upstream-man-pages/manglsl/textureProjLodOffset.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="textureProjLodOffsetOffset">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2011</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>textureProjLodOffset</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>textureProjLodOffset</refname>
  17         <refpurpose>perform a texture lookup with projection and explicit level-of-detail and offset</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>Declaration</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>gvec4 <function>textureProjLodOffset</function></funcdef>
  23                 <paramdef>gsampler1D <parameter>sampler</parameter></paramdef>
  24                 <paramdef>vec2 <parameter>P</parameter></paramdef>
  25                 <paramdef>float <parameter>lod</parameter></paramdef>
  26                 <paramdef>int <parameter>offset</parameter></paramdef>
  27             </funcprototype>
  28             <funcprototype>
  29                 <funcdef>gvec4 <function>textureProjLodOffset</function></funcdef>
  30                 <paramdef>gsampler1D <parameter>sampler</parameter></paramdef>
  31                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  32                 <paramdef>float <parameter>lod</parameter></paramdef>
  33                 <paramdef>int <parameter>offset</parameter></paramdef>
  34             </funcprototype>
  35             <funcprototype>
  36                 <funcdef>gvec4 <function>textureProjLodOffset</function></funcdef>
  37                 <paramdef>gsampler2D <parameter>sampler</parameter></paramdef>
  38                 <paramdef>vec3 <parameter>P</parameter></paramdef>
  39                 <paramdef>float <parameter>lod</parameter></paramdef>
  40                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  41             </funcprototype>
  42             <funcprototype>
  43                 <funcdef>gvec4 <function>textureProjLodOffset</function></funcdef>
  44                 <paramdef>gsampler2D <parameter>sampler</parameter></paramdef>
  45                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  46                 <paramdef>float <parameter>lod</parameter></paramdef>
  47                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  48             </funcprototype>
  49             <funcprototype>
  50                 <funcdef>gvec4 <function>textureProjLodOffset</function></funcdef>
  51                 <paramdef>gsampler3D <parameter>sampler</parameter></paramdef>
  52                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  53                 <paramdef>float <parameter>lod</parameter></paramdef>
  54                 <paramdef>ivec3 <parameter>offset</parameter></paramdef>
  55             </funcprototype>
  56             <funcprototype>
  57                 <funcdef>float <function>textureProjLodOffset</function></funcdef>
  58                 <paramdef>sampler1DShadow <parameter>sampler</parameter></paramdef>
  59                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  60                 <paramdef>float <parameter>lod</parameter></paramdef>
  61                 <paramdef>int <parameter>offset</parameter></paramdef>
  62             </funcprototype>
  63             <funcprototype>
  64                 <funcdef>float <function>textureProjLodOffset</function></funcdef>
  65                 <paramdef>sampler2DShadow <parameter>sampler</parameter></paramdef>
  66                 <paramdef>vec4 <parameter>P</parameter></paramdef>
  67                 <paramdef>float <parameter>lod</parameter></paramdef>
  68                 <paramdef>ivec2 <parameter>offset</parameter></paramdef>
  69             </funcprototype>
  70         </funcsynopsis>
  71     </refsynopsisdiv>
  72     <refsect1 id="parameters"><title>Parameters</title>
  73         <variablelist>
  74         <varlistentry>
  75             <term><parameter>sampler</parameter></term>
  76             <listitem>
  77                 <para>
  78                     Specifies the sampler to which the texture from which texels will be retrieved is bound.
  79                 </para>
  80             </listitem>
  81         </varlistentry>
  82         <varlistentry>
  83             <term><parameter>P</parameter></term>
  84             <listitem>
  85                 <para>
  86                     Specifies the texture coordinates at which texture will be sampled.
  87                 </para>
  88             </listitem>
  89         </varlistentry>
  90         <varlistentry>
  91             <term><parameter>lod</parameter></term>
  92             <listitem>
  93                 <para>
  94                     Specifies the explicit level-of-detail from which to fetch texels.
  95                 </para>
  96             </listitem>
  97         </varlistentry>
  98         <varlistentry>
  99             <term><parameter>offset</parameter></term>
 100             <listitem>
 101                 <para>
 102                     Specifies the offset, in texels, to be applied to <parameter>P</parameter> before fetching texels.
