upstream-man-pages/man2/gluNurbsSurface.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="gluNurbsSurface">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>gluNurbsSurface</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>gluNurbsSurface</refname>
  17         <refpurpose>define the shape of a NURBS surface</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>gluNurbsSurface</function></funcdef>
  23                 <paramdef>GLUnurbs* <parameter>nurb</parameter></paramdef>
  24                 <paramdef>GLint <parameter>sKnotCount</parameter></paramdef>
  25                 <paramdef>GLfloat* <parameter>sKnots</parameter></paramdef>
  26                 <paramdef>GLint <parameter>tKnotCount</parameter></paramdef>
  27                 <paramdef>GLfloat* <parameter>tKnots</parameter></paramdef>
  28                 <paramdef>GLint <parameter>sStride</parameter></paramdef>
  29                 <paramdef>GLint <parameter>tStride</parameter></paramdef>
  30                 <paramdef>GLfloat* <parameter>control</parameter></paramdef>
  31                 <paramdef>GLint <parameter>sOrder</parameter></paramdef>
  32                 <paramdef>GLint <parameter>tOrder</parameter></paramdef>
  33                 <paramdef>GLenum <parameter>type</parameter></paramdef>
  34             </funcprototype>
  35         </funcsynopsis>
  36     </refsynopsisdiv>
  37     <!-- eqn: ignoring delim $$ -->
  38     <refsect1 id="parameters"><title>Parameters</title>
  39         <variablelist>
  40         <varlistentry>
  41             <term><parameter>nurb</parameter></term>
  42             <listitem>
  43                 <para>
  44                     Specifies the NURBS object (created with <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>).
  45                 </para>
  46             </listitem>
  47         </varlistentry>
  48         <varlistentry>
  49             <term><parameter>sKnotCount</parameter></term>
  50             <listitem>
  51                 <para>
  52                     Specifies the number of knots in the parametric <emphasis>u</emphasis> direction.
  53                 </para>
  54             </listitem>
  55         </varlistentry>
  56         <varlistentry>
  57             <term><parameter>sKnots</parameter></term>
  58             <listitem>
  59                 <para>
  60                     Specifies an array of <parameter>sKnotCount</parameter> nondecreasing knot values in the parametric
  61                     <emphasis>u</emphasis> direction.
  62                 </para>
  63             </listitem>
  64         </varlistentry>
  65         <varlistentry>
  66             <term><parameter>tKnotCount</parameter></term>
  67             <listitem>
  68                 <para>
  69                     Specifies the number of knots in the parametric <emphasis>v</emphasis> direction.
  70                 </para>
  71             </listitem>
  72         </varlistentry>
  73         <varlistentry>
  74             <term><parameter>tKnots</parameter></term>
  75             <listitem>
  76                 <para>
  77                     Specifies an array of <parameter>tKnotCount</parameter> nondecreasing knot values in the parametric
  78                     <emphasis>v</emphasis> direction.
  79                 </para>
  80             </listitem>
  81         </varlistentry>
  82         <varlistentry>
  83             <term><parameter>sStride</parameter></term>
  84             <listitem>
  85                 <para>
  86                     Specifies the offset (as a number of single-precision floating-point values)
  87                     between successive control points in the parametric <emphasis>u</emphasis> direction
  88                     in <parameter>control</parameter>.
  89                 </para>
  90             </listitem>
  91         </varlistentry>
  92         <varlistentry>
  93             <term><parameter>tStride</parameter></term>
  94             <listitem>
  95                 <para>
  96                     Specifies the offset (in single-precision floating-point values)
  97                     between successive control points in the parametric <emphasis>v</emphasis> direction
  98                     in <parameter>control</parameter>.
  99                 </para>
 100             </listitem>
 101         </varlistentry>
 102         <varlistentry>
 103             <term><parameter>control</parameter></term>
 104             <listitem>
 105                 <para>
 106                     Specifies an array containing control points for the NURBS surface.
 107                     The offsets between successive control points in the parametric <emphasis>u</emphasis>
 108                     and <emphasis>v</emphasis> directions are given by <parameter>sStride</parameter> and <parameter>tStride</parameter>.
 109                 </para>
 110             </listitem>
 111         </varlistentry>
 112         <varlistentry>
 113             <term><parameter>sOrder</parameter></term>
 114             <listitem>
 115                 <para>
 116                     Specifies the order of the NURBS surface in the parametric <emphasis>u</emphasis>
 117                     direction. The order is one more than the degree, hence
 118                     a surface that is cubic in <emphasis>u</emphasis> has a <emphasis>u</emphasis> order of 4.
