Minecraft-Console-Client/MinecraftClient/Mapping/Movement.cs
2022-07-25 03:19:24 +08:00

375 lines
19 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
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>
/// <param name="motionY">Current vertical motion speed</param>
/// <returns>Updated location after applying gravity</returns>
public static Location HandleGravity(World world, Location location, ref double motionY)
{
if (Settings.GravityEnabled)
{
Location onFoots = new Location(location.X, Math.Floor(location.Y), location.Z);
Location belowFoots = Move(location, Direction.Down);
if (location.Y > Math.Truncate(location.Y) + 0.0001)
{
belowFoots = location;
belowFoots.Y = Math.Truncate(location.Y);
}
//Console.WriteLine("IsOnGround = " + IsOnGround(world, location));
if (!IsOnGround(world, location) && !IsSwimming(world, location))
{
while (!IsOnGround(world, belowFoots) &&
belowFoots.Y >= 1 + (world.GetDimension() == null ? 0 : world.GetDimension().minY))
belowFoots = Move(belowFoots, Direction.Down);
location = Move2Steps(location, belowFoots, ref motionY, true).Dequeue();
}
else if (!(world.GetBlock(onFoots).Type.IsSolid()))
location = Move2Steps(location, onFoots, ref motionY, true).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="motionY">Current vertical motion speed</param>
/// <param name="falling">Specify if performing falling steps</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, ref double motionY, bool falling = false, int stepsByBlock = 8)
{
if (stepsByBlock <= 0)
stepsByBlock = 1;
if (falling)
{
//Use MC-Like falling algorithm
double Y = start.Y;
Queue<Location> fallSteps = new Queue<Location>();
fallSteps.Enqueue(start);
double motionPrev = motionY;
motionY -= 0.08D;
motionY *= 0.9800000190734863D;
Y += motionY;
if (Y < goal.Y)
return new Queue<Location>(new[] { goal });
else return new Queue<Location>(new[] { new Location(start.X, Y, start.Z) });
}
else
{
//Regular MCC moving algorithm
motionY = 0; //Reset motion speed
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>
/// <param name="maxOffset">If no valid path can be found, also allow locations within specified distance of destination</param>
/// <param name="minOffset">Do not get closer of destination than specified distance</param>
/// <param name="timeout">How long to wait before stopping computation</param>
/// <remarks>When location is unreachable, computation will reach timeout, then optionally fallback to a close location within maxOffset</remarks>
/// <returns>A list of locations, or null if calculation failed</returns>
public static Queue<Location> CalculatePath(World world, Location start, Location goal, bool allowUnsafe, int maxOffset, int minOffset, TimeSpan timeout)
{
CancellationTokenSource cts = new CancellationTokenSource();
Task<Queue<Location>> pathfindingTask = Task.Factory.StartNew(() => Movement.CalculatePath(world, start, goal, allowUnsafe, maxOffset, minOffset, cts.Token));
pathfindingTask.Wait(timeout);
if (!pathfindingTask.IsCompleted)
{
cts.Cancel();
pathfindingTask.Wait();
}
return pathfindingTask.Result;
}
/// <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>
/// <param name="maxOffset">If no valid path can be found, also allow locations within specified distance of destination</param>
/// <param name="minOffset">Do not get closer of destination than specified distance</param>
/// <param name="ct">Token for stopping computation after a certain time</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, int maxOffset, int minOffset, CancellationToken ct)
{
if (minOffset > maxOffset)
throw new ArgumentException("minOffset must be lower or equal to maxOffset", "minOffset");
// We always use distance squared so our limits must also be squared.
minOffset *= minOffset;
maxOffset *= maxOffset;
Location current = new Location(); // Location that is currently processed
Location closestGoal = new Location(); // Closest Location to the goal. Used for approaching if goal can not be reached or was not found.
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)
{
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).
// Sort for h-score (f-score - g-score) to get smallest distance to goal if f-scores are equal
ThenBy(pair => f_score[pair.Key]-g_score[pair.Key]).First().Key;
// Only assert a value if it is of actual use later
if (maxOffset > 0 && ClosedSet.Count > 0)
// Get the block that currently is closest to the goal
closestGoal = ClosedSet.OrderBy(checkedLocation => checkedLocation.DistanceSquared(goal)).First();
// Stop when goal is reached or we are close enough
if (current == goal || (minOffset > 0 && current.DistanceSquared(goal) <= minOffset))
return ReconstructPath(Came_From, current);
else if (ct.IsCancellationRequested)
break; // Return if we are cancelled
OpenSet.Remove(current);
ClosedSet.Add(current);
foreach (Location neighbor in GetAvailableMoves(world, current, allowUnsafe))
{
if (ct.IsCancellationRequested)
break; // Stop searching for blocks if we are cancelled.
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)
}
}
// Goal could not be reached. Set the path to the closest location if close enough
if (maxOffset == int.MaxValue || goal.DistanceSquared(closestGoal) <= maxOffset)
return ReconstructPath(Came_From, closestGoal);
else
return null;
}
/// <summary>
/// Helper function for CalculatePath(). Backtrack from goal to start to reconstruct a step-by-step path.
/// </summary>
/// <param name="Came_From">The collection of Locations that leads back to the start</param>
/// <param name="current">Endpoint of our later walk</param>
/// <returns>the path that leads to current from the start position</returns>
private static Queue<Location> ReconstructPath(Dictionary<Location, Location> Came_From, Location current)
{
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();
return new Queue<Location>(total_path);
}
/* ========= 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)
{
if (world.GetChunkColumn(location) == null || world.GetChunkColumn(location).FullyLoaded == false)
return true; // avoid moving downward in a not loaded chunk
return world.GetBlock(Move(location, Direction.Down)).Type.IsSolid()
&& (location.Y <= Math.Truncate(location.Y) + 0.0001);
}
/// <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");
}
}
}
}