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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.
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 {
25 } DispatchIndirectCommand;
</pre><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);
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.
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.
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>