| 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="gluPwlCurve"> |
| 5 | <refmeta> |
| 6 | <refmetainfo> |
| 7 | <copyright> |
| 8 | <year>1991-2006</year> |
| 9 | <holder>Silicon Graphics, Inc.</holder> |
| 10 | </copyright> |
| 11 | </refmetainfo> |
| 12 | <refentrytitle>gluPwlCurve</refentrytitle> |
| 13 | <manvolnum>3G</manvolnum> |
| 14 | </refmeta> |
| 15 | <refnamediv> |
| 16 | <refname>gluPwlCurve</refname> |
| 17 | <refpurpose>describe a piecewise linear NURBS trimming curve</refpurpose> |
| 18 | </refnamediv> |
| 19 | <refsynopsisdiv><title>C Specification</title> |
| 20 | <funcsynopsis> |
| 21 | <funcprototype> |
| 22 | <funcdef>void <function>gluPwlCurve</function></funcdef> |
| 23 | <paramdef>GLUnurbs* <parameter>nurb</parameter></paramdef> |
| 24 | <paramdef>GLint <parameter>count</parameter></paramdef> |
| 25 | <paramdef>GLfloat* <parameter>data</parameter></paramdef> |
| 26 | <paramdef>GLint <parameter>stride</parameter></paramdef> |
| 27 | <paramdef>GLenum <parameter>type</parameter></paramdef> |
| 28 | </funcprototype> |
| 29 | </funcsynopsis> |
| 30 | </refsynopsisdiv> |
| 31 | <!-- eqn: ignoring delim $$ --> |
| 32 | <refsect1 id="parameters"><title>Parameters</title> |
| 33 | <variablelist> |
| 34 | <varlistentry> |
| 35 | <term><parameter>nurb</parameter></term> |
| 36 | <listitem> |
| 37 | <para> |
| 38 | Specifies the NURBS object (created with <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>). |
| 39 | </para> |
| 40 | </listitem> |
| 41 | </varlistentry> |
| 42 | <varlistentry> |
| 43 | <term><parameter>count</parameter></term> |
| 44 | <listitem> |
| 45 | <para> |
| 46 | Specifies the number of points on the curve. |
| 47 | </para> |
| 48 | </listitem> |
| 49 | </varlistentry> |
| 50 | <varlistentry> |
| 51 | <term><parameter>data</parameter></term> |
| 52 | <listitem> |
| 53 | <para> |
| 54 | Specifies an array containing the curve points. |
| 55 | </para> |
| 56 | </listitem> |
| 57 | </varlistentry> |
| 58 | <varlistentry> |
| 59 | <term><parameter>stride</parameter></term> |
| 60 | <listitem> |
| 61 | <para> |
| 62 | Specifies the offset (a number of single-precision floating-point values) |
| 63 | between points on the curve. |
| 64 | </para> |
| 65 | </listitem> |
| 66 | </varlistentry> |
| 67 | <varlistentry> |
| 68 | <term><parameter>type</parameter></term> |
| 69 | <listitem> |
| 70 | <para> |
| 71 | Specifies the type of curve. |
| 72 | Must be either <constant>GLU_MAP1_TRIM_2</constant> or <constant>GLU_MAP1_TRIM_3</constant>. |
| 73 | </para> |
| 74 | </listitem> |
| 75 | </varlistentry> |
| 76 | </variablelist> |
| 77 | </refsect1> |
| 78 | <refsect1 id="description"><title>Description</title> |
| 79 | <para> |
| 80 | <function>gluPwlCurve</function> describes a piecewise linear trimming curve for a NURBS surface. |
| 81 | A piecewise linear curve consists of a list of |
| 82 | coordinates of points in the parameter space for the |
| 83 | NURBS surface to be trimmed. These points are connected |
| 84 | with line segments to form a curve. If the curve is |
| 85 | an approximation to a curve that is not piecewise linear, |
| 86 | the points should be close enough in parameter space that the |
| 87 | resulting path appears curved at the resolution used in the application. |
| 88 | </para> |
| 89 | <para> |
| 90 | If <parameter>type</parameter> is |
| 91 | <constant>GLU_MAP1_TRIM_2</constant>, then it describes a curve in two-dimensional (<emphasis>u</emphasis> |
| 92 | and <emphasis>v</emphasis>) parameter space. If it is <constant>GLU_MAP1_TRIM_3</constant>, then it |
| 93 | describes a curve in two-dimensional homogeneous (<emphasis>u</emphasis>, <emphasis>v</emphasis>, |
| 94 | and <emphasis>w</emphasis>) parameter space. |
| 95 | See the <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry> reference page for more information |
| 96 | about trimming curves. |
| 97 | </para> |
| 98 | </refsect1> |
| 99 | <refsect1 id="notes"><title>Notes</title> |
| 100 | <para> |
| 101 | To describe a trim curve that closely follows the contours of a NURBS |
| 102 | surface, call <citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry>. |
| 103 | </para> |
| 104 | </refsect1> |
| 105 | <refsect1 id="seealso"><title>See Also</title> |
| 106 | <para> |
| 107 | <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>, |
| 108 | <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>, |
| 109 | <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>, |
| 110 | <citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry> |
| 111 | </para> |
| 112 | </refsect1> |
| 113 | <refsect1 id="Copyright"><title>Copyright</title> |
| 114 | <para> |
| 115 | Copyright <trademark class="copyright"></trademark> 1991-2006 |
| 116 | Silicon Graphics, Inc. This document is licensed under the SGI |
| 117 | Free Software B License. For details, see |
| 118 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. |
| 119 | </para> |
| 120 | </refsect1> |
| 121 | </refentry> |