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>faceforward - 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=
"faceforward"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>faceforward — return a vector pointing in the same direction as another
</p></div><div class=
"refsynopsisdiv"><h2>Declaration
</h2><div class=
"funcsynopsis"><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0" style=
"padding-bottom: 1em"><tr><td><code class=
"funcdef">genType
<b class=
"fsfunc">faceforward
</b>(
</code></td><td>genType
</td><td><var class=
"pdparam">N
</var>,
</td></tr><tr><td> </td><td>genType
</td><td><var class=
"pdparam">I
</var>,
</td></tr><tr><td> </td><td>genType
</td><td><var class=
"pdparam">Nref
</var><code>)
</code>;
</td></tr></table><table border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">genDType
<b class=
"fsfunc">faceforward
</b>(
</code></td><td>genDType
</td><td><var class=
"pdparam">N
</var>,
</td></tr><tr><td> </td><td>genDType
</td><td><var class=
"pdparam">I
</var>,
</td></tr><tr><td> </td><td>genDType
</td><td><var class=
"pdparam">Nref
</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>N
</code></em></span></dt><dd><p>
5 Specifies the vector to orient.
6 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>I
</code></em></span></dt><dd><p>
7 Specifies the incident vector.
8 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>Nref
</code></em></span></dt><dd><p>
9 Specifies the reference vector.
10 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
11 <code class=
"function">faceforward
</code> orients a vector to point away from a surface as defined by its normal.
12 If
<a href=
"dot.xml"><span class=
"citerefentry"><span class=
"refentrytitle">dot
</span></span></a><code class=
"code">(
<em class=
"parameter"><code>Nref
</code></em>,
<em class=
"parameter"><code>I
</code></em>)
< 0</code>
13 <code class=
"function">faceforward
</code> returns
<em class=
"parameter"><code>N
</code></em>, otherwise it returns
<code class=
"code">-
<em class=
"parameter"><code>N
</code></em></code>.
14 </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>Function
</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">faceforward (genType)
</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><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><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th><th align=
"center"><span class=
"emphasis"><em>Y
</em></span></th></tr><tr><th align=
"left">faceforward (genDType)
</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>
15 <a href=
"reflect.xml"><span class=
"citerefentry"><span class=
"refentrytitle">reflect
</span></span></a>,
16 <a href=
"refract.xml"><span class=
"citerefentry"><span class=
"refentrytitle">refract
</span></span></a>
17 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
18 Copyright
<span class=
"trademark"></span>©
2011 Khronos Group.
19 This material may be distributed subject to the terms and conditions set forth in
20 the Open Publication License, v
1.0,
8 June
1999.
21 <a href=
"http://opencontent.org/openpub/" target=
"_top">http://opencontent.org/openpub/
</a>.
22 </p></div></div></body></html>