]> git.mxchange.org Git - flightgear.git/blobdiff - src/Instrumentation/wxradar.cxx
Performance optimization
[flightgear.git] / src / Instrumentation / wxradar.cxx
index 7319a5b418a4c6c29e26d9d0941a1be10b02f699..b1f81be656ebf2e293ba902f662e6331943a4990 100644 (file)
@@ -1,6 +1,9 @@
 // Wx Radar background texture
 //
 // Written by Harald JOHNSEN, started May 2005.
+// With major amendments by Vivian MEAZZA May 2007
+// Ported to OSG by Tim Moore Jun 2007
+//
 //
 // Copyright (C) 2005  Harald JOHNSEN
 //
 #  include "config.h"
 #endif
 
-#include <plib/sg.h>
+#include <osg/Array>
+#include <osg/Geometry>
+#include <osg/Matrixf>
+#include <osg/PrimitiveSet>
+#include <osg/StateSet>
+#include <osg/Version>
+#include <osgDB/ReaderWriter>
+#include <osgDB/WriteFile>
+
+#include <simgear/constants.h>
+#include <simgear/misc/sg_path.hxx>
+#include <simgear/scene/model/model.hxx>
+#include <simgear/structure/exception.hxx>
+#include <simgear/misc/sg_path.hxx>
+#include <simgear/math/sg_geodesy.hxx>
+
+#include <sstream>
+#include <iomanip>
+
+using std::stringstream;
+using std::endl;
+using std::setprecision;
+using std::fixed;
+using std::setw;
+using std::setfill;
+using std::string;
+
 #include <Main/fg_props.hxx>
 #include <Main/globals.hxx>
 #include <Cockpit/panel.hxx>
-#include <Cockpit/hud.hxx>
 
-#include <simgear/constants.h>
-#include <simgear/misc/sg_path.hxx>
-#include <simgear/environment/visual_enviro.hxx>
 #include "instrument_mgr.hxx"
 #include "od_gauge.hxx"
 #include "wxradar.hxx"
 
-// texture name to use in 2D and 3D instruments
-static const char *odgauge_name = "Aircraft/Instruments/Textures/od_wxradar.rgb";
+#include <iostream>             // for cout, endl
+
+using std::cout;
+using std::endl;
 
-wxRadarBg::wxRadarBg ( SGPropertyNode *node) :
-    _name(node->getStringValue("name", "wxRadar")),
+static const float UNIT = 1.0f / 8.0f;  // 8 symbols in a row/column in the texture
+static const char *DEFAULT_FONT = "typewriter.txf";
+
+wxRadarBg::wxRadarBg(SGPropertyNode *node) :
+    _name(node->getStringValue("name", "radar")),
     _num(node->getIntValue("number", 0)),
-    resultTexture( 0 ),
-    wxEcho( 0 ),
-    last_switchKnob( "off" ),
-    sim_init_done ( false ),
-    odg( 0 )
+    _time(0.0),
+    _interval(node->getDoubleValue("update-interval-sec", 1.0)),
+    _elapsed_time(0),
+    _persistance(0),
+    _odg(0),
+    _range_nm(0),
+    _scale(0),
+    _angle_offset(0),
+    _view_heading(0),
+    _x_offset(0),
+    _y_offset(0),
+    _radar_ref_rng(0),
+    _lat(0),
+    _lon(0),
+    _antenna_ht(node->getDoubleValue("antenna-ht-ft", 0.0)),
+    _resultTexture(0),
+    _wxEcho(0),
+    _font_size(0),
+    _font_spacing(0)
 {
+    string branch;
+    branch = "/instrumentation/" + _name;
+    _Instrument = fgGetNode(branch.c_str(), _num, true);
+
+    const char *tacan_source = node->getStringValue("tacan-source", "/instrumentation/tacan");
+    _Tacan = fgGetNode(tacan_source, true);
+
+    _font_node = _Instrument->getNode("font", true);
+
+#define INITFONT(p, val, type) if (!_font_node->hasValue(p)) _font_node->set##type##Value(p, val)
+    INITFONT("name", DEFAULT_FONT, String);
+    INITFONT("size", 8, Float);
+    INITFONT("line-spacing", 0.25, Float);
+    INITFONT("color/red", 0, Float);
+    INITFONT("color/green", 0.8, Float);
+    INITFONT("color/blue", 0, Float);
+    INITFONT("color/alpha", 1, Float);
+#undef INITFONT
+
+    _font_node->addChangeListener(this, true);
 }
 
+
 wxRadarBg::~wxRadarBg ()
 {
+    _font_node->removeChangeListener(this);
+    delete _odg;
 }
 
+
 void
 wxRadarBg::init ()
 {
-    string branch;
-    branch = "/instrumentation/" + _name;
+    _serviceable_node = _Instrument->getNode("serviceable", true);
+    _sceneryLoaded = fgGetNode("/sim/sceneryloaded", true);
+
+    // texture name to use in 2D and 3D instruments
+    _texture_path = _Instrument->getStringValue("radar-texture-path",
+        "Aircraft/Instruments/Textures/od_wxradar.rgb");
+    _resultTexture = FGTextureManager::createTexture(_texture_path.c_str(), false);
+
+    string path = _Instrument->getStringValue("echo-texture-path",
+        "Aircraft/Instruments/Textures/wxecho.rgb");
+    SGPath tpath = globals->resolve_aircraft_path(path);
 
-    _Instrument = fgGetNode(branch.c_str(), _num, true );
-    _serviceable_node = _Instrument->getChild("serviceable", 0, true);
-    resultTexture = FGTextureManager::createTexture( odgauge_name );
-    SGPath tpath(globals->get_fg_root());
-    tpath.append("Aircraft/Instruments/Textures/wxecho.rgb");
     // no mipmap or else alpha will mix with pixels on the border of shapes, ruining the effect
+    _wxEcho = SGLoadTexture2D(tpath, NULL, false, false);
 
-    // OSGFIXME
-//     wxEcho = new ssgTexture( tpath.c_str(), false, false, false);
-    wxEcho = new osg::Texture2D;
 
     _Instrument->setFloatValue("trk", 0.0);
     _Instrument->setFloatValue("tilt", 0.0);
-    _Instrument->setStringValue("status","");
+    _Instrument->setStringValue("status", "");
     // those properties are used by a radar instrument of a MFD
     // input switch = OFF | TST | STBY | ON
     // input mode = WX | WXA | MAP
-    // ouput status = STBY | TEST | WX | WXA | MAP | blank
+    // output status = STBY | TEST | WX | WXA | MAP | blank
     // input lightning = true | false
     // input TRK = +/- n degrees
     // input TILT = +/- n degree
@@ -86,241 +156,960 @@ wxRadarBg::init ()
     // input range = n nm (20/40/80)
     // input display-mode = arc | rose | map | plan
 
-    FGInstrumentMgr *imgr = (FGInstrumentMgr *) globals->get_subsystem("instrumentation");
-    odg = (FGODGauge *) imgr->get_subsystem("od_gauge");
+    _odg = new FGODGauge;
+    _odg->setSize(512);
+
+    _ai_enabled_node = fgGetNode("/sim/ai/enabled", true);
+
