Add simple movements with /move command

- Determine if we can move to the specified direction
 - Add moving ability to the specified direction
 - Add /move command for triggering moves
 - Add move decomp. into steps (more natural)
 - Add pathfinding routines (still WIP)
 - SO YES YOU CAN NOW WALK USING MCC!!!

MinecraftClient/Mapping/Direction.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace MinecraftClient.Mapping
+{
+    /// <summary>
+    /// Represents a unit movement in the world
+    /// </summary>
+    /// <see href="http://minecraft.gamepedia.com/Coordinates"/>
+    public enum Direction
+    {
+        South = 0,
+        West = 1,
+        North = 2,
+        East = 3,
+        Up = 4,
+        Down = 5
+    }
+}

MinecraftClient/Mapping/Location.cs

@@ -127,6 +127,28 @@ namespace MinecraftClient.Mapping
             }
         }
 
+        /// <summary>
+        /// Get a squared distance to the specified location
+        /// </summary>
+        /// <param name="location">Other location for computing distance</param>
+        /// <returns>Distance to the specified location, without using a square root</returns>
+        public double DistanceSquared(Location location)
+        {
+            return ((X - location.X) * (X - location.X))
+                 + ((Y - location.Y) * (Y - location.Y))
+                 + ((Z - location.Z) * (Z - location.Z));
+        }
+
+        /// <summary>
+        /// Get exact distance to the specified location
+        /// </summary>
+        /// <param name="location">Other location for computing distance</param>
+        /// <returns>Distance to the specified location, with square root so lower performances</returns>
+        public double Distance(Location location)
+        {
+            return Math.Sqrt(DistanceSquared(location));
+        }
+
         /// <summary>
         /// Compare two locations. Locations are equals if the integer part of their coordinates are equals.
         /// </summary>
@@ -156,7 +178,7 @@ namespace MinecraftClient.Mapping
         /// </remarks>
         /// <returns>Location representation as ulong</returns>
 
-        public ulong GetLongRepresentation()
+        public ulong GetLong()
         {
             return ((((ulong)X) & 0x3FFFFFF) << 38) | ((((ulong)Y) & 0xFFF) << 26) | (((ulong)Z) & 0x3FFFFFF);
         }
@@ -166,7 +188,7 @@ namespace MinecraftClient.Mapping
         /// </summary>
         /// <returns>Location represented by the ulong</returns>
 
-        public static Location FromLongRepresentation(ulong location)
+        public static Location FromLong(ulong location)
         {
             int x = (int)(location >> 38);
             int y = (int)((location >> 26) & 0xFFF);
@@ -186,7 +208,7 @@ namespace MinecraftClient.Mapping
         /// <param name="loc1">First location to compare</param>
         /// <param name="loc2">Second location to compare</param>
         /// <returns>TRUE if the locations are equals</returns>
-        public static bool operator == (Location loc1, Location loc2)
+        public static bool operator ==(Location loc1, Location loc2)
         {
             if (loc1 == null && loc2 == null)
                 return true;
@@ -201,7 +223,7 @@ namespace MinecraftClient.Mapping
         /// <param name="loc1">First location to compare</param>
         /// <param name="loc2">Second location to compare</param>
         /// <returns>TRUE if the locations are equals</returns>
-        public static bool operator != (Location loc1, Location loc2)
+        public static bool operator !=(Location loc1, Location loc2)
         {
             if (loc1 == null && loc2 == null)
                 return true;
@@ -219,7 +241,7 @@ namespace MinecraftClient.Mapping
         /// <param name="loc1">First location to sum</param>
         /// <param name="loc2">Second location to sum</param>
         /// <returns>Sum of the two locations</returns>
-        public static Location operator + (Location loc1, Location loc2)
+        public static Location operator +(Location loc1, Location loc2)
         {
             return new Location
             (
@@ -229,6 +251,57 @@ namespace MinecraftClient.Mapping
             );
         }
 
+        /// <summary>
+        /// Substract a location to another
+        /// </summary>
+        /// <exception cref="NullReferenceException">
+        /// Thrown if one of the provided location is null
+        /// </exception>
+        /// <param name="loc1">First location</param>
+        /// <param name="loc2">Location to substract to the first one</param>
+        /// <returns>Sum of the two locations</returns>
+        public static Location operator -(Location loc1, Location loc2)
+        {
+            return new Location
+            (
+                loc1.X - loc2.X,
+                loc1.Y - loc2.Y,
+                loc1.Z - loc2.Z
+            );
+        }
+
+        /// <summary>
+        /// Multiply a location by a scalar value
+        /// </summary>
+        /// <param name="loc">Location to multiply</param>
+        /// <param name="val">Scalar value</param>
+        /// <returns>Product of the location and the scalar value</returns>
+        public static Location operator *(Location loc, double val)
+        {
+            return new Location
+            (
+                loc.X * val,
+                loc.Y * val,
+                loc.Z * val
+            );
+        }
+
+        /// <summary>
+        /// Divide a location by a scalar value
+        /// </summary>
+        /// <param name="loc">Location to divide</param>
+        /// <param name="val">Scalar value</param>
+        /// <returns>Result of the division</returns>
+        public static Location operator /(Location loc, double val)
+        {
+            return new Location
+            (
+                loc.X / val,
+                loc.Y / val,
+                loc.Z / val
+            );
+        }
+
         /// <summary>
         /// DO NOT USE. Defined to comply with C# requirements requiring a GetHashCode() when overriding Equals() or ==
         /// </summary>

