#!/usr/bin/awk -f
#
# anim-earth   make animated gif with spinning earth
#
# 11-oct-97   Heiko Purnhagen   (purnhage@tnt.uni-hannover.de)
#
# requires:
#   xearth
#   gifmerge   (http://www.iis.ee.ethz.ch/~kiwi/GIFMerge/)

BEGIN {
  num = 24;
  system("rm e?.gif e??.gif");
  for (i=0; i<num; i++) {
    printf("%d\n",i);
    system(sprintf("xearth -size 64,64 -night 50 -term 100 -ncolors 6 -pos sunrel,-23.5,45 -sunpos 23.5,%d -gif -nostars > e%d.gif\n",(-i*360/num+360)%360-180,i));
  }
  system("gifmerge -0,0,0 -l1000 -20 e?.gif e??.gif > e.gif");
  system("ls -l e.gif");
}