🗺️ Tilemap Pathfinding Game

This project demonstrates 2D scene construction using tilemaps and pathfinding algorithms in Unity. It builds on concepts from Unity Week 5: Two-dimensional Scene-building and Pathfinding.

📖 Foundational text explanations are available here in folder 07.

---

🎮 Play the Game on Itch.io

You can play the game directly from our Itch.io page.

🕹️ Gameplay Overview

Part 1: Tilemap Movement with Helpers

• 🎯 Goal: Navigate the tilemap and collect items to unlock movement on specific tiles.
• 🛠️ Power-Ups:
  • 🛶 Boat: Allows movement across water tiles.
  • 🐐 Goat: Enables traversal of mountain tiles.
  • ⛏️ Pickaxe: Transforms mountain tiles into grass.
• ⚠️ Rules:
  • Without power-ups, the player can only walk on grass and swamp tiles.
  • Stepping on an invalid tile ends the game and transitions to the next part.

---

Part 2: Click-Based Movement with Dijkstra

• 🎯 Goal: Click on a valid target tile to navigate the map using the fastest path.
• 🛠️ Features:
  • Each tile type has a specific movement cost.
  • The game uses Dijkstra’s algorithm to calculate the least-cost path.
  • Invalid clicks display a warning but do not end the game.

---

🛠️ Code Architecture

1. AllowedTiles 🟩

Purpose: Manages the tiles the player is allowed to walk on.

void Awake()
{
    InitializeAllowedTiles();
}

private void InitializeAllowedTiles()
{
    allowedTileSet = new HashSet<TileBase>(defaultAllowedTiles);
    Debug.Log("Initial allowed tiles: " + string.Join(", ", allowedTileSet));
}

public void AddTile(TileBase tile)
{
    if (tile != null && !allowedTileSet.Contains(tile))
    {
        allowedTileSet.Add(tile);
        Debug.Log($"Tile '{tile.name}' added to allowed tiles.");
    }
}

---

2. ItemTileDetector 🎯

Purpose: Detects when the player interacts with item tiles and updates allowed movement.

switch (tileName)
{
    case "BoatTile":
        allowedTiles.AddTile(TileManager.Instance.GetDeepSeaTile());
        Debug.Log("Boat collected! You can now sail on water.");
        break;

    case "GoatTile":
        allowedTiles.AddTile(TileManager.Instance.GetMountainTile());
        Debug.Log("Goat collected! Mountains are now passable.");
        break;

    case "PickaxeTile":
        PlayerInteraction.Instance.EnableTileModification(
            TileManager.Instance.GetMountainTile(),
            TileManager.Instance.GetGrassTile()
        );
        Debug.Log("Pickaxe collected! You can now transform mountains into grass.");
        break;
}

---

3. TilemapGraph 🔗

Purpose: Represents the tilemap as a graph for pathfinding. Provides neighbors and edge weights for Dijkstra's Algorithm.

public float GetEdgeWeight(Vector3Int from, Vector3Int to)
{
    TileBase tile = tilemap.GetTile(to);
    if (tile != null && tileWeights.ContainsKey(tile))
    {
        return tileWeights[tile];
    }
    return float.MaxValue; // Treat unknown tiles as impassable
}

public IEnumerable<Vector3Int> Neighbors(Vector3Int node)
{
    foreach (var direction in directions)
    {
        Vector3Int neighborPos = node + direction;
        TileBase neighborTile = tilemap.GetTile(neighborPos);

        if (neighborTile != null)
            yield return neighborPos;
    }
}

---

4. Dijkstra Algorithm Integration 📈

Purpose: Calculates the least-cost path for click-based navigation.

public static List<NodeType> GetPath<NodeType>(
    IGraph<NodeType> graph,
    NodeType startNode,
    NodeType endNode,
    Func<NodeType, NodeType, float> getEdgeWeight,
    int maxIterations = 1000
)
{
    var distances = new Dictionary<NodeType, float>();
    var previousNodes = new Dictionary<NodeType, NodeType>();
    var visited = new HashSet<NodeType>();
    // Implementation continues
}

---

5. TargetMover 🎯

Purpose: Handles click-based movement on the tilemap. Ensures that clicks are valid and calculates the least-cost path to the target using Dijkstra's Algorithm.

public void SetTarget(Vector3 newTarget)
{
    Vector3Int gridPosition = tilemap.WorldToCell(newTarget);

    if (!tilemap.HasTile(gridPosition))
    {
        Debug.LogWarning("Invalid Target: Clicked outside the tilemap.");
        return;
    }

    if (gridPosition == tilemap.WorldToCell(transform.position))
    {
        Debug.LogWarning("Invalid Target: You are already on this tile.");
        return;
    }

    targetInWorld = tilemap.GetCellCenterWorld(gridPosition);
    targetInGrid = gridPosition;
    atTarget = false;

    StartCoroutine(MoveTowardsTheTarget());
}

---

🎮 How to Play

Part 1: Tilemap Movement

1. Use the arrow keys to move the player.
2. Collect items to unlock movement across specific tiles:
   • 🛶 Boat: Sail on water.
   • 🐐 Goat: Climb mountains.
   • ⛏️ Pickaxe: Transform mountains into grass.
3. Step on an invalid tile to transition to the next part.

Part 2: Dijkstra Navigation

1. Click on a valid target tile.
2. The player will move to the target using the fastest path based on tile weights.
3. Invalid clicks display a warning but do not end the game.

---