public List <PathFindingNode> FindPath(MapNode startMapNode, MapNode endMapNode)
{
PathFindingGrid pathFindingGrid = new PathFindingGrid();
PathFindingNode startNode = pathFindingGrid.GetGridNode(startMapNode);
PathFindingNode endNode = pathFindingGrid.GetGridNode(endMapNode);
openList = new List <PathFindingNode> {
startNode
};
closedList = new List <PathFindingNode>();
startNode.gCost = 0;
startNode.hCost = CalculateDistanceCost(startNode, endNode);
startNode.CalculateFCost();
while (openList.Count > 0)
{
PathFindingNode curNode = GetLowestFCostNode(openList);
if (curNode == endNode)
{
return(CalculatePath(endNode));
}
openList.Remove(curNode);
closedList.Add(curNode);
foreach (PathFindingNode neighborNode in GetNeighborList(pathFindingGrid, curNode))
{
if (closedList.Contains(neighborNode))
{
continue;
}
int tentativeCost = curNode.gCost + CalculateDistanceCost(curNode, neighborNode);
if (tentativeCost < neighborNode.gCost)
{
neighborNode.cameFrom = curNode;
neighborNode.gCost = tentativeCost;
neighborNode.hCost = CalculateDistanceCost(neighborNode, endNode);
neighborNode.CalculateFCost();
if (!openList.Contains(neighborNode))
{
openList.Add(neighborNode);
}
}
}
}
return(null);
}
private List <PathFindingNode> GetNeighborList(PathFindingGrid grid, PathFindingNode curNode)
{
List <PathFindingNode> neighborList = new List <PathFindingNode>();
// TODO: Take wall corner case into account, i.e. an object cannot pass
// from (0,0) to (1,1) if (0,1) and (1,0) are walls
for (int x = -1; x <= 1; x++)
{
for (int y = -1; y <= 1; y++)
{
if (x == 0 && y == 0)
{
continue;
}
PathFindingNode neighborNode = grid.GetGridNode(curNode.x + x, curNode.y + y);
if (neighborNode != null && !neighborNode.IsWall())
{
neighborList.Add(neighborNode);
}
}
}
return(neighborList);
}
