Pathfinder rework (#11452)

Content.Shared/NPC/SharedPathfindingSystem.cs

@@ -0,0 +1,22 @@
+namespace Content.Shared.NPC;
+
+public abstract class SharedPathfindingSystem : EntitySystem
+{
+    /// <summary>
+    /// This is equivalent to agent radii for navmeshes. In our case it's preferable that things are cleanly
+    /// divisible per tile so we'll make sure it works as a discrete number.
+    /// </summary>
+    public const byte SubStep = 4;
+
+    public const byte ChunkSize = 8;
+
+    /// <summary>
+    /// We won't do points on edges so we'll offset them slightly.
+    /// </summary>
+    protected const float StepOffset = 1f / SubStep / 2f;
+
+    public Vector2 GetCoordinate(Vector2i chunk, Vector2i index)
+    {
+        return new Vector2(index.X, index.Y) / SubStep+ (chunk) * ChunkSize + StepOffset;
+    }
+}