public List <GridTile> FindPath(GridTile[,] _grid, GridTile startTile, GridTile endTile)
{
grid = _grid;
if (grid == null || startTile == null || endTile == null)
{
return(null);// Invalid Path
}
openList = new List <GridTile> {
startTile
};
closedList = new List <GridTile>();
for (int x = 0; x < grid.GetLength(0); x++)
{
for (int y = 0; y < grid.GetLength(1); y++)
{
GridTile gridTile = grid[x, y];
gridTile.GCost = int.MaxValue;
gridTile.CalculateFCost();
gridTile.CameFromTile = null;
}
}
startTile.GCost = 0;
startTile.HCost = CalculateDistanceCost(startTile, endTile);
startTile.CalculateFCost();
while (openList.Count > 0)
{
GridTile currentTile = GetLowestFCostTile(openList);
if (currentTile == endTile)
{
// Reached final node
//visual
return(CalculatePath(endTile));
}
openList.Remove(currentTile);
closedList.Add(currentTile);
foreach (GridTile neighbourTile in GetNeighbourList(currentTile))
{
if (closedList.Contains(neighbourTile))
{
continue;
}
if (!neighbourTile.IsWalkable)
{
closedList.Add(neighbourTile);
continue;
}
int tentativeGCost = currentTile.GCost + CalculateDistanceCost(currentTile, neighbourTile);
if (tentativeGCost < neighbourTile.GCost)
{
neighbourTile.CameFromTile = currentTile;
neighbourTile.GCost = tentativeGCost;
neighbourTile.HCost = CalculateDistanceCost(neighbourTile, endTile);
neighbourTile.CalculateFCost();
if (!openList.Contains(neighbourTile))
{
openList.Add(neighbourTile);
}
}
//visual
//PathfindingDebugStepVisual.Instance.TakeSnapshot(grid, currentTile, openList, closedList);
}
}
// Out of nodes on the openList
return(null);
}