Support for convoy "spawn-route" in campaign design

Resolves #91

'Assault On Damascus' was revamped using this new technique

changelog.md

@@ -25,6 +25,7 @@
 * **[Squadrons]** Warning messages when opening up a squadron through the air wing dialog, indicating squadrons that potentially won't fit w.r.t. parking space.
 * **[Squadrons Transfers]** Determine number of available parking slots more accurately w.r.t. squadron transfers, taking aircraft dimensions into account which should prevent forced air-starts.
 * **[UX]** Allow usage of CTRL/SHIFT modifiers in ground unit transfer window.
+* **[Campaign Design]** Ability to define "spawn-routes" for convoys, allowing them to start from the road without having to edit the mission
 
 ## Fixes
 * **[New Game Wizard]** Settings would not persist when going back to a previous page (obsolete due to overhaul).

game/campaignloader/mizcampaignloader.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 import itertools
 from functools import cached_property
 from pathlib import Path
-from typing import Iterator, List, TYPE_CHECKING, Tuple
+from typing import Iterator, List, TYPE_CHECKING, Tuple, Optional
 from uuid import UUID
 
 from dcs import Mission
@@ -28,7 +28,7 @@ from game.theater.controlpoint import (
     OffMapSpawn,
 )
 from game.theater.presetlocation import PresetLocation
-from game.utils import Distance, meters
+from game.utils import Distance, meters, feet
 
 if TYPE_CHECKING:
     from game.theater.conflicttheater import ConflictTheater
@@ -45,6 +45,7 @@ class MizCampaignLoader:
     LHA_UNIT_TYPE = LHA_Tarawa.id
     FRONT_LINE_UNIT_TYPE = Armor.M_113.id
     SHIPPING_LANE_UNIT_TYPE = HandyWind.id
+    CP_CONVOY_SPAWN_TYPE = Armor.M1043_HMMWV_Armament.id
 
     FOB_UNIT_TYPE = Unarmed.SKP_11.id
     FARP_HELIPADS_TYPE = ["Invisible FARP", "SINGLE_HELIPAD"]
@@ -317,6 +318,50 @@ class MizCampaignLoader:
             if group.units[0].type in self.POWER_SOURCE_UNIT_TYPE:
                 yield group
 
+    @property
+    def cp_convoy_spawns(self) -> Iterator[VehicleGroup]:
+        for group in self.country(blue=True).vehicle_group:
+            if group.units[0].type == self.CP_CONVOY_SPAWN_TYPE:
+                yield group
+
+    def _construct_cp_spawnpoints(self, start: Point) -> Tuple[Point, ...]:
+        closest = self._find_closest_cp_spawn(start)
+        if closest:
+            return self._interpolate_points(closest, start)
+        return tuple()
+
+    @staticmethod
+    def _interpolate_points(closest: VehicleGroup, start: Point) -> Tuple[Point, ...]:
+        points = [start]
+        waypoints = points + [wpt.position for wpt in closest.points]
+        last = waypoints[0]
+        meters100ft = feet(100).meters
+        residual = 0.0
+        for wpt in waypoints[1:]:
+            dist = wpt.distance_to_point(last)
+            fraction = meters100ft / dist  # 100ft separation
+            interpol_count = int((dist + residual) / meters100ft - 1)
+            offset = (meters100ft - residual) / dist
+            if offset <= 1:
+                points.append(last.lerp(wpt, offset))
+            if offset + fraction <= 1:
+                for i in range(1, interpol_count + 1):
+                    points.append(last.lerp(wpt, i * fraction + offset))
+            residual = (residual + dist - meters100ft * interpol_count) % meters100ft
+            last = wpt
+        return tuple(points)
+
+    def _find_closest_cp_spawn(self, start: Point) -> Optional[VehicleGroup]:
+        closest: Optional[VehicleGroup] = None
+        for spawn in self.cp_convoy_spawns:
+            if closest is None:
+                closest = spawn
+                continue
+            dist = start.distance_to_point(closest.position)
+            if start.distance_to_point(spawn.position) < dist:
+                closest = spawn
+        return closest
+
     def add_supply_routes(self) -> None:
         for group in self.front_line_path_groups:
             # The unit will have its first waypoint at the source CP and the final
@@ -334,9 +379,14 @@ class MizCampaignLoader:
                     f"No control point near the final waypoint of {group.name}"
                 )
 
