Esempio n. 1
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        /// <summary>
        /// Calculate a path from the start location to the destination location
        /// </summary>
        /// <remarks>
        /// Based on the A* pathfinding algorithm described on Wikipedia
        /// </remarks>
        /// <see href="https://en.wikipedia.org/wiki/A*_search_algorithm#Pseudocode"/>
        /// <param name="start">Start location</param>
        /// <param name="goal">Destination location</param>
        /// <param name="allowUnsafe">Allow possible but unsafe locations</param>
        /// <returns>A list of locations, or null if calculation failed</returns>
        public static Queue<Location> CalculatePath(World world, Location start, Location goal, bool allowUnsafe = false)
        {
            Queue<Location> result = null;

            AutoTimeout.Perform(() =>
            {
                HashSet<Location> ClosedSet = new HashSet<Location>(); // The set of locations already evaluated.
                HashSet<Location> OpenSet = new HashSet<Location>(new[] { start });  // The set of tentative nodes to be evaluated, initially containing the start node
                Dictionary<Location, Location> Came_From = new Dictionary<Location, Location>(); // The map of navigated nodes.

                Dictionary<Location, int> g_score = new Dictionary<Location, int>(); //:= map with default value of Infinity
                g_score[start] = 0; // Cost from start along best known path.
                // Estimated total cost from start to goal through y.
                Dictionary<Location, int> f_score = new Dictionary<Location, int>(); //:= map with default value of Infinity
                f_score[start] = (int)start.DistanceSquared(goal); //heuristic_cost_estimate(start, goal)

                while (OpenSet.Count > 0)
                {
                    Location current = //the node in OpenSet having the lowest f_score[] value
                        OpenSet.Select(location => f_score.ContainsKey(location)
                        ? new KeyValuePair<Location, int>(location, f_score[location])
                        : new KeyValuePair<Location, int>(location, int.MaxValue))
                        .OrderBy(pair => pair.Value).First().Key;
                    if (current == goal)
                    { //reconstruct_path(Came_From, goal)
                        List<Location> total_path = new List<Location>(new[] { current });
                        while (Came_From.ContainsKey(current))
                        {
                            current = Came_From[current];
                            total_path.Add(current);
                        }
                        total_path.Reverse();
                        result = new Queue<Location>(total_path);
                    }
                    OpenSet.Remove(current);
                    ClosedSet.Add(current);
                    foreach (Location neighbor in GetAvailableMoves(world, current, allowUnsafe))
                    {
                        if (ClosedSet.Contains(neighbor))
                            continue;		// Ignore the neighbor which is already evaluated.
                        int tentative_g_score = g_score[current] + (int)current.DistanceSquared(neighbor); //dist_between(current,neighbor) // length of this path.
                        if (!OpenSet.Contains(neighbor))	// Discover a new node
                            OpenSet.Add(neighbor);
                        else if (tentative_g_score >= g_score[neighbor])
                            continue;		// This is not a better path.

                        // This path is the best until now. Record it!
                        Came_From[neighbor] = current;
                        g_score[neighbor] = tentative_g_score;
                        f_score[neighbor] = g_score[neighbor] + (int)neighbor.DistanceSquared(goal); //heuristic_cost_estimate(neighbor, goal)
                    }
                }
            }, TimeSpan.FromSeconds(5));

