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<?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="glRect">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glRect</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glRect</refname>
<refpurpose>draw a rectangle</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectd</function></funcdef>
<paramdef>GLdouble <parameter>x1</parameter></paramdef>
<paramdef>GLdouble <parameter>y1</parameter></paramdef>
<paramdef>GLdouble <parameter>x2</parameter></paramdef>
<paramdef>GLdouble <parameter>y2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectf</function></funcdef>
<paramdef>GLfloat <parameter>x1</parameter></paramdef>
<paramdef>GLfloat <parameter>y1</parameter></paramdef>
<paramdef>GLfloat <parameter>x2</parameter></paramdef>
<paramdef>GLfloat <parameter>y2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRecti</function></funcdef>
<paramdef>GLint <parameter>x1</parameter></paramdef>
<paramdef>GLint <parameter>y1</parameter></paramdef>
<paramdef>GLint <parameter>x2</parameter></paramdef>
<paramdef>GLint <parameter>y2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRects</function></funcdef>
<paramdef>GLshort <parameter>x1</parameter></paramdef>
<paramdef>GLshort <parameter>y1</parameter></paramdef>
<paramdef>GLshort <parameter>x2</parameter></paramdef>
<paramdef>GLshort <parameter>y2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>x1</parameter></term>
<term><parameter>y1</parameter></term>
<listitem>
<para>
Specify one vertex of a rectangle.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>x2</parameter></term>
<term><parameter>y2</parameter></term>
<listitem>
<para>
Specify the opposite vertex of the rectangle.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectdv</function></funcdef>
<paramdef>const GLdouble * <parameter>v1</parameter></paramdef>
<paramdef>const GLdouble * <parameter>v2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectfv</function></funcdef>
<paramdef>const GLfloat * <parameter>v1</parameter></paramdef>
<paramdef>const GLfloat * <parameter>v2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectiv</function></funcdef>
<paramdef>const GLint * <parameter>v1</parameter></paramdef>
<paramdef>const GLint * <parameter>v2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glRectsv</function></funcdef>
<paramdef>const GLshort * <parameter>v1</parameter></paramdef>
<paramdef>const GLshort * <parameter>v2</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="parameters2"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>v1</parameter></term>
<listitem>
<para>
Specifies a pointer to one vertex of a rectangle.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>v2</parameter></term>
<listitem>
<para>
Specifies a pointer to the opposite vertex of the rectangle.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
<function>glRect</function> supports efficient specification of rectangles as two corner points.
Each
rectangle command takes four arguments,
organized either as two consecutive pairs of
<inlineequation><mml:math>
<!-- eqn: (x,y):-->
<mml:mfenced open="(" close=")">
<mml:mi mathvariant="italic">x</mml:mi>
<mml:mi mathvariant="italic">y</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>
coordinates
or as two pointers to arrays,
each containing an
<inlineequation><mml:math>
<!-- eqn: (x,y):-->
<mml:mfenced open="(" close=")">
<mml:mi mathvariant="italic">x</mml:mi>
<mml:mi mathvariant="italic">y</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>
pair.
The resulting rectangle is defined in 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.
</para>
<para>
<function>glRect</function>(<parameter>x1</parameter>, <parameter>y1</parameter>, <parameter>x2</parameter>, <parameter>y2</parameter>)
is exactly equivalent to the following sequence:
<programlisting>
glBegin(<constant>GL_POLYGON</constant>);
glVertex2(<parameter>x1</parameter>, <parameter>y1</parameter>);
glVertex2(<parameter>x2</parameter>, <parameter>y1</parameter>);
glVertex2(<parameter>x2</parameter>, <parameter>y2</parameter>);
glVertex2(<parameter>x1</parameter>, <parameter>y2</parameter>);
glEnd();
</programlisting>
Note that if the second vertex is above and to the right of the first vertex,
the rectangle is constructed with a counterclockwise winding.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glRect</function>
is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glVertex</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>