167 lines
7.8 KiB
XML
167 lines
7.8 KiB
XML
<?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="glPolygonMode">
|
|
<refmeta>
|
|
<refmetainfo>
|
|
<copyright>
|
|
<year>1991-2006</year>
|
|
<holder>Silicon Graphics, Inc.</holder>
|
|
</copyright>
|
|
</refmetainfo>
|
|
<refentrytitle>glPolygonMode</refentrytitle>
|
|
<manvolnum>3G</manvolnum>
|
|
</refmeta>
|
|
<refnamediv>
|
|
<refname>glPolygonMode</refname>
|
|
<refpurpose>select a polygon rasterization mode</refpurpose>
|
|
</refnamediv>
|
|
<refsynopsisdiv><title>C Specification</title>
|
|
<funcsynopsis>
|
|
<funcprototype>
|
|
<funcdef>void <function>glPolygonMode</function></funcdef>
|
|
<paramdef>GLenum <parameter>face</parameter></paramdef>
|
|
<paramdef>GLenum <parameter>mode</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
<refsect1 id="parameters"><title>Parameters</title>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><parameter>face</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies the polygons that <parameter>mode</parameter> applies to.
|
|
Must be
|
|
<constant>GL_FRONT</constant> for front-facing polygons,
|
|
<constant>GL_BACK</constant> for back-facing polygons,
|
|
or <constant>GL_FRONT_AND_BACK</constant> for front- and back-facing polygons.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>mode</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies how polygons will be rasterized.
|
|
Accepted values are
|
|
<constant>GL_POINT</constant>,
|
|
<constant>GL_LINE</constant>, and
|
|
<constant>GL_FILL</constant>.
|
|
The initial value is <constant>GL_FILL</constant> for both front- and back-facing polygons.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
<refsect1 id="description"><title>Description</title>
|
|
<para>
|
|
<function>glPolygonMode</function> controls the interpretation of polygons for rasterization.
|
|
<parameter>face</parameter> describes which polygons <parameter>mode</parameter> applies to:
|
|
front-facing polygons (<constant>GL_FRONT</constant>),
|
|
back-facing polygons (<constant>GL_BACK</constant>),
|
|
or both (<constant>GL_FRONT_AND_BACK</constant>).
|
|
The polygon mode affects only the final rasterization of polygons.
|
|
In particular,
|
|
a polygon's vertices are lit and
|
|
the polygon is clipped and possibly culled before these modes are applied.
|
|
</para>
|
|
<para>
|
|
Three modes are defined and can be specified in <parameter>mode</parameter>:
|
|
</para>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><constant>GL_POINT</constant></term>
|
|
<listitem>
|
|
<para>
|
|
Polygon vertices that are marked as the start of a boundary edge
|
|
are drawn as points.
|
|
Point attributes such as
|
|
<constant>GL_POINT_SIZE</constant> and
|
|
<constant>GL_POINT_SMOOTH</constant> control
|
|
the rasterization of the points.
|
|
Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><constant>GL_LINE</constant></term>
|
|
<listitem>
|
|
<para>
|
|
Boundary edges of the polygon are drawn as line segments.
|
|
They are treated as connected line segments for line stippling;
|
|
the line stipple counter and pattern are not reset between segments
|
|
(see <citerefentry><refentrytitle>glLineStipple</refentrytitle></citerefentry>).
|
|
Line attributes such as
|
|
<constant>GL_LINE_WIDTH</constant> and
|
|
<constant>GL_LINE_SMOOTH</constant> control
|
|
the rasterization of the lines.
|
|
Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><constant>GL_FILL</constant></term>
|
|
<listitem>
|
|
<para>
|
|
The interior of the polygon is filled.
|
|
Polygon attributes such as
|
|
<constant>GL_POLYGON_STIPPLE</constant> and
|
|
<constant>GL_POLYGON_SMOOTH</constant> control the rasterization of the polygon.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
<refsect1 id="examples"><title>Examples</title>
|
|
<para>
|
|
To draw a surface with filled back-facing polygons
|
|
and outlined front-facing polygons,
|
|
call
|
|
<programlisting>
|
|
glPolygonMode(<constant>GL_FRONT</constant>, <constant>GL_LINE</constant>);
|
|
</programlisting>
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 id="notes"><title>Notes</title>
|
|
<para>
|
|
Vertices are marked as boundary or nonboundary with an edge flag.
|
|
Edge flags are generated internally by the GL when it decomposes
|
|
polygons; they can be set explicitly using <citerefentry><refentrytitle>glEdgeFlag</refentrytitle></citerefentry>.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 id="errors"><title>Errors</title>
|
|
<para>
|
|
<constant>GL_INVALID_ENUM</constant> is generated if either <parameter>face</parameter> or <parameter>mode</parameter> is not
|
|
an accepted value.
|
|
</para>
|
|
<para>
|
|
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glPolygonMode</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="associatedgets"><title>Associated Gets</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POLYGON_MODE</constant>
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 id="seealso"><title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glEdgeFlag</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glLineStipple</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glLineWidth</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glPointSize</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glPolygonStipple</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>
|