AI pickup changes (#1811)

* AI pickup changes

Eating and drinking isn't spammed anymore.
AI can do InRangeUnobstructed checks for item pickups.
AI can open drink cans.

AI littering to be coded.

* #nullable enable

* github's nullable fails are actively shortening my lifespan

* Use a const instead

So it's easier to find given the performance implications.

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Content.Server/GameObjects/EntitySystems/AI/Steering/AiSteeringSystem.cs

@@ -7,6 +7,7 @@ using Content.Server.GameObjects.Components.Movement;
 using Content.Server.GameObjects.EntitySystems.AI.Pathfinding;
 using Content.Server.GameObjects.EntitySystems.AI.Pathfinding.Pathfinders;
 using Content.Server.GameObjects.EntitySystems.JobQueues;
+using Content.Server.Utility;
 using Content.Shared.GameObjects.EntitySystems;
 using Robust.Server.Interfaces.Timing;
 using Robust.Shared.GameObjects.Components;
@@ -42,6 +43,11 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
         /// </summary>
         private const float TileTolerance = 0.8f;
 
+        /// <summary>
+        ///     How long to wait between checks (if necessary).
+        /// </summary>
+        private const float InRangeUnobstructedCooldown = 0.25f;
+
         private Dictionary<IEntity, IAiSteeringRequest> RunningAgents => _agentLists[_listIndex];
 
         // We'll cycle the running list every tick as all we're doing is getting a vector2 for the
@@ -208,7 +214,8 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
 
             foreach (var (agent, steering) in RunningAgents)
             {
-                var result = Steer(agent, steering);
+                // Yeah look it's not true frametime but good enough.
+                var result = Steer(agent, steering, frameTime * RunningAgents.Count);
                 steering.Status = result;
 
                 switch (result)
@@ -236,9 +243,10 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
         /// </summary>
         /// <param name="entity"></param>
         /// <param name="steeringRequest"></param>
+        /// <param name="frameTime"></param>
         /// <returns></returns>
         /// <exception cref="NotImplementedException"></exception>
-        private SteeringStatus Steer(IEntity entity, IAiSteeringRequest steeringRequest)
+        private SteeringStatus Steer(IEntity entity, IAiSteeringRequest steeringRequest, float frameTime)
         {
             // Main optimisation to be done below is the redundant calls and adding more variables
             if (!entity.TryGetComponent(out AiControllerComponent controller) || !ActionBlockerSystem.CanMove(entity))
@@ -262,13 +270,27 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
 
             // Check if we have arrived
             var targetDistance = (entity.Transform.MapPosition.Position - steeringRequest.TargetMap.Position).Length;
-            if (targetDistance <= steeringRequest.ArrivalDistance)
+            steeringRequest.TimeUntilInteractionCheck -= frameTime;
+            
+            if (targetDistance <= steeringRequest.ArrivalDistance && steeringRequest.TimeUntilInteractionCheck <= 0.0f)
+            {
+                if (!steeringRequest.RequiresInRangeUnobstructed || 
+                    InteractionChecks.InRangeUnobstructed(entity, steeringRequest.TargetMap, steeringRequest.ArrivalDistance, ignoredEnt: entity))
+                {
+                    // TODO: Need cruder LOS checks for ranged weaps
+                    controller.VelocityDir = Vector2.Zero;
+                    return SteeringStatus.Arrived;
+                }
+
+                steeringRequest.TimeUntilInteractionCheck = InRangeUnobstructedCooldown;
+                // Welp, we'll keep on moving.
+            }
+
+            // If we're really close don't swiggity swoogity back and forth and just wait for the interaction check maybe?
+            if (steeringRequest.TimeUntilInteractionCheck > 0.0f && targetDistance <= 0.1f)
             {
-                // TODO: If we need LOS and are moving to an entity then we may not be in range yet
-                // Chuck out a ray every half second or so and keep moving until we are?
-                // Alternatively could use tile-based LOS checks via the pathfindingsystem I guess
                 controller.VelocityDir = Vector2.Zero;
-                return SteeringStatus.Arrived;
+                return SteeringStatus.Moving;
             }
 
             // Handle pathfinding job

Content.Server/GameObjects/EntitySystems/AI/Steering/EntityTargetSteeringRequest.cs

@@ -10,20 +10,26 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
         public GridCoordinates TargetGrid => _target.Transform.GridPosition;
         public IEntity Target => _target;
         private IEntity _target;
+
         /// <inheritdoc />
         public float ArrivalDistance { get; }
+        
         /// <inheritdoc />
         public float PathfindingProximity { get; }
+        
         /// <summary>
-        /// How far the target can move before we re-path
+        ///     How far the target can move before we re-path
         /// </summary>
         public float TargetMaxMove { get; } = 1.5f;
 
-        /// <summary>
-        /// If we need LOS on the entity first before interaction
-        /// </summary>
+        /// <inheritdoc />
         public bool RequiresInRangeUnobstructed { get; }
         
+        /// <summary>
+        ///     To avoid spamming InRangeUnobstructed we'll apply a cd to it.
+        /// </summary>
+        public float TimeUntilInteractionCheck { get; set; }
+        
         public EntityTargetSteeringRequest(IEntity target, float arrivalDistance, float pathfindingProximity = 0.5f, bool requiresInRangeUnobstructed = false)
         {
             _target = target;

Content.Server/GameObjects/EntitySystems/AI/Steering/GridTargetSteeringRequest.cs

@@ -14,7 +14,12 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
         /// <inheritdoc />
         public float PathfindingProximity { get; }
 
-        public GridTargetSteeringRequest(GridCoordinates targetGrid, float arrivalDistance, float pathfindingProximity = 0.5f)
+        public bool RequiresInRangeUnobstructed { get; }
+
+        public float TimeUntilInteractionCheck { get; set; } = 0.0f;
+
+
+        public GridTargetSteeringRequest(GridCoordinates targetGrid, float arrivalDistance, float pathfindingProximity = 0.5f, bool requiresInRangeUnobstructed = false)
         {
             // Get it once up front so we the manager doesn't have to continuously get it
             var mapManager = IoCManager.Resolve<IMapManager>();
@@ -22,6 +27,7 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
             TargetGrid = targetGrid;
             ArrivalDistance = arrivalDistance;
             PathfindingProximity = pathfindingProximity;
+            RequiresInRangeUnobstructed = requiresInRangeUnobstructed;
         }
     }
 }

Content.Server/GameObjects/EntitySystems/AI/Steering/IAiSteeringRequest.cs

@@ -8,13 +8,23 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Steering
         MapCoordinates TargetMap { get; }
         GridCoordinates TargetGrid { get; }
         /// <summary>
-        /// How close we have to get before we've arrived
+        ///     How close we have to get before we've arrived
         /// </summary>
         float ArrivalDistance { get; }
         
         /// <summary>
-        /// How close the pathfinder needs to get. Typically you want this set lower than ArrivalDistance
+        ///     How close the pathfinder needs to get. Typically you want this set lower than ArrivalDistance
         /// </summary>
         float PathfindingProximity { get; }
+        
+        /// <summary>
+        ///     If we need LOS on the entity first before interaction
+        /// </summary>
+        bool RequiresInRangeUnobstructed { get; }
+        
+        /// <summary>
+        ///     To avoid spamming InRangeUnobstructed we'll apply a cd to it.
+        /// </summary>
+        public float TimeUntilInteractionCheck { get; set; }
     }
 }