1 <?xml version=
"1.0" encoding=
"UTF-8"?>
2 <!DOCTYPE html PUBLIC
"-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
3 <!-- saved from url=(0013)about:internet -->
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>gl_SamplePosition - 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_SamplePosition"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>gl_SamplePosition — contains the location of the current sample within the current fragment
</p></div><div class=
"refsynopsisdiv"><h2>Declaration
</h2><div class=
"funcsynopsis"><code class=
"function">in vec2 gl_SamplePosition;
</code></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
5 <code class=
"function">gl_SamplePosition
</code> is a fragment language input variable that contains
6 the location within a fragment of the sample currently being processed. The x and y components
7 of
<code class=
"function">gl_SamplePosition
</code> contain the sub-pixel coordinate of the current
8 sample and will have values in the range
0.0 to
1.0. The sub-pixel coordinates of the center
9 of the pixel are always (
0.5,
0.5). Any static use of
<code class=
"function">gl_SamplePosition
</code>
10 causes the entire fragment shader to be evaluated per-sample rather than per-fragment. When rendering
11 to a non-multisample buffer, or if multisample rasterization is disabled,
<code class=
"function">gl_SamplePosition
</code>
13 </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" /></colgroup><thead><tr><th align=
"left"><span class=
"bold"><strong>
15 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
17 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
19 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
21 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
23 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
25 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
27 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
29 </strong></span></th><th align=
"left"><span class=
"bold"><strong>
31 </strong></span></th></tr><tr><th align=
"left">
33 </th><th align=
"center">
34 <span class=
"emphasis"><em>-
</em></span>
35 </th><th align=
"center">
36 <span class=
"emphasis"><em>-
</em></span>
37 </th><th align=
"center">
38 <span class=
"emphasis"><em>-
</em></span>
39 </th><th align=
"center">
40 <span class=
"emphasis"><em>-
</em></span>
41 </th><th align=
"center">
42 <span class=
"emphasis"><em>-
</em></span>
43 </th><th align=
"center">
44 <span class=
"emphasis"><em>-
</em></span>
45 </th><th align=
"center">
46 <span class=
"emphasis"><em>Y
</em></span>
47 </th><th align=
"center">
48 <span class=
"emphasis"><em>Y
</em></span>
49 </th></tr></thead></table></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
50 <a href=
"gl_SampleID.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_SampleID
</span></span></a>,
51 <a href=
"gl_SampleMask.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_SampleMask
</span></span></a>,
52 <a href=
"gl_FragCoord.xml"><span class=
"citerefentry"><span class=
"refentrytitle">gl_FragCoord
</span></span></a>
53 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
54 Copyright
<span class=
"trademark"></span>©
2011 Khronos Group.
55 This material may be distributed subject to the terms and conditions set forth in
56 the Open Publication License, v
1.0,
8 June
1999.
57 <a href=
"http://opencontent.org/openpub/" target=
"_top">http://opencontent.org/openpub/
</a>.
58 </p></div></div></body></html>