<?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="glCopyImageSubData">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>2012</year>
                <holder>Khronos Group</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glCopyImageSubData</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glCopyImageSubData</refname>
        <refpurpose>perform a raw data copy between two images</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glCopyImageSubData</function></funcdef>
                <paramdef>GLuint <parameter>srcName</parameter></paramdef>
                <paramdef>GLenum <parameter>srcTarget</parameter></paramdef>
                <paramdef>GLint <parameter>srcLevel</parameter></paramdef>
                <paramdef>GLint <parameter>srcX</parameter></paramdef>
                <paramdef>GLint <parameter>srcY</parameter></paramdef>
                <paramdef>GLint <parameter>srcZ</parameter></paramdef>
                <paramdef>GLuint <parameter>dstName</parameter></paramdef>
                <paramdef>GLenum <parameter>dstTarget</parameter></paramdef>
                <paramdef>GLint <parameter>dstLevel</parameter></paramdef>
                <paramdef>GLint <parameter>dstX</parameter></paramdef>
                <paramdef>GLint <parameter>dstY</parameter></paramdef>
                <paramdef>GLint <parameter>dstZ</parameter></paramdef>
                <paramdef>GLsizei <parameter>srcWidth</parameter></paramdef>
                <paramdef>GLsizei <parameter>srcHeight</parameter></paramdef>
                <paramdef>GLsizei <parameter>srcDepth</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>srcName</parameter></term>
            <listitem>
                <para>
                    The name of a texture or renderbuffer object from which to copy.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcTarget</parameter></term>
            <listitem>
                <para>
                    The target representing the namespace of the source name <parameter>srcName</parameter>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcLevel</parameter></term>
            <listitem>
                <para>
                    The mipmap level to read from the source.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcX</parameter></term>
            <listitem>
                <para>
                    The X coordinate of the left edge of the souce region to copy.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcY</parameter></term>
            <listitem>
                <para>
                    The Y coordinate of the top edge of the souce region to copy.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcZ</parameter></term>
            <listitem>
                <para>
                    The Z coordinate of the near edge of the souce region to copy.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstName</parameter></term>
            <listitem>
                <para>
                    The name of a texture or renderbuffer object to which to copy.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstTarget</parameter></term>
            <listitem>
                <para>
                    The target representing the namespace of the destination name <parameter>dstName</parameter>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstX</parameter></term>
            <listitem>
                <para>
                    The X coordinate of the left edge of the destination region.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstY</parameter></term>
            <listitem>
                <para>
                    The Y coordinate of the top edge of the destination region.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>dstZ</parameter></term>
            <listitem>
                <para>
                    The Z coordinate of the near edge of the destination region.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcWidth</parameter></term>
            <listitem>
                <para>
                    The width of the region to be copied.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcHeight</parameter></term>
            <listitem>
                <para>
                    The height of the region to be copied.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>srcDepth</parameter></term>
            <listitem>
                <para>
                    The depth of the region to be copied.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>glCopyImageSubData</function> may be used to copy data from
            one image (i.e. texture or renderbuffer) to another. <function>glCopyImageSubData</function>
            does not perform general-purpose conversions
            such as scaling, resizing, blending, color-space, or format
            conversions. It should be considered to operate in a manner
            similar to a CPU memcpy. CopyImageSubData can copy between
            images with different internal formats, provided
            the formats are compatible.
        </para>
        <para>
            <function>glCopyImageSubData</function> also allows copying between certain 
            types of compressed and uncompressed internal formats. This copy does not perform on-the-fly compression
            or decompression. When copying from an uncompressed internal format
            to a compressed internal format, each texel of uncompressed data
            becomes a single block of compressed data. When copying from a
            compressed internal format to an uncompressed internal format,
            a block of compressed data becomes a single texel of uncompressed
            data. The texel size of the uncompressed format must be the same
            size the block size of the compressed formats. Thus it is permitted
            to copy between a 128-bit uncompressed format and a compressed
            format which uses 8-bit 4x4 blocks, or between a 64-bit uncompressed
            format and a compressed format which uses 4-bit 4x4 blocks.
        </para>
        <para>
            The source object is identified by <parameter>srcName</parameter> and
            <parameter>srcTarget</parameter> and the destination object is identified
            by <parameter>dstName</parameter> and <parameter>dstTarget</parameter>.
            The interpretation of the name depends on the value
            of the corresponding <parameter>target</parameter> parameter.
            If <parameter>target</parameter> is
            <constant>GL_RENDERBUFFER</constant>, the name is interpreted as the name of a
            renderbuffer object.  If the target parameter is a texture target,
            the name is interpreted as a texture object.  All non-proxy
            texture targets are accepted, with the exception of <constant>GL_TEXTURE_BUFFER</constant>
            and the cubemap face selectors.
        </para>
        <para>
            <parameter>srcLevel</parameter> and <parameter>dstLevel</parameter> identify the source and destination
            level of detail.  For textures, this must be a valid level of
            detail in the texture object.  For renderbuffers, this value must
            be zero.
        </para>
        <para>
            <parameter>srcX</parameter>, <parameter>srcY</parameter>, and <parameter>srcZ</parameter> specify the lower left texel
            coordinates of a <parameter>srcWidth</parameter>-wide by <parameter>srcHeight</parameter>-high by 
            <parameter>srcDepth</parameter>-deep rectangular subregion of the source texel array.  
