1 // util.cxx - general-purpose utility functions.
2 // Copyright (C) 2002 Curtis L. Olson - curt@me.umn.edu
4 // This program is free software; you can redistribute it and/or
5 // modify it under the terms of the GNU General Public License as
6 // published by the Free Software Foundation; either version 2 of the
7 // License, or (at your option) any later version.
9 // This program is distributed in the hope that it will be useful, but
10 // WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 // General Public License for more details.
14 // You should have received a copy of the GNU General Public License
15 // along with this program; if not, write to the Free Software
16 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include <simgear/debug/logstream.hxx>
26 #include "fg_props.hxx"
27 #include "globals.hxx"
30 #if defined(FG_NETWORK_OLK)
31 #include <NetworkOLK/network.h>
38 SG_LOG(SG_GENERAL, SG_INFO, "Exiting FlightGear with status " << status);
40 #if defined(FG_NETWORK_OLK)
41 if (fgGetBool("/sim/networking/network-olk"))
42 fgd_send_com("8", FGFS_host);
45 globals->get_io()->shutdown_all();
50 // Originally written by Alex Perry.
52 fgGetLowPass (double current, double target, double timeratio)
54 if ( timeratio < 0.0 ) {
55 if ( timeratio < -1.0 ) {
56 // time went backwards; kill the filter
59 // ignore mildly negative time
61 } else if ( timeratio < 0.2 ) {
62 // Normal mode of operation; fast
63 // approximation to exp(-timeratio)
64 current = current * (1.0 - timeratio) + target * timeratio;
65 } else if ( timeratio > 5.0 ) {
66 // Huge time step; assume filter has settled
69 // Moderate time step; non linear response
70 double keep = exp(-timeratio);
71 current = current * keep + target * (1.0 - keep);