MinecraftClient/Mapping/Material.cs

@@ -342,5 +342,24 @@
                     return false;
             }
         }
+
+        /// <summary>
+        /// Check if the provided material is a liquid a player can swim into
+        /// </summary>
+        /// <param name="m">Material to test</param>
+        /// <returns>True if the material is a liquid</returns>
+        public static bool IsLiquid(this Material m)
+        {
+            switch (m)
+            {
+                case Material.Water:
+                case Material.StationaryWater:
+                case Material.Lava:
+                case Material.StationaryLava:
+                    return true;
+                default:
+                    return false;
+            }
+        }
     }
 }

MinecraftClient/Mapping/Movement.cs

@@ -0,0 +1,264 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace MinecraftClient.Mapping
+{
+    /// <summary>
+    /// Allows moving through a Minecraft world
+    /// </summary>
+    public static class Movement
+    {
+        /* ========= 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;
+        }
+
+        /// <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;
+        }
+
+        /// <summary>
+        /// Decompose a single move from a block to another into several steps
+        /// </summary>
+        /// <remarks>
+        /// Allows moving by little steps instead or directly moving between blocks,
+        /// which would be rejected by anti-cheat plugins anyway.
+        /// </remarks>
+        /// <param name="start">Start location</param>
+        /// <param name="goal">Destination location</param>
+        /// <param name="stepsByBlock">Amount of steps by block</param>
+        /// <returns>A list of locations corresponding to the requested steps</returns>
+        public static Queue<Location> Move2Steps(Location start, Location goal, int stepsByBlock = 8)
+        {
+            if (stepsByBlock <= 0)
+                stepsByBlock = 1;
+
+            double totalStepsDouble = start.Distance(goal) * stepsByBlock;
+            int totalSteps = (int)Math.Ceiling(totalStepsDouble);
+            Location step = (goal - start) / totalSteps;
+
+            if (totalStepsDouble >= 1)
+            {
+                Queue<Location> movementSteps = new Queue<Location>();
+                for (int i = 1; i <= totalSteps; i++)
+                    movementSteps.Enqueue(start + step * i);
+                return movementSteps;
+            }
+            else return new Queue<Location>(new[] { goal });
+        }
+
+        /// <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)
+        {
+            HashSet<Location> ClosedSet = new HashSet<Location>(); // The set of locations already evaluated.
+            HashSet<Location> OpenSet = new HashSet<Location>();  // 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)
+                    Queue<Location> total_path = new Queue<Location>(new Location[] { current });
+                    while (Came_From.ContainsKey(current))
+                    {
+                        current = Came_From[current];
+                        total_path.Enqueue(current);
+                    }
+                    return 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)
+                }
+            }
+
+            return null;
+        }
+
+        /* ========= 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();
+        }
+
+        /// <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();
+        }
+
+        /// <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());
+        }
+
+        /* ========= 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");
+            }
+        }
+
+        /// <summary>
+        /// Get an updated location for moving in the specified direction
+        /// </summary>
+        /// <param name="location">Current location</param>
+        /// <param name="direction">Direction to move to</param>
+        /// <param name="length">Distance, in blocks</param>
+        /// <returns>Updated location</returns>
+        public static Location Move(Location location, Direction direction, int length = 1)
+        {
+            return location + Move(direction) * length;
+        }
+
+        /// <summary>
+        /// Get a location delta for moving in the specified direction
+        /// </summary>
+        /// <param name="direction">Direction to move to</param>
+        /// <returns>A location delta for moving in that direction</returns>
+        public static Location Move(Direction direction)
+        {
+            switch (direction)
+            {
+                case Direction.Down:
+                    return new Location(0, -1, 0);
+                case Direction.Up:
+                    return new Location(0, 1, 0);
+                case Direction.East:
+                    return new Location(1, 0, 0);
+                case Direction.West:
+                    return new Location(-1, 0, 0);
+                case Direction.South:
+                    return new Location(0, 0, 1);
+                case Direction.North:
+                    return new Location(0, 0, -1);
+                default:
+                    throw new ArgumentException("Unknown direction", "direction");
+            }
+        }
+    }
+}