void CalculatePath(Vector3 cp_start, Vector3 cp_target)
{
grid.Reset();
Tile startTile = grid.TileFromWorldPosition(cp_start); // translate the start position to a grid tile.
Tile targetTile = grid.TileFromWorldPosition(cp_target); // translate the target position to a grid tile.
List <Tile> openList = new List <Tile>(); // List to check for neighbours.
HashSet <Tile> closedList = new HashSet <Tile>(); // HashSet for checked neighbours.
// (HashSet for better performance).
Vector3[] waypoints = null;
bool pathSucces = false;
if (!startTile.isWall && !targetTile.isWall) // Only if the start and end tile are walkable initiate the pathfinding.
{
openList.Add(startTile); // Start with the first tile (Start Position).
while (openList.Count > 0)
{
Tile currentTile = openList[0];
for (int i = 0; i < openList.Count; i++)
{
// Check if the current node's f-cost is lower or the same as
if (openList[i].f < currentTile.f || (openList[i].f == currentTile.f && openList[i].h < currentTile.h))
{
currentTile = openList[i];
}
}
openList.Remove(currentTile); // If the tile has been checked, remove it from the openList.
closedList.Add(currentTile); // And add it to the closedList, so it won't be checked again.
if (currentTile == targetTile) // If the current tile is the target tile
{
pathSucces = true;
break;
}
foreach (Tile neighbour in grid.GetNeighbourTiles(currentTile))
{
if (neighbour.isWall || closedList.Contains(neighbour))
{
continue; // Ignore the neighbour if it's a wall.
}
int moveCost = currentTile.g + GetManhattenDistance(currentTile, neighbour);
if (!openList.Contains(neighbour) || moveCost < neighbour.g)
{
neighbour.g = moveCost; // Assigns the move cost (g);
neighbour.h = GetManhattenDistance(neighbour, targetTile); // the manhatten distance to target (h);
neighbour.parent = currentTile; // and sets the current tile to the last tile's parent.
if (!openList.Contains(neighbour))
{
openList.Add(neighbour); // Adds the neighbours to the openList.
}
}
}
}
}
//yield return null; // Waits for one frame.
if (pathSucces)
{
waypoints = GetFinalPath(startTile, targetTile); // Backtrace the parents to calculate the actual path.
}
requestManager.FinishedProcessingPath(waypoints, pathSucces);
}