+    _user_lat_node = fgGetNode("/position/latitude-deg", true);
+    _user_lon_node = fgGetNode("/position/longitude-deg", true);
+    _user_alt_node = fgGetNode("/position/altitude-ft", true);
+
+    _user_speed_east_fps_node   = fgGetNode("/velocities/speed-east-fps", true);
+    _user_speed_north_fps_node  = fgGetNode("/velocities/speed-north-fps", true);
+
+    _tacan_serviceable_node = _Tacan->getNode("serviceable", true);
+    _tacan_distance_node    = _Tacan->getNode("indicated-distance-nm", true);
+    _tacan_name_node        = _Tacan->getNode("name", true);
+    _tacan_bearing_node     = _Tacan->getNode("indicated-bearing-true-deg", true);
+    _tacan_in_range_node    = _Tacan->getNode("in-range", true);
+
+    _radar_mode_control_node = _Instrument->getNode("mode-control", true);
+    _radar_coverage_node     = _Instrument->getNode("limit-deg", true);
+    _radar_ref_rng_node      = _Instrument->getNode("reference-range-nm", true);
+    _radar_hdg_marker_node   = _Instrument->getNode("heading-marker", true);
+
+    SGPropertyNode *n = _Instrument->getNode("display-controls", true);
+    _radar_weather_node     = n->getNode("WX", true);
+    _radar_position_node    = n->getNode("pos", true);
+    _radar_data_node        = n->getNode("data", true);
+    _radar_symbol_node      = n->getNode("symbol", true);
+    _radar_centre_node      = n->getNode("centre", true);
+    _radar_rotate_node      = n->getNode("rotate", true);
+    _radar_tcas_node        = n->getNode("tcas", true);
+    _radar_absalt_node      = n->getNode("abs-altitude", true);
+
+    _radar_centre_node->setBoolValue(false);
+    if (!_radar_coverage_node->hasValue())
+        _radar_coverage_node->setFloatValue(120);
+    if (!_radar_ref_rng_node->hasValue())
+        _radar_ref_rng_node->setDoubleValue(35);
+    if (!_radar_hdg_marker_node->hasValue())
+        _radar_hdg_marker_node->setBoolValue(true);
+
+    _x_offset = 0;
+    _y_offset = 0;
+
+    // OSG geometry setup. The polygons for the radar returns will be
+    // stored in a single Geometry. The geometry will have several
+    // primitive sets so we can have different kinds of polys and
+    // choose a different overall color for each set.
+    _radarGeode = new osg::Geode;
+    osg::StateSet *stateSet = _radarGeode->getOrCreateStateSet();
+    stateSet->setTextureAttributeAndModes(0, _wxEcho.get());
+    _geom = new osg::Geometry;
+    _geom->setUseDisplayList(false);
+    // Initially allocate space for 128 quads
+    _vertices = new osg::Vec2Array;
+    _vertices->setDataVariance(osg::Object::DYNAMIC);
+    _vertices->reserve(128 * 4);
+    _geom->setVertexArray(_vertices);
+    _texCoords = new osg::Vec2Array;
+    _texCoords->setDataVariance(osg::Object::DYNAMIC);
+    _texCoords->reserve(128 * 4);
+    _geom->setTexCoordArray(0, _texCoords);
+    osg::Vec3Array *colors = new osg::Vec3Array;
+    colors->push_back(osg::Vec3(1.0f, 1.0f, 1.0f)); // color of echos
+    colors->push_back(osg::Vec3(1.0f, 0.0f, 0.0f)); // arc mask
+    colors->push_back(osg::Vec3(0.0f, 0.0f, 0.0f)); // rest of mask
+    _geom->setColorBinding(osg::Geometry::BIND_PER_PRIMITIVE_SET);
+    _geom->setColorArray(colors);
+    osg::PrimitiveSet *pset = new osg::DrawArrays(osg::PrimitiveSet::QUADS);
+    pset->setDataVariance(osg::Object::DYNAMIC);
+    _geom->addPrimitiveSet(pset);
+    pset = new osg::DrawArrays(osg::PrimitiveSet::QUADS);
+    pset->setDataVariance(osg::Object::DYNAMIC);
+    _geom->addPrimitiveSet(pset);
+    pset = new osg::DrawArrays(osg::PrimitiveSet::TRIANGLES);
+    pset->setDataVariance(osg::Object::DYNAMIC);
+    _geom->addPrimitiveSet(pset);
+    _geom->setInitialBound(osg::BoundingBox(osg::Vec3f(-256.0f, -256.0f, 0.0f),
+        osg::Vec3f(256.0f, 256.0f, 0.0f)));
+    _radarGeode->addDrawable(_geom);
+    _odg->allocRT();
+    // Texture in the 2D panel system
+    FGTextureManager::addTexture(_texture_path.c_str(), _odg->getTexture());
+
+    _textGeode = new osg::Geode;
+
+    osg::Camera *camera = _odg->getCamera();
+    camera->addChild(_radarGeode.get());
+    camera->addChild(_textGeode.get());
+
+    updateFont();
 }
 
+
+// Local coordinates for each echo
+const osg::Vec3f echoCoords[4] = {
+    osg::Vec3f(-.7f, -.7f, 0.0f), osg::Vec3f(.7f, -.7f, 0.0f),
+    osg::Vec3f(.7f, .7f, 0.0f), osg::Vec3f(-.7f, .7f, 0.0f)
+};
+
+
+const osg::Vec2f echoTexCoords[4] = {
+    osg::Vec2f(0.0f, 0.0f), osg::Vec2f(UNIT, 0.0f),
+    osg::Vec2f(UNIT, UNIT), osg::Vec2f(0.0f, UNIT)
+};
+
+
+// helper
+static void
+addQuad(osg::Vec2Array *vertices, osg::Vec2Array *texCoords,
+        const osg::Matrixf& transform, const osg::Vec2f& texBase)
+{
+    for (int i = 0; i < 4; i++) {
+        const osg::Vec3f coords = transform.preMult(echoCoords[i]);
+        texCoords->push_back(texBase + echoTexCoords[i]);
+        vertices->push_back(osg::Vec2f(coords.x(), coords.y()));
+    }
+}
+
+
+// Rotate by a heading value
+static inline
+osg::Matrixf wxRotate(float angle)
+{
+    return osg::Matrixf::rotate(angle, 0.0f, 0.0f, -1.0f);
+}
+
+
 void
 wxRadarBg::update (double delta_time_sec)
 {
-  //OSGFIXME
-#if 0
-    if ( ! sim_init_done ) {
-        if ( ! fgGetBool("sim/sceneryloaded", false) )
-            return;
-        sim_init_done = true;
+    if (!_sceneryLoaded->getBoolValue())
+        return;
+
+    if (!_odg || !_serviceable_node->getBoolValue()) {
+        _Instrument->setStringValue("status", "");
+        return;
     }
-    if ( !odg || ! _serviceable_node->getBoolValue() ) {
-        _Instrument->setStringValue("status","");
+
+    _time += delta_time_sec;
+    if (_time < _interval)
         return;
+
+    _time = 0.0;
+
+    string mode = _Instrument->getStringValue("display-mode", "arc");
+    if (mode == "map") {
+        if (_display_mode != MAP) {
+            _display_mode = MAP;
