Add websocket event stream for sim updates.

As a proof of concept this only covers the flight positions.

game/ato/flightstate/navigating.py

@@ -22,7 +22,7 @@ class Navigating(InFlight):
         self, events: GameUpdateEvents, time: datetime, duration: timedelta
     ) -> None:
         super().on_game_tick(events, time, duration)
-        events.update_flight(self.flight)
+        events.update_flight(self.flight, self.estimate_position())
 
     def progress(self) -> float:
         return (

game/server/__init__.py

@@ -1,2 +1,3 @@
 from .dependencies import GameContext
+from .eventstream import EventStream
 from .server import Server

game/server/app.py

@@ -1,6 +1,7 @@
 from fastapi import FastAPI
 
-from . import debuggeometries
+from . import debuggeometries, eventstream
 
 app = FastAPI()
 app.include_router(debuggeometries.router)
+app.include_router(eventstream.router)

game/server/eventstream/__init__.py

@@ -0,0 +1,2 @@
+from .eventstream import EventStream
+from .routes import router

game/server/eventstream/eventstream.py

@@ -0,0 +1,29 @@
+from asyncio import Queue
+
+from game.sim.gameupdateevents import GameUpdateEvents
+
+
+class EventStream:
+    _queue: Queue[GameUpdateEvents] = Queue()
+
+    @classmethod
+    def drain(cls) -> None:
+        while not cls._queue.empty():
+            cls._queue.get_nowait()
+            cls._queue.task_done()
+
+    @classmethod
+    async def put(cls, events: GameUpdateEvents) -> None:
+        await cls._queue.put(events)
+
+    @classmethod
+    def put_nowait(cls, events: GameUpdateEvents) -> None:
+        # The queue has infinite size so this should never need to block anyway. If for
+        # some reason the queue is full this will throw QueueFull.
+        cls._queue.put_nowait(events)
+
+    @classmethod
+    async def get(cls) -> GameUpdateEvents:
+        events = await cls._queue.get()
+        cls._queue.task_done()
+        return events

game/server/eventstream/models.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+from uuid import UUID
+
+from pydantic import BaseModel
+
+from game.server.leaflet import LeafletLatLon
+
+if TYPE_CHECKING:
+    from game import Game
+    from game.sim.gameupdateevents import GameUpdateEvents
+
+
+class GameUpdateEventsJs(BaseModel):
+    updated_flights: dict[UUID, LeafletLatLon]
+
+    @classmethod
+    def from_events(cls, events: GameUpdateEvents, game: Game) -> GameUpdateEventsJs:
+        return GameUpdateEventsJs(
+            updated_flights={
+                f[0].id: game.theater.point_to_ll(f[1]).as_list()
+                for f in events.updated_flights
+            }
+        )

game/server/eventstream/routes.py

@@ -0,0 +1,21 @@
+from fastapi import APIRouter
+from fastapi.encoders import jsonable_encoder
+from starlette.websockets import WebSocket
+
+from .eventstream import EventStream
+from .models import GameUpdateEventsJs
+from .. import GameContext
+
+router = APIRouter()
+
+
+@router.websocket("/eventstream")
+async def event_stream(websocket: WebSocket) -> None:
+    await websocket.accept()
+    while True:
+        if not (events := await EventStream.get()).empty:
+            await websocket.send_json(
+                jsonable_encoder(
+                    GameUpdateEventsJs.from_events(events, GameContext.get())
+                )
+            )

game/sim/gameloop.py

@@ -72,6 +72,11 @@ class GameLoop:
         self.completed = True
 
     def send_update(self, rate_limit: bool) -> None:
+        # We don't skip empty events because we still want the tick in the Qt part of
+        # the UI, which will update things like the current simulation time. The time
+        # probably be an "event" of its own. For now the websocket endpoint will filter
+        # out empty events to avoid the map handling unnecessary events, but we still
+        # pass the events through to Qt.
         now = datetime.now()
         time_since_update = now - self.last_update_time
         if not rate_limit or time_since_update >= timedelta(seconds=1 / 60):

