Opentk/Source/Bind/Specifications/Docs/GL/glPolygonStipple.xml

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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="glPolygonStipple">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glPolygonStipple</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glPolygonStipple</refname>
<refpurpose>set the polygon stippling pattern</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glPolygonStipple</function></funcdef>
<paramdef>const GLubyte * <parameter>pattern</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>pattern</parameter></term>
<listitem>
<para>
Specifies a pointer to a
<inlineequation><mml:math>
<!-- eqn: 32 times 32:-->
<mml:mrow>
<mml:mn>32</mml:mn>
<mml:mo>&times;</mml:mo>
<mml:mn>32</mml:mn>
</mml:mrow>
</mml:math></inlineequation>
stipple pattern that will be unpacked
from memory in the same way that <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry> unpacks pixels.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
Polygon stippling,
like line stippling
(see <citerefentry><refentrytitle>glLineStipple</refentrytitle></citerefentry>),
masks out certain fragments produced by rasterization,
creating a pattern.
Stippling is independent of polygon antialiasing.
</para>
<para>
<parameter>pattern</parameter> is a pointer to a
<inlineequation><mml:math>
<!-- eqn: 32 times 32:-->
<mml:mrow>
<mml:mn>32</mml:mn>
<mml:mo>&times;</mml:mo>
<mml:mn>32</mml:mn>
</mml:mrow>
</mml:math></inlineequation>
stipple pattern that is stored
in memory just like the pixel data supplied to a <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>
call with
<emphasis></emphasis>
height
and
<emphasis>width</emphasis>
both equal to 32, a pixel format
of <constant>GL_COLOR_INDEX</constant>, and data type
of <constant>GL_BITMAP</constant>.
That is,
the stipple pattern is represented as a
<inlineequation><mml:math>
<!-- eqn: 32 times 32:-->
<mml:mrow>
<mml:mn>32</mml:mn>
<mml:mo>&times;</mml:mo>
<mml:mn>32</mml:mn>
</mml:mrow>
</mml:math></inlineequation>
array
of 1-bit color indices packed in unsigned bytes.
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry> parameters like <constant>GL_UNPACK_SWAP_BYTES</constant>
and <constant>GL_UNPACK_LSB_FIRST</constant> affect the assembling of the bits into a
stipple pattern.
Pixel transfer operations
(shift, offset, pixel map)
are not applied to the stipple image,
however.
</para>
<para>
If a non-zero named buffer object is bound to the <constant>GL_PIXEL_UNPACK_BUFFER</constant> target
(see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a stipple pattern is
specified, <parameter>pattern</parameter> is treated as a byte offset into the buffer object's data store.
</para>
<para>
To enable and disable polygon stippling, call
<citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glDisable</refentrytitle></citerefentry>
with argument <constant>GL_POLYGON_STIPPLE</constant>. Polygon stippling is initially
disabled. If it's enabled,
a rasterized polygon fragment with window coordinates
<inlineequation><mml:math>
<!-- eqn: x sub w:-->
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
<mml:mi mathvariant="italic">w</mml:mi>
</mml:msub>
</mml:math></inlineequation>
and
<inlineequation><mml:math>
<!-- eqn: y sub w:-->
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
<mml:mi mathvariant="italic">w</mml:mi>
</mml:msub>
</mml:math></inlineequation>
is sent to the next stage of the GL if and only if the
(<inlineequation><mml:math>
<!-- eqn: x sub w mod 32:-->
<mml:mrow>
<mml:msub><mml:mi mathvariant="italic">x</mml:mi>
<mml:mi mathvariant="italic">w</mml:mi>
</mml:msub>
<mml:mo>%</mml:mo>
<mml:mn>32</mml:mn>
</mml:mrow>
</mml:math></inlineequation>)th
bit in the
(<inlineequation><mml:math>
<!-- eqn: y sub w mod 32:-->
<mml:mrow>
<mml:msub><mml:mi mathvariant="italic">y</mml:mi>
<mml:mi mathvariant="italic">w</mml:mi>
</mml:msub>
<mml:mo>%</mml:mo>
<mml:mn>32</mml:mn>
</mml:mrow>
</mml:math></inlineequation>)th
row
of the stipple pattern is 1 (one).
When polygon stippling is disabled, it is as if the stipple pattern
consists of all 1's.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's data store is currently mapped.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
<constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be unpacked from the buffer
object such that the memory reads required would exceed the data store size.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glPolygonStipple</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>glGetPolygonStipple</refentrytitle></citerefentry>
</para>
<para>
<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_POLYGON_STIPPLE</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant>
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glLineStipple</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPixelTransfer</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>