Rework sim status update to not need a thread.

Rather than polling at 60Hz (which may be faster than the tick rate,
wasting cycles; and also makes synchronization annoying), collect events
during the tick and emit them after (rate limited, pooling events until
it is time for another event to send).

This can be improved by paying attention to the aircraft update list,
which would allow us to avoid updating aircraft that don't have a status
change. To do that we need to be able to quickly lookup a FlightJs
matching a Flight through, and Flight isn't hashable.

We should also be removing dead events and de-duplicating. Currently
each flight has an update for every tick, but only the latest one
matters. Combat update events also don't matter if the same combat is
new in the update.

https://github.com/dcs-liberation/dcs_liberation/issues/1680

game/sim/aircraftsimulation.py

@@ -18,35 +18,36 @@ from game.ato.flightstate import (
 from game.ato.starttype import StartType
 from gen.flights.traveltime import TotEstimator
 from .combat import CombatInitiator, FrozenCombat
-from .gameupdatecallbacks import GameUpdateCallbacks
 
 if TYPE_CHECKING:
     from game import Game
+    from .gameupdateevents import GameUpdateEvents
 
 
 class AircraftSimulation:
-    def __init__(self, game: Game, callbacks: GameUpdateCallbacks) -> None:
+    def __init__(self, game: Game) -> None:
         self.game = game
-        self.callbacks = callbacks
         self.combats: list[FrozenCombat] = []
 
     def begin_simulation(self) -> None:
         self.reset()
         self.set_initial_flight_states()
 
-    def on_game_tick(self, time: datetime, duration: timedelta) -> bool:
+    def on_game_tick(
+        self, events: GameUpdateEvents, time: datetime, duration: timedelta
+    ) -> None:
         for flight in self.iter_flights():
-            flight.on_game_tick(time, duration)
+            flight.on_game_tick(events, time, duration)
 
         # Finish updating all flights before checking for combat so that the new
         # positions are used.
-        CombatInitiator(self.game, self.combats, self.callbacks).update_active_combats()
+        CombatInitiator(self.game, self.combats, events).update_active_combats()
 
         # After updating all combat states, check for halts.
         for flight in self.iter_flights():
             if flight.should_halt_sim():
-                return True
-        return False
+                events.complete_simulation()
+                return
 
     def set_initial_flight_states(self) -> None:
         now = self.game.conditions.start_time

game/sim/combat/combatinitiator.py

@@ -12,7 +12,7 @@ from .atip import AtIp
 from .defendingsam import DefendingSam
 from .joinablecombat import JoinableCombat
 from .samengagementzones import SamEngagementZones
-from ..gameupdatecallbacks import GameUpdateCallbacks
+from ..gameupdateevents import GameUpdateEvents
 
 if TYPE_CHECKING:
     from game import Game
@@ -22,11 +22,11 @@ if TYPE_CHECKING:
 
 class CombatInitiator:
     def __init__(
-        self, game: Game, combats: list[FrozenCombat], callbacks: GameUpdateCallbacks
+        self, game: Game, combats: list[FrozenCombat], events: GameUpdateEvents
     ) -> None:
         self.game = game
         self.combats = combats
-        self.callbacks = callbacks
+        self.events = events
 
     def update_active_combats(self) -> None:
         blue_a2a = AircraftEngagementZones.from_ato(self.game.blue.ato)
@@ -64,7 +64,7 @@ class CombatInitiator:
             logging.info(f"{flight} is joining existing combat {joined}")
             joined.join(flight)
             own_a2a.remove_flight(flight)
-            self.callbacks.on_combat_changed(joined)
+            self.events.update_combat(joined)
         elif (combat := self.check_flight_for_new_combat(flight, a2a, sam)) is not None:
             logging.info(f"Interrupting simulation because {combat.because()}")
             combat.update_flight_states()
@@ -75,7 +75,7 @@ class CombatInitiator:
             a2a.update_for_combat(combat)
             own_a2a.update_for_combat(combat)
             self.combats.append(combat)
-            self.callbacks.on_add_combat(combat)
+            self.events.new_combat(combat)
 
     def check_flight_for_joined_combat(
         self, flight: Flight

game/sim/gameloop.py

@@ -7,6 +7,7 @@ from typing import TYPE_CHECKING
 
 from .gamelooptimer import GameLoopTimer
 from .gameupdatecallbacks import GameUpdateCallbacks
+from .gameupdateevents import GameUpdateEvents
 from .missionsimulation import MissionSimulation, SimulationAlreadyCompletedError
 from .simspeedsetting import SimSpeedSetting
 
@@ -20,7 +21,9 @@ class GameLoop:
         self.game = game
         self.callbacks = callbacks
         self.timer = GameLoopTimer(self.tick)
-        self.sim = MissionSimulation(self.game, self.callbacks)
+        self.sim = MissionSimulation(self.game)
+        self.events = GameUpdateEvents()
+        self.last_update_time = datetime.now()
         self.started = False
         self.completed = False
 
