Atmospheric Effects

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

fogcolor thinness Add exponential fog with the specified thinness and color. *************** *** 125,131 **** mistcolor thinness zero scale Add global low-altitude mist of the specified color. The color of a ray is modulated by a fog with density that varies linearly with ! the difference in z coordinate (altitude) between the ray origin and the point of intersection. The thinness values specify the transmissivity of the fog for each color channel. The base altitude of the — 124,132 —-
\begin{defkey}{mist}{\evec{color} \evec{thinness} {\emzero scale}}
Add global l...
...* 134,139 ****
--- 135,146 ----
altitude used to compute the fog.
\end{defkey}

+
\begin{defkey}{fogdeck}{{\em altitude} {\em offset} \evec{scale} {\em chaoscale}...
...itude fog, with transmissivity modulated by
+ a chaotic function.
+ \end{defkey}
+