Add negative borders for grid graph

BrainAI.Tests/GridGraphTest.cs

@@ -0,0 +1,113 @@
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+
+namespace BrainAI.Pathfinding
+{
+    [TestFixture]
+    public class GridGraphTest
+    {
+        [Test]
+        public void GetNeighboursForTopLeftCorner_WidthHeightSet_Two()
+        {
+            var graph = new GridGraph(10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(0, 0), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(1, 0), new Point(0, 1) }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForOutsideTopLeftCorner_WidthHeightSet_None()
+        {
+            var graph = new GridGraph(10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(-1, -1), result);
+
+            CollectionAssert.AreEquivalent(new Point[] { }, result);
+        }
+
+
+        [Test]
+        public void GetNeighboursForBottomRightCorner_WidthHeightSet_Two()
+        {
+            var graph = new GridGraph(10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(9, 9), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(9, 8), new Point(8, 9) }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForOutsideBottomRight_WidthHeightSet_None()
+        {
+            var graph = new GridGraph(10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(10, 10), result);
+
+            CollectionAssert.AreEquivalent(new Point[] { }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForInside_WidthHeightSet_None()
+        {
+            var graph = new GridGraph(10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(5, 5), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(4, 5), new Point(5, 4), new Point(5, 6), new Point(6, 5) }, result);
+        }
+
+
+        [Test]
+        public void GetNeighboursForTopLeftCorner_BordersSet_Two()
+        {
+            var graph = new GridGraph(-10, -10, 10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(-10, -10), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(-10, -9), new Point(-9, -10) }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForOutsideTopLeftCorner_BordersSet_None()
+        {
+            var graph = new GridGraph(-10, -10, 10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(-11, -11), result);
+
+            CollectionAssert.AreEquivalent(new Point[] { }, result);
+        }
+
+
+        [Test]
+        public void GetNeighboursForBottomRightCorner_BordersSet_Two()
+        {
+            var graph = new GridGraph(-10, -10, 10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(10, 10), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(9, 10), new Point(10, 9) }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForOutsideBottomRight_BordersSet_None()
+        {
+            var graph = new GridGraph(-10, -10, 10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(11, 11), result);
+
+            CollectionAssert.AreEquivalent(new Point[] { }, result);
+        }
+
+        [Test]
+        public void GetNeighboursForInside_BordersSet_None()
+        {
+            var graph = new GridGraph(-10, -10, 10, 10, false);
+            var result = new List<Point>();
+            graph.GetNeighbors(new Point(0, 0), result);
+
+            CollectionAssert.AreEquivalent(new[] { new Point(-1, 0), new Point(1, 0), new Point(0, -1), new Point(0, 1) }, result);
+        }
+    }
+}

BrainAI/Pathfinding/Graphs/GridGraph.cs

@@ -31,14 +31,20 @@ public class GridGraph : IAstarGraph<Point>
         public readonly Dictionary<Point, int> Weights = new Dictionary<Point, int>();
         public int DefaultWeight = 1;
 
-        public readonly int Width, Height;
+        public readonly int Left, Top, Right, Bottom;
 
         private readonly Point[] dirs;
 
-        public GridGraph(int width, int height, bool allowDiagonalSearch = false)
+        public GridGraph(int width, int height, bool allowDiagonalSearch = false) : this(0, 0, width - 1, height - 1, allowDiagonalSearch)
         {
-            this.Width = width;
-            this.Height = height;
+        }
+
+        public GridGraph(int left, int top, int right, int bottom, bool allowDiagonalSearch = false)
+        {
+            this.Left = Math.Min(left, right);
+            this.Top = Math.Min(top, bottom);
+            this.Right = Math.Max(left, right);
+            this.Bottom = Math.Max(top, bottom);
             this.dirs = allowDiagonalSearch ? CompassDirs : CardinalDirs;
         }
 
@@ -68,7 +74,7 @@ public int Heuristic(Point node, Point goal)
 
         private bool IsNodeInBounds(Point node)
         {
-            return 0 <= node.X && node.X < this.Width && 0 <= node.Y && node.Y < this.Height;
+            return this.Left <= node.X && node.X <= this.Right && this.Top <= node.Y && node.Y <= this.Bottom;
         }
 
         private bool IsNodePassable(Point node)
@@ -82,9 +88,9 @@ public override string ToString()
         {
             sb.Clear();
 
-            for (var y = 0; y < this.Height; y++)
+            for (var y = Left; y <= this.Right; y++)
             {
-                for (var x = 0; x < this.Width; x++)
+                for (var x = Top; x <= this.Bottom; x++)
                 {
                     var pos = new Point(x, y);
                     var isWall = this.Walls.Contains(pos);