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flightgear/src/FDM/ExternalPipe/ExternalPipe.cxx

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// ExternalPipe.cxx -- a "pipe" interface to an external flight dynamics model
//
// Written by Curtis Olson, started March 2003.
//
// Copyright (C) 2003 Curtis L. Olson - curt@flightgear.org
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
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#ifdef HAVE_MKFIFO
# include <sys/types.h> // mkfifo() open() umask()
# include <sys/stat.h> // mkfifo() open() umask()
# include <errno.h> // perror()
# include <fcntl.h> // open()
# include <unistd.h> // unlink()
#endif
#include <simgear/debug/logstream.hxx>
#include <simgear/io/lowlevel.hxx> // endian tests
#include <Main/fg_props.hxx>
#include <Network/native_ctrls.hxx>
#include <Network/native_fdm.hxx>
#include "ExternalPipe.hxx"
static const int MAX_BUF = 32768;
FGExternalPipe::FGExternalPipe( double dt, string name ) {
valid = true;
last_weight = 0.0;
last_cg_offset = -9999.9;
buf = new char[MAX_BUF];
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#ifdef HAVE_MKFIFO
fifo_name_1 = name + "1";
fifo_name_2 = name + "2";
SG_LOG( SG_IO, SG_ALERT, "ExternalPipe Inited with " << name );
// Make the named pipe
umask(0);
int result;
result = mkfifo( fifo_name_1.c_str(), 0644 );
if ( result == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to create named pipe: "
<< fifo_name_1 );
perror( "ExternalPipe()" );
}
result = mkfifo( fifo_name_2.c_str(), 0644 );
if ( result == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to create named pipe: "
<< fifo_name_2 );
perror( "ExternalPipe()" );
}
pd1 = open( fifo_name_1.c_str(), O_RDWR );
if ( pd1 == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to open named pipe: " << fifo_name_1 );
valid = false;
}
pd2 = open( fifo_name_2.c_str(), O_RDWR );
if ( pd2 == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to open named pipe: " << fifo_name_2 );
valid = false;
}
#endif
}
FGExternalPipe::~FGExternalPipe() {
delete [] buf;
SG_LOG( SG_IO, SG_INFO, "Closing up the ExternalPipe." );
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#ifdef HAVE_MKFIFO
// close
int result;
result = close( pd1 );
if ( result == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to close named pipe: "
<< fifo_name_1 );
perror( "~FGExternalPipe()" );
}
result = close( pd2 );
if ( result == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Unable to close named pipe: "
<< fifo_name_2 );
perror( "~FGExternalPipe()" );
}
#endif
}
static int write_fifo( char cmd_type, int pd, char *cmd, int len ) {
#ifdef HAVE_MKFIFO
char *buf = new char[len + 3];
// write 2 byte command length + command type + command
char hi = (len + 1) / 256;
char lo = (len + 1) - (hi * 256);
buf[0] = hi;
buf[1] = lo;
buf[2] = cmd_type;
// strncpy( buf + 3, cmd, len );
memcpy( buf + 3, cmd, len );
if ( cmd_type == '1' ) {
// cout << "writing '" << cmd << "'" << endl;
} else if ( cmd_type == '2' ) {
// cout << "writing controls packet" << endl;
} else {
// cout << "writing unknown command?" << endl;
}
// for ( int i = 0; i < len + 3; ++i ) {
// cout << " " << (int)buf[i];
// }
// cout << endl;
int result = ::write( pd, buf, len + 3 );
if ( result == -1 ) {
perror( "write_fifo()" );
SG_LOG( SG_IO, SG_ALERT, "Write error to named pipe: " << pd );
}
// cout << "wrote " << len + 3 << " bytes." << endl;
delete [] buf;
return result;
#else
return 0;
#endif
}
// Initialize the ExternalPipe flight model, dt is the time increment
// for each subsequent iteration through the EOM
void FGExternalPipe::init() {
// Explicitly call the superclass's
// init method first.
common_init();
double lon = fgGetDouble( "/sim/presets/longitude-deg" );
double lat = fgGetDouble( "/sim/presets/latitude-deg" );
double alt = fgGetDouble( "/sim/presets/altitude-ft" );
double ground = fgGetDouble( "/environment/ground-elevation-m" );
double heading = fgGetDouble("/sim/presets/heading-deg");
double speed = fgGetDouble( "/sim/presets/airspeed-kt" );
double weight = fgGetDouble( "/sim/aircraft-weight-lbs" );
double cg_offset = fgGetDouble( "/sim/aircraft-cg-offset-inches" );
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#ifdef HAVE_MKFIFO
char cmd[256];
int result;
sprintf( cmd, "longitude-deg=%.8f", lon );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
sprintf( cmd, "latitude-deg=%.8f", lat );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
sprintf( cmd, "altitude-ft=%.8f", alt );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
sprintf( cmd, "ground-m=%.8f", ground );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
sprintf( cmd, "speed-kts=%.8f", speed );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
sprintf( cmd, "heading-deg=%.8f", heading );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
if ( weight > 1000.0 ) {
sprintf( cmd, "aircraft-weight-lbs=%.2f", weight );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
}
last_weight = weight;
if ( cg_offset > -5.0 || cg_offset < 5.0 ) {
sprintf( cmd, "aircraft-cg-offset-inches=%.2f", cg_offset );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
}
last_cg_offset = cg_offset;
SG_LOG( SG_IO, SG_INFO, "before sending reset command." );
if( fgGetBool("/sim/presets/onground") ) {
sprintf( cmd, "reset=ground" );
} else {
sprintf( cmd, "reset=air" );
}
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
SG_LOG( SG_IO, SG_INFO, "Remote FDM init() finished." );
#endif
}
// Run an iteration of the EOM.
void FGExternalPipe::update( double dt ) {
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#ifdef HAVE_MKFIFO
// SG_LOG( SG_IO, SG_INFO, "Start FGExternalPipe::udpate()" );
int length;
int result;
if ( is_suspended() ) {
return;
}
int iterations = _calc_multiloop(dt);
double weight = fgGetDouble( "/sim/aircraft-weight-lbs" );
static double last_weight = 0.0;
if ( fabs( weight - last_weight ) > 0.01 ) {
char cmd[256];
sprintf( cmd, "aircraft-weight-lbs=%.2f", weight );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
}
last_weight = weight;
double cg_offset = fgGetDouble( "/sim/aircraft-cg-offset-inches" );
if ( fabs( cg_offset - last_cg_offset ) > 0.01 ) {
char cmd[256];
sprintf( cmd, "aircraft-cg-offset-inches=%.2f", cg_offset );
result = write_fifo( '1', pd1, cmd, strlen(cmd) );
}
last_cg_offset = cg_offset;
// Send control positions to remote fdm
length = sizeof(ctrls);
FGProps2NetCtrls( &ctrls, true, false );
char *ptr = buf;
*((int *)ptr) = iterations;
// cout << "iterations = " << iterations << endl;
ptr += sizeof(int);
memcpy( ptr, (char *)(&ctrls), length );
// cout << "writing control structure, size = "
// << length + sizeof(int) << endl;
result = write_fifo( '2', pd1, buf, length + sizeof(int) );
// Read fdm values
length = sizeof(fdm);
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// cout << "about to read fdm data from remote fdm." << endl;
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result = read( pd2, (char *)(& fdm), length );
if ( result == -1 ) {
SG_LOG( SG_IO, SG_ALERT, "Read error from named pipe: "
<< fifo_name_2 );
} else {
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// cout << " read successful." << endl;
}
FGNetFDM2Props( &fdm, false );
#endif
}