+            center_map();
+        }
+    } else if (mode == "plan") {
+        _display_mode = PLAN;}
+    else if (mode == "bscan") {
+        _display_mode = BSCAN;
+    } else {
+        _display_mode = ARC;
     }
+
     string switchKnob = _Instrument->getStringValue("switch", "on");
-    string modeButton = _Instrument->getStringValue("mode", "wx");
-    bool drawLightning = _Instrument->getBoolValue("lightning", true);
-    float range_nm = _Instrument->getFloatValue("range", 40.0);
-    float range_m = range_nm * SG_NM_TO_METER;
-
-    if ( last_switchKnob != switchKnob ) {
-        // since 3D models don't share textures with the rest of the world
-        // we must locate them and replace their handle by hand
-        // only do that when the instrument is turned on
-        if ( last_switchKnob == "off" )
-            odg->set_texture( odgauge_name, resultTexture.get());
-        last_switchKnob = switchKnob;
-    }
-    FGViewer *current__view = globals->get_current_view();
-    if ( current__view->getInternal() &&
-        (current__view->getHeadingOffset_deg() <= 15.0 || current__view->getHeadingOffset_deg() >= 345.0) &&
-        (current__view->getPitchOffset_deg() <= 15.0 || current__view->getPitchOffset_deg() >= 350.0) ) {
-
-        // we don't update the radar echo if the pilot looks around
-        // this is a copy
-        radarEchoBuffer = *sgEnviro.get_radar_echo();
-    }
-    odg->beginCapture(256);
-    odg->Clear();
-
-    glMatrixMode(GL_MODELVIEW);
-    glLoadIdentity();
-    glPushMatrix();
-    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
-    glBindTexture(GL_TEXTURE_2D, 0);
-
-    if ( switchKnob == "off" ) {
-        _Instrument->setStringValue("status","");
-    } else if ( switchKnob == "stby" ) {
-        _Instrument->setStringValue("status","STBY");
-    } else if ( switchKnob == "tst" ) {
-        _Instrument->setStringValue("status","TST");
+    if (switchKnob == "off") {
+        _Instrument->setStringValue("status", "");
+    } else if (switchKnob == "stby") {
+        _Instrument->setStringValue("status", "STBY");
+    } else if (switchKnob == "tst") {
+        _Instrument->setStringValue("status", "TST");
         // find something interesting to do...
     } else {
-        string display_mode = _Instrument->getStringValue("display-mode", "arc");
-
-        // pretend we have a scan angle bigger then the FOV
-        // TODO:check real fov, enlarge if < nn, and do clipping if > mm
-        const float fovFactor = 1.45f;
-        float view_heading = get_heading() * SG_DEGREES_TO_RADIANS;
-        float range = 200.0f / range_nm;
-        _Instrument->setStringValue("status", modeButton.c_str());
-        if ( display_mode == "arc" ) {
-            glTranslatef(0.0f, -180.0f, 0.0f);
-            range = 2*180.0f / range_nm;
-        } else if ( display_mode == "map" ) {
-//            float view_heading = get_track() * SG_DEGREES_TO_RADIANS;
-        } else if ( display_mode == "plan" ) {
-            // no sense I presume
-            view_heading = 0;
+        float r = _Instrument->getFloatValue("range", 40.0);
+        if (r != _range_nm) {
+            center_map();
+            _range_nm = r;
+        }
+
+        _radar_ref_rng = _radar_ref_rng_node->getDoubleValue();
+        _view_heading = fgGetDouble("/orientation/heading-deg") * SG_DEGREES_TO_RADIANS;
+        _centerTrans.makeTranslate(0.0f, 0.0f, 0.0f);
+
+        _scale = 200.0 / _range_nm;
+        _angle_offset = 0;
+
+        if (_display_mode == ARC) {
+            _scale = 2*200.0f / _range_nm;
+            _angle_offset = -_view_heading;
+            _centerTrans.makeTranslate(0.0f, -200.0f, 0.0f);
+
+        } else if (_display_mode == MAP) {
+            apply_map_offset();
+
+            bool centre = _radar_centre_node->getBoolValue();
+            if (centre) {
+                center_map();
+                _radar_centre_node->setBoolValue(false);
+            }
+
+            //SG_LOG(SG_INSTR, SG_DEBUG, "Radar: displacement "
+            //        << _x_offset <<", "<<_y_offset
+            //        << " user_speed_east_fps * SG_FPS_TO_KT "
+            //        << user_speed_east_fps * SG_FPS_TO_KT
+            //        << " user_speed_north_fps * SG_FPS_TO_KT "
+            //        << user_speed_north_fps * SG_FPS_TO_KT
+            //        << " dt " << delta_time_sec);
+
+            _centerTrans.makeTranslate(_x_offset, _y_offset, 0.0f);
+
+        } else if (_display_mode == PLAN) {
+            if (_radar_rotate_node->getBoolValue()) {
+                _angle_offset = -_view_heading;
+            }
+        } else if (_display_mode == BSCAN) {
+            _angle_offset = -_view_heading;
         } else {
             // rose
         }
-        range /= SG_NM_TO_METER;
-        // we will rotate the echo quads, this gives a better rendering
-        const float rot_x = cos ( view_heading );
-        const float rot_y = sin ( view_heading );
-
-        list_of_SGWxRadarEcho *radarEcho = &radarEchoBuffer;
-        list_of_SGWxRadarEcho::iterator iradarEcho;
-        const float LWClevel[] = { 0.1f, 0.5f, 2.1f };
-        const float symbolSize = 1.0f / 8.0f ;
-        // draw the radar echo, we do that in 3 passes, one for each color level
+
+        _vertices->clear();
+        _texCoords->clear();
+        _textGeode->removeDrawables(0, _textGeode->getNumDrawables());
+
+#if 0
+        //TODO FIXME Mask below (only used for ARC mode) isn't properly aligned, i.e.
+        // it assumes the a/c position at the center of the display - though it's somewhere at
+        // bottom part for ARC mode.
+        // The mask hadn't worked at all for a while (probably since the OSG port) due to
+        // another bug (which is fixed now). Now, the mask is disabled completely until s.o.
