public bool IsNextTo(Tile tile)
{
if (((this.Position.X + TileMap.TILE_SIZE == tile.Position.X) || (this.Position.X - TileMap.TILE_SIZE == tile.Position.X) || (this.Position.X == tile.Position.X))
&& ((this.Position.Y + TileMap.TILE_SIZE == tile.Position.Y) || (this.Position.Y - TileMap.TILE_SIZE == tile.Position.Y) || (this.Position.Y == tile.Position.Y)))
return true;
return false;
}
public static List<Tile> FindPath(Tile start, Tile destination, List<Tile> tileMap)
{
List<Tile> walkableTiles = tileMap;
List<Tile> neighbours = new List<Tile>();
Tile currentTile;
List<Tile> openTiles = new List<Tile>();
List<Tile> closedTiles = new List<Tile>();
start.G = 0;
openTiles.Add(start);
while(openTiles.Count > 0)
{
openTiles = openTiles.OrderBy(tile => tile.F).ToList();
currentTile = openTiles[0];
closedTiles.Add(currentTile);
openTiles.Remove(currentTile);
if(currentTile.IsNextTo(destination))
{
destination.ParentTile = currentTile;
return GetPath(destination, start, destination);
}
neighbours = walkableTiles.Where(tile => tile.IsNextTo(currentTile) && !closedTiles.Contains(tile)).ToList();
foreach(Tile tile in neighbours)
{
if(openTiles.Contains(tile))
{
int g = currentTile.G + tile.X == currentTile.X || tile.Y == currentTile.Y ? HORIZONTAL_COST : DIAGONAL_COST;
if (g < tile.G) tile.ParentTile = currentTile;
else continue;
}
tile.H = Heuristic(tile, destination);
tile.G = currentTile.G + tile.X == currentTile.X || tile.Y == currentTile.Y ? HORIZONTAL_COST : DIAGONAL_COST;
tile.F = tile.G + tile.H;
tile.ParentTile = currentTile;
openTiles.Add(tile);
}
}
return new List<Tile>();
}
private static List<Tile> GetPath(Tile currentTile, Tile start, Tile destination)
{
List<Tile> path = new List<Tile>();
path.Add(currentTile);
while(currentTile.Position != start.Position)
{
currentTile.Color = Color.Red;
path.Add(currentTile.ParentTile);
currentTile = currentTile.ParentTile;
}
path.Reverse();
path.Add(destination);
return path;
}
private static int Heuristic(Tile tile, Tile destinationTile)
{
Vector2 tilePosition = tile.Position;
int steps = 0;
if(tilePosition.X < destinationTile.X)
{
while(tilePosition.X < destinationTile.X)
{
tilePosition.X += TileMap.TILE_SIZE;
steps++;
}
}
else if(tilePosition.X > destinationTile.X)
{
while(tilePosition.X > destinationTile.X)
{
tilePosition.X -= TileMap.TILE_SIZE;
steps++;
}
}
if (tilePosition.Y < destinationTile.Y)
{
while (tilePosition.Y < destinationTile.Y)
{
tilePosition.Y += TileMap.TILE_SIZE;
steps++;
}
}
else if (tilePosition.Y > destinationTile.Y)
{
while (tilePosition.Y > destinationTile.Y)
{
tilePosition.Y -= TileMap.TILE_SIZE;
steps++;
}
}
return steps * 10;
}