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