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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>textureGatherOffset - OpenGL Shading Language (GLSL)</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="textureGatherOffset"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>textureGatherOffset — gathers four texels from a texture with offset</p></div><div class="refsynopsisdiv"><h2>Declaration</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">gvec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2D  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec2  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var>, </td></tr><tr><td> </td><td>[int  </td><td><var class="pdparam">comp]</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">gvec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2DArray  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec3  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var>, </td></tr><tr><td> </td><td>[int  </td><td><var class="pdparam">comp]</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">gvec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2DRect  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec3  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var>, </td></tr><tr><td> </td><td>[int  </td><td><var class="pdparam">comp]</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">vec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2DShadow  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec2  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>float  </td><td><var class="pdparam">refZ</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">vec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2DArrayShadow  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec3  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>float  </td><td><var class="pdparam">refZ</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var><code>)</code>;</td></tr></table><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">vec4 <b class="fsfunc">textureGatherOffset</b>(</code></td><td>gsampler2DRectShadow  </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>vec3  </td><td><var class="pdparam">P</var>, </td></tr><tr><td> </td><td>float  </td><td><var class="pdparam">refZ</var>, </td></tr><tr><td> </td><td>ivec2  </td><td><var class="pdparam">offset</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>sampler</code></em></span></dt><dd><p>
                    Specifies the sampler to which the texture from which texels will be retrieved is bound.
                </p></dd><dt><span class="term"><em class="parameter"><code>P</code></em></span></dt><dd><p>
                    Specifies the texture coordinates at which texture will be sampled.
                </p></dd><dt><span class="term"><em class="parameter"><code>comp</code></em></span></dt><dd><p>
                    Specifies the component of the source texture that will be used to generate the resulting vector.
                </p></dd><dt><span class="term"><em class="parameter"><code>refZ</code></em></span></dt><dd><p>
                    Specifies the reference Z value used in the comparison for shadow forms.
                </p></dd><dt><span class="term"><em class="parameter"><code>offset</code></em></span></dt><dd><p>
                    Specifies the offset from the specified texture coordinate <em class="parameter"><code>P</code></em> from which the texels will be gathered.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">textureGatherOffset</code> returns the value:
        </p><p>
</p><pre class="programlisting">    vec4(Sample_i0_j1(P + offset, base).comp,
         Sample_i1_j1(P + offset, base).comp,
         Sample_i1_j0(P + offset, base).comp,
         Sample_i0_j9(P + offset, base).comp);</pre><p>
    </p><p>
        It perfoms as <a href="textureGather.xml"><span class="citerefentry"><span class="refentrytitle">textureGather</span></span></a> but with <em class="parameter"><code>offset</code></em>
        applied as described in <a href="textureOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureOffset</span></span></a>, except that the
        implementation-dependent minimum and maximum offset values are given by <code class="constant">GL_MIN_PROGRRAM_TEXTURE_GATHER_OFFSET</code>
        and <code class="constant">GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET</code>, respectively.
    </p><p>
        If specified, the value of <em class="parameter"><code>comp</code></em> must ba constant integer expression with a value
        of 0, 1, 2, or 3, identifying the x, y, z or w component of the four-component vector lookup result for each
        texel, respectively. If <em class="parameter"><code>comp</code></em> is not specified, it is treated as 0, selecting the x
        component of each texel to generate the result.
    </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="versions"></a><h2>Version Support</h2><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /></colgroup><thead><tr><th align="left"><span class="bold"><strong>Function</strong></span></th><th align="left"><span class="bold"><strong>Version 1.10</strong></span></th><th align="left"><span class="bold"><strong>Version 1.20</strong></span></th><th align="left"><span class="bold"><strong>Version 1.30</strong></span></th><th align="left"><span class="bold"><strong>Version 1.40</strong></span></th><th align="left"><span class="bold"><strong>Version 1.50</strong></span></th><th align="left"><span class="bold"><strong>Version 3.30</strong></span></th><th align="left"><span class="bold"><strong>Version 4.00</strong></span></th><th align="left"><span class="bold"><strong>Version 4.10</strong></span></th><th align="left"><span class="bold"><strong>Version 4.20</strong></span></th><th align="center"><span class="bold"><strong>Version 4.30</strong></span></th></tr><tr><th align="left">textureGatherOffset</th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>-</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th><th align="center"><span class="emphasis"><em>Y</em></span></th></tr></thead></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a href="texelFetch.xml"><span class="citerefentry"><span class="refentrytitle">texelFetch</span></span></a>,
            <a href="texelFetchOffset.xml"><span class="citerefentry"><span class="refentrytitle">texelFetchOffset</span></span></a>,
            <a href="texture.xml"><span class="citerefentry"><span class="refentrytitle">texture</span></span></a>,
            <a href="textureGather.xml"><span class="citerefentry"><span class="refentrytitle">textureGather</span></span></a>,
            <a href="textureGatherOffsets.xml"><span class="citerefentry"><span class="refentrytitle">textureGatherOffsets</span></span></a>,
            <a href="textureGrad.xml"><span class="citerefentry"><span class="refentrytitle">textureGrad</span></span></a>,
            <a href="textureGradOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureGradOffset</span></span></a>,
            <a href="textureLod.xml"><span class="citerefentry"><span class="refentrytitle">textureLod</span></span></a>,
            <a href="textureLodOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureLodOffset</span></span></a>,
            <a href="textureOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureOffset</span></span></a>,
            <a href="textureProj.xml"><span class="citerefentry"><span class="refentrytitle">textureProj</span></span></a>,
            <a href="textureProjGrad.xml"><span class="citerefentry"><span class="refentrytitle">textureProjGrad</span></span></a>,
            <a href="textureProjGradOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureProjGradOffset</span></span></a>,
            <a href="textureProjLod.xml"><span class="citerefentry"><span class="refentrytitle">textureProjLod</span></span></a>,
            <a href="textureProjLodOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureProjLodOffset</span></span></a>,
            <a href="textureProjOffset.xml"><span class="citerefentry"><span class="refentrytitle">textureProjOffset</span></span></a>,
            <a href="textureQueryLod.xml"><span class="citerefentry"><span class="refentrytitle">textureQueryLod</span></span></a>,
            <a href="textureSize.xml"><span class="citerefentry"><span class="refentrytitle">textureSize</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2011 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.
            <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
