/// <summary>
/// Returns list of possible moves, sorted by
/// 1) amount of increase, 2) distance to influence map source
/// THIS METHOD SHOULD BE IMPROVED
/// </summary>
public List <Direction> PossibleMoves(Coords currentPosition)
{
List <Direction> dirList = new List <Direction>();
// Dangerous cast?
TilePassable currentTile = (TilePassable)this._currentMap.GetTile(currentPosition);
for (byte i = 1; i <= 8; i++)
{
Direction currentDir = (Direction)i;
if (currentTile.AllowedMovesCheckInDirection(currentDir))
{
dirList.Add(currentDir);
}
}
dirList.Sort(
delegate(Direction d1, Direction d2)
{
Coords c1 = StaticMathFunctions.CoordsNeighboringInDirection(currentPosition, d1);
Coords c2 = StaticMathFunctions.CoordsNeighboringInDirection(currentPosition, d2);
Int32 returnVal = (this._influenceMap[c1.X, c1.Y]).CompareTo(this._influenceMap[c2.X, c2.Y]);
if (returnVal == 0)
{
returnVal = (StaticMathFunctions.DistanceBetweenTwoCoordsEucledean(c1, currentPosition)).CompareTo
(StaticMathFunctions.DistanceBetweenTwoCoordsEucledean(c2, currentPosition));
}
return(returnVal);
}
);
return(dirList);
}
/// <summary>
/// Analyzes and remembers tile accessibility. Starts at northwest corner and goes through the array,
/// checking east / southeast / south / southwest on the current tile and in case of accessibility
/// recording the result in both directions.
/// </summary>
public void AnalyzeTileAccessibility()
{
Tile currentTile;
for (UInt16 i = 0; i < this._xMax; i++)
{
for (UInt16 j = 0; j < this._yMax; j++)
{
Tile east, southEast, south, southWest;
currentTile = this._tiles[i, j];
if (currentTile is TileImpassable)
{
continue;
}
_passabilityMap[i][j] = true;
_visibilityMap[i, j] = (currentTile is TilePassable) ? 1 : 0;
// Sort of wasteful, hopefully compiler does this smartly
if (i < _xMax - 1)
{
east = this.GetTile(StaticMathFunctions.CoordsNeighboringInDirection(new Coords(CoordsType.Tile, i, j), Direction.East));
if (east is TilePassable)
{
(currentTile as TilePassable).AllowedMovesSet(Direction.East, true);
(east as TilePassable).AllowedMovesSet(Direction.West, true);
}
}
if ((i < _xMax - 1) & (j < _yMax - 1))
{
southEast = this.GetTile(StaticMathFunctions.CoordsNeighboringInDirection(new Coords(CoordsType.Tile, i, j), Direction.Southeast));
if (southEast is TilePassable)
{
(currentTile as TilePassable).AllowedMovesSet(Direction.Southeast, true);
(southEast as TilePassable).AllowedMovesSet(Direction.Northwest, true);
}
}
if (j < _yMax - 1)
{
south = this.GetTile(StaticMathFunctions.CoordsNeighboringInDirection(new Coords(CoordsType.Tile, i, j), Direction.South));
if (south is TilePassable)
{
(currentTile as TilePassable).AllowedMovesSet(Direction.South, true);
(south as TilePassable).AllowedMovesSet(Direction.North, true);
}
}
if ((i > 0) & (j < _yMax - 1))
{
southWest = this.GetTile(StaticMathFunctions.CoordsNeighboringInDirection(new Coords(CoordsType.Tile, i, j), Direction.Southwest));
if (southWest is TilePassable)
{
(currentTile as TilePassable).AllowedMovesSet(Direction.Southwest, true);
(southWest as TilePassable).AllowedMovesSet(Direction.Northeast, true);
}
}
}
}
}
private List <Direction> _PathfinderAStar(Coords start, Coords endTopLeft, Coords endBottomRight, BitArray[] _passabilityMap, hFunction h)
{
// NOTE: Should later implemented a collision predictor mechanic to work in tandem
// with the path-finder to provide better agent behavior.
// NOTE: Consider returning the number of tiles scanned in case no path is found.
// This will alert a boxed-in creature of its predicament.
// NOTE: Introduce a flag for a straight-line initial check(for outdoors environmens and
// for when the goal is near).
Int32 rangeX = _passabilityMap.Length;
Int32 rangeY = _passabilityMap[0].Count;
NodeAStar?[,] nodeArray = new NodeAStar?[rangeX, rangeY];
NodeAStar startNode = new NodeAStar();
startNode.costSoFar = 0;
startNode.estimatedTotalCost = h(start);
nodeArray[start.X, start.Y] = startNode;
List <Coords> ListOpen = new List <Coords>();
ListOpen.Add(start);
while (ListOpen.Count > 0)
{
// I have to use this bool the way I've implemented the algo. Consider rewriting.
bool resortList = false;
Coords currentCoords = ListOpen.First();
// Check to see if goal is reached.
//if (currentCoords.Equals(endTopLeft))
if (StaticMathFunctions.CoordinateIsInBox(currentCoords, endTopLeft, endBottomRight))
{
break;
}
NodeAStar currentNode = nodeArray[currentCoords.X, currentCoords.Y].Value;
for (byte i = 0; i <= 3; ++i)
{
Direction currentDir = (Direction)(2 * i + 1);
Coords dirCoords = StaticMathFunctions.DirectionToCoords(currentDir);
Coords potential = currentCoords + dirCoords;
// check if move in dir is allowed
if (potential.X >= 0 && potential.X < rangeX && potential.Y >= 0 && potential.Y < rangeY && // bounds check
_passabilityMap[potential.X][potential.Y]) // passability check
{
// Using the simplest cost function possible. Can be easily updated
// once tile walkability coefficients are added.