+        // adapted the coordinates below. And the mask is only really useful to limit displayed
+        // weather blobs (not support yet).
+        // Aircraft echos are already limited properly through wxradar's "limit-deg" property.
+        {
+            osg::DrawArrays *maskPSet
+                = static_cast<osg::DrawArrays*>(_geom->getPrimitiveSet(1));
+            osg::DrawArrays *trimaskPSet
+                = static_cast<osg::DrawArrays*>(_geom->getPrimitiveSet(2));
+
+            if (_display_mode == ARC) {
+                // erase what is out of sight of antenna
+                /*
+                |\     /|
+                | \   / |
+                |  \ /  |
+                ---------
+                |       |
+                |       |
+                ---------
+                */
+                float xOffset = 256.0f;
+                float yOffset = 200.0f;
+
+                int firstQuadVert = _vertices->size();
+                _texCoords->push_back(osg::Vec2f(0.5f, 0.25f));
+                _vertices->push_back(osg::Vec2f(-xOffset, 0.0 + yOffset));
+                _texCoords->push_back(osg::Vec2f(1.0f, 0.25f));
+                _vertices->push_back(osg::Vec2f(xOffset, 0.0 + yOffset));
+                _texCoords->push_back(osg::Vec2f(1.0f, 0.5f));
+                _vertices->push_back(osg::Vec2f(xOffset, 256.0 + yOffset));
+                _texCoords->push_back(osg::Vec2f(0.5f, 0.5f));
+                _vertices->push_back(osg::Vec2f(-xOffset, 256.0 + yOffset));
+                maskPSet->set(osg::PrimitiveSet::QUADS, firstQuadVert, 4);
+                firstQuadVert += 4;
+
+                // The triangles aren't supposed to be textured, but there's
+                // no need to set up a different Geometry, switch modes,
+                // etc. I happen to know that there's a white pixel in the
+                // texture at 1.0, 0.0 :)
+                float centerY = tan(30 * SG_DEGREES_TO_RADIANS);
+                _vertices->push_back(osg::Vec2f(0.0, 0.0));
+                _vertices->push_back(osg::Vec2f(-256.0, 0.0));
+                _vertices->push_back(osg::Vec2f(-256.0, 256.0 * centerY));
+
+                _vertices->push_back(osg::Vec2f(0.0, 0.0));
+                _vertices->push_back(osg::Vec2f(256.0, 0.0));
+                _vertices->push_back(osg::Vec2f(256.0, 256.0 * centerY));
+
+                _vertices->push_back(osg::Vec2f(-256, 0.0));
+                _vertices->push_back(osg::Vec2f(256.0, 0.0));
+                _vertices->push_back(osg::Vec2f(-256.0, -256.0));
+
+                _vertices->push_back(osg::Vec2f(256, 0.0));
+                _vertices->push_back(osg::Vec2f(256.0, -256.0));
+                _vertices->push_back(osg::Vec2f(-256.0, -256.0));
+
+                const osg::Vec2f whiteSpot(1.0f, 0.0f);
+                for (int i = 0; i < 3 * 4; i++)
+                    _texCoords->push_back(whiteSpot);
+
+                trimaskPSet->set(osg::PrimitiveSet::TRIANGLES, firstQuadVert, 3 * 4);
+
+            } else
+            {
+                maskPSet->set(osg::PrimitiveSet::QUADS, 0, 0);
+                trimaskPSet->set(osg::PrimitiveSet::TRIANGLES, 0, 0);
+            }
+
+            maskPSet->dirty();
+            trimaskPSet->dirty();
+        }
+#endif
+
+        // remember index of next vertex
+        int vIndex = _vertices->size();
+
+        update_weather();
+
+        osg::DrawArrays *quadPSet
+            = static_cast<osg::DrawArrays*>(_geom->getPrimitiveSet(0));
+
+        update_aircraft();
+        update_tacan();
+        update_heading_marker();
+
+        // draw all new vertices are quads
+        quadPSet->set(osg::PrimitiveSet::QUADS, vIndex, _vertices->size()-vIndex);
+        quadPSet->dirty();
+    }
+}
+
+
+void
+wxRadarBg::update_weather()
+{
+    string modeButton = _Instrument->getStringValue("mode", "WX");
+// FIXME: implementation of radar echoes missing
+//    _radarEchoBuffer = *sgEnviro.get_radar_echo();
+
+    // pretend we have a scan angle bigger then the FOV
+    // TODO:check real fov, enlarge if < nn, and do clipping if > mm
+//    const float fovFactor = 1.45f;
+    _Instrument->setStringValue("status", modeButton.c_str());
+
+// FIXME: implementation of radar echoes missing
+#if 0
+    list_of_SGWxRadarEcho *radarEcho = &_radarEchoBuffer;
+    list_of_SGWxRadarEcho::iterator iradarEcho, end = radarEcho->end();
+    const float LWClevel[] = { 0.1f, 0.5f, 2.1f };
+
+    // draw the cloud radar echo
+    bool drawClouds = _radar_weather_node->getBoolValue();
+    if (drawClouds) {
+
+        // we do that in 3 passes, one for each color level
         // this is to 'merge' same colors together
-        // OSGFIXME
-//         glBindTexture(GL_TEXTURE_2D, wxEcho->getHandle() );
-        glColor3f(1.0f, 1.0f, 1.0f);
-        glBegin( GL_QUADS );
-
-        for (int level = 0; level <= 2 ; level++ ) {
-            float col = level * symbolSize;
-            for (iradarEcho = radarEcho->begin() ; iradarEcho != radarEcho->end() ; iradarEcho++ ) {
-                int cloudId = (iradarEcho->cloudId) ;
-                bool upgrade = ((cloudId >> 5) & 1);
+        for (int level = 0; level <= 2; level++) {
+            float col = level * UNIT;
+
+            for (iradarEcho = radarEcho->begin(); iradarEcho != end; ++iradarEcho) {
+                int cloudId = iradarEcho->cloudId;
+                bool upgrade = (cloudId >> 5) & 1;
                 float lwc = iradarEcho->LWC + (upgrade ? 1.0f : 0.0f);
+
                 // skip ns
-                if ( iradarEcho->LWC >= 0.5 && iradarEcho->LWC <= 0.6)
+                if (iradarEcho->LWC >= 0.5 && iradarEcho->LWC <= 0.6)
                     continue;
-                if ( (! iradarEcho->lightning) && ( lwc >= LWClevel[level]) ) {
-                    float dist = sgSqrt( iradarEcho->dist );
-                    float size = iradarEcho->radius * 2.0;
-                    if ( dist - size > range_m )
-                        continue;
-                    dist = dist * range;
-                    size = size * range;
-                    // compute the relative angle from the view direction
-                    float angle = ( view_heading + iradarEcho->heading );
-                    if ( angle > SG_PI )
-                        angle -= 2.0*SG_PI;
-                    if ( angle < - SG_PI )
-                        angle += 2.0*SG_PI;
-                    // and apply a fov factor to simulate a greater scan angle
-                    angle =  angle * fovFactor + SG_PI / 2.0;
-                    float x = cos( angle ) * dist;
-                    float y = sin( angle ) * dist;
-                    // use different shapes so the display is less boring
-                    float row = symbolSize * (float) (4 + (cloudId & 3) );
-                    float size_x = rot_x * size;
-                    float size_y = rot_y * size;
-                    glTexCoord2f( col, row);
-                    glVertex2f( x - size_x, y - size_y);
-                    glTexCoord2f( col+symbolSize, row);
-                    glVertex2f( x + size_y, y - size_x);
-                    glTexCoord2f( col+symbolSize, row+symbolSize);
-                    glVertex2f( x + size_x, y + size_y);
-                    glTexCoord2f( col, row+symbolSize);
-                    glVertex2f( x - size_y, y + size_x);
-                }
+
+                if (iradarEcho->lightning || lwc < LWClevel[level])
+                    continue;
+
+                float radius = sqrt(iradarEcho->dist) * SG_METER_TO_NM * _scale;
+                float size = iradarEcho->radius * 2.0 * SG_METER_TO_NM * _scale;
+
+                if (radius - size > 180)
+                    continue;
+
+                float angle = (iradarEcho->heading - _angle_offset) //* fovFactor
+                    + 0.5 * SG_PI;
+
+                // Rotate echo into position, and rotate echo to have
+                // a constant orientation towards the
+                // airplane. Compass headings increase in clockwise
+                // direction, while graphics rotations follow
+                // right-hand (counter-clockwise) rule.
