[xscreensaver] / hacks / vidwhacker

#!/bin/sh
#
# vidwhacker, for xscreensaver.  Copyright (c) 1998 Jamie Zawinski.
#
# This script grabs a frame of video, then uses various pbm filters to
# munge the image in random nefarious ways, then uses xv to put it on
# the root window.  This works out really nicely if you just feed some
# random TV station into it...
#
# The video grabbing part is SGI-specific -- if you want to use this on
# another system, add a new clause to the grab() procedure.


# Process command-line args...

onroot=false
verbose=false
delay=3

if [ "$1" = "-root" ]; then
  onroot=true
  shift
fi

if [ "$1" = "-verbose" ]; then
  verbose=true
  shift
fi

if [ "$1" != "" ]; then
  echo "usage: $0 [-root] [-verbose]" >&2
  exit 1
fi


xvargs="-quick24"

if [ "$onroot" = true ]; then
  xvargs="$xvargs -root -rmode 5 -quit"
else
  xvargs="$xvargs -geom +0+0"
fi

screen_width=`xdpyinfo | sed -n 's/.* dimensions: *\([0-9]*\).*/\1/p'`

# global vars...

tmp=/tmp/vd$$
tmp_rgb=$tmp-00000.rgb
tmp_ppm=$tmp.ppm
tmp_ppm2=$tmp-2.ppm
tmp_ppm3=$tmp-3.ppm

clean() {
  rm -f $tmp_rgb $tmp_ppm $tmp_ppm2 $tmp_ppm3
}


# Grab a frame of video.
#
grab() {
  if [ `uname` = IRIX ]; then
    #
    # SGI's "vidtomem" returns an SGI RGB image of the default video input,
    # and has stupid non-overridable ouput-file-naming conventions.  So, let 
    # it write its file; and then convert it to a pgm.
    #
    vidtomem -f $tmp
    sgitopnm $tmp_rgb > $tmp_ppm
    # Cut off the close-captioning blips in the NTSC overscan region.  YMMV.
    #  | pnmcut 12 7 695 477 

  else
    echo "$0: don't know how to grab video on this OS." >&2
    clean
    exit 1
  fi


  # I got this message from Marcus Herbert <rhoenie@chillout.org>.
  # I'm not sure of the best way to make the presence of qcam be
  #  auto-detected, but here's what he said, FYI...
  #
  #    i am using a black/white Connectix Qcam on linux and its very simple
  #    to adept the script:
  #
  #    # qcam: Version 0.91
  #    #   Options:
  #    #   O  -x width   Set width
  #    #   O  y height   Setheight
  #    #   O  B bpp      Setbits per pixel
  #    #   O  W         Auto-set white balance
  #    #   O  E "vals"  Autoexposure mode, parameters required
  #    #   O  D         Remove dark speckling
  #    #   O  s val     Set scaling factor (1, 2, or 4)
  #    #
  #    qcam -x 320 -y 240 -B 6 -W -E 1 -D -s 1 > $tmp_ppm
  #
  #   You dont really need the parameters for qcam as it reads out a system
  #   config file where you store the values for brightnes, contrast and
  #   white balance.  But with this parameters you are independant of the
  #   light ratios at the place the cam is set up.
  #
  #   Other versions of qcam (0.7, 0.96..) don't support the autoexposure and
  #   auto- whitebalance commandline parameters. On such systems (and on
  #   color-qcam systems) a simple qcam > $tmp_ppm (or cqcam > $tmp_ppm) is
  #   enough.
  #
  #   I dont know about other systems but afaik fBSD uses the Qcam in this way:
  #
  #     qcamcontrol -bla -foo -bar > picture.pgm    
  #
}


# Use perl to pick a random foreground/background color in pbm's syntax.
#
randcolor() {
  perl -e 'srand; 
           printf("#%02x%02x%02x-#%02x%02x%02x",
                  int(rand()*60),
                  int(rand()*60),
                  int(rand()*60),
                  120+int(rand()*135),
                  120+int(rand()*135),
                  120+int(rand()*135))'
}

