1 // flight.hxx -- define shared flight model parameters
3 // Written by Curtis Olson, started May 1997.
5 // Copyright (C) 1997 Curtis L. Olson - http://www.flightgear.org/~curt
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
29 # error This library requires C++
35 `FGInterface::get_Longitude ()'
36 `FGInterface::get_Latitude ()'
37 `FGInterface::get_Altitude ()'
38 `FGInterface::get_Phi ()'
39 `FGInterface::get_Theta ()'
40 `FGInterface::get_Psi ()'
41 `FGInterface::get_V_equiv_kts ()'
43 `FGInterface::get_Mass ()'
44 `FGInterface::get_I_xx ()'
45 `FGInterface::get_I_yy ()'
46 `FGInterface::get_I_zz ()'
47 `FGInterface::get_I_xz ()'
49 `FGInterface::get_V_north ()'
50 `FGInterface::get_V_east ()'
51 `FGInterface::get_V_down ()'
53 `FGInterface::get_P_Body ()'
54 `FGInterface::get_Q_Body ()'
55 `FGInterface::get_R_Body ()'
57 `FGInterface::get_Gamma_vert_rad ()'
58 `FGInterface::get_Climb_Rate ()'
59 `FGInterface::get_Alpha ()'
60 `FGInterface::get_Beta ()'
62 `FGInterface::get_Runway_altitude ()'
64 `FGInterface::get_Lon_geocentric ()'
65 `FGInterface::get_Lat_geocentric ()'
66 `FGInterface::get_Sea_level_radius ()'
67 `FGInterface::get_Earth_position_angle ()'
69 `FGInterface::get_Latitude_dot()'
70 `FGInterface::get_Longitude_dot()'
71 `FGInterface::get_Radius_dot()'
73 `FGInterface::get_Dx_cg ()'
74 `FGInterface::get_Dy_cg ()'
75 `FGInterface::get_Dz_cg ()'
77 `FGInterface::get_Radius_to_vehicle ()'
88 #include <simgear/compiler.h>
89 #include <simgear/constants.h>
90 #include <simgear/structure/subsystem_mgr.hxx>
91 #include <FDM/groundcache.hxx>
97 // This is based heavily on LaRCsim/ls_generic.h
98 class FGInterface : public SGSubsystem {
102 // Has the init() method been called. This is used to delay
103 // initialization until scenery can be loaded and we know the true
107 // Have we bound to the property system
110 // periodic update management variable. This is a scheme to run
111 // the fdm with a fixed delta-t. We control how many iteration of
112 // the fdm to run with the fixed dt based on the elapsed time from
113 // the last update. This allows us to maintain sync with the real
114 // time clock, even though each frame could take a random amount
115 // of time. Since "dt" is unlikely to divide evenly into the
116 // elapse time, we keep track of the remainder and add it into the
117 // next elapsed time. This yields a small amount of temporal
118 // jitter ( < dt ) but in practice seems to work well.
120 double remainder; // remainder time from last run
122 // CG position w.r.t. ref. point
123 SGVec3d d_cg_rp_body_v;
126 SGVec3d v_dot_local_v;
127 SGVec3d v_dot_body_v;
129 SGVec3d a_pilot_body_v;
131 SGVec3d omega_dot_body_v;
135 SGVec3d v_local_rel_ground_v; // V rel w.r.t. earth surface
136 SGVec3d v_local_airmass_v; // velocity of airmass (steady winds)
137 SGVec3d v_wind_body_v; // Wind-relative velocities in body axis
139 SGVec3d omega_body_v; // Angular B rates
140 SGVec3d euler_rates_v;
141 SGVec3d geocentric_rates_v; // Geocentric linear velocities
144 SGGeod geodetic_position_v;
145 SGVec3d cartesian_position_v;
146 SGGeoc geocentric_position_v;
147 SGVec3d euler_angles_v;
150 double mass, i_xx, i_yy, i_zz, i_xz;
152 // Normal Load Factor
156 double v_rel_wind, v_true_kts;
157 double v_ground_speed, v_equiv_kts;
158 double v_calibrated_kts;
160 // Miscellaneious Quantities
161 double alpha, beta; // in radians
162 double gamma_vert_rad; // Flight path angles
163 double density, mach_number;
164 double static_pressure, total_pressure;
165 double dynamic_pressure;
166 double static_temperature, total_temperature;
167 double sea_level_radius, earth_position_angle;
168 double runway_altitude;
169 double climb_rate; // in feet per second
172 double daux[16]; // auxilliary doubles
173 float faux[16]; // auxilliary floats
174 int iaux[16]; // auxilliary ints
176 // the ground cache object itself.
