healing projectile

Source/TurnBasedTutorial/BattleMode/Trooper/Projectile.cpp

@@ -69,10 +69,17 @@ void AProjectile::NotifyActorBeginOverlap(AActor *OtherActor) {
                ),
                OtherTrooper->GetId(), OtherTrooper->GetPlayerIndex(), Damage,
                PlayerIndex);
+        if (Damage > 0) {
             if (PlayerIndex != -1 && PlayerIndex != OtherTrooper->
                 GetPlayerIndex()) {
                 OtherTrooper->TrooperTakeDamage(Damage);
             }
+        } else {
+            if (PlayerIndex != -1 && PlayerIndex == OtherTrooper->
+                GetPlayerIndex()) {
+                OtherTrooper->TrooperTakeDamage(Damage);
+            }
+        }
     } else {
         UE_LOG(LogTemp, Warning, TEXT("Overlapped not a trooper"));
     }

Source/TurnBasedTutorial/BattleMode/Trooper/Trooper.cpp

@@ -308,16 +308,21 @@ void ATrooper::TrooperTakeDamage_Implementation(float Damage) {
     if (bIsTakingDamage || bIsDead) {
         return;
     }
+    if (Damage > 0) {
         HitPoints = FMath::Max<float>(0, HitPoints - Damage);
         if (HitPoints == 0) {
             bIsDead = true;
             SetLifeSpan(DyingAnimationDuration);
-        GetWorld()->GetGameState<ABattleGameState>()->DecreaseLivingTroopers(
+            GetWorld()->GetGameState<ABattleGameState>()->
+                        DecreaseLivingTroopers(
                             PlayerIndex);
         } else {
             // bIsTakingDamage = true;
             SetIsTakingDamage(true);
         }
+    } else {
+        HitPoints = FMath::Min<float>(StartHitPoints, HitPoints - Damage);
+    }
 }
 
 TSubclassOf<AProjectile> ATrooper::GetProjectileClass(