(24c49c72a) Added swarm behavior to crawlers. Any group of monsters spawned by a single MonsterEvent will now act as a swarm if they have SwarmBehavior defined in their xml

Barotrauma/BarotraumaShared/SharedCode.projitems

@@ -45,6 +45,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\AI\PathFinder.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\AI\SteeringManager.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\AI\SteeringPath.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\AI\SwarmBehavior.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\Animation\AnimController.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\Animation\FishAnimController.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Source\Characters\Animation\HumanoidAnimController.cs" />

Barotrauma/BarotraumaShared/Source/Characters/AI/EnemyAIController.cs

@@ -122,6 +122,7 @@ namespace Barotrauma
         private readonly float memoryFadeTime = 0.5f;
 
         public LatchOntoAI LatchOntoAI { get; private set; }
+        public SwarmBehavior SwarmBehavior { get; private set; }
 
         public bool AttackHumans
         {
@@ -215,6 +216,10 @@ namespace Barotrauma
                     case "latchonto":
                         LatchOntoAI = new LatchOntoAI(subElement, this);
                         break;
+                    case "swarm":
+                    case "swarmbehavior":
+                        SwarmBehavior = new SwarmBehavior(subElement, this);
+                        break;
                     case "targetpriority":
                         targetingPriorities.Add(subElement.GetAttributeString("tag", "").ToLowerInvariant(), new TargetingPriority(subElement));
                         break;
@@ -364,12 +369,8 @@ namespace Barotrauma
                 default:
                     throw new NotImplementedException();
             }
-
-            // Just some debug code that makes the characters to follow the mouse cursor 
-            //run = true;
-            //Vector2 mousePos = ConvertUnits.ToSimUnits(Screen.Selected.Cam.ScreenToWorld(PlayerInput.MousePosition));
-            //steeringManager.SteeringSeek(mousePos, Character.AnimController.GetCurrentSpeed(run));
-
+            
+            SwarmBehavior?.Update(deltaTime);
             steeringManager.Update(Character.AnimController.GetCurrentSpeed(run));
         }
 
@@ -790,6 +791,7 @@ namespace Barotrauma
             {
                 UpdateLimbAttack(deltaTime, AttackingLimb, attackSimPos, distance);
             }
+            return false;
         }
 
         private bool SteerThroughGap(Structure wall, WallSection section, Vector2 targetWorldPos, float deltaTime)

Barotrauma/BarotraumaShared/Source/Characters/AI/SwarmBehavior.cs

@@ -0,0 +1,95 @@
+using FarseerPhysics;
+using Microsoft.Xna.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Xml.Linq;
+
+namespace Barotrauma
+{
+    class SwarmBehavior
+    {
+        private float minDistFromClosest;
+        private float maxDistFromCenter;
+        private float cohesion;
+
+        private List<AICharacter> members = new List<AICharacter>();
+
+        private AIController ai;
+
+        public SwarmBehavior(XElement element, AIController ai)
+        {
+            this.ai = ai;
+            minDistFromClosest = ConvertUnits.ToSimUnits(element.GetAttributeFloat("mindistfromclosest", 10.0f));
+            maxDistFromCenter = ConvertUnits.ToSimUnits(element.GetAttributeFloat("maxdistfromcenter", 1000.0f));
+            cohesion = element.GetAttributeFloat("cohesion", 0.1f);
+        }
+
+        public static void CreateSwarm(IEnumerable<AICharacter> swarm)
+        {
+            foreach (AICharacter character in swarm)
+            {
+                if (character.AIController is EnemyAIController enemyAI && enemyAI.SwarmBehavior != null)
+                {
+                    enemyAI.SwarmBehavior.members = swarm.ToList();
+                }
+            }
+        }
+
+        public void Update(float deltaTime)
+        {
+            members.RemoveAll(m => m.IsDead || m.Removed);
+            if (members.Count < 2) { return; }
+
+            //calculate the "center of mass" of the swarm and the distance to the closest character in the swarm
+            float closestDistSqr = float.MaxValue;
+            Vector2 center = Vector2.Zero;
+            AICharacter closest = null;
+            foreach (AICharacter member in members)
+            {
+                center += member.SimPosition;
+                if (member == ai.Character) { continue; }
+                float distSqr = Vector2.DistanceSquared(member.SimPosition, ai.Character.SimPosition);
+                if (distSqr < closestDistSqr)
+                {
+                    closestDistSqr = distSqr;
+                    closest = member;
+                }
+            }
+            center /= members.Count;
+
+            if (closest == null) { return; }
+
+            //steer away from the closest if too close
+            float closestDist = (float)Math.Sqrt(closestDistSqr);
+            if (closestDist < minDistFromClosest)
+            {
+                Vector2 diff = closest.SimPosition - ai.SimPosition;
+                if (diff.LengthSquared() < 0.0001f)
+                {
+                    diff = Vector2.UnitX;
+                }
+                ai.SteeringManager.SteeringManual(deltaTime, -diff);
+            }
+            //steer closer to the center of mass if too far
+            else if (Vector2.DistanceSquared(center, ai.SimPosition) > maxDistFromCenter * maxDistFromCenter)
+            {
+                float distFromCenter = Vector2.Distance(center, ai.SimPosition);
+                ai.SteeringManager.SteeringSeek(center, distFromCenter - maxDistFromCenter);
+            }
+
+            //keep the characters moving in roughly the same direction
+            if (cohesion > 0.0f)
+            {
+                Vector2 avgVel = Vector2.Zero;
+                foreach (AICharacter member in members)
+                {
+                    avgVel += member.AnimController.TargetMovement;
+                }
+                avgVel /= members.Count;
+                ai.SteeringManager.SteeringManual(deltaTime, avgVel * cohesion);
+            }
+        }
+    }
+}

Barotrauma/BarotraumaShared/Source/Events/MonsterEvent.cs

@@ -227,17 +227,17 @@ namespace Barotrauma
                 monsters = new List<Character>();
                 float offsetAmount = spawnPosType == Level.PositionType.MainPath ? 1000 : 100;
                 for (int i = 0; i < amount; i++)
-                {                    
+                {
                     CoroutineManager.InvokeAfter(() =>
                     {
-                        bool isClient = false;
-#if CLIENT
-                        isClient = GameMain.Client != null;
-#endif
+                        bool isClient = GameMain.NetworkMember != null && GameMain.NetworkMember.IsClient;
                         monsters.Add(Character.Create(characterFile, spawnPos + Rand.Vector(offsetAmount, Rand.RandSync.Server), i.ToString(), null, isClient, true, true));
                         if (monsters.Count == amount)
                         {
                             spawnReady = true;
+                            //this will do nothing if the monsters have no swarm behavior defined, 
+                            //otherwise it'll make the spawned characters act as a swarm
+                            SwarmBehavior.CreateSwarm(monsters.Cast<AICharacter>());
                         }
                     }, Rand.Range(0f, amount / 2, Rand.RandSync.Server));
                 }