/// <summary>
/// Walk backwards from TargetNode and set parents' IsPartOfTheSolution.
/// </summary>
private void SetSolution(CancellationToken cancellationToken)
{
Node node = grid.TargetNode;
List <Node> solution = new List <Node>();
while (node != grid.StartingNode)
{
solution.Add(node);
node = node.Parent;
}
solution.Reverse();
foreach (var n in solution)
{
if (cancellationToken.IsCancellationRequested)
{
ClearPath();
PathfindingFinished?.Invoke(this, null);
return;
}
n.IsPartOfTheSolution = true;
//n = n.Parent;
Thread.Sleep(VisualizationTime * 2);
}
}
public async Task FindPathAsync(CancellationToken cancellationToken)
{
await Task.Factory.StartNew(() =>
{
if (grid.Algorithm == null)
{
throw new NullReferenceException("Scenario grid does not have an assigned pathfinding algorithim!");
}
while (true)
{
if (OpenNodes.Count == 1 && OpenNodes[0] == grid.StartingNode)
{
CurrentNode = OpenNodes[0];
}
else
{
CurrentNode = GetNodeWithLowestFCost(OpenNodes);
}
Thread.Sleep(VisualizationTime);
OpenNodes.Remove(CurrentNode);
ClosedNodes.Add(CurrentNode);
Thread.Sleep(VisualizationTime);
if (CurrentNode == grid.TargetNode)
{
SetSolution(cancellationToken);
PathfindingFinished?.Invoke(this, null);
return;
}
neighbouringNodes = GetNeighbouringNodes(CurrentNode, allowDiagonals: AllowDiagonalMovement);
foreach (Node n in neighbouringNodes)
{
if (cancellationToken.IsCancellationRequested)
{
ClearPath();
PathfindingFinished?.Invoke(this, null);
return;
}
if (!n.IsTraversable || ClosedNodes.Contains(n))
{
continue;
}
if (IsNewPathShorter(CurrentNode, n) || !OpenNodes.Contains(n))
{
n.GCost = CurrentNode.GCost + GetDistance(CurrentNode, n);
n.HCost = GetDistance(n, grid.TargetNode);
n.Parent = CurrentNode;
if (!OpenNodes.Contains(n))
{
OpenNodes.Add(n);
}
}
Thread.Sleep(VisualizationTime / 3);
}
}
});
}