+                const osg::Vec2f texBase(col, (UNIT * (float) (4 + (cloudId & 3))));
+
+                osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                    * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                    * wxRotate(angle) * _centerTrans);
+                addQuad(_vertices, _texCoords, m, texBase);
+
+                //SG_LOG(SG_INSTR, SG_DEBUG, "Radar: drawing clouds"
+                //        << " ID=" << cloudId
+                //        << " x=" << x
+                //        << " y="<< y
+                //        << " radius=" << radius
+                //        << " view_heading=" << _view_heading * SG_RADIANS_TO_DEGREES
+                //        << " heading=" << iradarEcho->heading * SG_RADIANS_TO_DEGREES
+                //        << " angle=" << angle * SG_RADIANS_TO_DEGREES);
             }
         }
-        glEnd(); // GL_QUADS
-
-        // draw lightning echos
-        if ( drawLightning ) {
-            float col = 3 * symbolSize;
-            float row = 4 * symbolSize;
-            for (iradarEcho = radarEcho->begin() ; iradarEcho != radarEcho->end() ; iradarEcho++ ) {
-                if ( iradarEcho->lightning ) {
-                    float dist = iradarEcho->dist;
-                    dist = dist * range;
-                    float angle = (view_heading - iradarEcho->heading);
-                    if ( angle > SG_PI )
-                        angle -= 2.0*SG_PI;
-                    if ( angle < - SG_PI )
-                        angle += 2.0*SG_PI;
-                    angle =  angle * fovFactor - SG_PI / 2.0;
-                    float x = cos( angle ) * dist;
-                    float y = sin( angle ) * dist;
-                    glColor3f(1.0f, 1.0f, 1.0f);
-                    float size = symbolSize * 0.5f;
-                    glBegin( GL_QUADS );
-                        glTexCoord2f( col, row);
-                        glVertex2f( x - size, y - size);
-                        glTexCoord2f( col+symbolSize, row);
-                        glVertex2f( x + size, y - size);
-                        glTexCoord2f( col+symbolSize, row+symbolSize);
-                        glVertex2f( x + size, y + size);
-                        glTexCoord2f( col, row+symbolSize);
-                        glVertex2f( x - size, y + size);
-                    glEnd();
+    }
+
+    // draw lightning echos
+    bool drawLightning = _Instrument->getBoolValue("lightning", true);
+    if (drawLightning) {
+        const osg::Vec2f texBase(3 * UNIT, 4 * UNIT);
+
+        for (iradarEcho = radarEcho->begin(); iradarEcho != end; ++iradarEcho) {
+            if (!iradarEcho->lightning)
+                continue;
+
+            float size = UNIT * 0.5f;
+            float radius = iradarEcho->dist * _scale;
+            float angle = iradarEcho->heading * SG_DEGREES_TO_RADIANS
+                - _angle_offset;
+
+            osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                * wxRotate(-angle)
+                * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                * wxRotate(angle) * _centerTrans);
+            addQuad(_vertices, _texCoords, m, texBase);
+        }
+    }
+#endif
+}
+
+
+void
+wxRadarBg::update_data(const SGPropertyNode *ac, double altitude, double heading,
+                       double radius, double bearing, bool selected)
+{
+    osgText::Text *callsign = new osgText::Text;
+    callsign->setFont(_font.get());
+    callsign->setFontResolution(12, 12);
+    callsign->setCharacterSize(_font_size);
+    callsign->setColor(selected ? osg::Vec4(1, 1, 1, 1) : _font_color);
+    osg::Matrixf m(wxRotate(-bearing)
+        * osg::Matrixf::translate(0.0f, radius, 0.0f)
+        * wxRotate(bearing) * _centerTrans);
+
+    osg::Vec3 pos = m.preMult(osg::Vec3(16, 16, 0));
+    // cast to int's, otherwise text comes out ugly
+    callsign->setPosition(osg::Vec3((int)pos.x(), (int)pos.y(), 0));
+    callsign->setAlignment(osgText::Text::LEFT_BOTTOM_BASE_LINE);
+    callsign->setLineSpacing(_font_spacing);
+
+    const char *identity = ac->getStringValue("transponder-id");
+    if (!identity[0])
+        identity = ac->getStringValue("callsign");
+
+    stringstream text;
+    text << identity << endl
+        << setprecision(0) << fixed
+        << setw(3) << setfill('0') << heading * SG_RADIANS_TO_DEGREES << "\xB0 "
+        << setw(0) << altitude << "ft" << endl
+        << ac->getDoubleValue("velocities/true-airspeed-kt") << "kts";
+
+    callsign->setText(text.str());
+    _textGeode->addDrawable(callsign);
+}
+
+
+void
+wxRadarBg::update_aircraft()
+{
+    double diff;
+    double age_factor = 1.0;
+    double test_rng;
+    double test_brg;
+    double range;
+    double bearing;
+    float echo_radius;
+    double angle;
+
+    if (!ground_echoes.empty()){
+        ground_echoes_iterator = ground_echoes.begin();
+
+        while(ground_echoes_iterator != ground_echoes.end()) {
+            diff = _elapsed_time - (*ground_echoes_iterator)->elapsed_time;
+
+            if( diff > _persistance) {
+                ground_echoes.erase(ground_echoes_iterator++);
+            } else {
+//                double test_brg = (*ground_echoes_iterator)->bearing;
+//                double bearing = test_brg * SG_DEGREES_TO_RADIANS;
+//                float angle = calcRelBearing(bearing, _view_heading);
+                double bumpinessFactor  = (*ground_echoes_iterator)->bumpiness;
+                float heading = fgGetDouble("/orientation/heading-deg");
+                if ( _display_mode == BSCAN ){
+                    test_rng = (*ground_echoes_iterator)->elevation * 6;
+                    test_brg = (*ground_echoes_iterator)->bearing;
+                    angle = calcRelBearingDeg(test_brg, heading) * 6;
+                    range = sqrt(test_rng * test_rng + angle * angle);
+                    bearing = atan2(angle, test_rng);