177 FGGroundCache ground_cache;
181 int _calc_multiloop (double dt);
185 // deliberately not virtual so that
186 // FGInterface constructor will call
191 void _updatePositionM(const SGVec3d& cartPos);
192 void _updatePositionFt(const SGVec3d& cartPos) {
193 _updatePositionM(SG_FEET_TO_METER*cartPos);
195 void _updatePosition(const SGGeod& geod);
196 void _updatePosition(const SGGeoc& geoc);
198 void _updateGeodeticPosition( double lat, double lon, double alt );
199 void _updateGeocentricPosition( double lat_geoc, double lon, double alt );
200 void _update_ground_elev_at_pos( void );
202 inline void _set_Inertias( double m, double xx, double yy,
203 double zz, double xz)
211 inline void _set_CG_Position( double dx, double dy, double dz ) {
212 d_cg_rp_body_v[0] = dx;
213 d_cg_rp_body_v[1] = dy;
214 d_cg_rp_body_v[2] = dz;
216 inline void _set_Accels_Local( double north, double east, double down ) {
217 v_dot_local_v[0] = north;
218 v_dot_local_v[1] = east;
219 v_dot_local_v[2] = down;
221 inline void _set_Accels_Body( double u, double v, double w ) {
226 inline void _set_Accels_CG_Body( double x, double y, double z ) {
231 inline void _set_Accels_Pilot_Body( double x, double y, double z ) {
232 a_pilot_body_v[0] = x;
233 a_pilot_body_v[1] = y;
234 a_pilot_body_v[2] = z;
236 inline void _set_Accels_CG_Body_N( double x, double y, double z ) {
241 void _set_Nlf(double n) { nlf=n; }
242 inline void _set_Velocities_Local( double north, double east, double down ){
243 v_local_v[0] = north;
247 inline void _set_Velocities_Ground(double north, double east, double down) {
248 v_local_rel_ground_v[0] = north;
249 v_local_rel_ground_v[1] = east;
250 v_local_rel_ground_v[2] = down;
252 inline void _set_Velocities_Local_Airmass( double north, double east,
255 v_local_airmass_v[0] = north;
256 v_local_airmass_v[1] = east;
257 v_local_airmass_v[2] = down;
259 inline void _set_Velocities_Wind_Body( double u, double v, double w) {
260 v_wind_body_v[0] = u;
261 v_wind_body_v[1] = v;
262 v_wind_body_v[2] = w;
264 inline void _set_V_rel_wind(double vt) { v_rel_wind = vt; }
265 inline void _set_V_ground_speed( double v) { v_ground_speed = v; }
266 inline void _set_V_equiv_kts( double kts ) { v_equiv_kts = kts; }
267 inline void _set_V_calibrated_kts( double kts ) { v_calibrated_kts = kts; }
268 inline void _set_Omega_Body( double p, double q, double r ) {
273 inline void _set_Euler_Rates( double phi, double theta, double psi ) {
274 euler_rates_v[0] = phi;
275 euler_rates_v[1] = theta;
276 euler_rates_v[2] = psi;
278 inline void _set_Geocentric_Rates( double lat, double lon, double rad ) {
279 geocentric_rates_v[0] = lat;
280 geocentric_rates_v[1] = lon;
281 geocentric_rates_v[2] = rad;
283 inline void _set_Geocentric_Position( double lat, double lon, double rad ) {
284 geocentric_position_v.setLatitudeRad(lat);
285 geocentric_position_v.setLongitudeRad(lon);
286 geocentric_position_v.setRadiusFt(rad);
288 inline void _set_Latitude(double lat) {
289 geodetic_position_v.setLatitudeRad(lat);
291 inline void _set_Longitude(double lon) {
292 geodetic_position_v.setLongitudeRad(lon);
294 inline void _set_Altitude(double altitude) {
295 geodetic_position_v.setElevationFt(altitude);
297 inline void _set_Altitude_AGL(double agl) {
300 inline void _set_Geodetic_Position( double lat, double lon, double alt ) {
301 geodetic_position_v.setLatitudeRad(lat);
302 geodetic_position_v.setLongitudeRad(lon);
303 geodetic_position_v.setElevationFt(alt);
305 inline void _set_Euler_Angles( double phi, double theta, double psi ) {
306 euler_angles_v[0] = phi;
307 euler_angles_v[1] = theta;
308 euler_angles_v[2] = psi;
310 // FIXME, for compatibility with JSBSim
311 inline void _set_T_Local_to_Body( int i, int j, double value) { }
312 inline void _set_Alpha( double a ) { alpha = a; }
313 inline void _set_Beta( double b ) { beta = b; }
