private List <HexCell> GetVisibleCells(HexCell fromCell, int range)
{
List <HexCell> visibleCells = ListPool <HexCell> .Get();
searchFrontierPhase += 2;
if (searchFrontier == null)
{
searchFrontier = new HexCellPriorityQueue();
}
else
{
searchFrontier.Clear();
}
range += fromCell.ViewElevation;
fromCell.SearchPhase = searchFrontierPhase;
fromCell.Distance = 0;
searchFrontier.Enqueue(fromCell);
HexCoordinate fromCoordinate = fromCell.coordinate;
while (searchFrontier.Count > 0)
{
HexCell current = searchFrontier.Dequeue();
current.SearchPhase += 1;
visibleCells.Add(current);
for (HexDirection d = HexDirection.NE; d <= HexDirection.NW; d++)
{
HexCell neighbor = current.GetNeighbor(d);
if (neighbor == null ||
neighbor.SearchPhase > searchFrontierPhase ||
!neighbor.Explorable)
{
continue;
}
int distance = current.Distance + 1;
if (distance + neighbor.ViewElevation > range ||
distance > fromCoordinate.DistanceTo(neighbor.coordinate))
{
continue;
}
if (neighbor.SearchPhase < searchFrontierPhase)
{
neighbor.SearchPhase = searchFrontierPhase;
neighbor.Distance = distance;
neighbor.SearchHeuristic = 0;
searchFrontier.Enqueue(neighbor);
}
else if (distance < neighbor.Distance)
{
int oldPriority = neighbor.SearchPriority;
neighbor.Distance = distance;
searchFrontier.Change(neighbor, oldPriority);
}
}
}
return(visibleCells);
}