+                    //cout << "angle " << angle <<" bearing "
+                    //    << bearing / SG_DEGREES_TO_RADIANS <<  endl;
+                    echo_radius = (0.1 + (1.9 * bumpinessFactor)) * 240 * age_factor;
+                } else {
+                    test_rng = (*ground_echoes_iterator)->range;
+                    range = test_rng * SG_METER_TO_NM;
+                    test_brg = (*ground_echoes_iterator)->bearing;
+                    bearing = test_brg * SG_DEGREES_TO_RADIANS;
+                    echo_radius = (0.1 + (1.9 * bumpinessFactor)) * 120 * age_factor;
+                    bearing += _angle_offset;
                 }
+
+                float radius = range * _scale;
+                //double heading = 90 * SG_DEGREES_TO_RADIANS;
+                //heading += _angle_offset;
+
+                age_factor = 1;
+
+                if (diff != 0)
+                    age_factor = 1 - (0.5 * diff/_persistance);
+
+                float size = echo_radius * UNIT;
+
+                const osg::Vec2f texBase(3 * UNIT, 3 * UNIT);
+                osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                    * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                    * wxRotate(bearing) * _centerTrans);
+                addQuad(_vertices, _texCoords, m, texBase);
+
+                ++ground_echoes_iterator;
+
+                //cout << "test bearing " << test_brg 
+                //<< " test_rng " << test_rng * SG_METER_TO_NM
+                //<< " persistance " << _persistance
+                //<< endl;
+            }
+
+        }
+
+    }
+    if (!_ai_enabled_node->getBoolValue())
+        return;
+
+    bool draw_tcas     = _radar_tcas_node->getBoolValue();
+    bool draw_absolute = _radar_absalt_node->getBoolValue();
+    bool draw_echoes   = _radar_position_node->getBoolValue();
+    bool draw_symbols  = _radar_symbol_node->getBoolValue();
+    bool draw_data     = _radar_data_node->getBoolValue();
+    if (!draw_echoes && !draw_symbols && !draw_data)
+        return;
+
+    double user_lat = _user_lat_node->getDoubleValue();
+    double user_lon = _user_lon_node->getDoubleValue();
+    double user_alt = _user_alt_node->getDoubleValue();
+
+    float limit = _radar_coverage_node->getFloatValue();
+    if (limit > 180)
+        limit = 180;
+    else if (limit < 0)
+        limit = 0;
+    limit *= SG_DEGREES_TO_RADIANS;
+
+    int selected_id = fgGetInt("/instrumentation/radar/selected-id", -1);
+
+    const SGPropertyNode *selected_ac = 0;
+    const SGPropertyNode *ai = fgGetNode("/ai/models", true);
+
+    for (int i = ai->nChildren() - 1; i >= -1; i--) {
+        const SGPropertyNode *model;
+
+        if (i < 0) { // last iteration: selected model
+            model = selected_ac;
+        } else {
+            model = ai->getChild(i);
+            if (!model->nChildren())
+                continue;
+            if ((model->getIntValue("id") == selected_id)&&
+                (!draw_tcas)) {
+                selected_ac = model;  // save selected model for last iteration
+                continue;
             }
         }
-        // erase what is out of sight of antenna
-        /*
-            |\     /|
-            | \   / |
-            |  \ /  |
-            ---------
-            |       |
-            |       |
-            ---------
-        */
-        float yOffset = 180.0f, xOffset = 256.0f;
-
-        if ( display_mode != "arc" ) {
-            yOffset = 40.0f;
-            xOffset = 240.0f;
+        if (!model)
+            continue;
+
+        double echo_radius, sigma;
+        const string name = model->getName();
+
+        //cout << "name "<<name << endl;
+        if (name == "aircraft" || name == "tanker")
+            echo_radius = 1, sigma = 1;
+        else if (name == "multiplayer" || name == "wingman" || name == "static")
+            echo_radius = 1.5, sigma = 1;
+        else if (name == "ship" || name == "carrier" || name == "escort" ||name == "storm")
+            echo_radius = 1.5, sigma = 100;
+        else if (name == "thermal")
+            echo_radius = 2, sigma = 100;
+        else if (name == "rocket")
+            echo_radius = 0.1, sigma = 0.1;
+        else if (name == "ballistic")
+            echo_radius = 0.001, sigma = 0.001;
+        else
+            continue;
+
+        double lat = model->getDoubleValue("position/latitude-deg");
+        double lon = model->getDoubleValue("position/longitude-deg");
+        double alt = model->getDoubleValue("position/altitude-ft");
+        double heading = model->getDoubleValue("orientation/true-heading-deg");
+
+        double range, bearing;
+        calcRangeBearing(user_lat, user_lon, lat, lon, range, bearing);
+        //cout << _antenna_ht << _interval<< endl;
+        bool isVisible = withinRadarHorizon(user_alt, alt, range);
+
+        if (!isVisible)
+            continue;
+
+        if (!inRadarRange(sigma, range))
+            continue;
+
+        bearing *= SG_DEGREES_TO_RADIANS;
+        heading *= SG_DEGREES_TO_RADIANS;
+
+        float radius = range * _scale;
+        float angle = calcRelBearing(bearing, _view_heading);
+
+        if (angle > limit || angle < -limit)
+            continue;
+
+        bearing += _angle_offset;
+        heading += _angle_offset;
+
+        bool is_tcas_contact = false;
+        if (draw_tcas)
+        {
+            is_tcas_contact = update_tcas(model,range,user_alt,alt,bearing,radius,draw_absolute);
+        }
+
+        // pos mode
+        if (draw_echoes && (!is_tcas_contact)) {
+            float size = echo_radius * 120 * UNIT;
+
+            const osg::Vec2f texBase(3 * UNIT, 3 * UNIT);
+            osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                * wxRotate(bearing) * _centerTrans);
+            addQuad(_vertices, _texCoords, m, texBase);
+        }
+
+        // data mode
+        if (draw_symbols && (!draw_tcas)) {
+            const osg::Vec2f texBase(0, 3 * UNIT);
