Commit | Line | Data |
---|---|---|
7faf1d71 AW |
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="gluNurbsCurve"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>gluNurbsCurve</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>gluNurbsCurve</refname> | |
17 | <refpurpose>define the shape of a NURBS curve</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>gluNurbsCurve</function></funcdef> | |
23 | <paramdef>GLUnurbs* <parameter>nurb</parameter></paramdef> | |
24 | <paramdef>GLint <parameter>knotCount</parameter></paramdef> | |
25 | <paramdef>GLfloat * <parameter>knots</parameter></paramdef> | |
26 | <paramdef>GLint <parameter>stride</parameter></paramdef> | |
27 | <paramdef>GLfloat * <parameter>control</parameter></paramdef> | |
28 | <paramdef>GLint <parameter>order</parameter></paramdef> | |
29 | <paramdef>GLenum <parameter>type</parameter></paramdef> | |
30 | </funcprototype> | |
31 | </funcsynopsis> | |
32 | </refsynopsisdiv> | |
33 | <!-- eqn: ignoring delim $$ --> | |
34 | <refsect1 id="parameters"><title>Parameters</title> | |
35 | <variablelist> | |
36 | <varlistentry> | |
37 | <term><parameter>nurb</parameter></term> | |
38 | <listitem> | |
39 | <para> | |
40 | Specifies the NURBS object (created with <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>). | |
41 | </para> | |
42 | </listitem> | |
43 | </varlistentry> | |
44 | <varlistentry> | |
45 | <term><parameter>knotCount</parameter></term> | |
46 | <listitem> | |
47 | <para> | |
48 | Specifies the number of knots in <parameter>knots</parameter>. | |
49 | <parameter>knotCount</parameter> equals the number of control points plus the order. | |
50 | </para> | |
51 | </listitem> | |
52 | </varlistentry> | |
53 | <varlistentry> | |
54 | <term><parameter>knots</parameter></term> | |
55 | <listitem> | |
56 | <para> | |
57 | Specifies an array of <parameter>knotCount</parameter> nondecreasing knot values. | |
58 | </para> | |
59 | </listitem> | |
60 | </varlistentry> | |
61 | <varlistentry> | |
62 | <term><parameter>stride</parameter></term> | |
63 | <listitem> | |
64 | <para> | |
65 | Specifies the offset (as a number of single-precision floating-point values) | |
66 | between successive curve control points. | |
67 | </para> | |
68 | </listitem> | |
69 | </varlistentry> | |
70 | <varlistentry> | |
71 | <term><parameter>control</parameter></term> | |
72 | <listitem> | |
73 | <para> | |
74 | Specifies a pointer to an array of control points. The coordinates must | |
75 | agree with <parameter>type</parameter>, specified below. | |
76 | </para> | |
77 | </listitem> | |
78 | </varlistentry> | |
79 | <varlistentry> | |
80 | <term><parameter>order</parameter></term> | |
81 | <listitem> | |
82 | <para> | |
83 | Specifies the order of the NURBS curve. <parameter>order</parameter> equals degree + 1, hence | |
84 | a cubic curve has an order of 4. | |
85 | </para> | |
86 | </listitem> | |
87 | </varlistentry> | |
88 | <varlistentry> | |
89 | <term><parameter>type</parameter></term> | |
90 | <listitem> | |
91 | <para> | |
92 | Specifies the type of the curve. If this curve is defined within a | |
93 | <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndCurve</refentrytitle></citerefentry> pair, then | |
94 | the type can be any of the valid | |
95 | one-dimensional evaluator types (such as <constant>GLU_MAP1_VERTEX_3</constant> or | |
96 | <constant>GLU_MAP1_COLOR_4</constant>). Between a <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndTrim</refentrytitle></citerefentry> pair, | |
97 | the only valid types are <constant>GLU_MAP1_TRIM_2</constant> and <constant>GLU_MAP1_TRIM_3</constant>. | |
98 | </para> | |
99 | </listitem> | |
100 | </varlistentry> | |
101 | </variablelist> | |
102 | </refsect1> | |
103 | <refsect1 id="description"><title>Description</title> | |
104 | <para> | |
105 | Use <function>gluNurbsCurve</function> to describe a NURBS curve. | |
106 | </para> | |
107 | <para> | |
108 | When <function>gluNurbsCurve</function> appears between a <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndCurve</refentrytitle></citerefentry> pair, it is | |
109 | used to describe a curve to be rendered. | |
110 | Positional, texture, and color coordinates are associated | |
111 | by presenting each as a separate <function>gluNurbsCurve</function> between a | |
112 | <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndCurve</refentrytitle></citerefentry> pair. No more than | |
113 | one call to <function>gluNurbsCurve</function> for each of color, position, and texture | |
114 | data can be made within a single <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndCurve</refentrytitle></citerefentry> | |
115 | pair. Exactly one call must be made to describe the position of the | |
116 | curve (a <parameter>type</parameter> of <constant>GLU_MAP1_VERTEX_3</constant> or <constant>GLU_MAP1_VERTEX_4</constant>). | |
117 | </para> | |
118 | <para> | |
119 | When <function>gluNurbsCurve</function> appears between a <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>/<citerefentry><refentrytitle>gluEndTrim</refentrytitle></citerefentry> pair, it is | |
120 | used to describe a trimming curve on a NURBS surface. If <parameter>type</parameter> is | |
121 | <constant>GLU_MAP1_TRIM_2</constant>, then it describes a curve in two-dimensional (<emphasis>u</emphasis> | |
122 | and <emphasis>v</emphasis>) | |
123 | parameter space. If it is <constant>GLU_MAP1_TRIM_3</constant>, then it describes a | |
124 | curve in two-dimensional homogeneous (<emphasis>u</emphasis>, <emphasis>v</emphasis>, and <emphasis>w</emphasis>) | |
125 | parameter space. | |
126 | See the <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry> reference page for more discussion about trimming | |
127 | curves. | |
128 | </para> | |
129 | </refsect1> | |
130 | <refsect1 id="example"><title>Example</title> | |
131 | <para> | |
132 | The following commands render a textured NURBS curve with normals: | |
133 | <programlisting> | |
134 | gluBeginCurve(nobj); | |
135 | gluNurbsCurve(nobj, ..., GL_MAP1_TEXTURE_COORD_2); | |
136 | gluNurbsCurve(nobj, ..., GL_MAP1_NORMAL); | |
137 | gluNurbsCurve(nobj, ..., GL_MAP1_VERTEX_4); | |
138 | gluEndCurve(nobj); | |
139 | </programlisting> | |
140 | </para> | |
141 | </refsect1> | |
142 | <refsect1 id="notes"><title>Notes</title> | |
143 | <para> | |
144 | To define trim curves that stitch well, use <citerefentry><refentrytitle>gluPwlCurve</refentrytitle></citerefentry>. | |
145 | </para> | |
146 | </refsect1> | |
147 | <refsect1 id="seealso"><title>See Also</title> | |
148 | <para> | |
149 | <citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>, | |
150 | <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>, | |
151 | <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>, | |
152 | <citerefentry><refentrytitle>gluPwlCurve</refentrytitle></citerefentry> | |
153 | </para> | |
154 | </refsect1> | |
155 | <refsect1 id="Copyright"><title>Copyright</title> | |
156 | <para> | |
157 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
158 | Silicon Graphics, Inc. This document is licensed under the SGI | |
159 | Free Software B License. For details, see | |
160 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
161 | </para> | |
162 | </refsect1> | |
163 | </refentry> |