 103                 </para>
 104             </listitem>
 105         </varlistentry>
 106         </variablelist>
 107     </refsect1>
 108     <refsect1 id="description"><title>Description</title>
 109         <para>
 110             <function>textureProjLodOffset</function> performs a texture lookup with projection from an explicitly specified level-of-detail with an offset applied
 111             to the texture coordinates before sampling. The texture coordinates
 112             consumed from <parameter>P</parameter>, not including the last component of <parameter>P</parameter>,
 113             are divided by the last component of <parameter>P</parameter>. The resulting <inlineequation><mml:math><mml:msup><mml:mn>3</mml:mn><mml:mi>rd</mml:mi></mml:msup></mml:math></inlineequation>
 114             component of <parameter>P</parameter> in the shadow forms is used as
 115             <inlineequation><mml:math><mml:msub><mml:mi>D</mml:mi><mml:mi>ref</mml:mi></mml:msub></mml:math></inlineequation>.
 116             After these values are computed, the texture lookup proceeds as in <citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,
 117             with <parameter>lod</parameter> used to specify the level-of-detail from which the texture will be sampled and <parameter>offset</parameter>
 118             used to specifiy the offset, in texels, to be applied to the texture coordinates before sampling.
 119         </para>
 120     </refsect1>
 121     <refsect1 id="versions"><title>Version Support</title>
 122         <informaltable frame="topbot">
 123             #VARTABLECOLS#
 124                 <thead>
 125                     #FUNCTABLEHEADER#
 126                     <row>
 127                         <entry>textureProjLodOffset</entry>#newin13#
 128                     </row>
 129                 </thead>
 130             </tgroup>
 131         </informaltable>
 132     </refsect1>
 133     <refsect1 id="seealso"><title>See Also</title>
 134         <para>
 135             <citerefentry><refentrytitle>texelFetch</refentrytitle></citerefentry>,
 136             <citerefentry><refentrytitle>texelFetchOffset</refentrytitle></citerefentry>,
 137             <citerefentry><refentrytitle>texture</refentrytitle></citerefentry>,
 138             <citerefentry><refentrytitle>textureGather</refentrytitle></citerefentry>,
 139             <citerefentry><refentrytitle>textureGatherOffset</refentrytitle></citerefentry>,
 140             <citerefentry><refentrytitle>textureGatherOffsets</refentrytitle></citerefentry>,
 141             <citerefentry><refentrytitle>textureGrad</refentrytitle></citerefentry>,
 142             <citerefentry><refentrytitle>textureGradOffset</refentrytitle></citerefentry>,
 143             <citerefentry><refentrytitle>textureLod</refentrytitle></citerefentry>,
 144             <citerefentry><refentrytitle>textureLodOffset</refentrytitle></citerefentry>,
 145             <citerefentry><refentrytitle>textureOffset</refentrytitle></citerefentry>,
 146             <citerefentry><refentrytitle>textureProj</refentrytitle></citerefentry>,
 147             <citerefentry><refentrytitle>textureProjGrad</refentrytitle></citerefentry>,
 148             <citerefentry><refentrytitle>textureProjGradOffset</refentrytitle></citerefentry>,
 149             <citerefentry><refentrytitle>textureProjLod</refentrytitle></citerefentry>,
 150             <citerefentry><refentrytitle>textureProjOffset</refentrytitle></citerefentry>,
 151             <citerefentry><refentrytitle>textureQueryLod</refentrytitle></citerefentry>,
 152             <citerefentry><refentrytitle>textureSize</refentrytitle></citerefentry>
 153         </para>
 154     </refsect1>
 155     <refsect1 id="Copyright"><title>Copyright</title>
 156         <para>
 157             Copyright <trademark class="copyright"></trademark> 2011 Khronos Group.
 158             This material may be distributed subject to the terms and conditions set forth in
 159             the Open Publication License, v 1.0, 8 June 1999.
 160             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 161         </para>
 162     </refsect1>
 163 </refentry>