314 inline void _set_Gamma_vert_rad( double gv ) { gamma_vert_rad = gv; }
315 inline void _set_Density( double d ) { density = d; }
316 inline void _set_Mach_number( double m ) { mach_number = m; }
317 inline void _set_Static_pressure( double sp ) { static_pressure = sp; }
318 inline void _set_Static_temperature( double t ) { static_temperature = t; }
319 inline void _set_Total_temperature( double tat ) { total_temperature = tat; } //JW
320 inline void _set_Sea_level_radius( double r ) { sea_level_radius = r; }
321 inline void _set_Earth_position_angle(double a) { earth_position_angle = a; }
322 inline void _set_Runway_altitude( double alt ) { runway_altitude = alt; }
323 inline void _set_Climb_Rate(double rate) { climb_rate = rate; }
325 inline void _set_daux( int n, double value ) { daux[n] = value; }
326 inline void _set_faux( int n, float value ) { faux[n] = value; }
327 inline void _set_iaux( int n, int value ) { iaux[n] = value; }
332 FGInterface( double dt );
333 virtual ~FGInterface();
335 virtual void init ();
336 virtual void bind ();
337 virtual void unbind ();
338 virtual void update(double dt);
339 virtual bool ToggleDataLogging(bool state) { return false; }
340 virtual bool ToggleDataLogging(void) { return false; }
342 // Define the various supported flight models (many not yet implemented)
347 // The NASA LaRCsim (Navion) flight model
350 // Jon S. Berndt's new FDM written from the ground up in C++
353 // Christian's hot air balloon simulation
356 // Aeronautical DEvelopment AGEncy, Bangalore India
359 // The following aren't implemented but are here to spark
360 // thoughts and discussions, and maybe even action.
367 // Driven externally via a serial port, net, file, etc.
372 inline bool get_inited() const { return inited; }
373 inline void set_inited( bool value ) { inited = value; }
375 inline bool get_bound() const { return bound; }
377 //perform initializion that is common to all FDM's
381 virtual void set_Latitude(double lat); // geocentric
382 virtual void set_Longitude(double lon);
383 virtual void set_Altitude(double alt); // triggers re-calc of AGL altitude
384 virtual void set_AltitudeAGL(double altagl); // and vice-versa
385 virtual void set_Latitude_deg (double lat) {
386 set_Latitude(lat * SGD_DEGREES_TO_RADIANS);
388 virtual void set_Longitude_deg (double lon) {
389 set_Longitude(lon * SGD_DEGREES_TO_RADIANS);
392 // Speeds -- setting any of these will trigger a re-calc of the rest
393 virtual void set_V_calibrated_kts(double vc);
394 virtual void set_Mach_number(double mach);
395 virtual void set_Velocities_Local( double north, double east, double down );
396 inline void set_V_north (double north) {
397 set_Velocities_Local(north, v_local_v[1], v_local_v[2]);
399 inline void set_V_east (double east) {
400 set_Velocities_Local(v_local_v[0], east, v_local_v[2]);
402 inline void set_V_down (double down) {
403 set_Velocities_Local(v_local_v[0], v_local_v[1], down);
405 virtual void set_Velocities_Wind_Body( double u, double v, double w);
406 virtual void set_uBody (double uBody) {
407 set_Velocities_Wind_Body(uBody, v_wind_body_v[1], v_wind_body_v[2]);
409 virtual void set_vBody (double vBody) {
410 set_Velocities_Wind_Body(v_wind_body_v[0], vBody, v_wind_body_v[2]);
412 virtual void set_wBody (double wBody) {
413 set_Velocities_Wind_Body(v_wind_body_v[0], v_wind_body_v[1], wBody);
417 virtual void set_Euler_Angles( double phi, double theta, double psi );
418 virtual void set_Phi (double phi) {
419 set_Euler_Angles(phi, get_Theta(), get_Psi());
421 virtual void set_Theta (double theta) {
422 set_Euler_Angles(get_Phi(), theta, get_Psi());
424 virtual void set_Psi (double psi) {
425 set_Euler_Angles(get_Phi(), get_Theta(), psi);
427 virtual void set_Phi_deg (double phi) {
428 set_Phi(phi * SGD_DEGREES_TO_RADIANS);
430 virtual void set_Theta_deg (double theta) {
431 set_Theta(theta * SGD_DEGREES_TO_RADIANS);
