#!/bin/sh

usage()
{
    echo "usage: $(basename $0) [-3 | -6 | -8] povray_parameters" >&2
    exit 1
}

geometry="-geometry +188+120"; sizeopts="+W640 +H480"
while getopts ":368" c
do
    case "$c" in
    3)      geometry="-geometry +348+240"; sizeopts="+W320 +H240";;
    6)      geometry="-geometry +188+120"; sizeopts="+W640 +H480";;
    8)      geometry="-geometry +108+25"; sizeopts="+W800 +H600";;
    :|'?')  usage;;
    esac
done
shift $(($OPTIND - 1))
if [ $# -lt 1 ]; then usage; fi

povray +D +P -F $geometry $sizeopts "$@"
.