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    <title>Fog Volumes on Miles Macklin</title>
    <link>http://blog.mmacklin.com/tags/fog-volumes/</link>
    <description>Recent content in Fog Volumes on Miles Macklin</description>
    <generator>Hugo -- gohugo.io</generator>
    <language>en-us</language>
    <copyright>&amp;copy; 2019 Miles Macklin</copyright>
    <lastBuildDate>Fri, 11 Jun 2010 03:24:11 +0000</lastBuildDate><atom:link href="http://blog.mmacklin.com/tags/fog-volumes/index.xml" rel="self" type="application/rss+xml" />
    <item>
      <title>Faster Fog</title>
      <link>http://blog.mmacklin.com/2010/06/10/faster-fog/</link>
      <pubDate>Fri, 11 Jun 2010 03:24:11 +0000</pubDate>
      
      <guid>http://blog.mmacklin.com/2010/06/10/faster-fog/</guid>
      <description>Cedrick at Lucas suggested some nice optimisations for the in-scattering equation I posted last time.
I had left off at:
\[L_{s} = \frac{\sigma_{s}I}{v}( \tan^{-1}\left(\frac{d+b}{v}\right) - \tan^{-1}\left(\frac{b}{v}\right) )\]
But we can remove one of the two inverse trigonometric functions by using the following identity:
\[\tan^{-1}x - \tan^{-1}y = \tan^{-1}\frac{x-y}{1+xy}\]
Which simplifies the expression for $L_{s}$ to:
\[L_{s} = \frac{\sigma_{s}I}{v}( \tan^{-1}\frac{x-y}{1+xy} )\]
With $x$ and $y$ being replaced by:
\[\begin{array}{lcl} x = \frac{d+b}{v} \\ y = \frac{b}{v}\end{array}\]</description>
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    <item>
      <title>In-Scattering Demo</title>
      <link>http://blog.mmacklin.com/2010/05/29/in-scattering-demo/</link>
      <pubDate>Sat, 29 May 2010 23:32:07 +0000</pubDate>
      
      <guid>http://blog.mmacklin.com/2010/05/29/in-scattering-demo/</guid>
      <description>This demo shows an analytic solution to the differential in-scattering equation for light in participating media. It&#39;s a similar but simplified version of equations found in[1], [2] and as I recently discovered [3]. However I thought showing the derivation might be interesting for some out there, plus it was a good excuse for me to brush up on my  \(\LaTeX\).
You might notice I also updated the site&#39;s theme, unfortunately you need a white background to make wordpress.</description>
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