// antenna.cxx -- implementation of FGRadioAntenna
// Class to represent a virtual radio antenna properties
-// Written by Adrian Musceac, started December 2011.
+// Written by Adrian Musceac YO8RZZ, started December 2011.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <math.h>
+#include <iostream>
+#include <stdlib.h>
+#include <fstream>
+#include <Scenery/scenery.hxx>
+#include "antenna.hxx"
+
+using namespace std;
+
+FGRadioAntenna::FGRadioAntenna(string type) {
+
+ _mirror_y = 1; // normally we want to mirror these axis because the pattern is simetric
+ _mirror_z = 1;
+ _invert_ground = 0; // TODO: use for inverting the antenna ground, for instance aircraft body reflection
+ load_NEC_antenna_pattern(type);
+}
+
+FGRadioAntenna::~FGRadioAntenna() {
+ for (unsigned i =0; i < _pattern.size(); i++) {
+ AntennaGain *point_gain = _pattern[i];
+ delete point_gain;
+ }
+ _pattern.clear();
+}
+
+// WIP
+double FGRadioAntenna::calculate_gain(double bearing, double angle) {
+
+ // TODO: what if the pattern is assimetric?
+ bearing = fabs(bearing);
+ if (bearing > 180)
+ bearing = 360 - bearing;
+ // for plots with 2 degrees resolution:
+ int azimuth = (int)floor(bearing);
+ azimuth += azimuth % 2;
+ int elevation = (int)floor(angle);
+ elevation += elevation % 2;
+ //cerr << "Bearing: " << bearing << " angle: " << angle << " azimuth: " << azimuth << " elevation: " << elevation << endl;
+ for (unsigned i =0; i < _pattern.size(); i++) {
+ AntennaGain *point_gain = _pattern[i];
+
+ if ( (azimuth == point_gain->azimuth) && (elevation == point_gain->elevation)) {
+ return point_gain->gain;
+ }
+ }
+
+ return 0;
+}
+
+
+void FGRadioAntenna::load_NEC_antenna_pattern(string type) {
+
+ //SGPath pattern_file(globals->get_fg_home());
+ SGPath pattern_file(globals->get_fg_root());
+ pattern_file.append("Navaids/Antennas");
+ pattern_file.append(type + ".txt");
+ if (!pattern_file.exists()) {
+ return;
+ }
+ ifstream file_in(pattern_file.c_str());
+ int heading, elevation;
+ double gain;
+ while(!file_in.eof()) {
+ file_in >> heading >> elevation >> gain;
+ if( (_mirror_y == 1) && (heading > 180) ) {
+ continue;
+ }
+ if ( (_mirror_z == 1) && (elevation < 0) ) {
+ continue;
+ }
+ //cerr << "head: " << heading << " elev: " << elevation << " gain: " << gain << endl;
+ AntennaGain *datapoint = new AntennaGain;
+ datapoint->azimuth = heading;
+ datapoint->elevation = 90.0 - abs(elevation);
+ datapoint->gain = gain;
+ _pattern.push_back(datapoint);
+ }
+}