upstream-doc/man2/xhtml/glPolygonStipple.xml

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glPolygonStipple</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><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 border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><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>
   4                     Specifies a pointer to a
   5                     <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
   6
   7                         <mml:mrow>
   8                             <mml:mn>32</mml:mn>
   9                             <mml:mo>×</mml:mo>
  10                             <mml:mn>32</mml:mn>
  11                         </mml:mrow>
  12                     </mml:math>
  13                     stipple pattern that will be unpacked
  14                     from memory in the same way that <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a> unpacks pixels.
  15                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  16             Polygon stippling,
  17             like line stippling
  18             (see <a class="citerefentry" href="glLineStipple.xml"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>),
  19             masks out certain fragments produced by rasterization,
  20             creating a pattern.
  21             Stippling is independent of polygon antialiasing.
  22         </p><p>
  23             <em class="parameter"><code>pattern</code></em> is a pointer to a
  24             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  25
  26                 <mml:mrow>
  27                     <mml:mn>32</mml:mn>
  28                     <mml:mo>×</mml:mo>
  29                     <mml:mn>32</mml:mn>
  30                 </mml:mrow>
  31             </mml:math>
  32             stipple pattern that is stored
  33             in memory just like the pixel data supplied to a <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>
  34             call with
  35             <span class="emphasis"><em></em></span>
  36             height
  37             and
  38             <span class="emphasis"><em>width</em></span>
  39             both equal to 32, a pixel format
  40             of <code class="constant">GL_COLOR_INDEX</code>, and data type
  41             of <code class="constant">GL_BITMAP</code>.
  42             That is,
  43             the stipple pattern is represented as a
  44             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  45
  46                 <mml:mrow>
  47                     <mml:mn>32</mml:mn>
  48                     <mml:mo>×</mml:mo>
  49                     <mml:mn>32</mml:mn>
  50                 </mml:mrow>
  51             </mml:math>
  52             array
  53             of 1-bit color indices packed in unsigned bytes.
  54             <a class="citerefentry" href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a> parameters like <code class="constant">GL_UNPACK_SWAP_BYTES</code>
  55             and <code class="constant">GL_UNPACK_LSB_FIRST</code> affect the assembling of the bits into a
  56             stipple pattern.
  57             Pixel transfer operations
  58             (shift, offset, pixel map)
  59             are not applied to the stipple image,
  60             however.
  61         </p><p>
  62             If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target
  63             (see <a class="citerefentry" href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a stipple pattern is
  64             specified, <em class="parameter"><code>pattern</code></em> is treated as a byte offset into the buffer object's data store.
  65         </p><p>
  66             To enable and disable polygon stippling, call
  67             <a class="citerefentry" href="glEnable.xml"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> and <a class="citerefentry" href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a>
  68             with argument <code class="constant">GL_POLYGON_STIPPLE</code>. Polygon stippling is initially
  69             disabled. If it's enabled,
  70             a rasterized polygon fragment with window coordinates
  71             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  72
  73                 <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  74                 <mml:mi mathvariant="italic">w</mml:mi>
  75                 </mml:msub>
  76             </mml:math>
  77             and
  78             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  79
  80                 <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
  81                 <mml:mi mathvariant="italic">w</mml:mi>
  82                 </mml:msub>
  83             </mml:math>
  84             is sent to the next stage of the GL if and only if the
  85             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  86
  87                 <mml:mrow>
  88                     <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  89                     <mml:mi mathvariant="italic">w</mml:mi>
  90                     </mml:msub>
  91                     <mml:mo>%</mml:mo>
  92                     <mml:mn>32</mml:mn>
  93                 </mml:mrow>
  94             </mml:math>)th
  95             bit in the
  96             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  97
  98                 <mml:mrow>
  99                     <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
 100                     <mml:mi mathvariant="italic">w</mml:mi>
 101                     </mml:msub>
 102                     <mml:mo>%</mml:mo>
 103                     <mml:mn>32</mml:mn>
 104                 </mml:mrow>
 105             </mml:math>)th
 106             row
 107             of the stipple pattern is 1 (one).
 108             When polygon stippling is disabled, it is as if the stipple pattern
 109             consists of all 1's.
 110         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 111             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 112             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the buffer object's data store is currently mapped.
 113         </p><p>
 114             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 115             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer
 116             object such that the memory reads required would exceed the data store size.
 117         </p><p>
 118             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glPolygonStipple</code>
 119             is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
 120             and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 121         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 122             <a class="citerefentry" href="glGetPolygonStipple.xml"><span class="citerefentry"><span class="refentrytitle">glGetPolygonStipple</span></span></a>
 123         </p><p>
 124             <a class="citerefentry" href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> with argument <code class="constant">GL_POLYGON_STIPPLE</code>
 125         </p><p>
 126             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_UNPACK_BUFFER_BINDING</code>
 127         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 128             <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>,
 129             <a class="citerefentry" href="glLineStipple.xml"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>,
 130             <a class="citerefentry" href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
 131             <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>
 132         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 133             Copyright <span class="trademark"></span>© 1991-2006
 134             Silicon Graphics, Inc. This document is licensed under the SGI
 135             Free Software B License. For details, see
 136             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 137         </p></div></div></body></html>