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