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    <title>read_imageh (3D)</title>
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      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="read_image2d"></a>
        <h1>read_imageh (3D)</h1>
        <p>
            Do an element lookup in the 3D image object, returning half floating-point values.
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
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              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    half4
                    <strong class="fsfunc">                   
                        read_imageh
                    </strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="otherDataTypes.html" target="_top">image3d_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">image</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="otherDataTypes.html" target="_top">sampler_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">sampler</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>int4 <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">coord</var><code>)</code></td>
            </tr>
          </table>
        </div>
        <div class="funcsynopsis">
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              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    half4
                    <strong class="fsfunc">                   
                        read_imageh
                    </strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="otherDataTypes.html" target="_top">image3d_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">image</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="otherDataTypes.html" target="_top">sampler_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">sampler</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>float4 <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">coord</var><code>)</code></td>
            </tr>
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        </div>
      </div>
      <div class="refsect1">
        <a id="description"></a>
        <h2>Description</h2>
        <p>
		Use the coordinate <span class="emphasis"><em>(coord.x, coord.y, coord.z)</em></span> to do an element lookup in the 3D image object specified by <code class="varname">image</code>. <code class="varname">coord.w</code> is ignored.
		</p>
        <p>		
<code class="function">read_imageh</code> returns half floating-point values in the range [0.0... 1.0] for image objects created with <code class="varname">image_channel_data_type</code> set to one of the predefined packed formats or CL_UNORM_INT8 or CL_UNORM_INT16.
		</p>
        <p>	
<code class="function">read_imageh</code> returns half floating-point values in the range [-1.0... 1.0] for image objects created with <code class="varname">image_channel_data_type</code> set to CL_SNORM_INT8, or CL_SNORM_INT16.
		</p>
        <p>	
<code class="function">read_imageh</code> returns half floating-point values for image objects created with <code class="varname">image_channel_data_type</code> set to CL_HALF_FLOAT.
		</p>
        <p>	
The <code class="function">read_imageh</code> calls that take integer coordinates must use a sampler with filter mode set to CLK_FILTER_NEAREST, normalized coordinates set to CLK_NORMALIZED_COORDS_FALSE and addressing mode set to CLK_ADDRESS_CLAMP_TO_EDGE, CLK_ADDRESS_CLAMP or CLK_ADDRESS_NONE; otherwise the values returned are undefined.
		</p>
        <p>	
Values returned by <code class="function">read_imageh</code> for image objects with <code class="varname">image_channel_data_type</code> values not specified in the description above are undefined.
		</p>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
	 
		</p>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />
                                               
            <a href="http://www.khronos.org/registry/cl/specs/opencl-1.x-latest.pdf#page=190" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="imageFunctions.html"><span class="citerefentry"><span class="refentrytitle">Image Functions</span></span></a> 
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2009 The Khronos Group Inc. 
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
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the condition that this copyright notice and permission notice shall be included
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