upstream-man-pages/manglsl/textureOffset.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="textureOffset">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2012</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>textureOffset</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>textureOffset</refname>
  17         <refpurpose>perform a texture lookup with offset</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>Declaration</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  23                 <paramdef>gsampler1D <parameter>sampler</parameter></paramdef>
  24                 <paramdef>float <parameter>P</parameter></paramdef>
  25                 <paramdef>int <parameter>offset</parameter></paramdef>
  26                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  27             </funcprototype>
  28             <funcprototype>
  29                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  30                 <paramdef>gsampler2D <parameter>sampler</parameter></paramdef>
  31                 <paramdef>vec2 <parameter>P</parameter></paramdef>
  32                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  33                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  34             </funcprototype>
  35             <funcprototype>
  36                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  37                 <paramdef>gsampler3D <parameter>sampler</parameter></paramdef>
  38                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  39                 <paramdef>ivec3 <parameter>offset</parameter></paramdef>
  40                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  41             </funcprototype>
  42             <funcprototype>
  43                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  44                 <paramdef>gsampler2DRect <parameter>sampler</parameter></paramdef>
  45                 <paramdef>vec2 <parameter>P</parameter></paramdef>
  46                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  47             </funcprototype>
  48             <funcprototype>
  49                 <funcdef>float <function>textureOffset</function></funcdef>
  50                 <paramdef>sampler2DRectShadow <parameter>sampler</parameter></paramdef>
  51                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  52                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  53             </funcprototype>
  54             <funcprototype>
  55                 <funcdef>float <function>textureOffset</function></funcdef>
  56                 <paramdef>sampler1DShadow <parameter>sampler</parameter></paramdef>
  57                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  58                 <paramdef>int <parameter>offset</parameter></paramdef>
  59                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  60             </funcprototype>
  61             <funcprototype>
  62                 <funcdef>float <function>textureOffset</function></funcdef>
  63                 <paramdef>sampler2DShadow <parameter>sampler</parameter></paramdef>
  64                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  65                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  66                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  67             </funcprototype>
  68             <funcprototype>
  69                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  70                 <paramdef>gsampler1DArray <parameter>sampler</parameter></paramdef>
  71                 <paramdef>vec2 <parameter>P</parameter></paramdef>
  72                 <paramdef>int <parameter>offset</parameter></paramdef>
  73                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  74             </funcprototype>
  75             <funcprototype>
  76                 <funcdef>gvec4 <function>textureOffset</function></funcdef>
  77                 <paramdef>gsampler2DArray <parameter>sampler</parameter></paramdef>
  78                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  79                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  80                 <paramdef>[float <parameter>bias</parameter>]</paramdef>
  81             </funcprototype>
  82             <funcprototype>
  83                 <funcdef>float <function>textureOffset</function></funcdef>
  84                 <paramdef>sampler1DArrayShadow <parameter>sampler</parameter></paramdef>
  85                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  86                 <paramdef>int <parameter>offset</parameter></paramdef>
  87             </funcprototype>
  88             <funcprototype>
  89                 <funcdef>float <function>textureOffset</function></funcdef>
  90                 <paramdef>sampler2DArrayShadow <parameter>sampler</parameter></paramdef>
  91                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  92                 <paramdef>vec2 <parameter>offset</parameter></paramdef>
  93             </funcprototype>
  94         </funcsynopsis>
  95     </refsynopsisdiv>
  96     <refsect1 id="parameters"><title>Parameters</title>
  97         <variablelist>
  98         <varlistentry>
  99             <term><parameter>sampler</parameter></term>
 100             <listitem>
 101                 <para>
 102                     Specifies the sampler to which the texture from which texels will be retrieved is bound.
 103                 </para>
 104             </listitem>
 105         </varlistentry>
 106         <varlistentry>
 107             <term><parameter>P</parameter></term>
 108             <listitem>
 109                 <para>
 110                     Specifies the texture coordinates at which texture will be sampled.
 111                 </para>
 112             </listitem>
 113         </varlistentry>
 114         <varlistentry>
 115             <term><parameter>offset</parameter></term>
 116             <listitem>
 117                 <para>
 118                     Specifies offset, in texels that will be applied to <parameter>P</parameter> before looking up the texel.
 119                 </para>
 120             </listitem>
 121         </varlistentry>
 122         </variablelist>
 123     </refsect1>
 124     <refsect1 id="description"><title>Description</title>
 125         <para>
 126             <function>textureOffset</function> performs a texture lookup at coordinate <parameter>P</parameter> from the
 127             texture bound to <parameter>sampler</parameter> with an an additional offset, specified in texels in <parameter>offset</parameter>
 128             that will be applied to the (u, v, w) texture coordinates before looking up each texel.
 129             The offset value must be a constant expression. A limited range of offset values are supported;
 130             the minimum and maximum offset values are implementation-dependent and may be determined
 131             by querying <constant>GL_MIN_PROGRAM_TEXEL_OFFSET</constant> and <constant>GL_MAX_PROGRAM_TEXEL_OFFSET</constant>,
 132             respectively.
 133         </para>
 134         <para>
 135             Note that <parameter>offset</parameter> does not apply to the layer coordinate for texture arrays. Also note
 136             that offsets are not supported for cube maps.
 137         </para>
 138     </refsect1>
 139     <refsect1 id="versions"><title>Version Support</title>
 140         <informaltable frame="topbot">
 141             #VARTABLECOLS#
 142                 <thead>
 143                     #FUNCTABLEHEADER#
 144                     <row>
 145                         <entry>textureOffset</entry>#newin13#
 146                     </row>
 147                     <row>
 148                         <entry>textureOffset (gsampler2DRect{Shadow})</entry>#newin14#
 149                     </row>
 150                 </thead>
 151             </tgroup>
 152         </informaltable>
 153     </refsect1>
 154     <refsect1 id="seealso"><title>See Also</title>
 155         <para>
 156             <citerefentry><refentrytitle>texelFetch</refentrytitle></citerefentry>,
 157             <citerefentry><refentrytitle>texelFetchOffset</refentrytitle></citerefentry>,
 158             <citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,
 159             <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,
 160             <citerefentry><refentrytitle>textureGatherOffset</refentrytitle></citerefentry>,
 161             <citerefentry><refentrytitle>textureGatherOffsets</refentrytitle></citerefentry>,
 162             <citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,
 163             <citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,
 164             <citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,
 165             <citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,
 166             <citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,
 167             <citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,
 168             <citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,
 169             <citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,
 170             <citerefentry><refentrytitle>textureProjLodOffset</refentrytitle></citerefentry>,
 171             <citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,
 172             <citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,
 173             <citerefentry><refentrytitle>textureSize</refentrytitle></citerefentry>
 174         </para>
 175     </refsect1>
 176     <refsect1 id="Copyright"><title>Copyright</title>
 177         <para>
 178             Copyright <trademark class="copyright"></trademark> 2011-2012 Khronos Group.
 179             This material may be distributed subject to the terms and conditions set forth in
 180             the Open Publication License, v 1.0, 8 June 1999.
 181             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 182         </para>
 183     </refsect1>
 184 </refentry>