+            float size = 600 * UNIT;
+            osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                * wxRotate(heading - bearing)
+                * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                * wxRotate(bearing) * _centerTrans);
+            addQuad(_vertices, _texCoords, m, texBase);
         }
 
-        if ( display_mode != "plan" ) {
-            glDisable(GL_BLEND);
-            glColor4f(1.0f, 0.0f, 0.0f, 0.01f);
-            glBegin( GL_QUADS );
-            glTexCoord2f( 0.5f, 0.25f);
-            glVertex2f(-xOffset, 0.0 + yOffset);
-            glTexCoord2f( 1.0f, 0.25f);
-            glVertex2f(xOffset, 0.0 + yOffset);
-            glTexCoord2f( 1.0f, 0.5f);
-            glVertex2f(xOffset, 256.0 + yOffset);
-            glTexCoord2f( 0.5f, 0.5f);
-            glVertex2f(-xOffset, 256.0 + yOffset);
-            glEnd();
-
-            glColor4f(0.0f, 0.0f, 0.0f, 0.0f);
-//          glColor4f(0.0f, 1.0f, 0.0f, 1.0f);
-            glDisable(GL_ALPHA_TEST);
-            glBindTexture(GL_TEXTURE_2D, 0);
-
-            glBegin( GL_TRIANGLES );
-            glVertex2f(0.0, 0.0);
-            glVertex2f(-256.0, 0.0);
-            glVertex2f(-256.0, 256.0 * tan(30*SG_DEGREES_TO_RADIANS));
-
-            glVertex2f(0.0, 0.0);
-            glVertex2f(256.0, 0.0);
-            glVertex2f(256.0, 256.0 * tan(30*SG_DEGREES_TO_RADIANS));
-
-            glVertex2f(-256, 0.0);
-            glVertex2f(256.0, 0.0);
-            glVertex2f(-256.0, -256.0);
-
-            glVertex2f(256, 0.0);
-            glVertex2f(256.0, -256.0);
-            glVertex2f(-256.0, -256.0);
-            glEnd();
+        if ((draw_data || i < 0)&&  // selected one (i == -1) is always drawn
+            ((!draw_tcas)||(is_tcas_contact)||(draw_echoes)))
+            update_data(model, alt, heading, radius, bearing, i < 0);
+    }
+}
+
+/** Update TCAS display.
+ * Return true when processed as TCAS contact, false otherwise. */
+bool
+wxRadarBg::update_tcas(const SGPropertyNode *model,double range,double user_alt,double alt,
+                       double bearing,double radius,bool absMode)
+{
+    int threatLevel=0;
+    {
+        // update TCAS symbol
+        osg::Vec2f texBase;
+        threatLevel = model->getIntValue("tcas/threat-level",-1);
+        if (threatLevel == -1)
+        {
+            // no TCAS information (i.e. no transponder) => not visible to TCAS
+            return false;
         }
+        int row = 7 - threatLevel;
+        int col = 4;
+        double vspeed = model->getDoubleValue("velocities/vertical-speed-fps");
+        if (vspeed < -3.0) // descending
+            col+=1;
+        else
+        if (vspeed > 3.0) // climbing
+            col+=2;
+        texBase = osg::Vec2f(col*UNIT,row * UNIT);
+        float size = 200 * UNIT;
+            osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                * wxRotate(-bearing)
+                * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                * wxRotate(bearing) * _centerTrans);
+            addQuad(_vertices, _texCoords, m, texBase);
+    }
 
-        // DEBUG only
-/*      glColor4f(1.0f, 0.0f, 0.0f, 1.0f);
-        glBegin( GL_LINES );
-        glVertex2f(0.0, 0.0);
-        glVertex2f(-256.0, 256.0);
-        glVertex2f(0.0, 0.0);
-        glVertex2f(256.0, 256.0);
-        glEnd();*/
-
-        glEnable(GL_BLEND);
-        glEnable(GL_ALPHA_TEST);
+    {
+        // update TCAS data
+        osgText::Text *altStr = new osgText::Text;
+        altStr->setFont(_font.get());
+        altStr->setFontResolution(12, 12);
+        altStr->setCharacterSize(_font_size);
+        altStr->setColor(_tcas_colors[threatLevel]);
+        osg::Matrixf m(wxRotate(-bearing)
+            * osg::Matrixf::translate(0.0f, radius, 0.0f)
+            * wxRotate(bearing) * _centerTrans);
+    
+        osg::Vec3 pos = m.preMult(osg::Vec3(16, 16, 0));
+        // cast to int's, otherwise text comes out ugly
+        altStr->setLineSpacing(_font_spacing);
+    
+        stringstream text;
+        altStr->setAlignment(osgText::Text::LEFT_CENTER);
+        int altDif = (alt-user_alt+50)/100;
+        char sign = 0;
+        int dy=0;
+        if (altDif>=0)
+        {
+            sign='+';
+            dy=2;
+        }
+        else
+        if (altDif<0)
+        {
+            sign='-';
+            altDif = -altDif;
+            dy=-30;
+        }
+        altStr->setPosition(osg::Vec3((int)pos.x()-30, (int)pos.y()+dy, 0));
+        if (absMode)
+        {
+            // absolute altitude display
+            text << setprecision(0) << fixed
+                 << setw(3) << setfill('0') << alt/100 << endl;
+        }
+        else // relative altitude display
+        if (sign)
+        {
+            text << sign
+                 << setprecision(0) << fixed
+                 << setw(2) << setfill('0') << altDif << endl;
+        }
+    
+        altStr->setText(text.str());
+        _textGeode->addDrawable(altStr);
     }
-    glPopMatrix();
-    odg->endCapture( resultTexture.get() );
+
+    return true;
+}
+
+void
+wxRadarBg::update_tacan()
+{
+    // draw TACAN symbol
+    int mode = _radar_mode_control_node->getIntValue();
+    bool inRange = _tacan_in_range_node->getBoolValue();
+
+    if (mode != 1 || !inRange)
+        return;
+
+    float size = 600 * UNIT;
+    float radius = _tacan_distance_node->getFloatValue() * _scale;
+    float angle = _tacan_bearing_node->getFloatValue() * SG_DEGREES_TO_RADIANS
+        + _angle_offset;
+
+    const osg::Vec2f texBase(1 * UNIT, 3 * UNIT);
+    osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+        * wxRotate(-angle)
+        * osg::Matrixf::translate(0.0f, radius, 0.0f)
+        * wxRotate(angle) * _centerTrans);
+    addQuad(_vertices, _texCoords, m, texBase);
+
+    //SG_LOG(SG_INSTR, SG_DEBUG, "Radar:     drawing TACAN"
+    //        << " dist=" << radius