433 virtual void set_Psi_deg (double psi) {
434 set_Psi(psi * SGD_DEGREES_TO_RADIANS);
438 virtual void set_Climb_Rate( double roc);
439 virtual void set_Gamma_vert_rad( double gamma);
443 virtual void set_Static_pressure(double p);
444 virtual void set_Static_temperature(double T);
445 virtual void set_Density(double rho);
447 virtual void set_Velocities_Local_Airmass (double wnorth,
451 // ========== Mass properties and geometry values ==========
454 inline double get_Mass() const { return mass; }
455 inline double get_I_xx() const { return i_xx; }
456 inline double get_I_yy() const { return i_yy; }
457 inline double get_I_zz() const { return i_zz; }
458 inline double get_I_xz() const { return i_xz; }
460 // CG position w.r.t. ref. point
461 inline double get_Dx_cg() const { return d_cg_rp_body_v[0]; }
462 inline double get_Dy_cg() const { return d_cg_rp_body_v[1]; }
463 inline double get_Dz_cg() const { return d_cg_rp_body_v[2]; }
465 // ========== Accelerations ==========
467 inline double get_V_dot_north() const { return v_dot_local_v[0]; }
468 inline double get_V_dot_east() const { return v_dot_local_v[1]; }
469 inline double get_V_dot_down() const { return v_dot_local_v[2]; }
471 inline double get_U_dot_body() const { return v_dot_body_v[0]; }
472 inline double get_V_dot_body() const { return v_dot_body_v[1]; }
473 inline double get_W_dot_body() const { return v_dot_body_v[2]; }
475 inline double get_A_X_cg() const { return a_cg_body_v[0]; }
476 inline double get_A_Y_cg() const { return a_cg_body_v[1]; }
477 inline double get_A_Z_cg() const { return a_cg_body_v[2]; }
479 inline double get_A_X_pilot() const { return a_pilot_body_v[0]; }
480 inline double get_A_Y_pilot() const { return a_pilot_body_v[1]; }
481 inline double get_A_Z_pilot() const { return a_pilot_body_v[2]; }
483 inline double get_N_X_cg() const { return n_cg_body_v[0]; }
484 inline double get_N_Y_cg() const { return n_cg_body_v[1]; }
485 inline double get_N_Z_cg() const { return n_cg_body_v[2]; }
487 inline double get_Nlf(void) const { return nlf; }
489 // ========== Velocities ==========
491 inline double get_V_north() const { return v_local_v[0]; }
492 inline double get_V_east() const { return v_local_v[1]; }
493 inline double get_V_down() const { return v_local_v[2]; }
494 inline double get_uBody () const { return v_wind_body_v[0]; }
495 inline double get_vBody () const { return v_wind_body_v[1]; }
496 inline double get_wBody () const { return v_wind_body_v[2]; }
498 // Please dont comment these out. fdm=ada uses these (see
500 inline double get_V_north_rel_ground() const {
501 return v_local_rel_ground_v[0];
503 inline double get_V_east_rel_ground() const {
504 return v_local_rel_ground_v[1];
506 inline double get_V_down_rel_ground() const {
507 return v_local_rel_ground_v[2];
509 // <--- fdm=ada uses these (see cockpit.cxx)
511 inline double get_V_north_airmass() const { return v_local_airmass_v[0]; }
512 inline double get_V_east_airmass() const { return v_local_airmass_v[1]; }
513 inline double get_V_down_airmass() const { return v_local_airmass_v[2]; }
515 inline double get_U_body() const { return v_wind_body_v[0]; }
516 inline double get_V_body() const { return v_wind_body_v[1]; }
517 inline double get_W_body() const { return v_wind_body_v[2]; }
519 inline double get_V_rel_wind() const { return v_rel_wind; }
521 inline double get_V_true_kts() const { return v_true_kts; }
523 inline double get_V_ground_speed() const { return v_ground_speed; }
524 inline double get_V_ground_speed_kt() const { return v_ground_speed * SG_FEET_TO_METER * 3600 * SG_METER_TO_NM; }
526 inline double get_V_equiv_kts() const { return v_equiv_kts; }
528 inline double get_V_calibrated_kts() const { return v_calibrated_kts; }
530 inline double get_P_body() const { return omega_body_v[0]; }
531 inline double get_Q_body() const { return omega_body_v[1]; }
