From: curt Date: Fri, 8 Jan 1999 03:23:51 +0000 (+0000) Subject: Beginning work on compensating for sim time vs. real world time "jitter". X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=529e57a87c36af5bc86617a650f966a0f9652d7e;p=flightgear.git Beginning work on compensating for sim time vs. real world time "jitter". --- diff --git a/FDM/flight.cxx b/FDM/flight.cxx index cadf164c7..3225b3227 100644 --- a/FDM/flight.cxx +++ b/FDM/flight.cxx @@ -34,60 +34,77 @@ #include +// base_fdm_state is the internal state that is updated in integer +// multiples of "dt". This leads to "jitter" with respect to the real +// world time, so we introduce cur_fdm_state which is extrapolated by +// the difference between sim time and real world time + FGState cur_fdm_state; +FGState base_fdm_state; // Initialize the flight model parameters int fgFlightModelInit(int model, FGState& f, double dt) { double save_alt = 0.0; - int result; FG_LOG( FG_FLIGHT ,FG_INFO, "Initializing flight model" ); + base_fdm_state = f; + if ( model == FGState::FG_SLEW ) { // fgSlewInit(dt); } else if ( model == FGState::FG_LARCSIM ) { + // lets try to avoid really screwing up the LaRCsim model - if ( f.get_Altitude() < -9000.0 ) { - save_alt = f.get_Altitude(); - f.set_Altitude( 0.0 ); + if ( base_fdm_state.get_Altitude() < -9000.0 ) { + save_alt = base_fdm_state.get_Altitude(); + base_fdm_state.set_Altitude( 0.0 ); } - FGState_2_LaRCsim(f); // translate FG to LaRCsim structure + // translate FG to LaRCsim structure + FGState_2_LaRCsim(base_fdm_state); + + // initialize LaRCsim fgLaRCsimInit(dt); - FG_LOG( FG_FLIGHT, FG_INFO, "FG pos = " << f.get_Latitude() ); - fgLaRCsim_2_FGState(f); // translate LaRCsim back to FG structure + + FG_LOG( FG_FLIGHT, FG_INFO, "FG pos = " << + base_fdm_state.get_Latitude() ); + + // translate LaRCsim back to FG structure + fgLaRCsim_2_FGState(base_fdm_state); // but lets restore our original bogus altitude when we are done if ( save_alt < -9000.0 ) { - f.set_Altitude( save_alt ); + base_fdm_state.set_Altitude( save_alt ); } } else if ( model == FGState::FG_EXTERNAL ) { - fgExternalInit(f, dt); + fgExternalInit(base_fdm_state, dt); } else { FG_LOG( FG_FLIGHT, FG_WARN, "Unimplemented flight model == " << model ); } - result = 1; + f = base_fdm_state; - return(result); + return 1; } // Run multiloop iterations of the flight model -int fgFlightModelUpdate(int model, FGState& f, int multiloop) { +int fgFlightModelUpdate(int model, FGState& f, int multiloop, int jitter) { double time_step, start_elev, end_elev; - int result; + // printf("Altitude = %.2f\n", FG_Altitude * 0.3048); + // base_fdm_state = f; + time_step = (1.0 / DEFAULT_MODEL_HZ) * multiloop; - start_elev = f.get_Altitude(); + start_elev = base_fdm_state.get_Altitude(); if ( model == FGState::FG_SLEW ) { // fgSlewUpdate(f, multiloop); } else if ( model == FGState::FG_LARCSIM ) { - fgLaRCsimUpdate(f, multiloop); + fgLaRCsimUpdate(base_fdm_state, multiloop); } else if ( model == FGState::FG_EXTERNAL ) { // fgExternalUpdate(f, multiloop); } else { @@ -95,40 +112,44 @@ int fgFlightModelUpdate(int model, FGState& f, int multiloop) { "Unimplemented flight model == " << model ); } - end_elev = f.get_Altitude(); + end_elev = base_fdm_state.get_Altitude(); if ( time_step > 0.0 ) { // feet per second - f.set_Climb_Rate( (end_elev - start_elev) / time_step ); + base_fdm_state.set_Climb_Rate( (end_elev - start_elev) / time_step ); } - result = 1; + f = base_fdm_state; - return(result); + return 1; } // Set the altitude (force) -void fgFlightModelSetAltitude(int model, FGState& f, double alt_meters) { +void fgFlightModelSetAltitude(int model, double alt_meters) { double sea_level_radius_meters; double lat_geoc; + // Set the FG variables first - fgGeodToGeoc( f.get_Latitude(), alt_meters, + fgGeodToGeoc( base_fdm_state.get_Latitude(), alt_meters, &sea_level_radius_meters, &lat_geoc); - f.set_Altitude( alt_meters * METER_TO_FEET ); - f.set_Radius_to_vehicle( f.get_Altitude() + - (sea_level_radius_meters * METER_TO_FEET) ); + base_fdm_state.set_Altitude( alt_meters * METER_TO_FEET ); + base_fdm_state.set_Radius_to_vehicle( base_fdm_state.get_Altitude() + + (sea_level_radius_meters * + METER_TO_FEET) ); // additional work needed for some flight models if ( model == FGState::FG_LARCSIM ) { - ls_ForceAltitude( f.get_Altitude() ); + ls_ForceAltitude( base_fdm_state.get_Altitude() ); } - } // $Log$ +// Revision 1.8 1999/01/08 03:23:51 curt +// Beginning work on compensating for sim time vs. real world time "jitter". +// // Revision 1.7 1998/12/18 23:37:07 curt // Collapsed out the FGState variables not currently needed. They are just // commented out and can be readded easily at any time. The point of this diff --git a/FDM/flight.hxx b/FDM/flight.hxx index fdd514bd1..17d3c4733 100644 --- a/FDM/flight.hxx +++ b/FDM/flight.hxx @@ -781,16 +781,19 @@ extern FGState cur_fdm_state; int fgFlightModelInit(int model, FGState& f, double dt); // Run multiloop iterations of the flight model -int fgFlightModelUpdate(int model, FGState& f, int multiloop); +int fgFlightModelUpdate(int model, FGState& f, int multiloop, int jitter); // Set the altitude (force) -void fgFlightModelSetAltitude(int model, FGState& f, double alt_meters); +void fgFlightModelSetAltitude(int model, double alt_meters); #endif // _FLIGHT_HXX // $Log$ +// Revision 1.8 1999/01/08 03:23:52 curt +// Beginning work on compensating for sim time vs. real world time "jitter". +// // Revision 1.7 1998/12/18 23:37:09 curt // Collapsed out the FGState variables not currently needed. They are just // commented out and can be readded easily at any time. The point of this diff --git a/Main/GLUTmain.cxx b/Main/GLUTmain.cxx index 261df03cb..1b25327f8 100644 --- a/Main/GLUTmain.cxx +++ b/Main/GLUTmain.cxx @@ -367,7 +367,7 @@ static void fgRenderFrame( void ) { // Update internal time dependent calculations (i.e. flight model) -void fgUpdateTimeDepCalcs(int multi_loop) { +void fgUpdateTimeDepCalcs(int multi_loop, int remainder) { FGState *f = current_aircraft.fdm_state; fgLIGHT *l = &cur_light_params; fgTIME *t = &cur_time_params; @@ -385,10 +385,10 @@ void fgUpdateTimeDepCalcs(int multi_loop) { // printf("updating flight model x %d\n", multi_loop); fgFlightModelUpdate( current_options.get_flight_model(), - cur_fdm_state, multi_loop ); + cur_fdm_state, multi_loop, remainder ); } else { fgFlightModelUpdate( current_options.get_flight_model(), - cur_fdm_state, 0 ); + cur_fdm_state, 0, remainder ); } // update the view angle @@ -437,10 +437,9 @@ void fgUpdateTimeDepCalcs(int multi_loop) { void fgInitTimeDepCalcs( void ) { // initialize timer -#ifdef HAVE_SETITIMER - fgTimerInit( 1.0 / DEFAULT_TIMER_HZ, fgUpdateTimeDepCalcs ); -#endif HAVE_SETITIMER - + // #ifdef HAVE_SETITIMER + // fgTimerInit( 1.0 / DEFAULT_TIMER_HZ, fgUpdateTimeDepCalcs ); + // #endif HAVE_SETITIMER } static const double alt_adjust_ft = 3.758099; @@ -492,7 +491,6 @@ static void fgMainLoop( void ) { scenery.cur_elev + alt_adjust_m - 3.0, scenery.cur_elev + alt_adjust_m ); fgFlightModelSetAltitude( current_options.get_flight_model(), - cur_fdm_state, scenery.cur_elev + alt_adjust_m ); FG_LOG( FG_ALL, FG_DEBUG, @@ -555,7 +553,7 @@ static void fgMainLoop( void ) { // flight model if ( multi_loop > 0 ) { - fgUpdateTimeDepCalcs(multi_loop); + fgUpdateTimeDepCalcs(multi_loop, remainder); } else { FG_LOG( FG_ALL, FG_INFO, "Elapsed time is zero ... we're zinging" ); } @@ -1002,6 +1000,9 @@ int main( int argc, char **argv ) { // $Log$ +// Revision 1.79 1999/01/08 03:23:56 curt +// Beginning work on compensating for sim time vs. real world time "jitter". +// // Revision 1.78 1999/01/07 20:25:08 curt // Updated struct fgGENERAL to class FGGeneral. // diff --git a/Main/fg_init.cxx b/Main/fg_init.cxx index d6cf46f13..58ebc1a57 100644 --- a/Main/fg_init.cxx +++ b/Main/fg_init.cxx @@ -122,7 +122,7 @@ int fgInitPosition( void ) { // General house keeping initializations int fgInitGeneral( void ) { string root; - int i; + // int i; FG_LOG( FG_GENERAL, FG_INFO, "General Initialization" ); FG_LOG( FG_GENERAL, FG_INFO, "======= ==============" ); @@ -379,6 +379,9 @@ int fgInitSubsystems( void ) // $Log$ +// Revision 1.61 1999/01/08 03:23:57 curt +// Beginning work on compensating for sim time vs. real world time "jitter". +// // Revision 1.60 1999/01/07 20:25:09 curt // Updated struct fgGENERAL to class FGGeneral. //