121 lines
5.4 KiB
XML
121 lines
5.4 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
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<refentry id="gluPwlCurve">
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<refmeta>
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<refmetainfo>
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<copyright>
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<year>1991-2006</year>
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<holder>Silicon Graphics, Inc.</holder>
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</copyright>
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</refmetainfo>
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<refentrytitle>gluPwlCurve</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>gluPwlCurve</refname>
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<refpurpose>describe a piecewise linear NURBS trimming curve</refpurpose>
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</refnamediv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>gluPwlCurve</function></funcdef>
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<paramdef>GLUnurbs* <parameter>nurb</parameter></paramdef>
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<paramdef>GLint <parameter>count</parameter></paramdef>
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<paramdef>GLfloat* <parameter>data</parameter></paramdef>
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<paramdef>GLint <parameter>stride</parameter></paramdef>
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<paramdef>GLenum <parameter>type</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<!-- eqn: ignoring delim $$ -->
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<refsect1 id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>nurb</parameter></term>
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<listitem>
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<para>
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Specifies the NURBS object (created with <citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>).
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>count</parameter></term>
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<listitem>
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<para>
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Specifies the number of points on the curve.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>data</parameter></term>
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<listitem>
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<para>
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Specifies an array containing the curve points.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>stride</parameter></term>
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<listitem>
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<para>
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Specifies the offset (a number of single-precision floating-point values)
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between points on the curve.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>type</parameter></term>
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<listitem>
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<para>
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Specifies the type of curve.
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Must be either <constant>GLU_MAP1_TRIM_2</constant> or <constant>GLU_MAP1_TRIM_3</constant>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id="description"><title>Description</title>
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<para>
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<function>gluPwlCurve</function> describes a piecewise linear trimming curve for a NURBS surface.
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A piecewise linear curve consists of a list of
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coordinates of points in the parameter space for the
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NURBS surface to be trimmed. These points are connected
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with line segments to form a curve. If the curve is
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an approximation to a curve that is not piecewise linear,
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the points should be close enough in parameter space that the
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resulting path appears curved at the resolution used in the application.
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</para>
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<para>
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If <parameter>type</parameter> is
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<constant>GLU_MAP1_TRIM_2</constant>, then it describes a curve in two-dimensional (<emphasis>u</emphasis>
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and <emphasis>v</emphasis>) parameter space. If it is <constant>GLU_MAP1_TRIM_3</constant>, then it
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describes a curve in two-dimensional homogeneous (<emphasis>u</emphasis>, <emphasis>v</emphasis>,
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and <emphasis>w</emphasis>) parameter space.
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See the <citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry> reference page for more information
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about trimming curves.
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</para>
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</refsect1>
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<refsect1 id="notes"><title>Notes</title>
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<para>
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To describe a trim curve that closely follows the contours of a NURBS
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surface, call <citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry>.
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</para>
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</refsect1>
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<refsect1 id="seealso"><title>See Also</title>
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<para>
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<citerefentry><refentrytitle>gluBeginCurve</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluBeginTrim</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluNewNurbsRenderer</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>gluNurbsCurve</refentrytitle></citerefentry>
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</para>
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</refsect1>
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<refsect1 id="Copyright"><title>Copyright</title>
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<para>
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Copyright <trademark class="copyright"></trademark> 1991-2006
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Silicon Graphics, Inc. This document is licensed under the SGI
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Free Software B License. For details, see
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<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
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</para>
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</refsect1>
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</refentry>
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