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flightgear/src/Main/util.cxx

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C++

// util.cxx - general-purpose utility functions.
// Copyright (C) 2002 Curtis L. Olson - curt@me.umn.edu
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#include <simgear/compiler.h>
#include <math.h>
#include <vector>
SG_USING_STD(vector);
#include <simgear/debug/logstream.hxx>
#include "fg_io.hxx"
#include "fg_props.hxx"
#include "globals.hxx"
#include "util.hxx"
#if defined(FG_NETWORK_OLK)
#include <NetworkOLK/network.h>
#endif
void
fgDefaultWeatherValue (const char * propname, double value)
{
int i;
SGPropertyNode * branch = fgGetNode("/environment/config/boundary", true);
vector<SGPropertyNode_ptr> entries = branch->getChildren("entry");
for (i = 0; i < entries.size(); i++)
entries[i]->setDoubleValue(propname, value);
branch = fgGetNode("/environment/config/aloft", true);
entries = branch->getChildren("entry");
for (i = 0; i < entries.size(); i++)
entries[i]->setDoubleValue(propname, value);
}
void
fgExit (int status)
{
SG_LOG(SG_GENERAL, SG_INFO, "Exiting FlightGear with status " << status);
#if defined(FG_NETWORK_OLK)
if (fgGetBool("/sim/networking/network-olk"))
fgd_send_com("8", FGFS_host);
#endif
globals->get_io()->shutdown_all();
exit(status);
}
// Originally written by Alex Perry.
double
fgGetLowPass (double current, double target, double timeratio)
{
if ( timeratio < 0.0 ) {
if ( timeratio < -1.0 ) {
// time went backwards; kill the filter
current = target;
} else {
// ignore mildly negative time
}
} else if ( timeratio < 0.2 ) {
// Normal mode of operation; fast
// approximation to exp(-timeratio)
current = current * (1.0 - timeratio) + target * timeratio;
} else if ( timeratio > 5.0 ) {
// Huge time step; assume filter has settled
current = target;
} else {
// Moderate time step; non linear response
double keep = exp(-timeratio);
current = current * keep + target * (1.0 - keep);
}
return current;
}
// end of util.cxx