// Find grid cell successors if they are not building and soldier.
private List <CellModelForAStar> FindSuccessors(CellModelForAStar current)
{
List <CellModelForAStar> successors = new List <CellModelForAStar>();
if (current.XIndex + 1 < Config.VerticalGridNumber)
{
if (MapController.Instance().GetGridCellArray()[current.XIndex + 1, current.YIndex].GridCellType == GridCellTypes.Empty)
{
successors.Add(_cellModelAStarArray[current.XIndex + 1, current.YIndex]);
}
}
if (current.XIndex - 1 >= 0)
{
if (MapController.Instance().GetGridCellArray()[current.XIndex - 1, current.YIndex].GridCellType == GridCellTypes.Empty)
{
successors.Add(_cellModelAStarArray[current.XIndex - 1, current.YIndex]);
}
}
if (current.YIndex + 1 < Config.HorizontalGridNumber)
{
if (MapController.Instance().GetGridCellArray()[current.XIndex, current.YIndex + 1].GridCellType == GridCellTypes.Empty)
{
successors.Add(_cellModelAStarArray[current.XIndex, current.YIndex + 1]);
}
}
if (current.YIndex - 1 >= 0)
{
if (MapController.Instance().GetGridCellArray()[current.XIndex, current.YIndex - 1].GridCellType == GridCellTypes.Empty)
{
successors.Add(_cellModelAStarArray[current.XIndex, current.YIndex - 1]);
}
}
return(successors);
}
// Create AStar gridcell models for each grid cell
private void CreateCellArrayForAStar()
{
for (int i = 0; i < Config.VerticalGridNumber; i++)
{
for (int j = 0; j < Config.HorizontalGridNumber; j++)
{
CellModelForAStar cellModel = new CellModelForAStar();
_cellModelAStarArray[i, j] = cellModel;
_cellModelAStarArray[i, j].XIndex = i;
_cellModelAStarArray[i, j].YIndex = j;
}
}
}
// AStar algorithm search function and get shortest path for the soldier with given Target point
public List <GridCellModel> GetShortestPathWithAStarAlgorithm(GameObject soldier, int TargetXIndex, int TargetYIndex)
{
List <CellModelForAStar> openList = new List <CellModelForAStar>();
List <CellModelForAStar> closedList = new List <CellModelForAStar>();
List <GridCellModel> shortestPath = new List <GridCellModel>();
CreateCellArrayForAStar();
int startGridCellXIndex = (int)soldier.GetComponent <SoldierView>().GetSoldierController().GetSoldierXIndex();
int startGridCellYIndex = (int)soldier.GetComponent <SoldierView>().GetSoldierController().GetSoldierYIndex();
CellModelForAStar startCell = _cellModelAStarArray[startGridCellXIndex, startGridCellYIndex];
startCell.DistanceToEnd = CalculateDistanceValue(startGridCellXIndex, startGridCellYIndex, TargetXIndex, TargetYIndex);
startCell.DistanceToStart = 0;
_cellModelAStarArray[startCell.XIndex, startCell.YIndex].ParentXIndex = -1;
_cellModelAStarArray[startCell.XIndex, startCell.YIndex].ParentYIndex = -1;
openList.Add(startCell);
openList.Remove(startCell);
CellModelForAStar current = startCell;
List <CellModelForAStar> successors = FindSuccessors(current);
foreach (var successor in successors)
{
successor.DistanceToEnd = CalculateDistanceValue(successor.XIndex, successor.YIndex, TargetXIndex, TargetYIndex);
successor.DistanceToStart = CalculateDistanceValue(startCell.XIndex, startCell.YIndex, successor.XIndex, successor.YIndex);
successor.TotalDistance = successor.DistanceToEnd + successor.DistanceToStart;
if (!closedList.Contains(successor))
{
_cellModelAStarArray[successor.XIndex, successor.YIndex].ParentXIndex = current.XIndex;
_cellModelAStarArray[successor.XIndex, successor.YIndex].ParentYIndex = current.YIndex;
openList.Add(successor);
}
}
closedList.Add(startCell);
while (openList.Count > 0)
{
openList.OrderBy(o => o.DistanceToEnd).ToList();
current = openList[0];
if (current.XIndex == TargetXIndex && current.YIndex == TargetYIndex)
{
break;
}
successors = FindSuccessors(current);
foreach (var successor in successors)
{
successor.DistanceToEnd = CalculateDistanceValue(successor.XIndex, successor.YIndex, TargetXIndex, TargetYIndex);
successor.DistanceToStart = CalculateDistanceValue(startCell.XIndex, startCell.YIndex, successor.XIndex, successor.YIndex);
successor.TotalDistance = successor.DistanceToEnd + successor.DistanceToStart;
if (!closedList.Contains(successor) && !openList.Contains(successor))
{
_cellModelAStarArray[successor.XIndex, successor.YIndex].ParentXIndex = current.XIndex;
_cellModelAStarArray[successor.XIndex, successor.YIndex].ParentYIndex = current.YIndex;
openList.Add(successor);
}
}
openList.Remove(current);
closedList.Add(current);
}
while (_cellModelAStarArray[current.XIndex, current.YIndex].ParentXIndex != -1 &&
_cellModelAStarArray[current.XIndex, current.YIndex].ParentYIndex != -1)
{
GridCellModel currentGridCellModelPath = new GridCellModel();
currentGridCellModelPath.XIndex = current.XIndex;
currentGridCellModelPath.YIndex = current.YIndex;
shortestPath.Add(currentGridCellModelPath);
current = _cellModelAStarArray[_cellModelAStarArray[current.XIndex, current.YIndex].ParentXIndex,
_cellModelAStarArray[current.XIndex, current.YIndex].ParentYIndex];
}
shortestPath.Reverse();
if (shortestPath[shortestPath.Count - 1].XIndex != TargetXIndex &&
shortestPath[shortestPath.Count - 1].YIndex != TargetYIndex)
{
return(null);
}
return(shortestPath);
}
