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1 | <?xml version="1.0" encoding="UTF-8"?> |
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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</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> and | |
17 | <code class="constant">GL_TRIANGLES_ADJACENCY</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 < 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> |