public static List <Entity> AdjacentHostiles(EncounterState state, FactionName parentFaction, EncounterPosition position)
{
var adjacentHostiles = new List <Entity>();
foreach (var newpos in state.AdjacentPositions(position))
{
adjacentHostiles.AddRange(AIUtils.HostilesInPosition(state, parentFaction, newpos.X, newpos.Y));
}
return(adjacentHostiles);
}
// PERF: If this ends up being slow, we can mark with a dirty bit
/**
* Returns a path from start to end, exclusive - that is, the start and end nodes are *not* listed in the path. Does a full
* naive search every time.
*/
public static List <EncounterPosition> AStarWithNewGrid(
EncounterPosition start,
EncounterPosition end,
EncounterState state,
int maxAreaToExplore = 950
)
{
SimplePriorityQueue <EncounterPosition> frontier = new SimplePriorityQueue <EncounterPosition>();
frontier.Enqueue(start, 0f);
var cameFrom = new Dictionary <EncounterPosition, EncounterPosition>();
var costSoFar = new Dictionary <EncounterPosition, float>();
costSoFar[start] = 0f;
while (frontier.Count > 0 && cameFrom.Count < maxAreaToExplore)
{
var currentPosition = frontier.Dequeue();
var adjacentPositions = state.AdjacentPositions(currentPosition);
if (adjacentPositions.Contains(end))
{
var path = new List <EncounterPosition>()
{
currentPosition
};
EncounterPosition cameFromPos;
while (cameFrom.TryGetValue(path[path.Count - 1], out cameFromPos) && (cameFromPos != start))
{
path.Add(cameFromPos);
}
path.Reverse();
return(path);
}
var adjacentUnblocked = adjacentPositions.Where(adjacent => !state.IsPositionBlocked(adjacent)).ToList();
adjacentUnblocked.ForEach(adjacent => {
var newNextPositionCost = costSoFar[currentPosition] + 1f;
if (!costSoFar.ContainsKey(adjacent) || newNextPositionCost < costSoFar[adjacent])
{
costSoFar[adjacent] = newNextPositionCost;
// Uses straight-line distance as heuristic
float priority = newNextPositionCost + adjacent.DistanceTo(end);
frontier.Enqueue(adjacent, priority);
cameFrom[adjacent] = currentPosition;
}
});
}
return(null);
}