+    //        << " view_heading=" << _view_heading * SG_RADIANS_TO_DEGREES
+    //        << " bearing=" << angle * SG_RADIANS_TO_DEGREES
+    //        << " x=" << x << " y="<< y
+    //        << " size=" << size);
+}
+
+
+void
+wxRadarBg::update_heading_marker()
+{
+    if (!_radar_hdg_marker_node->getBoolValue())
+        return;
+
+    const osg::Vec2f texBase(2 * UNIT, 3 * UNIT);
+    float size = 600 * UNIT;
+    osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+        * wxRotate(_view_heading + _angle_offset));
+
+    m *= _centerTrans;
+    addQuad(_vertices, _texCoords, m, texBase);
+
+    //SG_LOG(SG_INSTR, SG_DEBUG, "Radar:   drawing heading marker"
+    //        << " x,y " << x <<","<< y
+    //        << " dist" << dist
+    //        << " view_heading" << _view_heading * SG_RADIANS_TO_DEGREES
+    //        << " heading " << iradarEcho->heading * SG_RADIANS_TO_DEGREES
+    //        << " angle " << angle * SG_RADIANS_TO_DEGREES);
+}
+
+
+void
+wxRadarBg::center_map()
+{
+    _lat = _user_lat_node->getDoubleValue();
+    _lon = _user_lon_node->getDoubleValue();
+    _x_offset = _y_offset = 0;
+}
+
+
+void
+wxRadarBg::apply_map_offset()
+{
+    double lat = _user_lat_node->getDoubleValue();
+    double lon = _user_lon_node->getDoubleValue();
+    double bearing, distance, az2;
+    geo_inverse_wgs_84(_lat, _lon, lat, lon, &bearing, &az2, &distance);
+    distance *= SG_METER_TO_NM * _scale;
+    bearing *= SG_DEGREES_TO_RADIANS;
+    _x_offset += sin(bearing) * distance;
+    _y_offset += cos(bearing) * distance;
+    _lat = lat;
+    _lon = lon;
+}
+
+
+bool
+wxRadarBg::withinRadarHorizon(double user_alt, double alt, double range_nm)
+{
+    // Radar Horizon  = 1.23(ht^1/2 + hr^1/2),
+    //don't allow negative altitudes (an approximation - yes altitudes can be negative)
+    // Allow antenna ht to be set, but only on ground
+    _antenna_ht = _Instrument->getDoubleValue("antenna-ht-ft");
+
+    if (user_alt <= 0)
+        user_alt = _antenna_ht;
+
+    if (alt <= 0)
+        alt = 0; // to allow some vertical extent of target
+
+    double radarhorizon = 1.23 * (sqrt(alt) + sqrt(user_alt));
+//    SG_LOG(SG_INSTR, SG_ALERT, "Radar: radar horizon " << radarhorizon);
+    return radarhorizon >= range_nm;
+}
+
+
+bool
+wxRadarBg::inRadarRange(double sigma, double range_nm)
+{
+    //The Radar Equation:
+    //
+    // MaxRange^4 = (TxPower * AntGain^2 * lambda^2 * sigma)/((constant) * MDS)
+    //
+    // Where (constant) = (4*pi)3 and MDS is the Minimum Detectable Signal power.
+    //
+    // For a given radar we can assume that the only variable is sigma,
+    // the target radar cross section.
+    //
+    // Here, we will use a normalised rcs (sigma) for a standard taget and assume that this
+    // will provide a maximum range of 35nm;
+    //
+    // TODO - make the maximum range adjustable at runtime
+
+    double constant = _radar_ref_rng;
+
+    if (constant <= 0)
+        constant = 35;
+
+    double maxrange = constant * pow(sigma, 0.25);
+    //SG_LOG(SG_INSTR, SG_DEBUG, "Radar: max range " << maxrange);
+    return maxrange >= range_nm;
+}
+
+
+void
+wxRadarBg::calcRangeBearing(double lat, double lon, double lat2, double lon2,
+                            double &range, double &bearing) const
+{
+    // calculate the bearing and range of the second pos from the first
+    double az2, distance;
+    geo_inverse_wgs_84(lat, lon, lat2, lon2, &bearing, &az2, &distance);
+    range = distance *= SG_METER_TO_NM;
+}
+
+
+float
+wxRadarBg::calcRelBearing(float bearing, float heading)
+{
+    float angle = bearing - heading;
+
+    if (angle >= SG_PI)
+        angle -= 2.0 * SG_PI;
+
+    if (angle < -SG_PI)
+        angle += 2.0 * SG_PI;
+
+    return angle;
+}
+
+float
+wxRadarBg::calcRelBearingDeg(float bearing, float heading)
+{
+    float angle = bearing - heading;
+
+    if (angle >= 180)
+        return angle -= 360;
+
+    if (angle < -180)
+        return angle += 360;
+
+    return angle;
+}
+
+
+void
+wxRadarBg::updateFont()
+{
+    float red = _font_node->getFloatValue("color/red");
+    float green = _font_node->getFloatValue("color/green");
+    float blue = _font_node->getFloatValue("color/blue");
+    float alpha = _font_node->getFloatValue("color/alpha");
+    _font_color.set(red, green, blue, alpha);
+
+    _font_size = _font_node->getFloatValue("size");
+    _font_spacing = _font_size * _font_node->getFloatValue("line-spacing");
+    string path = _font_node->getStringValue("name", DEFAULT_FONT);
+
+    SGPath tpath;
+    if (path[0] != '/') {
+        tpath = globals->get_fg_root();
+        tpath.append("Fonts");
+        tpath.append(path);
+    } else {
+        tpath = path;
+    }
+
+#if (FG_OSG_VERSION >= 21000)
+    osg::ref_ptr<osgDB::ReaderWriter::Options> fontOptions = new osgDB::ReaderWriter::Options("monochrome");
+    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.c_str(), fontOptions.get());
+#else
+    osg::ref_ptr<osgText::Font> font = osgText::readFontFile(tpath.c_str());
 #endif
+
+    if (font != 0) {
+        _font = font;
+        _font->setMinFilterHint(osg::Texture::NEAREST);
+        _font->setMagFilterHint(osg::Texture::NEAREST);
+        _font->setGlyphImageMargin(0);
+        _font->setGlyphImageMarginRatio(0);
+    }
+
+    for (int i=0;i<4;i++)
+    {
+        const float defaultColors[4][3] = {{0,1,1},{0,1,1},{1,0.5,0},{1,0,0}};
+        SGPropertyNode_ptr color_node = _font_node->getNode("tcas/color",i,true);
+        float red   = color_node->getFloatValue("red",defaultColors[i][0]);
+        float green = color_node->getFloatValue("green",defaultColors[i][1]);
+        float blue  = color_node->getFloatValue("blue",defaultColors[i][2]);
+        float alpha = color_node->getFloatValue("alpha",1);
+        _tcas_colors[i]=osg::Vec4(red, green, blue, alpha);
+    }
+}
+
+void
+wxRadarBg::valueChanged(SGPropertyNode*)
+{
+    updateFont();
+    _time = _interval;
 }
+