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flightgear/src/Instrumentation/marker_beacon.cxx
curt e2875babad Initialize the timer countdown value since this could conceivably start as 
any randomly large number (thus preventing the first station seach from
happening at least for a very long time.)
2005-01-03 00:16:16 +00:00

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// marker_beacon.cxx -- class to manage the marker beacons
//
// Written by Curtis Olson, started April 2000.
//
// Copyright (C) 2000 Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h> // snprintf
#include <simgear/compiler.h>
#include <simgear/math/sg_random.h>
#include <Aircraft/aircraft.hxx>
#include <Navaids/navlist.hxx>
#include "marker_beacon.hxx"
#include <string>
SG_USING_STD(string);
// Constructor
FGMarkerBeacon::FGMarkerBeacon(SGPropertyNode *node) :
need_update(true),
outer_blink(false),
middle_blink(false),
inner_blink(false),
name("marker-beacon"),
num(0),
_time_before_search_sec(0.0)
{
SGPath path( globals->get_fg_root() );
SGPath term = path;
term.append( "Navaids/range.term" );
SGPath low = path;
low.append( "Navaids/range.low" );
SGPath high = path;
high.append( "Navaids/range.high" );
term_tbl = new SGInterpTable( term.str() );
low_tbl = new SGInterpTable( low.str() );
high_tbl = new SGInterpTable( high.str() );
int i;
for ( i = 0; i < node->nChildren(); ++i ) {
SGPropertyNode *child = node->getChild(i);
string cname = child->getName();
string cval = child->getStringValue();
if ( cname == "name" ) {
name = cval;
} else if ( cname == "number" ) {
num = child->getIntValue();
} else {
SG_LOG( SG_INSTR, SG_WARN,
"Error in marker beacon config logic" );
if ( name.length() ) {
SG_LOG( SG_INSTR, SG_WARN, "Section = " << name );
}
}
}
}
// Destructor
FGMarkerBeacon::~FGMarkerBeacon()
{
delete term_tbl;
delete low_tbl;
delete high_tbl;
}
void
FGMarkerBeacon::init ()
{
string branch;
branch = "/instrumentation/" + name;
SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
// Inputs
lon_node = fgGetNode("/position/longitude-deg", true);
lat_node = fgGetNode("/position/latitude-deg", true);
alt_node = fgGetNode("/position/altitude-ft", true);
bus_power = fgGetNode("/systems/electrical/outputs/nav[0]", true);
power_btn = node->getChild("power-btn", 0, true);
audio_btn = node->getChild("audio-btn", 0, true);
serviceable = node->getChild("serviceable", 0, true);
power_btn->setBoolValue( true );
audio_btn->setBoolValue( true );
serviceable->setBoolValue( true );
morse.init();
beacon.init();
blink.stamp();
}
void
FGMarkerBeacon::bind ()
{
string branch;
branch = "/instrumentation/" + name;
fgTie((branch + "/inner").c_str(), this,
&FGMarkerBeacon::get_inner_blink);
fgTie((branch + "/middle").c_str(), this,
&FGMarkerBeacon::get_middle_blink);
fgTie((branch + "/outer").c_str(), this,
&FGMarkerBeacon::get_outer_blink);
}
void
FGMarkerBeacon::unbind ()
{
string branch;
branch = "/instrumentation/" + name;
fgUntie((branch + "/inner").c_str());
fgUntie((branch + "/middle").c_str());
fgUntie((branch + "/outer").c_str());
}
// Update the various nav values based on position and valid tuned in navs
void
FGMarkerBeacon::update(double dt)
{
need_update = false;
if ( has_power() && serviceable->getBoolValue() ) {
// On timeout, scan again
_time_before_search_sec -= dt;
if ( _time_before_search_sec < 0 ) {
search();
}
// marker beacon blinking
bool light_on = ( outer_blink || middle_blink || inner_blink );
SGTimeStamp current;
current.stamp();
if ( light_on && (current - blink > 400000) ) {
light_on = false;
blink.stamp();
} else if ( !light_on && (current - blink > 100000) ) {
light_on = true;
blink.stamp();
}
if ( outer_marker ) {
outer_blink = light_on;
} else {
outer_blink = false;
}
if ( middle_marker ) {
middle_blink = light_on;
} else {
middle_blink = false;
}
if ( inner_marker ) {
inner_blink = light_on;
} else {
inner_blink = false;
}
// cout << outer_blink << " " << middle_blink << " "
// << inner_blink << endl;
} else {
inner_blink = middle_blink = outer_blink = false;
}
}
static bool check_beacon_range( double lon_rad, double lat_rad, double elev_m,
FGNavRecord *b )
{
Point3D aircraft = sgGeodToCart( Point3D(lon_rad, lat_rad, elev_m) );
Point3D station = Point3D( b->get_x(), b->get_y(), b->get_z() );
// cout << " aircraft = " << aircraft << " station = " << station
// << endl;
double d = aircraft.distance3Dsquared( station ); // meters^2
// cout << " distance = " << d << " ("
// << FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER
// * FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER
// << ")" << endl;
// cout << " range = " << sqrt(d) << endl;
// cout << "elev = " << elev * SG_METER_TO_FEET
// << " current->get_elev() = " << current->get_elev() << endl;
double elev_ft = elev_m * SG_METER_TO_FEET;
double delev = elev_ft - b->get_elev_ft();
// max range is the area under r = 2.4 * alt or r^2 = 4000^2 - alt^2
// whichever is smaller. The intersection point is 1538 ...
