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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> | |
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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>glDispatchComputeIndirect - 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="glDispatchComputeIndirect"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glDispatchComputeIndirect — launch one or more compute work groups using parameters stored in a buffer</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">glDispatchComputeIndirect</b>(</code></td><td>GLintptr </td><td><var class="pdparam">indirect</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>indirect</code></em></span></dt><dd><p> | |
5 | The offset into the buffer object currently bound to the | |
6 | <code class="constant">GL_DISPATCH_INDIRECT_BUFFER</code> buffer target at | |
7 | which the dispatch parameters are stored. | |
8 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
9 | <code class="function">glDispatchComputeIndirect</code> launches one or more compute | |
10 | work groups using parameters stored in the buffer object currently bound | |
11 | to the <code class="constant">GL_DISPATCH_INDIRECT_BUFFER</code> target. | |
12 | Each work group is processed by the active program object for the compute | |
13 | shader stage. While the individual shader invocations within a work group are | |
14 | executed as a unit, work groups are executed completely independently and in | |
15 | unspecified order. <em class="parameter"><code>indirect</code></em> contains the offset | |
16 | into the data store of the buffer object bound to the <code class="constant">GL_DISPATCH_INDIRECT_BUFFER</code> | |
17 | target at which the parameters are stored. | |
18 | </p><p> | |
19 | The parameters addressed by <em class="parameter"><code>indirect</code></em> are packed a structure, | |
20 | which takes the form (in C): | |
21 | </p><pre class="programlisting"> typedef struct { | |
22 | uint num_groups_x; | |
23 | uint num_groups_y; | |
24 | uint num_groups_z; | |
25 | } DispatchIndirectCommand;</pre><p> | |
26 | </p><p> | |
27 | A call to <code class="function">glDispatchComputeIndirect</code> is equivalent, assuming no | |
28 | errors are generated, to: | |
29 | </p><pre class="programlisting"> cmd = (const DispatchIndirectCommand *)indirect; | |
30 | glDispatchComputeIndirect(cmd->num_groups_x, cmd->num_groups_y, cmd->num_groups_z); | |
31 | }</pre><p> | |
32 | </p><p> | |
33 | Unlike <a href="glDispatchCompute.xml"><span class="citerefentry"><span class="refentrytitle">glDispatchCompute</span></span></a>, | |
34 | no error is generated if any of the <code class="code">num_groups_x</code>, | |
35 | <code class="code">num_groups_y</code> or <code class="code">num_groups_z</code> members | |
36 | of the <code class="code">DispatchIndirectCommand</code> is larger than the | |
37 | value of <code class="constant">GL_MAX_COMPUTE_WORK_GROUP_COUNT</code> for the | |
38 | corresponding dimension. In such circumstances, behavior is undefined and | |
39 | may lead to application termination. | |
40 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
41 | <code class="constant">GL_INVALID_OPERATION</code> is generated if there is no active program | |
42 | for the compute shader stage. | |
43 | </p><p> | |
44 | <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>indirect</code></em> is | |
45 | less than zero or not a multiple of four. | |
46 | </p><p> | |
47 | <code class="constant">GL_INVALID_OPERATION</code> is generated if no buffer is bound to the | |
48 | <code class="constant">GL_DISPATCH_INDIRECT_BUFFER</code> target or if the command would | |
49 | source data beyond the end of the buffer object's data store. | |
50 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
51 | <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_MAX_COMPUTE_WORK_GROUP_COUNT</code> | |
52 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
53 | <a href="glDispatchCompute.xml"><span class="citerefentry"><span class="refentrytitle">glDispatchCompute</span></span></a>. | |
54 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
55 | Copyright <span class="trademark"></span>© 2012 Khronos Group. | |
56 | This material may be distributed subject to the terms and conditions set forth in | |
57 | the Open Publication License, v 1.0, 8 June 1999. | |
58 | <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
59 | </p></div></div></body></html> |