1 /**************************************************************************
2 * fg_timer.c -- time handling routines
4 * Written by Curtis Olson, started June 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
27 #include <signal.h> /* for timer routines */
28 #include <stdio.h> /* for printf() */
29 #include <sys/time.h> /* for get/setitimer, gettimeofday, struct timeval */
36 unsigned long int fgSimTime;
37 static struct itimerval t, ot;
38 static void (*callbackfunc)(int multi_loop);
41 /* This routine catches the SIGALRM */
43 /* ignore any SIGALRM's until we come back from our EOM iteration */
44 signal(SIGALRM, SIG_IGN);
46 /* printf("In fgTimerCatch()\n"); */
48 /* -1 tells the routine to use default interval rather than something
49 dynamically calculated based on frame rate */
52 signal(SIGALRM, fgTimerCatch);
56 /* this routine initializes the interval timer to generate a SIGALRM after
57 * the specified interval (dt) */
58 void fgTimerInit(float dt, void (*f)()) {
66 usec = 1000000* (dt - (float) isec);
68 t.it_interval.tv_sec = isec;
69 t.it_interval.tv_usec = usec;
70 t.it_value.tv_sec = isec;
71 t.it_value.tv_usec = usec;
72 /* printf("fgTimerInit() called\n"); */
73 fgTimerCatch(); /* set up for SIGALRM signal catch */
74 terr = setitimer( ITIMER_REAL, &t, &ot );
76 printf("Error returned from setitimer");
82 /* This function returns the number of milleseconds since the last
83 time it was called. */
84 int fgGetTimeInterval() {
85 static struct timeval last;
86 static struct timeval current;
87 static struct timezone tz;
88 static int inited = 0;
94 gettimeofday(&last, &tz);
97 gettimeofday(¤t, &tz);
98 interval = 1000000 * (current.tv_sec - last.tv_sec) +
99 (current.tv_usec - last.tv_usec);
100 interval /= 1000; /* convert back to milleseconds */
109 /* Revision 1.3 1997/06/17 16:52:04 curt
110 /* Timer interval stuff now uses gettimeofday() instead of ftime()
112 * Revision 1.2 1997/06/17 03:41:10 curt
113 * Nonsignal based interval timing is now working.
114 * This would be a good time to look at cleaning up the code structure a bit.
116 * Revision 1.1 1997/06/16 19:24:20 curt