upstream-man-pages/manglsl/xhtml/smoothstep.xml

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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>smoothstep - 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="smoothstep"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>smoothstep — perform Hermite interpolation between two values</p></div><div class="refsynopsisdiv"><h2>Declaration</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genType <b class="fsfunc">smoothstep</b>(</code></td><td>genType  </td><td><var class="pdparam">edge0</var>, </td></tr><tr><td> </td><td>genType  </td><td><var class="pdparam">edge1</var>, </td></tr><tr><td> </td><td>genType  </td><td><var class="pdparam">x</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genType <b class="fsfunc">smoothstep</b>(</code></td><td>float  </td><td><var class="pdparam">edge0</var>, </td></tr><tr><td> </td><td>float  </td><td><var class="pdparam">edge1</var>, </td></tr><tr><td> </td><td>genType  </td><td><var class="pdparam">x</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genDType <b class="fsfunc">smoothstep</b>(</code></td><td>genDType  </td><td><var class="pdparam">edge0</var>, </td></tr><tr><td> </td><td>genDType  </td><td><var class="pdparam">edge1</var>, </td></tr><tr><td> </td><td>genDType  </td><td><var class="pdparam">x</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">genDType <b class="fsfunc">smoothstep</b>(</code></td><td>double  </td><td><var class="pdparam">edge0</var>, </td></tr><tr><td> </td><td>double  </td><td><var class="pdparam">edge1</var>, </td></tr><tr><td> </td><td>genDType  </td><td><var class="pdparam">x</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>edge0</code></em></span></dt><dd><p>
   5                     Specifies the value of the lower edge of the Hermite function.
   6                 </p></dd><dt><span class="term"><em class="parameter"><code>edge1</code></em></span></dt><dd><p>
   7                     Specifies the value of the upper edge of the Hermite function.
   8                 </p></dd><dt><span class="term"><em class="parameter"><code>x</code></em></span></dt><dd><p>
   9                     Specifies the source value for interpolation.
  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">smoothstep</code> performs smooth Hermite interpolation between 0 and
  12             1 when <em class="parameter"><code>edge0</code></em> &lt; <em class="parameter"><code>x</code></em> &lt; <em class="parameter"><code>edge1</code></em>.
  13             This is useful in cases where a threshold function with a smooth transition is desired.
  14             <code class="function">smoothstep</code> is equivalent to:
  15         </p><p>
  16 </p><pre class="programlisting">    genType t;  /* Or genDType t; */
  17     t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
  18     return t * t * (3.0 - 2.0 * t);
  19 </pre><p>
  20         </p><p>
  21             Results are undefined if <em class="parameter"><code>edge0</code></em> ≥ <em class="parameter"><code>edge1</code></em>.
  22         </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">smoothstep (genType)</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><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">smoothstep (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>
  23             <a href="mix.xml"><span class="citerefentry"><span class="refentrytitle">mix</span></span></a>,
  24             <a href="step.xml"><span class="citerefentry"><span class="refentrytitle">step</span></span></a>
  25         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  26             Copyright <span class="trademark"></span>© 2011 Khronos Group.
  27             This material may be distributed subject to the terms and conditions set forth in
  28             the Open Publication License, v 1.0, 8 June 1999.
  29             <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
  30         </p></div></div></body></html>