 119                 </para>
 120             </listitem>
 121         </varlistentry>
 122         <varlistentry>
 123             <term><parameter>tOrder</parameter></term>
 124             <listitem>
 125                 <para>
 126                     Specifies the order of the NURBS surface in the parametric <emphasis>v</emphasis>
 127                     direction. The order is one more than the degree, hence
 128                     a surface that is cubic in <emphasis>v</emphasis> has a <emphasis>v</emphasis> order of 4.
 129                 </para>
 130             </listitem>
 131         </varlistentry>
 132         <varlistentry>
 133             <term><parameter>type</parameter></term>
 134             <listitem>
 135                 <para>
 136                     Specifies type of the surface. <parameter>type</parameter> can be any of the valid
 137                     two-dimensional evaluator types (such as <constant>GLU_MAP2_VERTEX_3</constant> or
 138                     <constant>GLU_MAP2_COLOR_4</constant>).
 139                 </para>
 140             </listitem>
 141         </varlistentry>
 142         </variablelist>
 143     </refsect1>
 144     <refsect1 id="description"><title>Description</title>
 145         <para>
 146             Use <function>gluNurbsSurface</function> within a NURBS (Non-Uniform Rational B-Spline) surface
 147             definition to describe the shape of a NURBS surface (before
 148             any trimming). To mark the beginning of
 149             a NURBS surface definition, use the <citerefentry><refentrytitle>gluBeginSurface</refentrytitle></citerefentry> command.
 150             To mark the end of a NURBS surface definition, use the
 151             <citerefentry><refentrytitle>gluEndSurface</refentrytitle></citerefentry> command. Call <function>gluNurbsSurface</function> within a NURBS
 152             surface definition only.
 153         </para>
 154         <para>
 155             Positional, texture, and color coordinates are associated
 156             with a surface by presenting each as a separate <function>gluNurbsSurface</function> between a
 157             <citerefentry><refentrytitle>gluBeginSurface</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndSurface</refentrytitle></citerefentry> pair. No more than
 158             one call to <function>gluNurbsSurface</function> for each of color, position, and texture
 159             data can be made within a single <citerefentry><refentrytitle>gluBeginSurface</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndSurface</refentrytitle></citerefentry>
 160             pair. Exactly one call must be made to describe the position of the
 161             surface (a <parameter>type</parameter> of <constant>GLU_MAP2_VERTEX_3</constant> or <constant>GLU_MAP2_VERTEX_4</constant>).
 162         </para>
 163         <para>
 164             A NURBS surface can be trimmed by using the commands
 165             <citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry> and <citerefentry><refentrytitle>gluPwlCurve</refentrytitle></citerefentry> between calls to
 166             <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry> and <citerefentry><refentrytitle>gluEndTrim</refentrytitle></citerefentry>.
 167         </para>
 168         <para>
 169             Note that a <function>gluNurbsSurface</function> with <parameter>sKnotCount</parameter> knots in the <emphasis>u</emphasis> direction
 170             and <parameter>tKnotCount</parameter> knots in the <emphasis>v</emphasis> direction with orders
 171             <parameter>sOrder</parameter> and <parameter>tOrder</parameter> must have
 172             (<parameter>sKnotCount</parameter> - <parameter>sOrder</parameter>)
 173             <inlineequation><mml:math><mml:mi mathvariant="italic">times</mml:mi></mml:math></inlineequation>
 174             (<parameter>tKnotCount</parameter> - <parameter>tOrder</parameter>) control points.
 175         </para>
 176     </refsect1>
 177     <refsect1 id="example"><title>Example</title>
 178         <para>
 179             The following commands render a textured NURBS surface with normals;
 180             the texture coordinates and normals are also NURBS surfaces:
 181             <programlisting>
 182 gluBeginSurface(nobj);
 183    gluNurbsSurface(nobj, ..., GL_MAP2_TEXTURE_COORD_2);
 184    gluNurbsSurface(nobj, ..., GL_MAP2_NORMAL);
 185    gluNurbsSurface(nobj, ..., GL_MAP2_VERTEX_4);
 186 gluEndSurface(nobj);
 187             </programlisting>
 188         </para>
 189     </refsect1>
 190     <refsect1 id="seealso"><title>See Also</title>
 191         <para>
 192             <citerefentry><refentrytitle>gluBeginSurface</refentrytitle></citerefentry>,
 193             <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>,
 194             <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>,
 195             <citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry>,
 196             <citerefentry><refentrytitle>gluPwlCurve</refentrytitle></citerefentry>
 197         </para>
 198     </refsect1>
 199     <refsect1 id="Copyright"><title>Copyright</title>
 200         <para>
 201             Copyright <trademark class="copyright"></trademark> 1991-2006
 202             Silicon Graphics, Inc. This document is licensed under the SGI
 203             Free Software B License. For details, see
 204             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 205         </para>
 206     </refsect1>
 207 </refentry>