<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//en">

<!–Converted with LaTeX2HTML 2022 (Released January 1, 2022) –> <HTML lang="en"> <HEAD> <TITLE>Contents of Atmospheric Effects</TITLE>

<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"> <META NAME="viewport" CONTENT="width=device-width, initial-scale=1.0"> <META NAME="Generator" CONTENT="LaTeX2HTML v2022">

<LINK REL="STYLESHEET" HREF="surfaces.css">

<LINK REL="next" HREF="node4_mn.html"> <LINK REL="previous" HREF="node2_mn.html"> <LINK REL="up" HREF="node1_mn.html"> <LINK REL="next" HREF="node4_mn.html"> </HEAD>

<BODY bgcolor="#ffffff" text="#000000" link="#9944EE" vlink="#0000ff" alink="#00ff00">

<H1><A ID="SECTION00120000000000000000"> Atmospheric Effects</A> </H1>

<P> Any number of atmospheric effects may be associated with the default medium (``air'').

<P> <BR> <IMG STYLE="height: 2.17ex; vertical-align: 176.68ex; " SRC="img11.png" ALT="
\begin{defkey}{fog}{\evec{color} \evec{thinness}}
Add exponential fog with the specified {\em thinness} and {\em color}.
\end{defkey}
"> <BR> Fog is simulated by blending the color of the fog with the color of each ray. The amount of fog color blended into a ray color is an exponential function of the distance from the ray origin to the point of intersection divided by the specified <EM>thinness</EM> for each color channel. If the distance is equal to <EM>thinness</EM>, a ray's new color will be half of the fog color plus half its original color.

<P> <BR> <A NAME="tex2html1" HREF="footnode_mn.html#foot73" TARGET="footer"><IMG STYLE="height: 2.17ex; vertical-align: 176.68ex; " SRC="img12.png" ALT="
\begin{defkey}{mist}{\evec{color} \evec{thinness} {\emzero scale}}
Add global l....
..... which scales the difference in
altitude used to compute the fog.
\end{defkey}
"></A> <BR>

<P> <BR> <IMG STYLE="height: 2.17ex; vertical-align: 176.40ex; " SRC="img13.png" ALT="
\begin{defkey}{fogdeck}{{\em altitude} {\em offset} \evec{scale} {\em chaoscale}...
.....ltitude fog, with transmissivity modulated by
a chaotic function.
\end{defkey}
"> <BR>

<P>

<HR>

</BODY> </HTML>