upstream-man-pages/man4/xhtml/glDrawElementsInstanced.xml

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   4 <?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" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glDrawElementsInstanced - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glDrawElementsInstanced"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glDrawElementsInstanced — draw multiple instances of a set of elements</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">glDrawElementsInstanced</b>(</code></td><td>GLenum  </td><td><var class="pdparam">mode</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">count</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>const void *  </td><td><var class="pdparam">indices</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">primcount</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>mode</code></em></span></dt><dd><p>
   5                     Specifies what kind of primitives to render.
   6                     Symbolic constants
   7                     <code class="constant">GL_POINTS</code>,
   8                     <code class="constant">GL_LINE_STRIP</code>,
   9                     <code class="constant">GL_LINE_LOOP</code>,
  10                     <code class="constant">GL_LINES</code>,
  11                     <code class="constant">GL_LINE_STRIP_ADJACENCY</code>,
  12                     <code class="constant">GL_LINES_ADJACENCY</code>,
  13                     <code class="constant">GL_TRIANGLE_STRIP</code>,
  14                     <code class="constant">GL_TRIANGLE_FAN</code>,
  15                     <code class="constant">GL_TRIANGLES</code>,
  16                     <code class="constant">GL_TRIANGLE_STRIP_ADJACENCY</code>,
  17                     <code class="constant">GL_TRIANGLES_ADJACENCY</code> and <code class="constant">GL_PATCHES</code>
  18                     are accepted.
  19                 </p></dd><dt><span class="term"><em class="parameter"><code>count</code></em></span></dt><dd><p>
  20                     Specifies the number of elements to be rendered.
  21                 </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
  22                     Specifies the type of the values in <em class="parameter"><code>indices</code></em>. Must be one of <code class="constant">GL_UNSIGNED_BYTE</code>,
  23                     <code class="constant">GL_UNSIGNED_SHORT</code>, or <code class="constant">GL_UNSIGNED_INT</code>.
  24                 </p></dd><dt><span class="term"><em class="parameter"><code>indices</code></em></span></dt><dd><p>
  25                     Specifies a pointer to the location where the indices are stored.
  26                 </p></dd><dt><span class="term"><em class="parameter"><code>primcount</code></em></span></dt><dd><p>
  27                     Specifies the number of instances of the specified range of indices to be rendered.
  28                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  29             <code class="function">glDrawElementsInstanced</code> behaves identically to <a href="glDrawElements.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElements</span></span></a>
  30             except that <em class="parameter"><code>primcount</code></em> instances of the set of elements are executed and the value of the internal counter
  31             <em class="parameter"><code>instanceID</code></em> advances for each iteration. <em class="parameter"><code>instanceID</code></em> is an internal 32-bit integer counter
  32             that may be read by a vertex shader as <code class="constant">gl_InstanceID</code>.
  33         </p><p>
  34             <code class="function">glDrawElementsInstanced</code> has the same effect as:
  35             </p><pre class="programlisting">    if (mode, count, or type is invalid )
  36         generate appropriate error
  37     else {
  38         for (int i = 0; i &lt; primcount ; i++) {
  39             instanceID = i;
  40             glDrawElements(mode, count, type, indices);
  41         }
  42         instanceID = 0;
  43     }</pre><p>
  44         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
  45             <code class="function">glDrawElementsInstanced</code> is available only if the GL version is 3.1 or greater.
  46         </p><p>
  47             <code class="constant">GL_LINE_STRIP_ADJACENCY</code>,
  48             <code class="constant">GL_LINES_ADJACENCY</code>,
  49             <code class="constant">GL_TRIANGLE_STRIP_ADJACENCY</code> and
  50             <code class="constant">GL_TRIANGLES_ADJACENCY</code>
  51             are available only if the GL version is 3.2 or greater.
  52         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
  53             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not one of <code class="constant">GL_POINTS</code>,
  54             <code class="constant">GL_LINE_STRIP</code>, <code class="constant">GL_LINE_LOOP</code>, <code class="constant">GL_LINES</code>,
  55             <code class="constant">GL_TRIANGLE_STRIP</code>, <code class="constant">GL_TRIANGLE_FAN</code>, or <code class="constant">GL_TRIANGLES</code>.
  56         </p><p>
  57             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>count</code></em> or <em class="parameter"><code>primcount</code></em> are negative.
  58         </p><p>
  59             <code class="constant">GL_INVALID_OPERATION</code> is generated if a geometry shader is active and <em class="parameter"><code>mode</code></em>
  60             is incompatible with the input primitive type of the geometry shader in the currently installed program object.
  61         </p><p>
  62             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to an
  63             enabled array and the buffer object's data store is currently mapped.
  64         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
  65             <a href="glDrawElements.xml"><span class="citerefentry"><span class="refentrytitle">glDrawElements</span></span></a>,
  66             <a href="glDrawArraysInstanced.xml"><span class="citerefentry"><span class="refentrytitle">glDrawArraysInstanced</span></span></a>
  67         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  68             Copyright <span class="trademark"></span>© 2010 Khronos Group.
  69             This material may be distributed subject to the terms and conditions set forth in
  70             the Open Publication License, v 1.0, 8 June 1999.
  71             <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
  72         </p></div></div></body></html>