532 inline double get_R_body() const { return omega_body_v[2]; }
534 inline double get_Phi_dot() const { return euler_rates_v[0]; }
535 inline double get_Theta_dot() const { return euler_rates_v[1]; }
536 inline double get_Psi_dot() const { return euler_rates_v[2]; }
537 inline double get_Phi_dot_degps() const { return euler_rates_v[0] * SGD_RADIANS_TO_DEGREES; }
538 inline double get_Theta_dot_degps() const { return euler_rates_v[1] * SGD_RADIANS_TO_DEGREES; }
539 inline double get_Psi_dot_degps() const { return euler_rates_v[2] * SGD_RADIANS_TO_DEGREES; }
541 inline double get_Latitude_dot() const { return geocentric_rates_v[0]; }
542 inline double get_Longitude_dot() const { return geocentric_rates_v[1]; }
543 inline double get_Radius_dot() const { return geocentric_rates_v[2]; }
545 // ========== Positions ==========
547 inline double get_Lat_geocentric() const {
548 return geocentric_position_v.getLatitudeRad();
550 inline double get_Lon_geocentric() const {
551 return geocentric_position_v.getLongitudeRad();
553 inline double get_Radius_to_vehicle() const {
554 return geocentric_position_v.getRadiusFt();
557 const SGGeod& getPosition() const { return geodetic_position_v; }
558 const SGGeoc& getGeocPosition() const { return geocentric_position_v; }
559 const SGVec3d& getCartPosition() const { return cartesian_position_v; }
561 inline double get_Latitude() const {
562 return geodetic_position_v.getLatitudeRad();
564 inline double get_Longitude() const {
565 return geodetic_position_v.getLongitudeRad();
567 inline double get_Altitude() const {
568 return geodetic_position_v.getElevationFt();
570 inline double get_Altitude_AGL(void) const { return altitude_agl; }
572 inline double get_Latitude_deg () const {
573 return geodetic_position_v.getLatitudeDeg();
575 inline double get_Longitude_deg () const {
576 return geodetic_position_v.getLongitudeDeg();
579 inline double get_Phi() const { return euler_angles_v[0]; }
580 inline double get_Theta() const { return euler_angles_v[1]; }
581 inline double get_Psi() const { return euler_angles_v[2]; }
582 inline double get_Phi_deg () const { return get_Phi() * SGD_RADIANS_TO_DEGREES; }
583 inline double get_Theta_deg () const { return get_Theta() * SGD_RADIANS_TO_DEGREES; }
584 inline double get_Psi_deg () const { return get_Psi() * SGD_RADIANS_TO_DEGREES; }
587 // ========== Miscellaneous quantities ==========
589 inline double get_Alpha() const { return alpha; }
590 inline double get_Alpha_deg() const { return alpha * SGD_RADIANS_TO_DEGREES; }
591 inline double get_Beta() const { return beta; }
592 inline double get_Beta_deg() const { return beta * SGD_RADIANS_TO_DEGREES; }
593 inline double get_Gamma_vert_rad() const { return gamma_vert_rad; }
595 inline double get_Density() const { return density; }
596 inline double get_Mach_number() const { return mach_number; }
598 inline double get_Static_pressure() const { return static_pressure; }
599 inline double get_Total_pressure() const { return total_pressure; }
600 inline double get_Dynamic_pressure() const { return dynamic_pressure; }
602 inline double get_Static_temperature() const { return static_temperature; }
603 inline double get_Total_temperature() const { return total_temperature; }
605 inline double get_Sea_level_radius() const { return sea_level_radius; }
606 inline double get_Earth_position_angle() const {
607 return earth_position_angle;
610 inline double get_Runway_altitude() const { return runway_altitude; }
611 inline double get_Runway_altitude_m() const { return SG_FEET_TO_METER * runway_altitude; }
613 inline double get_Climb_Rate() const { return climb_rate; }
615 // Auxilliary variables
616 inline double get_daux( int n ) const { return daux[n]; }
617 inline float get_faux( int n ) const { return faux[n]; }
618 inline int get_iaux( int n ) const { return iaux[n]; }
620 // Note that currently this is the "same" value runway altitude...
