Pathing

Assets/script/MapGen.cs

+using UnityEngine;
+using System.Collections;
+using System.Collections.Generic;
+
+public class MapGen : MonoBehaviour {
+
+	public int rows = 6;
+	public int cols = 6;
+
+	public GameObject tile;
+	public GameObject enemy;
+	public static Tile[,] map;
+
+	public Tile startPos;
+	public Tile endPos;
+
+	public List<Tile> open;
+	public List<Tile> closed;
+
+	void Start () {
+
+		map = new Tile[rows, cols];
+
+		float startx = -(float)rows / 2f * tile.transform.lossyScale.x;
+		float starty = (float)cols / 2f * tile.transform.lossyScale.y;
+
+		for (int y = 0; y < cols; y++) {
+			for (int x = 0; x < rows; x++) {
+
+				map[x, y] = ((GameObject) Instantiate (tile, new Vector2(startx + x * tile.GetComponent<BoxCollider2D>().size.x,
+					starty - y * tile.GetComponent<BoxCollider2D>().size.x), Quaternion.identity)).GetComponent<Tile> ();
+
+				map [x, y].x = x;
+				map [x, y].y = y;
+			}
+		}
+
+		open = new List<Tile> ();
+		closed = new List<Tile> ();
+
+		enemy = (GameObject)(Instantiate (enemy, map[0, 0].transform.position, Quaternion.identity));
+	}
+
+	void FixedUpdate () {
+
+		if (map[rows - 1, cols - 1].prev != null) {
+
+			Tile current = map [rows - 1, cols - 1];
+			while (current.prev != null) {
+				Debug.DrawLine (current.transform.position, current.prev.transform.position, Color.red);
+				current = current.prev;
+			}
+		}
+	}
+
+	public void BeginPath () {
+		Path (map[0, 0], map[rows - 1, cols - 1]);
+	}
+
+	void Path (Tile start, Tile finish) {
+
+		if (start == finish) {
+			return;
+		}
+
+		open.Add (start);
+		start.goal = 0;
+		start.fitness = EstimateHeuristic (start, finish);
+
+		while (open.Count != 0) {
+
+			Tile current = null;
+			int index = 0;
+			float lowestFitness = open[0].fitness;
+			for (int i = 0; i < open.Count; i++) {
+				if (open[i].fitness < lowestFitness) {
+					lowestFitness = open [i].fitness;
+					index = i;
+				}
+			}
+
+			current = open[index];
+
+			open.RemoveAt (index);
+			closed.Add (current);
+
+			List<Tile> neighbors = current.GetNeighbors();
+			for (int i = 0; i < neighbors.Count; i++) {
+				if (closed.Contains (neighbors[i])) {
+					continue;
+				}
+
+				float tempGoal = current.goal + DistBetween(current, neighbors[i]);
+				if (!open.Contains (neighbors[i])) {
+					open.Add (neighbors [i]);
+				}else if (tempGoal >= neighbors[i].goal) {
+					continue;
+				}
+
+				neighbors [i].prev = current;
+				neighbors [i].goal = tempGoal;
+				neighbors [i].fitness = neighbors[i].goal + EstimateHeuristic(neighbors[i], finish);
+			}
+		}
+
+//		PrintPathRetrace (finish);
+		enemy.GetComponent<TraversePath> ().BeginTraversingPath (CreatePath (finish));
+	}
+
+	float EstimateHeuristic (Tile current, Tile finish) {
+		return Mathf.Abs (current.x - finish.x) + Mathf.Abs (current.y - finish.y);
+	}
+
+	float DistBetween (Tile current, Tile neighbor) {
+		return Mathf.Pow(current.x - neighbor.x, 2) + Mathf.Pow(current.y - neighbor.y, 2);
+	}
+
+	void PrintPathRetrace (Tile end) {
+
+		while (end != null) {
+			Debug.Log (end.x + ", " + end.y);
+			end = end.prev;
+		}
+	}
+
+	Path CreatePath (Tile finish) {
+
+		Path path = new Path ();
+
+		while (finish != null) {
+			path.Push (finish);
+			finish = finish.prev;
+		}
+
+		return path;
+	}
+}

