Blame |
Last modification |
View Log
| RSS feed
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="gluPartialDisk">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>gluPartialDisk</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>gluPartialDisk</refname>
<refpurpose>draw an arc of a disk</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>gluPartialDisk</function></funcdef>
<paramdef>GLUquadric* <parameter>quad</parameter></paramdef>
<paramdef>GLdouble <parameter>inner</parameter></paramdef>
<paramdef>GLdouble <parameter>outer</parameter></paramdef>
<paramdef>GLint <parameter>slices</parameter></paramdef>
<paramdef>GLint <parameter>loops</parameter></paramdef>
<paramdef>GLdouble <parameter>start</parameter></paramdef>
<paramdef>GLdouble <parameter>sweep</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>quad</parameter></term>
<listitem>
<para>
Specifies a quadrics object (created with <citerefentry><refentrytitle>gluNewQuadric</refentrytitle></citerefentry>).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>inner</parameter></term>
<listitem>
<para>
Specifies the inner radius of the partial disk (can be 0).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>outer</parameter></term>
<listitem>
<para>
Specifies the outer radius of the partial disk.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>slices</parameter></term>
<listitem>
<para>
Specifies the number of subdivisions around the <emphasis>z</emphasis> axis.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>loops</parameter></term>
<listitem>
<para>
Specifies the number of concentric rings about the origin into which
the partial disk is subdivided.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>start</parameter></term>
<listitem>
<para>
Specifies the starting angle, in degrees, of the disk portion.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>sweep</parameter></term>
<listitem>
<para>
Specifies the sweep angle, in degrees, of the disk portion.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
<function>gluPartialDisk</function> renders a partial disk on the
<inlineequation><mml:math>
<!-- eqn: z = 0:-->
<mml:mrow>
<mml:mi mathvariant="italic">z</mml:mi>
<mml:mo>=</mml:mo>
<mml:mn>0</mml:mn>
</mml:mrow>
</mml:math></inlineequation>
plane. A partial disk is
similar to a full disk, except that only the subset of the disk from
<parameter>start</parameter> through <parameter>start</parameter> + <parameter>sweep</parameter> is included (where 0 degrees is along the
+\f2y\f axis,
90 degrees along the +<emphasis>x</emphasis> axis, 180 degrees along the \-<emphasis>y</emphasis> axis, and
270 degrees along the \-<emphasis>x</emphasis> axis).
</para>
<para>
The partial disk has a radius of
<parameter>outer</parameter> and contains a concentric circular hole with a radius
of <parameter>inner</parameter>. If <parameter>inner</parameter> is 0, then no hole is generated. The partial disk is
subdivided around the <emphasis>z</emphasis> axis into slices (like pizza slices) and also
about the <emphasis>z</emphasis> axis into rings
(as specified by <parameter>slices</parameter> and <parameter>loops</parameter>, respectively).
</para>
<para>
With respect to orientation, the +<emphasis>z</emphasis>
side of the partial disk is considered to
be outside (see <citerefentry><refentrytitle>gluQuadricOrientation</refentrytitle></citerefentry>).
This means that if the
orientation is set to <constant>GLU_OUTSIDE</constant>, then any normals generated
point along the +<emphasis>z</emphasis> axis. Otherwise, they point along the \-<emphasis>z</emphasis>
axis.
</para>
<para>
If texturing is turned on (with <citerefentry><refentrytitle>gluQuadricTexture</refentrytitle></citerefentry>), texture
coordinates are generated
linearly such that where
<inlineequation><mml:math>
<!-- eqn: r = outer:-->
<mml:mrow>
<mml:mi mathvariant="italic">r</mml:mi>
<mml:mo>=</mml:mo>
<mml:mi mathvariant="italic">outer</mml:mi>
</mml:mrow>
</mml:math></inlineequation>,
the value at (<emphasis>r</emphasis>, 0, 0) is
(1.0, 0.5), at (0, <emphasis>r</emphasis>, 0) it is (0.5, 1.0), at (\-<emphasis>r</emphasis>, 0, 0)
it is (0.0, 0.5), and
at (0, \-<emphasis>r</emphasis>, 0) it is (0.5, 0.0).
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>gluCylinder</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>gluDisk</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>gluNewQuadric</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>gluQuadricOrientation</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>gluQuadricTexture</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>gluSphere</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"></trademark> 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
</para>
</refsect1>
</refentry>