double maxrange2; // feet^2
if ( delev < 1538.0 ) {
maxrange2 = 2.4 * 2.4 * delev * delev;
} else if ( delev < 4000.0 ) {
maxrange2 = 4000 * 4000 - delev * delev;
} else {
maxrange2 = 0.0;
}
maxrange2 *= SG_FEET_TO_METER * SG_FEET_TO_METER; // convert to meter^2
// cout << "delev = " << delev << " maxrange = " << maxrange << endl;
// match up to twice the published range so we can model
// reduced signal strength
if ( d < maxrange2 ) {
return true;
} else {
return false;
}
}
// Update current nav/adf radio stations based on current postition
void FGMarkerBeacon::search()
{
// reset search time
_time_before_search_sec = 1.0;
static fgMkrBeacType last_beacon = NOBEACON;
double lon_rad = lon_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
double lat_rad = lat_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
double elev_m = alt_node->getDoubleValue() * SG_FEET_TO_METER;
////////////////////////////////////////////////////////////////////////
// Beacons.
////////////////////////////////////////////////////////////////////////
// get closest marker beacon
FGNavRecord *b
= globals->get_mkrlist()->findClosest( lon_rad, lat_rad, elev_m );
// cout << "marker beacon = " << b << " (" << b->get_type() << ")" << endl;
fgMkrBeacType beacon_type = NOBEACON;
bool inrange = false;
if ( b != NULL ) {
if ( b->get_type() == 7 ) {
beacon_type = OUTER;
} else if ( b->get_type() == 8 ) {
beacon_type = MIDDLE;
} else if ( b->get_type() == 9 ) {
beacon_type = INNER;
}
inrange = check_beacon_range( lon_rad, lat_rad, elev_m, b );
// cout << " inrange = " << inrange << endl;
}
outer_marker = middle_marker = inner_marker = false;
if ( b == NULL || !inrange || !has_power() || !serviceable->getBoolValue() )
{
// cout << "no marker" << endl;
globals->get_soundmgr()->stop( "outer-marker" );
globals->get_soundmgr()->stop( "middle-marker" );
globals->get_soundmgr()->stop( "inner-marker" );
} else if ( beacon_type == OUTER ) {
outer_marker = true;
// cout << "OUTER MARKER" << endl;
if ( last_beacon != OUTER ) {
if ( ! globals->get_soundmgr()->exists( "outer-marker" ) ) {
SGSoundSample *sound = beacon.get_outer();
sound->set_volume( 0.3 );
globals->get_soundmgr()->add( sound, "outer-marker" );
}
}
if ( audio_btn->getBoolValue() ) {
if ( !globals->get_soundmgr()->is_playing("outer-marker") ) {
globals->get_soundmgr()->play_looped( "outer-marker" );
}
} else {
globals->get_soundmgr()->stop( "outer-marker" );
}
} else if ( beacon_type == MIDDLE ) {
middle_marker = true;
// cout << "MIDDLE MARKER" << endl;
if ( last_beacon != MIDDLE ) {
if ( ! globals->get_soundmgr()->exists( "middle-marker" ) ) {
SGSoundSample *sound = beacon.get_middle();
sound->set_volume( 0.3 );
globals->get_soundmgr()->add( sound, "middle-marker" );
}
}
if ( audio_btn->getBoolValue() ) {
if ( !globals->get_soundmgr()->is_playing("middle-marker") ) {
globals->get_soundmgr()->play_looped( "middle-marker" );
}
} else {
globals->get_soundmgr()->stop( "middle-marker" );
}
} else if ( beacon_type == INNER ) {
inner_marker = true;
// cout << "INNER MARKER" << endl;
if ( last_beacon != INNER ) {
if ( ! globals->get_soundmgr()->exists( "inner-marker" ) ) {
SGSoundSample *sound = beacon.get_inner();
sound->set_volume( 0.3 );
globals->get_soundmgr()->add( sound, "inner-marker" );
}
}
if ( audio_btn->getBoolValue() ) {
if ( !globals->get_soundmgr()->is_playing("inner-marker") ) {
globals->get_soundmgr()->play_looped( "inner-marker" );
}
} else {
globals->get_soundmgr()->stop( "inner-marker" );
}
}
if ( inrange ) {
last_beacon = beacon_type;
} else {
last_beacon = NOBEACON;
}
}
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