# Frobnicate the image in some random way.
#
frob() {

  N=`perl -e 'srand; print int(rand() * 10)'`

  if [ "$verbose" = true ]; then
    echo "mode $N..." >&2
  fi

  if   [ $N = 0 ]; then
    ppmtopgm $tmp_ppm | pgmedge | pgmtoppm `randcolor` | ppmnorm

  elif [ $N = 1 ]; then
    ppmtopgm $tmp_ppm | 
    pgmenhance | 
    pgmtoppm `randcolor`

  elif [ $N = 2 ]; then
    ppmtopgm $tmp_ppm | pgmoil | pgmtoppm `randcolor`

  elif [ $N = 3 ]; then 
    ppmrelief $tmp_ppm | ppmtopgm | pgmedge | ppmrelief | ppmtopgm |
      pgmedge | pnminvert | pgmtoppm `randcolor`

  elif [ $N = 4 ]; then
    ppmspread 71 $tmp_ppm > $tmp_ppm2
    pnmarith -add $tmp_ppm $tmp_ppm2

  elif [ $N = 5 ]; then
    pnmflip -lr $tmp_ppm > $tmp_ppm2
    pnmarith -multiply $tmp_ppm $tmp_ppm2 > $tmp_ppm3
    pnmflip -tb $tmp_ppm3 | ppmnorm > $tmp_ppm2
    pnmarith -multiply $tmp_ppm $tmp_ppm2

  elif [ $N = 6 ]; then
    N2=`perl -e 'srand; print int(rand() * 3)'`
    if [ $N2 = 0 ]; then
      pnmflip -lr $tmp_ppm > $tmp_ppm2
    elif [ $N2 = 1 ]; then
      pnmflip -tb $tmp_ppm > $tmp_ppm2
    else
      pnmflip -lr $tmp_ppm > $tmp_ppm2
      pnmflip -tb $tmp_ppm2 > $tmp_ppm3
      cp $tmp_ppm3 $tmp_ppm2
    fi

    pnmarith -difference $tmp_ppm $tmp_ppm2

  elif [ $N = 7 ]; then

    for i in 1 2 3 ; do
      ppmtopgm $tmp_ppm | pgmedge > $tmp_ppm2
      pnmarith -difference $tmp_ppm $tmp_ppm2 > $tmp_ppm3
      cp $tmp_ppm3 $tmp_ppm
    done
    ppmnorm < $tmp_ppm

  elif [ $N = 8 ]; then
    pnmflip -lr $tmp_ppm > $tmp_ppm2
    pnmarith -multiply $tmp_ppm $tmp_ppm2 | ppmrelief | ppmnorm | pnminvert

  elif [ $N = 9 ]; then
    pnmflip -lr $tmp_ppm > $tmp_ppm2
    pnmarith -subtract $tmp_ppm $tmp_ppm2 | ppmrelief | ppmtopgm | pgmedge

  else cat $tmp_ppm
  fi
}



# Grab a frame and frob it.  leave it in $tmp_ppm3.
#
whack() {
  clean

  while [ ! -f $tmp_ppm ]; do
   grab
  done

  rm -f $tmp_rgb
  frob | pnmscale -width $screen_width > $tmp_ppm3
  rm -f $tmp_ppm $tmp_ppm2
}


pid=""

if [ "$onroot" != true ]; then
  trap "kill \$pid; clean; exit 1" 2 15
fi

while true; do

  # Loop grabbing and frobbing images.
  #
  # If we're running on the root, run xv in the foreground (with -exit)
  # and then wait.
  #
  # If we're running in a window, spawn xv in the background; then when
  # it's time to put up the new image, kill off the currently-running xv.

  if [ "$verbose" = true ]; then
    whack
  else
    whack >&- 2>&-
  fi

  if [ "$pid" != "" ]; then
    kill $pid
    pid=""
  fi

  if [ ! -s $tmp_ppm3 ]; then
    echo "$0: no image grabbed" >&2
  else

    pnmtosgi < $tmp_ppm3 > $tmp_ppm2
    rm -f $tmp_ppm3

    if [ "$onroot" = true ]; then
      xv $xvargs $tmp_ppm2
    else
      xv $xvargs $tmp_ppm2 &
      pid=$!
    fi

    #xv -geom =320x220 $tmp_ppm3 &
    #pid=
  fi

  clean
  sleep $delay

done