game/sim/gameupdateevents.py

@@ -2,6 +2,8 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
+from dcs import Point
+
 if TYPE_CHECKING:
     from game.ato import Flight
     from game.sim.combat import FrozenCombat
@@ -12,7 +14,18 @@ class GameUpdateEvents:
         self.simulation_complete = False
         self.new_combats: list[FrozenCombat] = []
         self.updated_combats: list[FrozenCombat] = []
-        self.updated_flights: list[Flight] = []
+        self.updated_flights: list[tuple[Flight, Point]] = []
+
+    @property
+    def empty(self) -> bool:
+        return not any(
+            [
+                self.simulation_complete,
+                self.new_combats,
+                self.updated_combats,
+                self.updated_flights,
+            ]
+        )
 
     def complete_simulation(self) -> None:
         self.simulation_complete = True
@@ -23,5 +36,5 @@ class GameUpdateEvents:
     def update_combat(self, combat: FrozenCombat) -> None:
         self.updated_combats.append(combat)
 
-    def update_flight(self, flight: Flight) -> None:
-        self.updated_flights.append(flight)
+    def update_flight(self, flight: Flight, new_position: Point) -> None:
+        self.updated_flights.append((flight, new_position))

qt_ui/main.py

@@ -18,7 +18,7 @@ from game.data.weapons import Pylon, Weapon, WeaponGroup
 from game.db import FACTIONS
 from game.dcs.aircrafttype import AircraftType
 from game.profiling import logged_duration
-from game.server import GameContext, Server
+from game.server import EventStream, GameContext, Server
 from game.settings import Settings
 from game.theater.start_generator import GameGenerator, GeneratorSettings, ModSettings
 from qt_ui import (
@@ -137,6 +137,7 @@ def run_ui(game: Optional[Game]) -> None:
     # Apply CSS (need works)
     GameUpdateSignal()
     GameUpdateSignal.get_instance().game_loaded.connect(GameContext.set)
+    GameUpdateSignal.get_instance().game_loaded.connect(EventStream.drain)
 
     # Start window
     window = QLiberationWindow(game)

qt_ui/widgets/map/model/flightjs.py

@@ -17,6 +17,7 @@ from .waypointjs import WaypointJs
 
 
 class FlightJs(QObject):
+    idChanged = Signal()
     positionChanged = Signal()
     flightPlanChanged = Signal()
     blueChanged = Signal()
@@ -50,6 +51,10 @@ class FlightJs(QObject):
         self.ato_model = ato_model
         self._waypoints = self.make_waypoints()
 
+    @Property(str, notify=idChanged)
+    def id(self) -> str:
+        return str(self.flight.id)
+
     def update_waypoints(self) -> None:
         for waypoint in self._waypoints:
             waypoint.timingChanged.emit()

qt_ui/widgets/map/model/mapmodel.py

@@ -125,12 +125,6 @@ class MapModel(QObject):
         self.cleared.emit()
 
     def on_sim_update(self, events: GameUpdateEvents) -> None:
-        # TODO: Only update flights with changes.
-        # We have the signal of which flights have updates, but no fast lookup for
-        # Flight -> FlightJs since Flight isn't hashable. Faster to update every flight
-        # than do do the O(n^2) filtered update.
-        for flight in self._flights.values():
-            flight.positionChanged.emit()
         for combat in events.new_combats:
             self.on_add_combat(combat)
         for combat in events.updated_combats:

qt_ui/windows/QLiberationWindow.py

@@ -20,6 +20,7 @@ from PySide2.QtWidgets import (
 import qt_ui.uiconstants as CONST
 from game import Game, VERSION, persistency
 from game.debriefing import Debriefing
+from game.server import EventStream
 from qt_ui import liberation_install
 from qt_ui.dialogs import Dialog
 from qt_ui.models import GameModel
@@ -50,6 +51,7 @@ class QLiberationWindow(QMainWindow):
 
