util.c

   1
   2 /**
   3  *
   4  * Tennix! SDL Port
   5  * Copyright (C) 2003, 2007, 2008, 2009 Thomas Perl <thp@thpinfo.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  20  * MA  02110-1301, USA.
  21  *
  22  **/
  23
  24 #include "tennix.h"
  25 #include "util.h"
  26
  27 #include <time.h>
  28 #include <assert.h>
  29
  30 void day_night(unsigned int width, unsigned int* start, unsigned int* end)
  31 {
  32     time_t t = time(NULL);
  33     unsigned int offset = 60; /* set this so the day/night fits for London */
  34
  35     assert(start != NULL);
  36     assert(end != NULL);
  37
  38     *start = (unsigned int)(offset - (t/60)*width/(60*24)) % width;
  39     *end = (unsigned int)(*start + width/2) % width;
  40 }
  41