1 // native_fdm.cxx -- FGFS "Native" flight dynamics protocal class
3 // Written by Curtis Olson, started September 2001.
5 // Copyright (C) 2001 Curtis L. Olson - curt@flightgear.org
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #include <simgear/debug/logstream.hxx>
29 #include <simgear/io/lowlevel.hxx> // endian tests
30 #include <simgear/io/iochannel.hxx>
31 #include <simgear/timing/sg_time.hxx>
33 #include <FDM/flight.hxx>
34 #include <Time/tmp.hxx>
35 #include <Main/fg_props.hxx>
36 #include <Main/globals.hxx>
38 #include "native_fdm.hxx"
40 // FreeBSD works better with this included last ... (?)
41 #if defined(WIN32) && !defined(__CYGWIN__)
44 # include <netinet/in.h> // htonl() ntohl()
48 // The function htond is defined this way due to the way some
49 // processors and OSes treat floating point values. Some will raise
50 // an exception whenever a "bad" floating point value is loaded into a
51 // floating point register. Solaris is notorious for this, but then
52 // so is LynxOS on the PowerPC. By translating the data in place,
53 // there is no need to load a FP register with the "corruped" floating
54 // point value. By doing the BIG_ENDIAN test, I can optimize the
55 // routine for big-endian processors so it can be as efficient as
57 static void htond (double &x)
59 if ( sgIsLittleEndian() ) {
63 Double_Overlay = (int *) &x;
64 Holding_Buffer = Double_Overlay [0];
66 Double_Overlay [0] = htonl (Double_Overlay [1]);
67 Double_Overlay [1] = htonl (Holding_Buffer);
74 FGNativeFDM::FGNativeFDM() {
77 FGNativeFDM::~FGNativeFDM() {
81 // open hailing frequencies
82 bool FGNativeFDM::open() {
84 SG_LOG( SG_IO, SG_ALERT, "This shouldn't happen, but the channel "
85 << "is already in use, ignoring" );
89 SGIOChannel *io = get_io_channel();
91 if ( ! io->open( get_direction() ) ) {
92 SG_LOG( SG_IO, SG_ALERT, "Error opening channel communication layer." );
98 cur_fdm_state->_set_Sea_level_radius( SG_EQUATORIAL_RADIUS_FT );
103 static void global2net( const FGInterface *global, FGNetFDM *net ) {
104 static const SGPropertyNode *visibility
105 = fgGetNode("/environment/visibility-m");
107 net->version = FG_NET_FDM_VERSION;
110 net->longitude = cur_fdm_state->get_Longitude();
111 net->latitude = cur_fdm_state->get_Latitude();
112 net->altitude = cur_fdm_state->get_Altitude() * SG_FEET_TO_METER;
113 net->phi = cur_fdm_state->get_Phi();
114 net->theta = cur_fdm_state->get_Theta();
115 net->psi = cur_fdm_state->get_Psi();
118 net->vcas = cur_fdm_state->get_V_calibrated_kts();
119 net->climb_rate = cur_fdm_state->get_Climb_Rate();
122 net->cur_time = globals->get_time_params()->get_cur_time();
123 net->warp = globals->get_warp();
124 net->visibility = visibility->getDoubleValue();
126 // Convert the net buffer to network format
127 net->version = htonl(net->version);
128 htond(net->longitude);
129 htond(net->latitude);
130 htond(net->altitude);
135 htond(net->climb_rate);
136 net->cur_time = htonl( net->cur_time );
137 net->warp = htonl( net->warp );
138 htond(net->visibility);
142 static void net2global( FGNetFDM *net, FGInterface *global ) {
143 static long int last_warp = 0;
145 // Convert to the net buffer from network format
146 net->version = ntohl(net->version);
147 htond(net->longitude);
148 htond(net->latitude);
149 htond(net->altitude);
154 htond(net->climb_rate);
155 net->cur_time = ntohl(net->cur_time);
156 net->warp = ntohl(net->warp);
157 htond(net->visibility);
159 if ( net->version == FG_NET_FDM_VERSION ) {
160 // cout << "pos = " << net->longitude << " " << net->latitude << endl;
161 // cout << "sea level rad = " << cur_fdm_state->get_Sea_level_radius() << endl;
162 cur_fdm_state->_updateGeodeticPosition( net->latitude,
165 * SG_METER_TO_FEET );
166 cur_fdm_state->_set_Euler_Angles( net->phi,
169 cur_fdm_state->_set_V_calibrated_kts( net->vcas );
170 cur_fdm_state->_set_Climb_Rate( net->climb_rate );
172 if ( net->cur_time ) {
173 fgSetLong("/sim/time/cur-time-override", net->cur_time);
176 globals->set_warp( net->warp );
177 if ( net->warp != last_warp ) {
178 fgUpdateSkyAndLightingParams();
180 last_warp = net->warp;
182 fgSetDouble( "/environment/visibility-m", net->visibility );
184 SG_LOG( SG_IO, SG_ALERT, "Error: version mismatch in net2global()" );
185 SG_LOG( SG_IO, SG_ALERT,
186 "\tread " << net->version << " need " << FG_NET_FDM_VERSION );
187 SG_LOG( SG_IO, SG_ALERT,
188 "\tsomeone needs to upgrade net_fdm.hxx and recompile." );
193 // process work for this port
194 bool FGNativeFDM::process() {
195 SGIOChannel *io = get_io_channel();
196 int length = sizeof(buf);
198 if ( get_direction() == SG_IO_OUT ) {
199 // cout << "size of cur_fdm_state = " << length << endl;
200 global2net( cur_fdm_state, &buf );
201 if ( ! io->write( (char *)(& buf), length ) ) {
202 SG_LOG( SG_IO, SG_ALERT, "Error writing data." );
205 } else if ( get_direction() == SG_IO_IN ) {
206 if ( io->get_type() == sgFileType ) {
207 if ( io->read( (char *)(& buf), length ) == length ) {
208 SG_LOG( SG_IO, SG_DEBUG, "Success reading data." );
209 net2global( &buf, cur_fdm_state );
212 while ( io->read( (char *)(& buf), length ) == length ) {
213 SG_LOG( SG_IO, SG_DEBUG, "Success reading data." );
214 net2global( &buf, cur_fdm_state );
224 bool FGNativeFDM::close() {
225 SGIOChannel *io = get_io_channel();
227 set_enabled( false );
229 if ( ! io->close() ) {