-            self.control_points[origin.id].create_convoy_route(destination, waypoints)
+            o_spawns = self._construct_cp_spawnpoints(waypoints[0])
+            d_spawns = self._construct_cp_spawnpoints(waypoints[-1])
+
+            self.control_points[origin.id].create_convoy_route(
+                destination, waypoints, o_spawns
+            )
             self.control_points[destination.id].create_convoy_route(
-                origin, list(reversed(waypoints))
+                origin, list(reversed(waypoints)), d_spawns
             )
 
     def add_shipping_lanes(self) -> None:

game/migrator.py

@@ -75,6 +75,7 @@ class Migrator:
                 try_set_attr(cp, "icls_channel")
                 try_set_attr(cp, "icls_name")
                 try_set_attr(cp, "link4")
+            try_set_attr(cp, "convoy_spawns", {})
 
     def _update_flights(self) -> None:
         for f in self.game.db.flights.objects.values():

game/missiongenerator/convoygenerator.py

@@ -1,7 +1,8 @@
 from __future__ import annotations
 
 import itertools
-from typing import TYPE_CHECKING
+import logging
+from typing import TYPE_CHECKING, List
 
 from dcs import Mission
 from dcs.mapping import Point
@@ -40,23 +41,46 @@ class ConvoyGenerator:
             convoy.units,
             convoy.player_owned,
         )
+        group.manualHeading = True
 
+        spawns_tuple = convoy.origin.convoy_spawns.get(convoy.destination)
+
+        if spawns_tuple:
+            spawns = list(spawns_tuple)
+            last_unit = group.units[0]
+            spawns.pop(0)
+            for u in group.units[1:]:
+                if spawns:
+                    u.position = spawns.pop(0)
+                    u.heading = u.position.heading_between_point(last_unit.position)
+                    if last_unit.heading == 0:
+                        last_unit.heading = u.heading
+                    last_unit = u
+                else:
+                    logging.warning(
+                        f"Insufficient convoy spawns at {convoy.origin.name} "
+                        f"with destination {convoy.destination.name}, "
+                        "convoy may experience issues at mission start"
+                    )
+                    break
+
+        wpts: List[Point] = []
+        route = convoy.origin.convoy_route_to(convoy.destination)
         if self.game.settings.convoys_travel_full_distance:
-            end_point = convoy.route_end
+            wpts.extend(route)
         else:
             # convoys_travel_full_distance is disabled, so have the convoy only move the
             # first segment on the route. This option aims to remove long routes for
             # ground vehicles between control points, since the CPU load for pathfinding
             # long routes on DCS can be pretty heavy.
-            route = convoy.origin.convoy_route_to(convoy.destination)
-
             # Select the first route segment from the origin towards the destination so
             # the convoy spawns at the origin CP. This allows the convoy to be targeted
             # by BAI flights and starts it within the protection umbrella of the CP.
-            end_point = route[1]
+            wpts.append(route[1])
 
+        for wpt in wpts:
             group.add_waypoint(
-            end_point,
+                wpt,
                 speed=kph(40).kph,
                 move_formation=PointAction.OnRoad,
             )

game/theater/controlpoint.py

@@ -347,6 +347,7 @@ class ControlPoint(MissionTarget, SidcDescribable, ABC):
         # TODO: Should be Airbase specific.
         self.connected_points: List[ControlPoint] = []
         self.convoy_routes: Dict[ControlPoint, Tuple[Point, ...]] = {}
+        self.convoy_spawns: Dict[ControlPoint, Tuple[Point, ...]] = {}
         self.shipping_lanes: Dict[ControlPoint, Tuple[Point, ...]] = {}
         self.base: Base = Base()
         self.cptype = cptype
@@ -604,10 +605,13 @@ class ControlPoint(MissionTarget, SidcDescribable, ABC):
     def convoy_route_to(self, destination: ControlPoint) -> Sequence[Point]:
         return self.convoy_routes[destination]
 
-    def create_convoy_route(self, to: ControlPoint, waypoints: Iterable[Point]) -> None:
+    def create_convoy_route(
+        self, to: ControlPoint, waypoints: Iterable[Point], spawns: Iterable[Point]
+    ) -> None:
         self.connected_points.append(to)
         self.stances[to.id] = CombatStance.DEFENSIVE
         self.convoy_routes[to] = tuple(waypoints)
+        self.convoy_spawns[to] = tuple(spawns)
 
     def create_shipping_lane(
         self, to: ControlPoint, waypoints: Iterable[Point]

game/version.py

@@ -182,5 +182,7 @@ VERSION = _build_version_string()
 #:
 #: Version 10.7
 #: * Support for defining squadron sizes.
+#: * Definition of "spawn-routes" allowing convoys to spawn on the road
+#:      please note that an insufficiently long route can cause trouble in case of large convoys
 
 CAMPAIGN_FORMAT_VERSION = (10, 7)