621 inline double get_ground_elev_ft() const { return runway_altitude; }
624 //////////////////////////////////////////////////////////////////////////
625 // Ground handling routines
626 //////////////////////////////////////////////////////////////////////////
630 Solid, // Whatever we will roll on with infinite load factor.
631 Water, // For the beaver ...
632 Catapult, // Carrier cats.
633 Wire // Carrier wires.
636 // Prepare the ground cache for the wgs84 position pt_*.
637 // That is take all vertices in the ball with radius rad around the
638 // position given by the pt_* and store them in a local scene graph.
639 bool prepare_ground_cache_m(double ref_time, const double pt[3],
641 bool prepare_ground_cache_ft(double ref_time, const double pt[3],
645 // Returns true if the cache is valid.
646 // Also the reference time, point and radius values where the cache
647 // is valid for are returned.
648 bool is_valid_m(double *ref_time, double pt[3], double *rad);
649 bool is_valid_ft(double *ref_time, double pt[3], double *rad);
651 // Return the nearest catapult to the given point
652 // pt in wgs84 coordinates.
653 double get_cat_m(double t, const double pt[3],
654 double end[2][3], double vel[2][3]);
655 double get_cat_ft(double t, const double pt[3],
656 double end[2][3], double vel[2][3]);
659 // Return the altitude above ground below the wgs84 point pt
660 // Search for the nearest triangle to pt.
661 // Return ground properties like the ground type, the maximum load
662 // this kind kind of ground can carry, the friction factor between
663 // 0 and 1 which can be used to model lower friction with wet runways
664 // and finally the altitude above ground.
665 bool get_agl_m(double t, const double pt[3],
666 double contact[3], double normal[3], double vel[3],
667 int *type, double *loadCapacity,
668 double *frictionFactor, double *agl);
669 bool get_agl_m(double t, const double pt[3],
670 double contact[3], double normal[3], double vel[3],
671 int *type, const SGMaterial **material,double *agl);
672 bool get_agl_ft(double t, const double pt[3],
673 double contact[3], double normal[3], double vel[3],
674 int *type, double *loadCapacity,
675 double *frictionFactor, double *agl);
677 // Return the altitude above ground below the wgs84 point pt
678 // Search for the nearest triangle to pt.
679 // Return ground properties like the ground type, a pointer to the
680 // material and finally the altitude above ground.
681 bool get_agl_m(double t, const double pt[3], double max_altoff,
682 double contact[3], double normal[3], double vel[3],
683 int *type, const SGMaterial** material, double *agl);
684 bool get_agl_ft(double t, const double pt[3], double max_altoff,
685 double contact[3], double normal[3], double vel[3],
686 int *type, const SGMaterial** material, double *agl);
687 double get_groundlevel_m(double lat, double lon, double alt);
688 double get_groundlevel_m(const SGGeod& geod);
691 // Return 1 if the hook intersects with a wire.
692 // That test is done by checking if the quad spanned by the points pt*
693 // intersects with the line representing the wire.
694 // If the wire is caught, the cache will trace this wires endpoints until
695 // the FDM calls release_wire().
696 bool caught_wire_m(double t, const double pt[4][3]);
697 bool caught_wire_ft(double t, const double pt[4][3]);
699 // Return the location and speed of the wire endpoints.
700 bool get_wire_ends_m(double t, double end[2][3], double vel[2][3]);
701 bool get_wire_ends_ft(double t, double end[2][3], double vel[2][3]);
703 // Tell the cache code that it does no longer need to care for
704 // the wire end position.
705 void release_wire(void);
708 extern FGInterface * cur_fdm_state;
710 // Toggle data logging on/off
711 void fgToggleFDMdataLogging(void);
714 #endif // _FLIGHT_HXX