Added support for analysing raw speed values when replaying.

Setting sim/replay/log-raw-speed logs raw speed to
/sim/replay/log-raw-speed-values/value[].

'scripts/python/recordreplay.py --test-motion' uses this to test for a bug
where the user aircraft simtime and signals information don't quite match in
continuous recordings.

scripts/python/recordreplay.py

@@ -26,6 +26,11 @@ Args:
         A second fgfs executable. If specified we run all tests twice, first
         using <fgfs-old> to create the recording and <fgfs> to replay it,
         second the other way round.
+    --test-motion
+        Checks that speed of aircraft on replay is not affected by frame rate.
+
+        We deliberately change frame rate while recording UFO moving at
+        constant speed.
     
     BOOLS is comma-sparated list of 0 or 1, with 1 activating the particular
     feature. So for example '--continuous 0' tests normal recording/replay',
@@ -77,20 +82,23 @@ class Fg:
         args += f' --telnet={port}'
         args2 = args.split()
         
+        environ = os.environ.copy()
         if isinstance(env, str):
-            env2 = dict()
             for nv in env.split():
                 n, v = nv.split('=', 1)
-                env2[n] = v
+                environ[n] = v
-            env = env2
-        environ = os.environ.copy()
-        if env:
-            environ.update(env)
         if 'DISPLAY' not in environ:
             environ['DISPLAY'] = ':0'
             
         # Run flightgear in new process, telling it to open telnet server.
-        self.child = subprocess.Popen(args2)
+        #
+        # We run not in a shell, otherwise self.child.terminate() doesn't
+        # work - it would kill the shell but leave fgfs running (there are
+        # workarounds for this, such as prefixing the command with 'exec').
+        #
+        log(f'Command is: {args}')
+        log(f'Running: {args2}')
+        self.child = subprocess.Popen(args2, env=environ)
         
         # Connect to flightgear's telnet server.
         timeout = 15
@@ -278,11 +286,80 @@ def test_record_replay(
     log('Test passed')
 
 
+def test_motion(fgfs):
+
+    aircraft = 'ufo'    
+    fg = Fg( aircraft, f'{fgfs} --aircraft={aircraft}')
+    path = f'{fg.aircraft}-continuous.fgtape'
+    
+    if 0:
+        items = fg.fg.ls( '/sim')
+        log( '/sim is:')
+        for item in items:
+            log( f'    {item}')
+        fg.close()
+        return
+    
+    fg.waitfor('/sim/fdm-initialized', 1, timeout=45)
+    
+    # Run UFO with constant speed, varying the framerate so we check whether
+    # recorded speeds are affected.
+    #
+    fg.fg['/controls/engines/engine[0]/throttle'] = 0.1
+    fg.fg['/sim/frame-rate-throttle-hz'] = 5
+    
+    # Delay to let frame rate settle.
+    time.sleep(10)
+    
+    # Start recording.
+    fg.fg['/sim/replay/record-continuous'] = 1
+    time.sleep(5)
+    
+    # Change frame rate.
+    fg.fg['/sim/frame-rate-throttle-hz'] = 2
+    time.sleep(5)
+    
+    # Restore original frame rate.
+    fg.fg['/sim/frame-rate-throttle-hz'] = 5
+    time.sleep(5)
+    
+    # Stop recording.
+    fg.fg['/sim/replay/record-continuous'] = 0
+    
+    fg.close()
+    
+    path2 = os.readlink( path)
+    g_cleanup.append(lambda: os.remove(path2))
+    
+    fg = Fg( aircraft, f'{fgfs} --load-tape={path} --prop:/sim/replay/log-raw-speed=true')
+    fg.waitfor('/sim/fdm-initialized', 1, timeout=45)
+    fg.fg['/sim/frame-rate-throttle-hz'] = 10
+    fg.waitfor('/sim/replay/replay-state', 1)
+    fg.waitfor('/sim/replay/replay-state-eof', 1)
+    
+    items0 = fg.fg.ls( '/sim/replay/log-raw-speed-values')
+    items = []
+    for item in items0:
+        if item.name == 'value':
+            items.append(item)
+    num_errors = 0
+    for item in items[:-1]: # Ignore last  item because replay at end interpolates.
+        speed = float(item.value)
+        prefix = ' '
+        if abs(speed - 200) > 0.5:
+            num_errors += 1
+            prefix = '*'
+        log( f'    {prefix} speed={speed} details: {item}')
+    fg.close()
+    assert num_errors == 0, 'Replay showed uneven speed.'
+
+
 if __name__ == '__main__':
 
     fgfs = f'./build-walk/fgfs.exe-run.sh'
     fgfs_old = None
     
+    do_test = 'all'
     continuous_s = [0, 1]
     extra_properties_s = [0, 1]
     main_view_s = [0, 1]
@@ -319,9 +396,14 @@ if __name__ == '__main__':
         elif arg == '--f-old':
             fgfs_old = next(args)
             fgfs_reverse = [0, 1]
+        elif arg == '--test-motion':
+            do_test = 'motion'
         else:
             raise Exception(f'Unrecognised arg: {arg!r}')
     
