upstream-man-pages/man2/gluLoadSamplingMatrices.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="gluLoadSamplingMatrices">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>gluLoadSamplingMatrices</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>gluLoadSamplingMatrices</refname>
  17         <refpurpose>load NURBS sampling and culling matrices</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>gluLoadSamplingMatrices</function></funcdef>
  23                 <paramdef>GLUnurbs* <parameter>nurb</parameter></paramdef>
  24                 <paramdef>const GLfloat * <parameter>model</parameter></paramdef>
  25                 <paramdef>const GLfloat * <parameter>perspective</parameter></paramdef>
  26                 <paramdef>const GLint * <parameter>view</parameter></paramdef>
  27             </funcprototype>
  28         </funcsynopsis>
  29     </refsynopsisdiv>
  30     <!-- eqn: ignoring delim $$ -->
  31     <refsect1 id="parameters"><title>Parameters</title>
  32         <variablelist>
  33         <varlistentry>
  34             <term><parameter>nurb</parameter></term>
  35             <listitem>
  36                 <para>
  37                     Specifies the NURBS object (created with <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>).
  38                 </para>
  39             </listitem>
  40         </varlistentry>
  41         <varlistentry>
  42             <term><parameter>model</parameter></term>
  43             <listitem>
  44                 <para>
  45                     Specifies a modelview matrix (as from a <citerefentry><refentrytitle>glGetFloatv</refentrytitle></citerefentry> call).
  46                 </para>
  47             </listitem>
  48         </varlistentry>
  49         <varlistentry>
  50             <term><parameter>perspective</parameter></term>
  51             <listitem>
  52                 <para>
  53                     Specifies a projection matrix (as from a <citerefentry><refentrytitle>glGetFloatv</refentrytitle></citerefentry> call).
  54                 </para>
  55             </listitem>
  56         </varlistentry>
  57         <varlistentry>
  58             <term><parameter>view</parameter></term>
  59             <listitem>
  60                 <para>
  61                     Specifies a viewport (as from a <citerefentry><refentrytitle>glGetIntegerv</refentrytitle></citerefentry> call).
  62                 </para>
  63             </listitem>
  64         </varlistentry>
  65         </variablelist>
  66     </refsect1>
  67     <refsect1 id="description"><title>Description</title>
  68         <para>
  69             <function>gluLoadSamplingMatrices</function> uses <parameter>model</parameter>, <parameter>perspective</parameter>, and <parameter>view</parameter> to recompute the sampling and culling
  70             matrices stored in <parameter>nurb</parameter>.
  71             The sampling matrix determines how finely a NURBS curve or surface
  72             must be tessellated to satisfy the sampling tolerance (as determined by the
  73             <constant>GLU_SAMPLING_TOLERANCE</constant> property).
  74             The culling matrix is used in deciding if a NURBS curve or surface
  75             should be culled before
  76             rendering (when the <constant>GLU_CULLING</constant> property is turned on).
  77         </para>
  78         <para>
  79             <function>gluLoadSamplingMatrices</function> is necessary only if the <constant>GLU_AUTO_LOAD_MATRIX</constant> property is turned
  80             off (see <citerefentry><refentrytitle>gluNurbsProperty</refentrytitle></citerefentry>).
  81             Although it can be convenient to leave the <constant>GLU_AUTO_LOAD_MATRIX</constant>
  82             property turned on, there can be a performance penalty for doing so.
  83             (A round trip to the GL server is needed to fetch the current values
  84             of the modelview matrix, projection matrix, and viewport.)
  85         </para>
  86     </refsect1>
  87     <refsect1 id="seealso"><title>See Also</title>
  88         <para>
  89             <citerefentry><refentrytitle>gluGetNurbsProperty</refentrytitle></citerefentry>,
  90             <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>,
  91             <citerefentry><refentrytitle>gluNurbsProperty</refentrytitle></citerefentry>
  92         </para>
  93     </refsect1>
  94     <refsect1 id="Copyright"><title>Copyright</title>
  95         <para>
  96             Copyright <trademark class="copyright"></trademark> 1991-2006
  97             Silicon Graphics, Inc. This document is licensed under the SGI
  98             Free Software B License. For details, see
  99             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 100         </para>
 101     </refsect1>
 102 </refentry>