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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glCopyTexSubImage1D">
    <info>
        <copyright>
            <year>2013</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glCopyTexSubImage1D</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glCopyTexSubImage1D</refname>
        <refpurpose>copy a one-dimensional texture subimage</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glCopyTexSubImage1D</function></funcdef>
                <paramdef>GLenum <parameter>target</parameter></paramdef>
                <paramdef>GLint <parameter>level</parameter></paramdef>
                <paramdef>GLint <parameter>xoffset</parameter></paramdef>
                <paramdef>GLint <parameter>x</parameter></paramdef>
                <paramdef>GLint <parameter>y</parameter></paramdef>
                <paramdef>GLsizei <parameter>width</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_1D</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 the texel offset within the texture array.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>x</parameter></term>
            <term><parameter>y</parameter></term>
            <listitem>
                <para>
                    Specify the window coordinates of the left corner
                    of the row of pixels to be copied.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>width</parameter></term>
            <listitem>
                <para>
                    Specifies the width of the texture subimage.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glCopyTexSubImage1D</function> replaces a portion of a one-dimensional
            texture image with pixels from the current <constant>GL_READ_BUFFER</constant> (rather
            than from main memory, as is the case for <citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>).
        </para>
        <para>
            The screen-aligned pixel row with left corner at (<parameter>x</parameter>,\ <parameter>y</parameter>), and with
            length <parameter>width</parameter> replaces the portion of the
            texture array with x indices <parameter>xoffset</parameter> through
            <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. The destination in the texture array may not
            include any texels outside the texture array as it was
            originally specified.
        </para>
        <para>
            The pixels in the row are processed exactly as if
            <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> had been called, but the process stops just before
            final conversion.
            At this point, all pixel component values are clamped to the range
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: [0,1]: -->
                <mml:mfenced open="[" close="]">
                    <mml:mn>0</mml:mn>
                    <mml:mn>1</mml:mn>
                </mml:mfenced>
            </mml:math></inlineequation>
            and then converted to the texture's internal format for storage in the texel
            array.
        </para>
        <para>
            It is not an error to specify a subtexture with zero width, but
            such a specification has no effect.
            If any of the pixels within the specified row of the current
            <constant>GL_READ_BUFFER</constant> are outside the read window associated with the current
            rendering context, then the values obtained for those pixels are undefined.
        </para>
        <para>
            No change is made to the <emphasis>internalformat</emphasis> or <emphasis>width</emphasis> parameters of the specified texture
            array or to texel values outside the specified subregion.
        </para>
    </refsect1>
    <refsect1 xml:id="notes"><title>Notes</title>
        <para>
            The <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> mode affects texture images.
        </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_1D</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the texture array has not
            been defined by a previous <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry> operation.
        </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
            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: level  >  log sub 2(max): -->
                <mml:mrow>
                    <mml:mi mathvariant="italic">level</mml:mi>
                    <mml:mo>&gt;</mml:mo>
                    <mml:mrow>
                        <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
                        <mml:mn>2</mml:mn>
                        </mml:msub>
                        <mml:mo>&af;</mml:mo>
                        <mml:mfenced open="(" close=")">
                            <mml:mi mathvariant="italic">max</mml:mi>
                        </mml:mfenced>
                    </mml:mrow>
                </mml:mrow>
            </mml:math></inlineequation>,
            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:mn>0</mml:mn>
                </mml:mrow>
            </mml:math></inlineequation>,
            or
            <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:mi mathvariant="italic">w</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">w</mml:mi></mml:math></inlineequation>
            is the <constant>GL_TEXTURE_WIDTH</constant>
            of the texture image being modified.
        </para>
        <para>
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGetTexImage</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glReadBuffer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexSubImage1D</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"/> 2012-2013 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>
