sdk/2.1/docs/man/imageMipmapFunctions2DInc.xml

<!-- imageMipmapFunctionsInc -->

    <bridgehead>Mipmap read image functions:</bridgehead>

    <para>
        For the forms that take an <type>image2d_t</type> object,
        use the coordinate <varname>coord.xy</varname> to
        do an element lookup in the mip-level specified by
        <varname>lod</varname> in the 2D image object specified
        by <varname>image</varname>.
    </para>

    <para>
        For the forms that use gradients, use the gradients to compute
        the lod and coordinate <emphasis>coord.xy</emphasis> to do an
        element lookup in
        the mip-level specified by the computed lod in
        the 2D image object specified by <varname>image</varname>.
    </para>

    <para>
        For the forms that take an <type>image2d_array_t</type> object,
        use the coordinate <emphasis>coord.xy</emphasis> to
        do an element lookup in the 2D image identified by
        <emphasis>coord.z</emphasis> and mip-level specified by
        <varname>lod</varname> in the 2D image object specified
        by <varname>image</varname>.
    </para>

    <para>
        For the forms that take an <type>image2d_array_t</type>
        object and that use gradients,
        use the gradients to compute the lod coordinate
        and <emphasis>coord.xy</emphasis> to
        do an element lookup in the 2D image identified by
        <emphasis>coord.z</emphasis> and mip-level specified by
        <varname>lod</varname> in the 2D image object specified
        by <varname>image</varname>.
    </para>

    <para>
        When a multisample image is accessed in a kernel,
        the access takes one vector of
        integers describing which pixel to fetch and an
        integer corresponding to the sample numbers
        describing which sample within the pixel to fetch.
        sample identifies the sample position in the
        multi-sample image.
    </para>

    <para>
        NOTE: <constant>CL_SAMPLER_NORMALIZED_COORDS</constant>
        must be <constant>CL_TRUE</constant> for built-in functions
        described in the table above that read from a
        mip-mapped image; otherwise the behavior is
        undefined. The value specified in the
        <varname>lod</varname> argument is clamped to the minimum of (actual
        number of mip-levels - 1) in the image or value
        specified for <constant>CL_SAMPLER_LOD_MAX_KHR</constant>.
    </para>

<!-- 17-Dec-2013, rev. 19 -->