Missile_lockedonto, second attempt

mccore/src/main/java/minecrafttransportsimulator/entities/instances/AEntityVehicleE_Powered.java

@@ -71,6 +71,7 @@ public abstract class AEntityVehicleE_Powered extends AEntityVehicleD_Moving {
     //Map containing incoming missiles and radar info, sorted by distance.
     public final List<EntityBullet> missilesIncoming = new ArrayList<>();
     public final List<AEntityD_Definable<?>> radarsTracking = new ArrayList<>();
+    public final List<PartGun> gunsLockedOn = new ArrayList<>();
 
     public AEntityVehicleE_Powered(AWrapperWorld world, IWrapperPlayer placingPlayer, ItemVehicle item, IWrapperNBT data) {
         super(world, placingPlayer, item, data);
@@ -197,6 +198,7 @@ public void update() {
 
         //Check to make sure we are still being tracked.
         radarsTracking.removeIf(tracker -> !tracker.isValid || (!tracker.aircraftOnRadar.contains(this) && !tracker.groundersOnRadar.contains(this)));
+        gunsLockedOn.removeIf(gun -> !gun.isValid || gun.engineTarget == null || gun.engineTarget.vehicleOn != this);
 
         //If we are supposed to de-spawn, do so.
         if (outOfHealth && ConfigSystem.settings.general.vehicleDeathDespawnTime.value > 0) {

mccore/src/main/java/minecrafttransportsimulator/entities/instances/EntityVehicleF_Physics.java

@@ -837,6 +837,8 @@ public ComputedVariable createComputedVariable(String variable, boolean createDe
                 return new ComputedVariable(this, variable, partialTicks -> radarsTracking.isEmpty() ? 0 : 1, false);
             case ("missile_incoming"):
                 return new ComputedVariable(this, variable, partialTicks -> missilesIncoming.isEmpty() ? 0 : 1, false);
+            case ("missile_lockedonto"):
+                return new ComputedVariable(this, variable, partialTicks -> gunsLockedOn.isEmpty() ? 0 : 1, false);
             default: {
                 //Missile incoming variables.
                 //Variable is in the form of missile_X_variablename.

mccore/src/main/java/minecrafttransportsimulator/entities/instances/PartGun.java

@@ -149,6 +149,10 @@ public class PartGun extends APart {
     private final Point3D normalizedConeVector = new Point3D();
     private final Point3D normalizedEntityVector = new Point3D();
 
+    //Track previous targets to detect changes for registration
+    private PartEngine prevEngineTarget = null;
+    private IWrapperEntity prevEntityTarget = null;
+
     //Global data.
     private static final int RAYTRACE_DISTANCE = 750;
     private static final double DEFAULT_CONE_ANGLE = 2.0;
@@ -333,6 +337,7 @@ public void update() {
                         currentController = null;
                         entityTarget = null;
                         engineTarget = null;
+                        updateTargetRegistration();
                     }
                 }
             }
@@ -390,6 +395,7 @@ public void update() {
                     currentController = null;
                     entityTarget = null;
                     engineTarget = null;
+                    updateTargetRegistration();
                 }
             }
 
@@ -598,6 +604,7 @@ public void update() {
             state = GunState.INACTIVE;
             entityTarget = null;
             engineTarget = null;
+            updateTargetRegistration();
             if (resetPosition) {
                 handleMovement(defaultYaw - internalOrientation.angles.y, defaultPitch - internalOrientation.angles.x);
             }
@@ -788,6 +795,7 @@ private void handleControl(IWrapperEntity controller) {
                     }
                 } else {
                     entityTarget = null;
+                    updateTargetRegistration();
                     state = state.demote(GunState.CONTROLLED);
                 }
             } else {
@@ -839,6 +847,7 @@ private void handleControl(IWrapperEntity controller) {
                 //First set targets to null to clear any existing targets.
                 engineTarget = null;
                 entityTarget = null;
+                updateTargetRegistration();
 
                 //If we have a start point, it means we're a cone-based target system and need to find a target.
                 if (startPoint != null) {
@@ -900,6 +909,7 @@ private void handleControl(IWrapperEntity controller) {
                             }
                         }
                     }
+                    updateTargetRegistration();
                 }
             }
 
@@ -1342,6 +1352,32 @@ public double getLeadAngleY() {
         return angle;
     }
 
+    /**
+     * Registers this gun with the target vehicle's gunsLockedOn list.
+     */
+    private void registerWithTargetVehicle() {
+        // Only register if we're locking onto a vehicle (via engineTarget)
+        if (engineTarget != null && engineTarget.vehicleOn != null && engineTarget.vehicleOn != vehicleOn) {
+            AEntityVehicleE_Powered targetVehicle = engineTarget.vehicleOn;
+            if (!targetVehicle.gunsLockedOn.contains(this)) {
+                targetVehicle.gunsLockedOn.add(this);
+            }
+        }
+    }
+
+    /**
+     * Updates target registration. Call this whenever entityTarget or engineTarget changes.
+     */
+    private void updateTargetRegistration() {
+        // Check if engine target changed
+        if (engineTarget != prevEngineTarget) {
+            prevEngineTarget = engineTarget;
+            registerWithTargetVehicle();
+        }
+        // Note: entityTarget targets are players/mobs, not vehicles, so we don't register for those
+        prevEntityTarget = entityTarget;
+    }
+
     @Override
     public ComputedVariable createComputedVariable(String variable, boolean createDefaultIfNotPresent) {
         switch (variable) {