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"opengl-man.css" /><title>gl_SampleID - OpenGL Shading Language (GLSL)
</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.69.1" /></head><body><div class=
"refentry" lang=
"en" xml:
lang=
"en"><a id=
"gl_SampleID"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>gl_SampleID — contains the index of the sample currently being processed
</p></div><div class=
"refsynopsisdiv"><h2>Declaration
</h2><div class=
"funcsynopsis"><code class=
"function">in int gl_SampleID;
</code></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
5 <code class=
"function">gl_SampleID
</code> is a fragment language input variable that contains
6 the index of the sample currently being processed. This variable is in the range
7 0 to
<a href=
"gl_NumSamples.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_NumSamples
</span></span></a> -
1, where
8 <a href=
"gl_NumSamples.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_NumSamples
</span></span></a>
9 is the total number of samples in each fragment for the current framebuffer (and thus
1 if
10 rendering to a non-multisample buffer). Any static use of this variable in a fragment
11 shader causes the entire shader to be evaluated per-sample rather than per-fragment.
13 When rendering to a non-multisample buffer, or if multisample rasterization is disabled,
14 <code class=
"function">gl_SampleID
</code> will always be zero.
<a href=
"gl_NumSamples.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_NumSamples
</span></span></a>
15 is the sample count of the framebuffer regardless of whether multisample rasterization is
17 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"versions"></a><h2>Version Support
</h2><div class=
"informaltable"><table border=
"1"><colgroup><col align=
"left" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /><col align=
"center" /></colgroup><thead><tr><th align=
"left"><span class=
"bold"><strong>Variable
</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
1.10</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
1.20</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
1.30</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
1.40</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
1.50</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
3.30</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
4.00</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
4.10</strong></span></th><th align=
"left"><span class=
"bold"><strong>Version
4.20</strong></span></th><th align=
"center"><span class=
"bold"><strong>Version
4.30</strong></span></th></tr><tr><th align=
"left">gl_SampleID
</th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>-
</em></span></th><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th></tr></thead></table></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
18 <a href=
"gl_SamplePosition.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_SamplePosition
</span></span></a>,
19 <a href=
"gl_NumSamples.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_NumSamples
</span></span></a>
20 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
21 Copyright
<span class=
"trademark"></span>©
2011 Khronos Group.
22 This material may be distributed subject to the terms and conditions set forth in
23 the Open Publication License, v
1.0,
8 June
1999.
24 <a href=
"http://opencontent.org/openpub/" target=
"_top">http://opencontent.org/openpub/
</a>.
25 </p></div></div></body></html>