implement beam rendering if shooter or target is already destroyed

src/test/CombatSystemTest.cpp

@@ -87,6 +87,7 @@ TEST_CASE("CombatSystem: ship fires when cooldown=0 and target in range", "[comb
     CombatSystem combat(cfg);
     std::vector<FireEvent> events;
     combat.tick(0, ships, buildings, events);
+    combat.applyPendingDamage(5, ships, buildings);
 
     float hpAfter = 0.0f;
     for (const Ship& s : ships.allShips())
@@ -324,6 +325,227 @@ TEST_CASE("CombatSystem: player ship fires at enemy station in range", "[combat]
     REQUIRE(playerFiredAtStation);
 }
 
+// ---------------------------------------------------------------------------
+// Deferred damage timing
+// ---------------------------------------------------------------------------
+
+TEST_CASE("CombatSystem: damage not applied before impact tick", "[combat]")
+{
+    const GameConfig cfg = loadConfig();
+    std::mt19937 rng(42);
+
+    const ShipDef* combatDef = findCombatShip(cfg);
+    REQUIRE(combatDef != nullptr);
+
+    BeltSystem belts(cfg.world.beltSpeedTilesPerSecond);
+    EntityId nextShipId = 1;
+    EntityId nextBldId  = 100;
+    ShipSystem ships(cfg, [&nextShipId]() { return nextShipId++; });
+    BuildingSystem buildings(cfg, belts,
+        [&nextBldId]() { return nextBldId++; },
+        [](int){},
+        [](const std::string&, QVector2D) {},
+        rng);
+
+    const EntityId enemyId  = ships.spawn(combatDef->id, 1, QVector2D(5.0f, 5.0f), true);
+    const EntityId playerId = ships.spawn(combatDef->id, 1, QVector2D(4.0f, 5.0f), false);
+
+    ships.forEach([&](Ship& s)
+    {
+        if (s.id == enemyId && s.weapon)
+        {
+            s.weapon->currentTarget = playerId;
+            s.weapon->cooldownTicks = 0.0f;
+            if (s.threatResponse)
+            {
+                s.threatResponse->currentTarget = playerId;
+            }
+        }
+    });
+
+    float hpBefore = 0.0f;
+    for (const Ship& s : ships.allShips())
+    {
+        if (s.id == playerId) { hpBefore = s.hp; }
+    }
+
+    CombatSystem combat(cfg);
+    std::vector<FireEvent> events;
+    combat.tick(0, ships, buildings, events);
+
+    // Ticks 1-4: damage must not have arrived yet.
+    for (Tick t = 1; t < 5; ++t)
+    {
+        combat.applyPendingDamage(t, ships, buildings);
+        float hp = 0.0f;
+        for (const Ship& s : ships.allShips())
+        {
+            if (s.id == playerId) { hp = s.hp; }
+        }
+        REQUIRE(hp == Approx(hpBefore));
+    }
+}
+
+TEST_CASE("CombatSystem: damage applied exactly at impact tick", "[combat]")
+{
+    const GameConfig cfg = loadConfig();
+    std::mt19937 rng(42);
+
+    const ShipDef* combatDef = findCombatShip(cfg);
+    REQUIRE(combatDef != nullptr);
+
+    BeltSystem belts(cfg.world.beltSpeedTilesPerSecond);
+    EntityId nextShipId = 1;
+    EntityId nextBldId  = 100;
+    ShipSystem ships(cfg, [&nextShipId]() { return nextShipId++; });
+    BuildingSystem buildings(cfg, belts,
+        [&nextBldId]() { return nextBldId++; },
+        [](int){},
+        [](const std::string&, QVector2D) {},
+        rng);
+
+    const EntityId enemyId  = ships.spawn(combatDef->id, 1, QVector2D(5.0f, 5.0f), true);
+    const EntityId playerId = ships.spawn(combatDef->id, 1, QVector2D(4.0f, 5.0f), false);
+
+    ships.forEach([&](Ship& s)
+    {
+        if (s.id == enemyId && s.weapon)
+        {
+            s.weapon->currentTarget = playerId;
+            s.weapon->cooldownTicks = 0.0f;
+            if (s.threatResponse)
+            {
+                s.threatResponse->currentTarget = playerId;
+            }
+        }
+    });
+
+    float hpBefore = 0.0f;
+    for (const Ship& s : ships.allShips())
+    {
+        if (s.id == playerId) { hpBefore = s.hp; }
+    }
