fix: fleeing entities must have a CharacterMovement component (#85)

Terasology · Dec 2, 2021 · 33560b2 · 33560b2
1 parent 7ae9ca0
commit 33560b2
Showing 1 changed file with 23 additions and 13 deletions.
diff --git a/src/main/java/org/terasology/behaviors/system/BehaviorsEventSystem.java b/src/main/java/org/terasology/behaviors/system/BehaviorsEventSystem.java
@@ -13,9 +13,8 @@
 import org.terasology.engine.entitySystem.systems.RegisterMode;
 import org.terasology.engine.entitySystem.systems.RegisterSystem;
 import org.terasology.engine.logic.characters.CharacterMovementComponent;
-import org.terasology.module.health.events.OnDamagedEvent;
 import org.terasology.engine.registry.In;
-
+import org.terasology.module.health.events.OnDamagedEvent;
 
 /*
  * Listens for events relevant to this module's animals and responds as necessary
@@ -26,20 +25,31 @@ public class BehaviorsEventSystem extends BaseComponentSystem {
     @In
     private Time time;
 
-    @ReceiveEvent(components = FleeOnHitComponent.class)
-    public void onDamage(OnDamagedEvent event, EntityRef entity) {
+    /**
+     * Make an entity with the a {@link FleeOnHitComponent} flee from the instigator when being damaged.
+     *
+     * @param event the {@link OnDamageEvent} notifying about the entity having taken damage
+     * @param entity the entity being damaged
+     * @param fleeOnHitComponent only entities with this component flee if they take damage
+     * @param characterMovementComponent a fleeing entity needs a character movement component to allow it to actually flee from the
+     *         attacker
+     */
+    @ReceiveEvent
+    public void onDamage(OnDamagedEvent event, EntityRef entity,
+                         FleeOnHitComponent fleeOnHitComponent,
+                         CharacterMovementComponent characterMovementComponent) {
 
-        // Make entity flee
-        FleeingComponent fleeingComponent = new FleeingComponent();
-        fleeingComponent.instigator = event.getInstigator();
-        fleeingComponent.minDistance = entity.getComponent(FleeOnHitComponent.class).minDistance;
-        entity.addOrSaveComponent(fleeingComponent);
+        // Make entity flee (update existing FleeingComponent or add fresh component if not present)
+        entity.upsertComponent(FleeingComponent.class, maybeFleeingComponent -> {
+            FleeingComponent fleeingComponent = maybeFleeingComponent.orElse(new FleeingComponent());
+            fleeingComponent.instigator = event.getInstigator();
+            fleeingComponent.minDistance = fleeOnHitComponent.minDistance;
+            return fleeingComponent;
+        });
 
         // Increase speed by multiplier factor
-        CharacterMovementComponent characterMovementComponent = entity.getComponent(CharacterMovementComponent.class);
-        characterMovementComponent.speedMultiplier = entity.getComponent(FleeOnHitComponent.class).speedMultiplier;
-        entity.addOrSaveComponent(characterMovementComponent);
-
+        characterMovementComponent.speedMultiplier = fleeOnHitComponent.speedMultiplier;
+        entity.saveComponent(characterMovementComponent);
     }
 
     /**