+    if do_test == 'motion':
+        test_motion( fgfs)
+    elif do_test == 'all':
         try:
             if fgfs_old:
                 for fgfs1, fgfs2 in [(fgfs, fgfs_old), (fgfs_old, fgfs)]:
@@ -373,6 +455,8 @@ if __name__ == '__main__':
                                     it += 1
         finally:
             pass
+    else:
+        assert 0, f'do_test={do_test}'
     
     # If everything passed, cleanup. Otherwise leave recordings in place, as
     # they can be useful for debugging.

src/Aircraft/flightrecorder.cxx

@@ -230,6 +230,7 @@ FGFlightRecorder::FGFlightRecorder(const char* pConfigName) :
     m_ReplayMainWindowSize      (fgGetNode("/sim/replay/replay-main-window-size", true)),
     m_RecordContinuous          (fgGetNode("/sim/replay/record-continuous", true)),
     m_RecordExtraProperties     (fgGetNode("/sim/replay/record-extra-properties", true)),
+    m_LogRawSpeed               (fgGetNode("/sim/replay/log-raw-speed", true)),
     m_TotalRecordSize(0),
     m_ConfigName(pConfigName),
     m_usingDefaultConfig(false),
@@ -775,6 +776,7 @@ FGFlightRecorder::replay(double SimTime, const FGReplayData* _pNextBuffer,
             const double* pDoubles = (const double*) &pBuffer[Offset];
             const double* pLastDoubles = (const double*) &pLastBuffer[Offset];
             unsigned int SignalCount = m_CaptureDouble.size();
+            
             for (unsigned int i=0; i<SignalCount; i++)
             {
                 double v = pDoubles[i];
@@ -785,6 +787,38 @@ FGFlightRecorder::replay(double SimTime, const FGReplayData* _pNextBuffer,
                 }
                 m_CaptureDouble[i].Signal->setDoubleValue(v);
             }
+            
+            if (m_LogRawSpeed->getBoolValue()) {
+                // Log raw speed values to
+                // /sim/replay/log-raw-speed-values/value[]. This is used by
+                // scripts/python/recordreplay.py --test-motion.
+                //
+                SGGeod pos_geod = SGGeod::fromDegFt(
+                        fgGetDouble("/position/longitude-deg"),
+                        fgGetDouble("/position/latitude-deg"),
+                        fgGetDouble("/position/altitude-ft")
+                        );
+                SGVec3d pos = SGVec3d::fromGeod(pos_geod);
+                static SGVec3d pos_prev;
+                static double simtime_prev = -1;
+                double dt = SimTime - simtime_prev;
+                if (simtime_prev != -1 && dt > 0) {
+                    double distance = length(pos - pos_prev);
+                    double speed = dt ? distance / dt : -1;
+                    SG_LOG(SG_GENERAL, SG_DEBUG, "User aircraft:"
+                            << " pLastBuffer=" << ((void*) pLastBuffer)
+                            << " SimTime=" << SimTime
+                            << " dt=" << dt
+                            << " distance=" << distance
+                            << " speed=" << speed
+                            );
+                    SGPropertyNode* n = fgGetNode("/sim/replay/log-raw-speed-values", true /*create*/);
+                    n->addChild("value")->setDoubleValue(speed);
+                }
+                pos_prev = pos;
+                simtime_prev = SimTime;
+            }
+            
             Offset += SignalCount * sizeof(double);
         }
 

src/Aircraft/flightrecorder.hxx

@@ -95,6 +95,8 @@ private:
     SGPropertyNode_ptr m_RecordContinuous;
     SGPropertyNode_ptr m_RecordExtraProperties;
     
+    SGPropertyNode_ptr m_LogRawSpeed;
+    
     // This contains copy of all properties that we are recording, so that we
     // can send only differences.
     //

src/Aircraft/replay.cxx

@@ -356,6 +356,7 @@ FGReplay::init()
 {
     disable_replay       = fgGetNode("/sim/replay/disable",      true);
     replay_master        = fgGetNode("/sim/replay/replay-state", true);
+    replay_master_eof    = fgGetNode("/sim/replay/replay-state-eof", true);
     replay_time          = fgGetNode("/sim/replay/time",         true);
     replay_time_str      = fgGetNode("/sim/replay/time-str",     true);
     replay_looped        = fgGetNode("/sim/replay/looped",       true);
@@ -552,6 +553,7 @@ FGReplay::start(bool NewTape)
     if (0 == replay_master->getIntValue())
     {
         replay_master->setIntValue(1);
+        replay_master_eof->setIntValue(0);
         if (NewTape)
         {
             // start replay at initial time, when loading a new tape
@@ -1010,6 +1012,7 @@ FGReplay::update( double dt )
             {
                 if (!was_finished_already)
                 {
+                    replay_master_eof->setIntValue(1);
                     guiMessage("End of tape. 'Esc' to return.");
                     was_finished_already = true;
                 }

src/Aircraft/replay.hxx

@@ -223,6 +223,7 @@ private:
 
     SGPropertyNode_ptr disable_replay;
     SGPropertyNode_ptr replay_master;
+    SGPropertyNode_ptr replay_master_eof;
     SGPropertyNode_ptr replay_time;
     SGPropertyNode_ptr replay_time_str;
     SGPropertyNode_ptr replay_looped;