Coords newNodePosition = new Coords(CoordsType.General, currentCoords.X + dirCoords.X, currentCoords.Y + dirCoords.Y);
float accruedCost = currentNode.costSoFar + Constants.MovementCost[(byte)currentDir];
// Straight line correction
if (currentDir == nodeArray[currentCoords.X, currentCoords.Y].Value.connection)
{
accruedCost -= Constants.PathfinderStraightPathCorrection;
}
// Check to see if the node under examination is in the closed list.
//NodeAStar? oldNode = nodeArray[newNodePosition.X, newNodePosition.Y];
if (nodeArray[newNodePosition.X, newNodePosition.Y] != null)
{
// If node is in closed list, see if it needs updating.
if (nodeArray[newNodePosition.X, newNodePosition.Y].Value.costSoFar > accruedCost)
{
float expectedAdditionalCost =
nodeArray[newNodePosition.X, newNodePosition.Y].Value.estimatedTotalCost -
nodeArray[newNodePosition.X, newNodePosition.Y].Value.costSoFar;
NodeAStar nodeToAdd =
new NodeAStar(currentDir, accruedCost, accruedCost + expectedAdditionalCost);
nodeArray[newNodePosition.X, newNodePosition.Y] = nodeToAdd;
ListOpen.Add(newNodePosition);
resortList = true;
}
}
// Node is in open list. Process it.
else
{
float expectedAdditionalCost = h(newNodePosition);
NodeAStar nodeToAdd =
new NodeAStar(currentDir, accruedCost, accruedCost + expectedAdditionalCost);
nodeArray[newNodePosition.X, newNodePosition.Y] = nodeToAdd;
ListOpen.Add(newNodePosition);
resortList = true;
}
}
}
ListOpen.RemoveAt(0);
if (resortList)
{
ListOpen.Sort(
delegate(Coords c1, Coords c2)
{
float difference = nodeArray[c1.X, c1.Y].Value.estimatedTotalCost -
nodeArray[c2.X, c2.Y].Value.estimatedTotalCost;
Int32 returnValue = 0;
if (difference > 0)
{
returnValue = 1;
}
else if (difference < 0)
{
returnValue = -1;
}
return(returnValue);
}
);
}
}
List <Direction> ListRoute = new List <Direction>();
// Return empty route if the open list is empty, i.e. there is no path to the target
// Ideally, the game logic should be fixed so that the search isn't even attempted
// if there is no path between the two points.
if (ListOpen.Count == 0)
{
return(ListRoute);
}
Coords trackbackCoords = endTopLeft;
while (trackbackCoords != start)
{
Direction newDirection = nodeArray[trackbackCoords.X, trackbackCoords.Y].Value.connection;
ListRoute.Add(newDirection);
trackbackCoords = StaticMathFunctions.CoordsNeighboringInDirection(new Coords(CoordsType.Tile, trackbackCoords),
StaticMathFunctions.OppositeDirection(newDirection));
}
// Might be faster without reversing
//ListRoute.Reverse();
// We skip the reversal, so pick directions from the END of the list.
return(ListRoute);
}
/// Generates the influence map.
/// Uses a silly recursive algorithm.
/// Stopping conditions: Let's use two, to avoid stupid infinite loops.
/// One is a distance threshold check.
// Second is a min influence threshold check.
/// <summary>
/// Generates the influence map.
/// Uses a silly recursive algorithm.
/// Stopping conditions: Let's use two, to avoid stupid infinite loops.
/// One is a distance threshold check.
/// Second is a min influence threshold check.
/// </summary>
public void GenerateInfluenceMap()
{
// boolean array to keep note of which tiles have been processed
//BitArray[,] takenCareOf = new BitArray[_currentMap.BoundX, _currentMap.BoundY];
BitArray[] takenCareOf = new BitArray[_currentMap.BoundX];
for (int i = 0; i < _currentMap.BoundX; ++i)
{
takenCareOf[i] = new BitArray(_currentMap.BoundY);
}
takenCareOf[Source.X][Source.Y] = true;
// sets up two queues - one for the current pass, one for the next one
// distance increments by one at each pass
// if too slow, the process should be broken up so it does a number of passes each tick
Queue <Coords> currentQueue = new Queue <Coords>();
Queue <Coords> nextQueue = new Queue <Coords>();
currentQueue.Enqueue(_source);
UInt32 currentDistance = 0;
// main loop
// Stopping conditions: the two queues are exhausted, OR InfluenceMapMaxDistance is reached
while
(
((currentQueue.Count > 0) & (nextQueue.Count > 0))
|
(currentDistance < Constants.InfluenceMapMaxDistance)
)
{
// Checks if it's time to start the next pass
if (currentQueue.Count == 0)
{
currentQueue = nextQueue;
nextQueue = new Queue <Coords>();
currentDistance++;
continue;
}
Coords currentCoords = currentQueue.Peek();
TilePassable currentTile = (TilePassable)CurrentMap.GetTile(currentCoords);
// Analyzes the neighbors of the current Tile for possible additions to nextQueue
for (byte i = 1; i <= 8; i++)
{
Direction currentDir = (Direction)i;
if (currentTile.AllowedMovesCheckInDirection(currentDir))
{
Coords toCheck = StaticMathFunctions.CoordsNeighboringInDirection(currentCoords, currentDir);
if (!takenCareOf[toCheck.X][toCheck.Y])
{
nextQueue.Enqueue(toCheck);
takenCareOf[toCheck.X][toCheck.Y] = true;
}
}
}
float newVal = _f(currentDistance);
// Check to avert infnite / excessively deep loop
if (newVal > Constants.InfluenceMapMinThreshold)
{
this.SetMapValue(currentCoords, newVal);
}
currentQueue.Dequeue();
}
}