upstream-man-pages/manglsl/faceforward.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="faceforward">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2011</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>faceforward</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>faceforward</refname>
  17         <refpurpose>return a vector pointing in the same direction as another</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>Declaration</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>genType <function>faceforward</function></funcdef>
  23                 <paramdef>genType <parameter>N</parameter></paramdef>
  24                 <paramdef>genType <parameter>I</parameter></paramdef>
  25                 <paramdef>genType <parameter>Nref</parameter></paramdef>
  26             </funcprototype>
  27             <funcprototype>
  28                 <funcdef>genDType <function>faceforward</function></funcdef>
  29                 <paramdef>genDType <parameter>N</parameter></paramdef>
  30                 <paramdef>genDType <parameter>I</parameter></paramdef>
  31                 <paramdef>genDType <parameter>Nref</parameter></paramdef>
  32             </funcprototype>
  33         </funcsynopsis>
  34     </refsynopsisdiv>
  35     <refsect1 id="parameters"><title>Parameters</title>
  36         <variablelist>
  37         <varlistentry>
  38             <term><parameter>N</parameter></term>
  39             <listitem>
  40                 <para>
  41                     Specifies the vector to orient.
  42                 </para>
  43             </listitem>
  44         </varlistentry>
  45         <varlistentry>
  46             <term><parameter>I</parameter></term>
  47             <listitem>
  48                 <para>
  49                     Specifies the incident vector.
  50                 </para>
  51             </listitem>
  52         </varlistentry>
  53         <varlistentry>
  54             <term><parameter>Nref</parameter></term>
  55             <listitem>
  56                 <para>
  57                     Specifies the reference vector.
  58                 </para>
  59             </listitem>
  60         </varlistentry>
  61         </variablelist>
  62     </refsect1>
  63     <refsect1 id="description"><title>Description</title>
  64         <para>
  65             <function>faceforward</function> orients a vector to point away from a surface as defined by its normal.
  66             If <citerefentry><refentrytitle>dot</refentrytitle></citerefentry><code>(<parameter>Nref</parameter>, <parameter>I</parameter>) &lt; 0</code>
  67             <function>faceforward</function> returns <parameter>N</parameter>, otherwise it returns <code>-<parameter>N</parameter></code>.
  68         </para>
  69     </refsect1>
  70     <refsect1 id="versions"><title>Version Support</title>
  71         <informaltable frame="topbot">
  72             #VARTABLECOLS#
  73                 <thead>
  74                     #FUNCTABLEHEADER#
  75                     <row>
  76                         <entry>faceforward (genType)</entry>#newin11#
  77                     </row>
  78                     <row>
  79                         <entry>faceforward (genDType)</entry>#newin40#
  80                     </row>
  81                 </thead>
  82             </tgroup>
  83         </informaltable>
  84     </refsect1>
  85     <refsect1 id="seealso"><title>See Also</title>
  86         <para>
  87             <citerefentry><refentrytitle>reflect</refentrytitle></citerefentry>,
  88             <citerefentry><refentrytitle>refract</refentrytitle></citerefentry>
  89         </para>
  90     </refsect1>
  91     <refsect1 id="Copyright"><title>Copyright</title>
  92         <para>
  93             Copyright <trademark class="copyright"></trademark> 2011 Khronos Group.
  94             This material may be distributed subject to the terms and conditions set forth in
  95             the Open Publication License, v 1.0, 8 June 1999.
  96             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
  97         </para>
  98     </refsect1>
  99 </refentry>