upstream-man-pages/manglsl/texelFetchOffset.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="texelFetchOffsetOffset">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2011</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>texelFetchOffset</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>texelFetchOffset</refname>
  17         <refpurpose>perform a lookup of a single texel within a texture with an offset</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>Declaration</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  23                 <paramdef>gsampler1D <parameter>sampler</parameter></paramdef>
  24                 <paramdef>int <parameter>P</parameter></paramdef>
  25                 <paramdef>int <parameter>lod</parameter></paramdef>
  26                 <paramdef>int <parameter>offset</parameter></paramdef>
  27             </funcprototype>
  28             <funcprototype>
  29                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  30                 <paramdef>gsampler2D <parameter>sampler</parameter></paramdef>
  31                 <paramdef>ivec2 <parameter>P</parameter></paramdef>
  32                 <paramdef>int <parameter>lod</parameter></paramdef>
  33                 <paramdef>int <parameter>offset</parameter></paramdef>
  34             </funcprototype>
  35             <funcprototype>
  36                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  37                 <paramdef>gsampler3D <parameter>sampler</parameter></paramdef>
  38                 <paramdef>ivec3 <parameter>P</parameter></paramdef>
  39                 <paramdef>int <parameter>lod</parameter></paramdef>
  40                 <paramdef>int <parameter>offset</parameter></paramdef>
  41             </funcprototype>
  42             <funcprototype>
  43                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  44                 <paramdef>gsampler2DRect <parameter>sampler</parameter></paramdef>
  45                 <paramdef>ivec2 <parameter>P</parameter></paramdef>
  46                 <paramdef>int <parameter>offset</parameter></paramdef>
  47             </funcprototype>
  48             <funcprototype>
  49                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  50                 <paramdef>gsampler1DArray <parameter>sampler</parameter></paramdef>
  51                 <paramdef>ivec2 <parameter>P</parameter></paramdef>
  52                 <paramdef>int <parameter>lod</parameter></paramdef>
  53                 <paramdef>int <parameter>offset</parameter></paramdef>
  54             </funcprototype>
  55             <funcprototype>
  56                 <funcdef>gvec4 <function>texelFetchOffset</function></funcdef>
  57                 <paramdef>gsampler2DArray <parameter>sampler</parameter></paramdef>
  58                 <paramdef>ivec3 <parameter>P</parameter></paramdef>
  59                 <paramdef>int <parameter>lod</parameter></paramdef>
  60                 <paramdef>int <parameter>offset</parameter></paramdef>
  61             </funcprototype>
  62         </funcsynopsis>
  63     </refsynopsisdiv>
  64     <refsect1 id="parameters"><title>Parameters</title>
  65         <variablelist>
  66         <varlistentry>
  67             <term><parameter>sampler</parameter></term>
  68             <listitem>
  69                 <para>
  70                     Specifies the sampler to which the texture from which texels will be retrieved is bound.
  71                 </para>
  72             </listitem>
  73         </varlistentry>
  74         <varlistentry>
  75             <term><parameter>P</parameter></term>
  76             <listitem>
  77                 <para>
  78                     Specifies the texture coordinates at which texture will be sampled.
  79                 </para>
  80             </listitem>
  81         </varlistentry>
  82         <varlistentry>
  83             <term><parameter>lod</parameter></term>
  84             <listitem>
  85                 <para>
  86                     If present, specifies the level-of-detail within the texture from which the texel will be fetched.
  87                 </para>
  88             </listitem>
  89         </varlistentry>
  90         <varlistentry>
  91             <term><parameter>offset</parameter></term>
  92             <listitem>
  93                 <para>
  94                     Specifies offset, in texels that will be applied to <parameter>P</parameter> before looking up the texel.
  95                 </para>
  96             </listitem>
  97         </varlistentry>
  98         </variablelist>
  99     </refsect1>
 100     <refsect1 id="description"><title>Description</title>
 101         <para>
 102             <function>texelFetchOffset</function> performs a lookup of a single texel from texture coordinate <parameter>P</parameter>
 103             in the texture bound to <parameter>sampler</parameter>. Before fetching the texel, the offset specified in <parameter>offset</parameter>
 104             is added to <parameter>P</parameter>. <parameter>offset</parameter> must be a constant expression. The array layer is specified in the last component of
 105             <parameter>P</parameter> for array forms. The <parameter>lod</parameter> parameter (if present) specifies the level-of-detail
 106             from which the texel will be fetched. The <parameter>sample</parameter> parameter specifies which sample within the texel will be
 107             returned when reading from a multi-sample texure.
 108         </para>
 109     </refsect1>
 110     <refsect1 id="versions"><title>Version Support</title>
 111         <informaltable frame="topbot">
 112             #VARTABLECOLS#
 113                 <thead>
 114                     #FUNCTABLEHEADER#
 115                     <row>
 116                         <entry>texelFetchOffset</entry>#newin13#
 117                     </row>
 118                     <row>
 119                         <entry>texelFetchOffset (gsampler2DRect)</entry>#newin14#
 120                     </row>
 121                     <row>
 122                         <entry>texelFetchOffset (gsampler2DMS, gsampler2DMSArray)</entry>#newin15#
 123                     </row>
 124                 </thead>
 125             </tgroup>
 126         </informaltable>
 127     </refsect1>
 128     <refsect1 id="seealso"><title>See Also</title>
 129         <para>
 130             <citerefentry><refentrytitle>texelFetch</refentrytitle></citerefentry>,
 131             <citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,
 132             <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,
 133             <citerefentry><refentrytitle>textureGatherOffset</refentrytitle></citerefentry>,
 134             <citerefentry><refentrytitle>textureGatherOffsets</refentrytitle></citerefentry>,
 135             <citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,
 136             <citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,
 137             <citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,
 138             <citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,
 139             <citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>,
 140             <citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,
 141             <citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,
 142             <citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,
 143             <citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,
 144             <citerefentry><refentrytitle>textureProjLodOffset</refentrytitle></citerefentry>,
 145             <citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,
 146             <citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,
 147             <citerefentry><refentrytitle>textureSize</refentrytitle></citerefentry>
 148         </para>
 149     </refsect1>
 150     <refsect1 id="Copyright"><title>Copyright</title>
 151         <para>
 152             Copyright <trademark class="copyright"></trademark> 2011 Khronos Group.
 153             This material may be distributed subject to the terms and conditions set forth in
 154             the Open Publication License, v 1.0, 8 June 1999.
 155             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 156         </para>
 157     </refsect1>
 158 </refentry>