Category : Printer + Display Graphics
Archive   : RAYSH386.ZIP
Filename : TRANSFOR.TEX

\chapter {Transformations}

{\Rayshade} supports the application of linear transformations to objects
and textures. If more than one transformation is specified, the
total resulting transformation is computed and applied.

\begin{defkey}{translate}{\evec{delta}}
Translate (move) by {\em delta}.
\end{defkey}

\begin{defkey}{rotate}{\evec{axis} $\theta$}
Rotate counter-clockwise about the given axis by $\theta$ degrees.
\end{defkey}

\begin{defkey}{scale}{\evec{v}}
Scale by {\em v}.
\end{defkey}
All three scaling components must be non-zero, else degenerate matrices
will result.

\begin{defkey}{transform}{\evec{row1} \evec{row2} \evec{row3} [\evec{delta}]}
Apply the given 3-by-3 transformation matrix. If given, {\em delta}
specifies a translation vector.
\end{defkey}

Transformations should
be specified in the order in which they are to be applied
immediately following the item to
be transformed. For example:

\begin{verbatim}
/*
* Ellipsoid, rotated cube
*/
sphere 1. 0 0 0 scale 2. 1. 1. translate 0 0 -2.5
box 0 0 0 .5 .5 .5
rotate 0 0 1 45 rotate 1 0 0 45 translate 0 0 2.5
\end{verbatim}

Transformations may also be applied to textures:

\begin{verbatim}
plane 0 0 -4 0 0 1
texture checker red scale 2 2 2 rotate 0 0 1 45
\end{verbatim}

Note that transformation parameters may be specified using
animated expressions, causing the transformations themselves
to be animated. See Appendix B for further details.