[Player] Add AI Pathfinding on a 2D grid to the player character

Assets/External/AstarPathfindingProject/Modifiers/Modifiers.cs

@@ -0,0 +1,89 @@
+using UnityEngine;
+
+namespace Pathfinding {
+	/// <summary>
+	/// Base for all path modifiers.
+	/// See: MonoModifier
+	/// Modifier
+	/// </summary>
+	public interface IPathModifier {
+		int Order { get; }
+
+		void Apply(Path path);
+		void PreProcess(Path path);
+	}
+
+	/// <summary>
+	/// Base class for path modifiers which are not attached to GameObjects.
+	/// See: MonoModifier
+	/// </summary>
+	[System.Serializable]
+	public abstract class PathModifier : IPathModifier {
+		[System.NonSerialized]
+		public Seeker seeker;
+
+		/// <summary>
+		/// Modifiers will be executed from lower order to higher order.
+		/// This value is assumed to stay constant.
+		/// </summary>
+		public abstract int Order { get; }
+
+		public void Awake (Seeker seeker) {
+			this.seeker = seeker;
+			if (seeker != null) {
+				seeker.RegisterModifier(this);
+			}
+		}
+
+		public void OnDestroy (Seeker seeker) {
+			if (seeker != null) {
+				seeker.DeregisterModifier(this);
+			}
+		}
+
+		public virtual void PreProcess (Path path) {
+			// Required by IPathModifier
+		}
+
+		/// <summary>Main Post-Processing function</summary>
+		public abstract void Apply(Path path);
+	}
+
+	/// <summary>
+	/// Base class for path modifiers which can be attached to GameObjects.
+	/// See: Menubar -> Component -> Pathfinding -> Modifiers
+	/// </summary>
+	[System.Serializable]
+	public abstract class MonoModifier : VersionedMonoBehaviour, IPathModifier {
+		[System.NonSerialized]
+		public Seeker seeker;
+
+		/// <summary>Alerts the Seeker that this modifier exists</summary>
+		protected virtual void OnEnable () {
+			seeker = GetComponent<Seeker>();
+
+			if (seeker != null) {
+				seeker.RegisterModifier(this);
+			}
+		}
+
+		protected virtual void OnDisable () {
+			if (seeker != null) {
+				seeker.DeregisterModifier(this);
+			}
+		}
+
+		/// <summary>
+		/// Modifiers will be executed from lower order to higher order.
+		/// This value is assumed to stay constant.
+		/// </summary>
+		public abstract int Order { get; }
+
+		public virtual void PreProcess (Path path) {
+			// Required by IPathModifier
+		}
+
+		/// <summary>Called for each path that the Seeker calculates after the calculation has finished</summary>
+		public abstract void Apply(Path path);
+	}
+}