Assets/script/Path.cs

+using UnityEngine;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Path {
+
+	public Tile start;
+	public Tile finish;
+
+	private Stack<Tile> path;
+
+	public Path () : this(0) { } 
+
+	public Path (int count) {
+		path = new Stack<Tile> (count);
+	}
+
+	public void Push (Tile t) {
+		path.Push (t);
+	}
+
+	public Tile Pop () {
+		return path.Pop ();
+	}
+
+	public Tile Peek () {
+		return path.Peek ();
+	}
+
+	public bool IsEmpty () {
+		return path.Count == 0;
+	}
+}

Assets/script/Tile.cs

+using UnityEngine;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Tile : MonoBehaviour {
+
+	public bool passable = true;
+
+	public Color canPas = new Color (255f, 255f, 255f);
+	public Color cantPas = new Color (0f, 0f, 0f);
+
+	private SpriteRenderer sprite;
+
+	public int x;
+	public int y;
+	public Tile prev;
+
+	public float goal = float.MaxValue;
+	public float fitness = float.MaxValue;
+
+	void Start () {
+
+		sprite = GetComponent<SpriteRenderer> ();
+	}
+
+	void OnMouseDown () {
+
+		passable = !passable;
+
+		if (passable) {
+			sprite.color = canPas;
+		} else {
+			sprite.color = cantPas;
+		}
+	}
+
+	public List<Tile> GetNeighbors () {
+
+		List<Tile> neighbors = new List<Tile> ();
+
+		if (x < MapGen.map.GetLength(0) - 1 && MapGen.map[x + 1, y].passable) {
+			neighbors.Add (MapGen.map[x + 1, y]);
+		}
+
+		if (x < MapGen.map.GetLength(0) - 1 && y < MapGen.map.GetLength(1) - 1 && MapGen.map[x + 1, y + 1].passable
+			&& MapGen.map[x, y + 1].passable && MapGen.map[x + 1, y].passable) {
+			neighbors.Add (MapGen.map[x + 1, y + 1]);
+		}
+
+		if (y < MapGen.map.GetLength (1) - 1 && MapGen.map [x, y + 1].passable) {
+			neighbors.Add (MapGen.map[x, y + 1]);
+		}
+
+		if (x > 0 && y < MapGen.map.GetLength(1) - 1 && MapGen.map[x - 1, y + 1].passable
+			&& MapGen.map[x, y + 1].passable && MapGen.map[x - 1, y].passable) {
+			neighbors.Add (MapGen.map[x - 1, y + 1]);
+		}
+
+		if (x > 0 && MapGen.map[x - 1, y].passable) {
+			neighbors.Add (MapGen.map[x - 1, y]);
+		}
+
+		if (x > 0 && y > 0 && MapGen.map[x - 1, y - 1].passable
+			&& MapGen.map[x, y - 1].passable && MapGen.map[x - 1, y].passable) {
+			neighbors.Add (MapGen.map[x - 1, y - 1]);
+		}
+
+		if (y > 0 && MapGen.map[x, y - 1].passable) {
+			neighbors.Add (MapGen.map[x, y - 1]);
+		}
+
+		if (x < MapGen.map.GetLength(0) - 1 && y > 0 && MapGen.map[x + 1, y - 1].passable
+			&& MapGen.map[x, y - 1].passable && MapGen.map[x + 1, y].passable) {
+			neighbors.Add (MapGen.map[x + 1, y - 1]);
+		}
+
+		return neighbors;
+	}
+}

Assets/script/TraversePath.cs

+using UnityEngine;
+using System.Collections;
+
+public class TraversePath : MonoBehaviour {
+
+	public float speed;
+	public float pathErrorRange;
+
+	private float speedLerpDistance;
+
+	private Rigidbody2D rb2d;
+	private Path path;
+
+	void Start () {
+
+		speedLerpDistance = speed * Time.fixedDeltaTime;
+
+		rb2d = GetComponent<Rigidbody2D> ();
+	}
+	
+	void FixedUpdate () {
+	
+		if (path != null && !path.IsEmpty ()) {
+
+			Vector3 tilePos = path.Peek ().transform.position;
+			float distance = Vector3.Distance (transform.position, tilePos);
+
+			transform.position = Vector3.Lerp (transform.position, tilePos, 1 / distance * speedLerpDistance);
+
+			if (distance <= pathErrorRange) {
+				path.Pop ();
+			}
+
+		}
+	}
+
+	//path must begin on current tile
+	public void BeginTraversingPath (Path path) {
+		this.path = path;
+	}
+}