         self.game = game
         self.sim_controller = SimController(self.game)
+        self.sim_controller.sim_update.connect(EventStream.put_nowait)
         self.game_model = GameModel(game, self.sim_controller)
         Dialog.set_game(self.game_model)
         self.ato_panel = QAirTaskingOrderPanel(self.game_model)

resources/ui/map/map.js

@@ -1,6 +1,7 @@
 const ENABLE_EXPENSIVE_DEBUG_TOOLS = false;
 // Must be kept in sync with game.server.settings.ServerSettings.
 const HTTP_BACKEND = "http://[::1]:5000";
+const WS_BACKEND = "ws://[::1]:5000/eventstream";
 
 function getJson(endpoint) {
   return fetch(`${HTTP_BACKEND}${endpoint}`).then((response) =>
@@ -343,6 +344,17 @@ L.control
 
 let game;
 new QWebChannel(qt.webChannelTransport, function (channel) {
+  const ws = new WebSocket(WS_BACKEND);
+  ws.addEventListener("message", (event) => {
+    handleStreamedEvents(JSON.parse(event.data));
+  });
+  ws.addEventListener("close", (event) => {
+    console.log(`Websocket closed: ${event}`);
+  });
+  ws.addEventListener("error", (error) => {
+    console.log(`Websocket error: ${error}`);
+  });
+
   game = channel.objects.game;
   drawInitialMap();
   game.cleared.connect(clearAllLayers);
@@ -362,6 +374,12 @@ new QWebChannel(qt.webChannelTransport, function (channel) {
   game.selectedFlightChanged.connect(updateSelectedFlight);
 });
 
+function handleStreamedEvents(events) {
+  for (const [flightId, position] of Object.entries(events.updated_flights)) {
+    Flight.withId(flightId).drawAircraftLocation(position);
+  }
+}
+
 function recenterMap(center) {
   map.setView(center, 8, { animate: true, duration: 1 });
 }
@@ -825,17 +843,32 @@ class Waypoint {
 }
 
 class Flight {
+  static registeredFlights = {};
+
   constructor(flight) {
     this.flight = flight;
+    this.id = flight.id;
     this.flightPlan = this.flight.flightPlan.map((p) => new Waypoint(p, this));
     this.aircraft = null;
     this.path = null;
     this.markers = [];
     this.commitBoundary = null;
     this.flight.selectedChanged.connect(() => this.draw());
-    this.flight.positionChanged.connect(() => this.drawAircraftLocation());
     this.flight.flightPlanChanged.connect(() => this.drawFlightPlan());
     this.flight.commitBoundaryChanged.connect(() => this.drawCommitBoundary());
+    Flight.registerFlight(this);
+  }
+
+  static clearRegisteredFlights() {
+    Flight.registeredFlights = {};
+  }
+
+  static registerFlight(flight) {
+    Flight.registeredFlights[flight.id] = flight;
+  }
+
+  static withId(id) {
+    return Flight.registeredFlights[id];
   }
 
   shouldMark(waypoint) {
@@ -876,12 +909,14 @@ class Flight {
     this.drawCommitBoundary();
   }
 
-  drawAircraftLocation() {
+  drawAircraftLocation(position = null) {
     if (this.aircraft != null) {
       this.aircraft.removeFrom(aircraftLayer);
       this.aircraft = null;
     }
-    const position = this.flight.position;
+    if (position == null) {
+      position = this.flight.position;
+    }
     if (position.length > 0) {
       this.aircraft = L.marker(position, {
         icon: Icons.AirIcons.icon(
@@ -966,6 +1001,7 @@ class Flight {
 }
 
 function drawAircraft() {
+  Flight.clearRegisteredFlights();
   aircraftLayer.clearLayers();
   blueFlightPlansLayer.clearLayers();
   redFlightPlansLayer.clearLayers();