            return result;
        }
Esempio n. 2
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 /* ========= SIMPLE MOVEMENTS ========= */
 /// <summary>
 /// Check if the player can move in the specified direction
 /// </summary>
 /// <param name="world">World the player is currently located in</param>
 /// <param name="location">Location the player is currently at</param>
 /// <param name="direction">Direction the player is moving to</param>
 /// <returns>True if the player can move in the specified direction</returns>
 public static bool CanMove(World world, Location location, Direction direction)
 {
     switch (direction)
     {
         case Direction.Down:
             return !IsOnGround(world, location);
         case Direction.Up:
             return (IsOnGround(world, location) || IsSwimming(world, location))
                 && !world.GetBlock(Move(Move(location, Direction.Up), Direction.Up)).Type.IsSolid();
         case Direction.East:
         case Direction.West:
         case Direction.South:
         case Direction.North:
             return !world.GetBlock(Move(location, direction)).Type.IsSolid()
                 && !world.GetBlock(Move(Move(location, direction), Direction.Up)).Type.IsSolid();
         default:
             throw new ArgumentException("Unknown direction", "direction");
     }
 }
Esempio n. 3
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 /// <summary>
 /// Check if the specified location implies swimming
 /// </summary>
 /// <param name="world">World for performing check</param>
 /// <param name="location">Location to check</param>
 /// <returns>True if the specified location implies swimming</returns>
 public static bool IsSwimming(World world, Location location)
 {
     return world.GetBlock(location).Type.IsLiquid();
 }
Esempio n. 4
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        /// <summary>
        /// Check if the specified location is safe
        /// </summary>
        /// <param name="world">World for performing check</param>
        /// <param name="location">Location to check</param>
        /// <returns>True if the destination location won't directly harm the player</returns>
        public static bool IsSafe(World world, Location location)
        {
            return
                //No block that can harm the player
                   !world.GetBlock(location).Type.CanHarmPlayers()
                && !world.GetBlock(Move(location, Direction.Up)).Type.CanHarmPlayers()
                && !world.GetBlock(Move(location, Direction.Down)).Type.CanHarmPlayers()

                //No fall from a too high place
                && (world.GetBlock(Move(location, Direction.Down)).Type.IsSolid()
                     || world.GetBlock(Move(location, Direction.Down, 2)).Type.IsSolid()
                     || world.GetBlock(Move(location, Direction.Down, 3)).Type.IsSolid())

                //Not an underwater location
                && !(world.GetBlock(Move(location, Direction.Up)).Type.IsLiquid());
        }
Esempio n. 5
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 /* ========= LOCATION PROPERTIES ========= */
 /// <summary>
 /// Check if the specified location is on the ground
 /// </summary>
 /// <param name="world">World for performing check</param>
 /// <param name="location">Location to check</param>
 /// <returns>True if the specified location is on the ground</returns>
 public static bool IsOnGround(World world, Location location)
 {
     return world.GetBlock(Move(location, Direction.Down)).Type.IsSolid();
 }
Esempio n. 6
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 /* ========= PATHFINDING METHODS ========= */
 /// <summary>
 /// Handle movements due to gravity
 /// </summary>
 /// <param name="world">World the player is currently located in</param>
 /// <param name="location">Location the player is currently at</param>
 /// <returns>Updated location after applying gravity</returns>
 public static Location HandleGravity(World world, Location location)
 {
     Location onFoots = new Location(location.X, Math.Floor(location.Y), location.Z);
     Location belowFoots = Move(location, Direction.Down);
     if (!IsOnGround(world, location) && !IsSwimming(world, location))
         location = Move2Steps(location, belowFoots).Dequeue();
     else if (!(world.GetBlock(onFoots).Type.IsSolid()))
         location = Move2Steps(location, onFoots).Dequeue();
     return location;
 }
Esempio n. 7
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 /// <summary>
 /// Return a list of possible moves for the player
 /// </summary>
 /// <param name="world">World the player is currently located in</param>
 /// <param name="location">Location the player is currently at</param>
 /// <param name="allowUnsafe">Allow possible but unsafe locations</param>
 /// <returns>A list of new locations the player can move to</returns>
 public static IEnumerable<Location> GetAvailableMoves(World world, Location location, bool allowUnsafe = false)
 {
     List<Location> availableMoves = new List<Location>();
     if (IsOnGround(world, location) || IsSwimming(world, location))
     {
         foreach (Direction dir in Enum.GetValues(typeof(Direction)))
             if (CanMove(world, location, dir) && (allowUnsafe || IsSafe(world, Move(location, dir))))
                 availableMoves.Add(Move(location, dir));
     }
     else
     {
         foreach (Direction dir in new []{ Direction.East, Direction.West, Direction.North, Direction.South })
             if (CanMove(world, location, dir) && IsOnGround(world, Move(location, dir)) && (allowUnsafe || IsSafe(world, Move(location, dir))))
                 availableMoves.Add(Move(location, dir));
         availableMoves.Add(Move(location, Direction.Down));
     }
     return availableMoves;
 }