+
+    CombatSystem combat(cfg);
+    std::vector<FireEvent> events;
+    combat.tick(0, ships, buildings, events);
+    combat.applyPendingDamage(5, ships, buildings);
+
+    float hpAfter = 0.0f;
+    for (const Ship& s : ships.allShips())
+    {
+        if (s.id == playerId) { hpAfter = s.hp; }
+    }
+
+    REQUIRE(hpAfter < hpBefore);
+}
+
+TEST_CASE("CombatSystem: damage silently dropped if target already dead", "[combat]")
+{
+    const GameConfig cfg = loadConfig();
+    std::mt19937 rng(42);
+
+    const ShipDef* combatDef = findCombatShip(cfg);
+    REQUIRE(combatDef != nullptr);
+
+    BeltSystem belts(cfg.world.beltSpeedTilesPerSecond);
+    EntityId nextShipId = 1;
+    EntityId nextBldId  = 100;
+    ShipSystem ships(cfg, [&nextShipId]() { return nextShipId++; });
+    BuildingSystem buildings(cfg, belts,
+        [&nextBldId]() { return nextBldId++; },
+        [](int){},
+        [](const std::string&, QVector2D) {},
+        rng);
+
+    const EntityId enemyId  = ships.spawn(combatDef->id, 1, QVector2D(5.0f, 5.0f), true);
+    const EntityId playerId = ships.spawn(combatDef->id, 1, QVector2D(4.0f, 5.0f), false);
+
+    ships.forEach([&](Ship& s)
+    {
+        if (s.id == enemyId && s.weapon)
+        {
+            s.weapon->currentTarget = playerId;
+            s.weapon->cooldownTicks = 0.0f;
+            if (s.threatResponse)
+            {
+                s.threatResponse->currentTarget = playerId;
+            }
+        }
+    });
+
+    CombatSystem combat(cfg);
+    std::vector<FireEvent> events;
+    combat.tick(0, ships, buildings, events);
+
+    // Target is removed before impact.
+    ships.despawn(playerId);
+
+    // Should not crash; damage is silently dropped.
+    combat.applyPendingDamage(5, ships, buildings);
+
+    REQUIRE(ships.findShip(playerId) == nullptr);
+}
+
+TEST_CASE("CombatSystem: damage still applied if shooter already dead", "[combat]")
+{
+    const GameConfig cfg = loadConfig();
+    std::mt19937 rng(42);
+
+    const ShipDef* combatDef = findCombatShip(cfg);
+    REQUIRE(combatDef != nullptr);
+
+    BeltSystem belts(cfg.world.beltSpeedTilesPerSecond);
+    EntityId nextShipId = 1;
+    EntityId nextBldId  = 100;
+    ShipSystem ships(cfg, [&nextShipId]() { return nextShipId++; });
+    BuildingSystem buildings(cfg, belts,
+        [&nextBldId]() { return nextBldId++; },
+        [](int){},
+        [](const std::string&, QVector2D) {},
+        rng);
+
+    const EntityId enemyId  = ships.spawn(combatDef->id, 1, QVector2D(5.0f, 5.0f), true);
+    const EntityId playerId = ships.spawn(combatDef->id, 1, QVector2D(4.0f, 5.0f), false);
+
+    ships.forEach([&](Ship& s)
+    {
+        if (s.id == enemyId && s.weapon)
+        {
+            s.weapon->currentTarget = playerId;
+            s.weapon->cooldownTicks = 0.0f;
+            if (s.threatResponse)
+            {
+                s.threatResponse->currentTarget = playerId;
+            }
+        }
+    });
+
+    float hpBefore = 0.0f;
+    for (const Ship& s : ships.allShips())
+    {
+        if (s.id == playerId) { hpBefore = s.hp; }
+    }
+
+    CombatSystem combat(cfg);
+    std::vector<FireEvent> events;
+    combat.tick(0, ships, buildings, events);
+
+    // Shooter is removed before impact.
+    ships.despawn(enemyId);
+
+    // Damage must still land on the target.
+    combat.applyPendingDamage(5, ships, buildings);
+
+    float hpAfter = 0.0f;
+    for (const Ship& s : ships.allShips())
+    {
+        if (s.id == playerId) { hpAfter = s.hp; }
+    }
+
+    REQUIRE(hpAfter < hpBefore);
+}
+
 // ---------------------------------------------------------------------------
 // Deaths & loot (tick step 9)
 // ---------------------------------------------------------------------------