@@ -53,7 +56,7 @@ class GameLoop:
         self.pause()
         logging.info("Running sim to first contact")
         while not self.completed:
-            self.tick()
+            self.tick(suppress_events=True)
 
     def pause_and_generate_miz(self, output: Path) -> None:
         self.pause()
@@ -68,13 +71,25 @@ class GameLoop:
         self.sim.process_results(debriefing)
         self.completed = True
 
-    def tick(self) -> None:
+    def send_update(self, rate_limit: bool) -> None:
+        now = datetime.now()
+        time_since_update = now - self.last_update_time
+        if not rate_limit or time_since_update >= timedelta(seconds=1 / 60):
+            self.callbacks.on_update(self.events)
+            self.events = GameUpdateEvents()
+            self.last_update_time = now
+
+    def tick(self, suppress_events: bool = False) -> None:
         if not self.started:
             raise RuntimeError("Attempted to tick game loop before initialization")
         try:
-            self.completed = self.sim.tick()
+            self.sim.tick(self.events)
+            self.completed = self.events.simulation_complete
+            if not suppress_events:
+                self.send_update(rate_limit=True)
             if self.completed:
                 self.pause()
+                self.send_update(rate_limit=False)
                 logging.info(f"Simulation completed at {self.sim.time}")
                 self.callbacks.on_simulation_complete()
         except SimulationAlreadyCompletedError:

game/sim/gameupdatecallbacks.py

@@ -2,10 +2,8 @@ from __future__ import annotations
 
 from collections.abc import Callable
 from dataclasses import dataclass
-from typing import TYPE_CHECKING
 
-if TYPE_CHECKING:
-    from game.sim.combat import FrozenCombat
+from game.sim.gameupdateevents import GameUpdateEvents
 
 
 # Ought to be frozen but mypy can't handle that:
@@ -13,5 +11,4 @@ if TYPE_CHECKING:
 @dataclass
 class GameUpdateCallbacks:
     on_simulation_complete: Callable[[], None]
-    on_add_combat: Callable[[FrozenCombat], None]
-    on_combat_changed: Callable[[FrozenCombat], None]
+    on_update: Callable[[GameUpdateEvents], None]

game/sim/gameupdateevents.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from game.ato import Flight
+    from game.sim.combat import FrozenCombat
+
+
+class GameUpdateEvents:
+    def __init__(self) -> None:
+        self.simulation_complete = False
+        self.new_combats: list[FrozenCombat] = []
+        self.updated_combats: list[FrozenCombat] = []
+        self.updated_flights: list[Flight] = []
+
+    def complete_simulation(self) -> None:
+        self.simulation_complete = True
+
+    def new_combat(self, combat: FrozenCombat) -> None:
+        self.new_combats.append(combat)
+
+    def update_combat(self, combat: FrozenCombat) -> None:
+        self.updated_combats.append(combat)
+
+    def update_flight(self, flight: Flight) -> None:
+        self.updated_flights.append(flight)

game/sim/missionsimulation.py

@@ -9,11 +9,11 @@ from game.debriefing import Debriefing
 from game.missiongenerator import MissionGenerator
 from game.unitmap import UnitMap
 from .aircraftsimulation import AircraftSimulation
-from .gameupdatecallbacks import GameUpdateCallbacks
 from .missionresultsprocessor import MissionResultsProcessor
 
 if TYPE_CHECKING:
     from game import Game
+    from .gameupdateevents import GameUpdateEvents
 
 
 TICK = timedelta(seconds=1)
@@ -25,10 +25,10 @@ class SimulationAlreadyCompletedError(RuntimeError):
 
 
 class MissionSimulation:
-    def __init__(self, game: Game, callbacks: GameUpdateCallbacks) -> None:
+    def __init__(self, game: Game) -> None:
         self.game = game
         self.unit_map: Optional[UnitMap] = None
-        self.aircraft_simulation = AircraftSimulation(self.game, callbacks)
+        self.aircraft_simulation = AircraftSimulation(self.game)
         self.completed = False
         self.time = self.game.conditions.start_time
 
@@ -36,12 +36,13 @@ class MissionSimulation:
         self.time = self.game.conditions.start_time
         self.aircraft_simulation.begin_simulation()
 
-    def tick(self) -> bool:
+    def tick(self, events: GameUpdateEvents) -> GameUpdateEvents:
         self.time += TICK
         if self.completed:
             raise RuntimeError("Simulation already completed")
-        self.completed = self.aircraft_simulation.on_game_tick(self.time, TICK)
-        return self.completed
+        self.aircraft_simulation.on_game_tick(events, self.time, TICK)
+        self.completed = events.simulation_complete
+        return events
 
     def generate_miz(self, output: Path) -> None:
         self.unit_map = MissionGenerator(self.game, self.time).generate_miz(output)