Merge branch 'next' of gitorious.org:fg/flightgear into next

[flightgear.git] / src / Radio / antenna.cxx

diff --git a/src/Radio/antenna.cxx b/src/Radio/antenna.cxx
index dc6983723cb4315ea44165c1efb633d7470d5bde..8a55707d55abad517810b3604648a7bf0c119b87 100644 (file)
--- a/src/Radio/antenna.cxx
+++ b/src/Radio/antenna.cxx
@@ -1,6 +1,6 @@
 // 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
@@ -22,33 +22,80 @@
 #endif
 
 #include <math.h>
-
+#include <iostream>
 #include <stdlib.h>
-
+#include <fstream>
 #include <Scenery/scenery.hxx>
 #include "antenna.hxx"
 
+using namespace std;
 
-FGRadioAntenna::FGRadioAntenna() {
+FGRadioAntenna::FGRadioAntenna(string type) {
        
-       _mirror_y = 1;
+       _mirror_y = 1;  // normally we want to mirror these axis because the pattern is simetric
        _mirror_z = 1;
-       _invert_ground = 0;
+       _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();
 }
 
-double FGRadioAntenna::calculate_gain(double azimuth, double elevation) {
+// 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;
 }
 
 
-
-/*** load external plot file generated by NEC4
-*
-***/
-void FGRadioAntenna::_load_antenna_pattern() {
+void FGRadioAntenna::load_NEC_antenna_pattern(string type) {
        
+       //SGPath pattern_file(fgGetString("/sim/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);
+       }
 }