flightgear/scripts/python/performance_replay.py

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Python
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2022-10-20 20:29:11 +08:00
#!/usr/bin/env python3
'''
Replays a Flightgear recording and shows framerate statistics.
Usage:
-f <fgfs>
Name of Flightear executable/script, e.g.: -f run_fgfs.sh
-i <tape>
Name of recording, for use with --load-tape.
'''
import math
import sys
import time
import recordreplay
def average_stddev(items):
'''
Returns (average, stddev).
'''
total = 0
total_sq = 0
for item in items:
total += item
total_sq += item*item
n = len(items)
average = total / n
variance = total_sq / n - (total / n)**2
stddev = math.sqrt(variance)
return average, stddev
if __name__ == '__main__':
fgfs = None
tape = None
args = iter(sys.argv[1:])
while 1:
try:
arg = next(args)
except StopIteration:
break
if arg in ('-h', '--help'):
print(__doc__)
elif arg == '-f':
fgfs = next(args)
elif arg == '-i':
tape = next(args)
else:
raise Exception(f'Unrecognised arg: {arg}')
if not fgfs:
raise Exception(f'Specify fgfs executable/run-script with -f')
if not tape:
raise Exception(f'Specify tape to replay with -i')
fg = recordreplay.Fg( None,
f'{fgfs}'
f' --load-tape={tape}'
f' --timeofday=noon'
f' --prop:bool:/sim/replay/log-frame-times=true'
f' --prop:bool:/sim/replay/replay-main-view=true'
f' --prop:bool:/sim/replay/replay-main-window-size=true'
f' --prop:bool:/sim/replay/looped=false'
)
fg.waitfor('/sim/fdm-initialized', 1, timeout=45)
fg.waitfor('/sim/replay/replay-state', 1)
fg.waitfor('/sim/replay/replay-state-eof', 1, timeout=600)
print(f'Reading frame-time statistics...')
t = time.time()
items = fg.fg.ls('/sim/replay/log-frame-times')
t = time.time() - t
print(f'fg.fg.ls took t={t}')
fg.close()
dts = []
for item in items:
if item.name == 'dt':
dts.append(float(item.value))
def statistics_text(dts):
dt_average, dt_stddev = average_stddev(dts)
t_total = sum(dts)
return f'n={len(dts)} dt_average={dt_average} dt_stddev={dt_stddev} t_total={t_total} fps={len(dts)/t_total}'
print(f'-' * 40)
print(f'')
print(f'Overall frame time (dt) statistics:')
print(f' {statistics_text(dts)}')
print(f'Ignoring first 4 frames:')
print(f' {statistics_text(dts[4:])}')
print(f'')
print(f'Raw frame times:')
dts_text = ' '.join(map(lambda dt: f'{dt:.4f}', dts))
print(f'dts: {dts_text}')