            Similarly, <parameter>dstX</parameter>, <parameter>dstY</parameter> and <parameter>dstZ</parameter> specify the coordinates of a subregion of the
            destination texel array.  The source and destination subregions
            must be contained entirely within the specified level of the
            corresponding image objects.
        </para>
        <para>
            The dimensions are always specified in texels, even for compressed
            texture formats. However, it should be noted that if only one of the
            source and destination textures is compressed then the number of
            texels touched in the compressed image will be a factor of the
            block size larger than in the uncompressed image.
        </para>
        <para>
            Slices of a <constant>GL_TEXTURE_1D_ARRAY</constant>, <constant>GL_TEXTURE_2D_ARRAY</constant>, <constant>GL_TEXTURE_CUBE_MAP_ARRAY</constant>
            <constant>GL_TEXTURE_3D</constant> and faces of <constant>GL_TEXTURE_CUBE_MAP</constant> are all compatible provided 
            they share a compatible internal format, and multiple slices or faces
            may be copied between these objects with a single call by specifying the
            starting slice with <parameter>srcZ</parameter> and <parameter>dstZ</parameter>, and the number of slices to
            be copied with <parameter>srcDepth</parameter>.  Cubemap textures always have six faces
            which are selected by a zero-based face index.
        </para>
        <para>
            For the purposes of CopyImageSubData, two internal formats
    are considered compatible if any of the following conditions are
    met:
     * the formats are the same,
     * the formats are considered compatible according to the 
       compatibility rules used for texture views as defined in 
       section 3.9.X. In particular, if both internal formats are listed
       in the same entry of Table 3.X.2, they are considered compatible, or
     * one format is compressed and the other is uncompressed and
       Table 4.X.1 lists the two formats in the same row.
    If the formats are not compatible INVALID_OPERATION is generated.
        </para>
<table frame="topbot"><title>Sized Internal Formats</title>
<tgroup cols="3" align="left">
    <colspec align="left"/>
    <colspec align="left"/>
    <colspec align="left"/>
    <thead>
        <row>
            <entry rowsep="1" align="left"><emphasis role="bold">
            Texel / Block Size
            </emphasis></entry>
            <entry rowsep="1" align="left"><emphasis role="bold">
            Uncompressed Internal Format
            </emphasis></entry>
            <entry rowsep="1" align="left"><emphasis role="bold">
            Compressed Internal Format(s)
            </emphasis></entry>
        </row>
    </thead>
    <tbody>
        <row>
            <entry>64-bit</entry>
            <entry><constant>GL_RGBA32UI</constant>, <constant>GL_RGBA32I</constant>, <constant>GL_RGBA32F</constant></entry>
            <entry><constant>GL_COMPRESSED_RGBA_S3TC_DXT3_EXT</constant>,
                   <constant>GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT</constant>,
                   <constant>GL_COMPRESSED_RGBA_S3TC_DXT5_EXT</constant>,
                   <constant>GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT</constant>,
                   <constant>GL_COMPRESSED_RG_RGTC2</constant>,
                   <constant>GL_COMPRESSED_SIGNED_RG_RGTC2</constant>,
                   <constant>GL_COMPRESSED_RGBA_BPTC_UNORM</constant>,
                   <constant>GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM</constant>,
                   <constant>GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT</constant>,
                   <constant>GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT</constant></entry>
        </row>
        <row>
            <entry>128-bit</entry>
            <entry><constant>GL_RGBA16UI</constant>,
                   <constant>GL_RGBA16I</constant>,
                   <constant>GL_RGBA16F</constant>,
                   <constant>GL_RG32F</constant>,
                   <constant>GL_RG32UI</constant>,
                   <constant>GL_RG32I</constant>,
                   <constant>GL_RGBA16</constant>,
                   <constant>GL_RGBA16_SNORM</constant></entry>
            <entry><constant>GL_COMPRESSED_RGB_S3TC_DXT1_EXT</constant>,
                   <constant>COMPRESSED_SRGB_S3TC_DXT1_EXT</constant>,
                   <constant>COMPRESSED_RGBA_S3TC_DXT1_EXT</constant>,
                   <constant>COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT</constant>,
                   <constant>COMPRESSED_RED_RGTC1</constant>,
                   <constant>COMPRESSED_SIGNED_RED_RGTC1</constant></entry>
        </row>
    </tbody>
</tgroup>
</table>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the texel size of
            the uncompressed image is not equal to the block size of the
            compressed image.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if either target parameter is not <constant>GL_RENDERBUFFER</constant>,
            a valid non-proxy texture target other than <constant>GL_TEXTURE_BUFFER</constant>, or is one
            of the cubemap face selectors.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> does not match the type of the object.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if either object is a texture and the texture is
            not complete.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if the source and 
            destination internal formats are not compatible, or if the number of samples do not match.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if either name does not correspond to a
            valid renderbuffer or texture object according to the corresponding
            target parameter.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if the specified level of either the source or destination is not
            a valid level for the corresponding image.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if the
            dimensions of the either subregion exceeds the boundaries of the
            corresponding image object, or if the image format is compressed
            and the dimensions of the subregion fail to meet the alignment
            constraints of the format.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_MAX_COMPUTE_WORK_GROUP_COUNT</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glDispatchComputeIndirect</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 2012 Khronos Group. 
            This material may be distributed subject to the terms and conditions set forth in 
            the Open Publication License, v 1.0, 8 June 1999.
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
        </para>
    </refsect1>
</refentry>
