Add pathfinding support for NPCs climbing tables (#17415)

Content.Server/NPC/Systems/NPCSteeringSystem.Context.cs

@@ -3,6 +3,7 @@ using System.Numerics;
 using Content.Server.Examine;
 using Content.Server.NPC.Components;
 using Content.Server.NPC.Pathfinding;
+using Content.Shared.Climbing;
 using Content.Shared.Interaction;
 using Content.Shared.Movement.Components;
 using Content.Shared.NPC;
@@ -35,6 +36,30 @@ public sealed partial class NPCSteeringSystem
 
     #region Seek
 
+    /// <summary>
+    /// Takes into account agent-specific context that may allow it to bypass a node which is not FreeSpace.
+    /// </summary>
+    private bool IsFreeSpace(
+        EntityUid uid,
+        NPCSteeringComponent steering,
+        PathPoly node)
+    {
+        if (node.Data.IsFreeSpace)
+        {
+            return true;
+        }
+        // Handle the case where the node is a climb, we can climb, and we are climbing.
+        else if ((node.Data.Flags & PathfindingBreadcrumbFlag.Climb) != 0x0 &&
+            (steering.Flags & PathFlags.Climbing) != 0x0 &&
+            TryComp<ClimbingComponent>(uid, out var climbing) &&
+            climbing.IsClimbing)
+        {
+            return true;
+        }
+
+        return false;
+    }
+
     /// <summary>
     /// Attempts to head to the target destination, either via the next pathfinding node or the final target.
     /// </summary>
@@ -90,7 +115,7 @@ public sealed partial class NPCSteeringSystem
         }
         // If next node is a free tile then get within its bounds.
         // This is to avoid popping it too early
-        else if (steering.CurrentPath.TryPeek(out var node) && node.Data.IsFreeSpace)
+        else if (steering.CurrentPath.TryPeek(out var node) && IsFreeSpace(uid, steering, node))
         {
             arrivalDistance = MathF.Min(node.Box.Width / 2f, node.Box.Height / 2f) - 0.01f;
         }
@@ -117,7 +142,7 @@ public sealed partial class NPCSteeringSystem
         if (direction.Length() <= arrivalDistance)
         {
             // Node needs some kind of special handling like access or smashing.
-            if (steering.CurrentPath.TryPeek(out var node) && !node.Data.IsFreeSpace)
+            if (steering.CurrentPath.TryPeek(out var node) && !IsFreeSpace(uid, steering, node))
             {
                 // Ignore stuck while handling obstacles.
                 ResetStuck(steering, ourCoordinates);

Content.Server/NPC/Systems/NPCSteeringSystem.Obstacles.cs

@@ -1,6 +1,7 @@
 using Content.Server.Destructible;
 using Content.Server.NPC.Components;
 using Content.Server.NPC.Pathfinding;
+using Content.Shared.Climbing;
 using Content.Shared.CombatMode;
 using Content.Shared.DoAfter;
 using Content.Shared.Doors.Components;
@@ -74,6 +75,7 @@ public sealed partial class NPCSteeringSystem
             GetObstacleEntities(poly, mask, layer, obstacleEnts);
             var isDoor = (poly.Data.Flags & PathfindingBreadcrumbFlag.Door) != 0x0;
             var isAccessRequired = (poly.Data.Flags & PathfindingBreadcrumbFlag.Access) != 0x0;
+            var isClimbable = (poly.Data.Flags & PathfindingBreadcrumbFlag.Climb) != 0x0;
 
             // Just walk into it stupid
             if (isDoor && !isAccessRequired)
@@ -121,6 +123,38 @@ public sealed partial class NPCSteeringSystem
                 if (obstacleEnts.Count == 0)
                     return SteeringObstacleStatus.Completed;
             }
+            // Try climbing obstacles
+            else if ((component.Flags & PathFlags.Climbing) != 0x0 && isClimbable)
+            {
+                if (TryComp<ClimbingComponent>(uid, out var climbing))
+                {
+                    if (climbing.IsClimbing)
+                    {
+                        return SteeringObstacleStatus.Completed;
+                    }
+                    else if (climbing.OwnerIsTransitioning)
+                    {
+                        return SteeringObstacleStatus.Continuing;
+                    }
+
+                    var climbableQuery = GetEntityQuery<ClimbableComponent>();
+
+                    // Get the relevant obstacle
+                    foreach (var ent in obstacleEnts)
+                    {
+                        if (climbableQuery.TryGetComponent(ent, out var table) &&
+                            _climb.CanVault(table, uid, uid, out _) &&
+                            _climb.TryClimb(uid, uid, ent, out id, table, climbing))
+                        {
+                            component.DoAfterId = id;
+                            return SteeringObstacleStatus.Continuing;
+                        }
+                    }
+                }
+
+                if (obstacleEnts.Count == 0)
+                    return SteeringObstacleStatus.Completed;
+            }
             // Try smashing obstacles.
             else if ((component.Flags & PathFlags.Smashing) != 0x0)
             {

Content.Server/NPC/Systems/NPCSteeringSystem.cs

@@ -3,6 +3,7 @@ using System.Numerics;
 using System.Threading;
 using System.Threading.Tasks;
 using Content.Server.Administration.Managers;
+using Content.Server.Climbing;
 using Content.Server.DoAfter;
 using Content.Server.Doors.Systems;
 using Content.Server.NPC.Components;
@@ -50,6 +51,7 @@ public sealed partial class NPCSteeringSystem : SharedNPCSteeringSystem
     [Dependency] private readonly IMapManager _mapManager = default!;
     [Dependency] private readonly IParallelManager _parallel = default!;
     [Dependency] private readonly IRobustRandom _random = default!;
+    [Dependency] private readonly ClimbSystem _climb = default!;
     [Dependency] private readonly DoAfterSystem _doAfter = default!;
     [Dependency] private readonly DoorSystem _doors = default!;
     [Dependency] private readonly EntityLookupSystem _lookup = default!;