Enforce Entities exist on only one object layer at the same time

engine/src/main/java/com/bartlomiejpluta/base/engine/world/entity/model/DefaultEntity.java

@@ -40,6 +40,9 @@ public class DefaultEntity extends MovableSprite implements Entity {
    @Setter
    private boolean blocking;
 
+   @Getter
+   private ObjectLayer layer;
+
    public DefaultEntity(Mesh mesh, EntitySetManager entitySetManager, Map<Direction, Integer> spriteDirectionRows, Map<Direction, Vector2fc> spriteDefaultRows, String entitySetUid) {
       super(mesh, entitySetManager.loadObject(requireNonNull(entitySetUid)));
       this.entitySetManager = entitySetManager;
@@ -124,12 +127,12 @@ public class DefaultEntity extends MovableSprite implements Entity {
 
    @Override
    public void onAdd(ObjectLayer layer) {
-      // Do nothing
+      this.layer = layer;
    }
 
    @Override
    public void onRemove(ObjectLayer layer) {
-      // Do nothing
+      this.layer = null;
    }
 
    @Override

engine/src/main/java/com/bartlomiejpluta/base/engine/world/map/layer/object/DefaultObjectLayer.java

@@ -68,6 +68,13 @@ public class DefaultObjectLayer extends BaseLayer implements ObjectLayer {
 
    @Override
    public void addEntity(Entity entity) {
+      var layer = (DefaultObjectLayer) entity.getLayer();
+
+      if (layer != null) {
+         layer.entities.remove(entity);
+      }
+
+      entity.setStepSize(stepSize.x(), stepSize.y());
       entitiesToAdd.add(entity);
    }
 
@@ -153,7 +160,6 @@ public class DefaultObjectLayer extends BaseLayer implements ObjectLayer {
       if(!entitiesToAdd.isEmpty()) {
          for (var entity : entitiesToAdd) {
             entity.onAdd(this);
-            entity.setStepSize(stepSize.x(), stepSize.y());
             entities.add(entity);
          }
 

engine/src/main/java/com/bartlomiejpluta/base/engine/world/movement/MovableSprite.java

@@ -105,6 +105,14 @@ public abstract class MovableSprite extends AnimatedSprite implements Movable, U
       return true;
    }
 
+   @Override
+   public void abortMove() {
+      setCoordinates(movement.getFrom());
+      setDefaultAnimationFrame();
+      movementVector = null;
+      movement = null;
+   }
+
    @Override
    public void setCoordinates(int x, int y) {
       coordinates.x = x;