi>
                    <mml:mo>+</mml:mo>
                    <mml:mi mathvariant="italic">width</mml:mi>
                    <mml:mo>-</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            inclusive,
            and y indices <parameter>yoffset</parameter> and
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: yoffset + height - 1: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">yoffset</mml:mi>
                    <mml:mo>+</mml:mo>
                    <mml:mi mathvariant="italic">height</mml:mi>
                    <mml:mo>-</mml:mo>
                    <mml:mn>1</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            inclusive.
            This region may not include any texels outside the range of the
            texture array as it was originally specified.
            It is not an error to specify a subtexture with zero width or height, but
            such a specification has no effect.
        </para>
        <para>
            If a non-zero named buffer object is bound to the <constant>GL_PIXEL_UNPACK_BUFFER</constant> target
            (see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a texture image is
            specified, <parameter>data</parameter> is treated as a byte offset into the buffer object's data store.
        </para>
    </refsect1>
    <refsect1 xml:id="notes"><title>Notes</title>
        <para>
            <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> modes affect texture images.
        </para>
        <para>
            <function>glTexSubImage2D</function> specifies a two-dimensional subtexture for the current texture unit,
            specified with <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>.
        </para>
        <para>
            <constant>GL_STENCIL_INDEX</constant> is accepted for <parameter>format</parameter> only if the GL version
            is 4.4 or higher.
        </para>
    </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not <constant>GL_TEXTURE_2D</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
            <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
            <constant>GL_TEXTURE_1D_ARRAY</constant>.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>format</parameter> is not an accepted
            format constant.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>type</parameter> is not a type constant.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>level</parameter> is less than 0.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> may be generated if <parameter>level</parameter> is greater
            than
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: log sub 2: -->
                <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                <mml:mn>2</mml:mn>
                </mml:msub>
            </mml:math></inlineequation>
            <emphasis>max</emphasis>,
            where <emphasis>max</emphasis> is the returned value of <constant>GL_MAX_TEXTURE_SIZE</constant>.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: xoffset  <   -b: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">xoffset</mml:mi>
                    <mml:mo>&lt;</mml:mo>
                    <mml:mrow>
                        <mml:mo>-</mml:mo>
                        <mml:mi mathvariant="italic">b</mml:mi>
                    </mml:mrow>
                </mml:mrow>
            </mml:math></inlineequation>,
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: (xoffset + width)  >  (w - b): -->
                <mml:mrow>
                    <mml:mfenced open="(" close=")">
                        <mml:mrow>
                            <mml:mi mathvariant="italic">xoffset</mml:mi>
                            <mml:mo>+</mml:mo>
                            <mml:mi mathvariant="italic">width</mml:mi>
                        </mml:mrow>
                    </mml:mfenced>
                    <mml:mo>&gt;</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mrow>
                            <mml:mi mathvariant="italic">w</mml:mi>
                            <mml:mo>-</mml:mo>
                            <mml:mi mathvariant="italic">b</mml:mi>
                        </mml:mrow>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math></inlineequation>,
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: yoffset  <   -b: -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">yoffset</mml:mi>
                    <mml:mo>&lt;</mml:mo>
                    <mml:mrow>
                        <mml:mo>-</mml:mo>
                        <mml:mi mathvariant="italic">b</mml:mi>
                    </mml:mrow>
                </mml:mrow>
            </mml:math></inlineequation>,
            or
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: (yoffset  +  height)  >  (h - b): -->
                <mml:mrow>
                    <mml:mfenced open="(" close=")">
                        <mml:mrow>
                            <mml:mi mathvariant="italic">yoffset</mml:mi>
                            <mml:mo>+</mml:mo>
                            <mml:mi mathvariant="italic">height</mml:mi>
                        </mml:mrow>
                    </mml:mfenced>
                    <mml:mo>&gt;</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mrow>
                            <mml:mi mathvariant="italic">h</mml:mi>
                            <mml:mo>-</mml:mo>
                            <mml:mi mathvariant="italic">b</mml:mi>
                        </mml:mrow>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math></inlineequation>,
            where
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math></inlineequation>
            is the <constant>GL_TEXTURE_WIDTH</constant>,
            <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 <constant>GL_TEXTURE_HEIGHT</constant>, and
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">b</mml:mi></mml:math></inlineequation>
            is the border width
            of the texture image being modified.
            Note that
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math></inlineequation>
            and
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math></inlineequation>
            include twice the border width.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>width</parameter> or <parameter>height</parameter> is less than 0.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the texture array has not
            been defined by a previous <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry> operation.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is one of
            <constant>GL_UNSIGNED_BYTE_3_3_2</constant>,
            <constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>,
            <constant>GL_UNSIGNED_SHORT_5_6_5</constant>, or
            <constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>
            and <parameter>format</parameter> is not <constant>GL_RGB</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is one of
            <constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>,
            <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>,
            <constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>,
            <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>,
            <constant>GL_UNSIGNED_INT_8_8_8_8</constant>,
            <constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>,
            <constant>GL_UNSIGNED_INT_10_10_10_2</constant>, or
            <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>
            and <parameter>format</parameter> is neither <constant>GL_RGBA</constant> nor <constant>GL_BGRA</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>format</parameter> is <constant>GL_STENCIL_INDEX</constant>
            and the base internal format is not <constant>GL_STENCIL_INDEX</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
            <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's data store is currently mapped.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
            <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be unpacked from the buffer
            object such that the memory reads required would exceed the data store size.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
            <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and <parameter>data</parameter> is not evenly divisible
            into the number of bytes needed to store in memory a datum indicated by <parameter>type</parameter>.
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGetTexImage</refentrytitle></citerefentry>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant>
        </para>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexParameter</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"/> 2010-2013 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>
