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<div class="refentry" lang="en" xml:lang="en"><a id="glPolygonStipple"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glPolygonStipple — set the polygon stippling pattern</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glPolygonStipple</b>(</code></td><td>const GLubyte *  </td><td><var class="pdparam">pattern</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>pattern</code></em></span></dt><dd><p>
Specifies a pointer to a
<math overflow="scroll">
<mrow>
<mn>32</mn>
<mo>×</mo>
<mn>32</mn>
</mrow>
</math>
stipple pattern that will be unpacked
from memory in the same way that <a class="citerefentry" href="glDrawPixels"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a> unpacks pixels.
</p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
Polygon stippling,
like line stippling
(see <a class="citerefentry" href="glLineStipple"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>),
masks out certain fragments produced by rasterization,
creating a pattern.
Stippling is independent of polygon antialiasing.
</p><p>
<em class="parameter"><code>pattern</code></em> is a pointer to a
<math overflow="scroll">
<mrow>
<mn>32</mn>
<mo>×</mo>
<mn>32</mn>
</mrow>
</math>
stipple pattern that is stored
in memory just like the pixel data supplied to a <a class="citerefentry" href="glDrawPixels"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>
call with
<span class="emphasis"><em></em></span>
height
and
<span class="emphasis"><em>width</em></span>
both equal to 32, a pixel format
of <code class="constant">GL_COLOR_INDEX</code>, and data type
of <code class="constant">GL_BITMAP</code>.
That is,
the stipple pattern is represented as a
<math overflow="scroll">
<mrow>
<mn>32</mn>
<mo>×</mo>
<mn>32</mn>
</mrow>
</math>
array
of 1-bit color indices packed in unsigned bytes.
<a class="citerefentry" href="glPixelStore"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a> parameters like <code class="constant">GL_UNPACK_SWAP_BYTES</code>
and <code class="constant">GL_UNPACK_LSB_FIRST</code> 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.
</p><p>
If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target
(see <a class="citerefentry" href="glBindBuffer"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a stipple pattern is
specified, <em class="parameter"><code>pattern</code></em> is treated as a byte offset into the buffer object's data store.
</p><p>
To enable and disable polygon stippling, call
<a class="citerefentry" href="glEnable"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> and <a class="citerefentry" href="glDisable"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a>
with argument <code class="constant">GL_POLYGON_STIPPLE</code>. Polygon stippling is initially
disabled. If it's enabled,
a rasterized polygon fragment with window coordinates
<math overflow="scroll">
<msub><mi mathvariant="italic">x</mi>
<mi mathvariant="italic">w</mi>
</msub>
</math>
and
<math overflow="scroll">
<msub><mi mathvariant="italic">y</mi>
<mi mathvariant="italic">w</mi>
</msub>
</math>
is sent to the next stage of the GL if and only if the
(<math overflow="scroll">
<mrow>
<msub><mi mathvariant="italic">x</mi>
<mi mathvariant="italic">w</mi>
</msub>
<mo>%</mo>
<mn>32</mn>
</mrow>
</math>)th
bit in the
(<math overflow="scroll">
<mrow>
<msub><mi mathvariant="italic">y</mi>
<mi mathvariant="italic">w</mi>
</msub>
<mo>%</mo>
<mn>32</mn>
</mrow>
</math>)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.
</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
<code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
<code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the buffer object's data store is currently mapped.
</p><p>
<code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
<code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer
object such that the memory reads required would exceed the data store size.
</p><p>
<code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glPolygonStipple</code>
is executed between the execution of <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
and the corresponding execution of <a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
</p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
<a class="citerefentry" href="glGetPolygonStipple"><span class="citerefentry"><span class="refentrytitle">glGetPolygonStipple</span></span></a>
</p><p>
<a class="citerefentry" href="glIsEnabled"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> with argument <code class="constant">GL_POLYGON_STIPPLE</code>
</p><p>
<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_UNPACK_BUFFER_BINDING</code>
</p></div>
{$pipelinestall}{$examples}
<div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
<a class="citerefentry" href="glDrawPixels"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>,
<a class="citerefentry" href="glLineStipple"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>,
<a class="citerefentry" href="glPixelStore"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
<a class="citerefentry" href="glPixelTransfer"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>
</p></div><div class="refsect1" lang="en" xml:lang="en"><div id="Copyright"><h2>Copyright</h2><p>
Copyright © 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
<a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
</p></div></div></div>
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