private Point getNextPoint(Point sourceLoc, Point targetLoc)
{
// clear the lists
openList.Clear();
closedList.Clear();
// find direction of targetLoc
GridFacing facing = findFacing(sourceLoc, targetLoc);
// get starting adjacent locations
foreach (Node node in getNeighbors(new Node(sourceLoc.X, sourceLoc.Y), (int)facing, targetLoc))
{
openList.Add(node);
}
Node previous = new Node();
while (openList.Count > 0)
{
// current lowest G+H
int indexS = openList.Min(f => f.F);
// get next node with lowest G+H that is not the previous node
Node node = openList.First(f => f.F == indexS && f != previous);
// check for goal
if (node.Loc == targetLoc)
{
return(recurseNextNode(node).Loc);
}
// remove from openset
openList.Remove(node);
// add to closedset
closedList.Add(node);
// get neighbors of current location
List <Node> sortedNeighbors = getNeighbors(node, (int)facing, targetLoc);
foreach (Node neighbor in sortedNeighbors)
{
// not in closed set
if (closedList.Contains(neighbor))
{
continue;
}
// steps from source
int tempG = node.G + 1;
// not already in openset or temp g less than existing g;
if (!openList.Any(f => f.Loc == neighbor.Loc && f.G <= tempG))//|| tempG < neighbor.G)
{
neighbor.Parent = node;
neighbor.G = tempG;
neighbor.H = Convert.ToInt32(neighbor.Loc.DistanceTo(targetLoc));
if (!openList.Contains(neighbor) && !closedList.Contains(neighbor))
{
openList.Add(neighbor);
}
}
}
previous = node;
}
return(new Point(0, 0));
}
private Node findNeighborInDirection(Node source, GridFacing direction)
{
Node result = new Node();
switch (direction)
{
case GridFacing.NorthEast:
result = new Node(source.Loc.X + 1, source.Loc.Y - 1);
break;
case GridFacing.East:
result = new Node(source.Loc.X + 1, source.Loc.Y);
break;
case GridFacing.SouthEast:
result = new Node(source.Loc.X + 1, source.Loc.Y + 1);
break;
case GridFacing.North:
result = new Node(source.Loc.X, source.Loc.Y - 1);
break;
case GridFacing.South:
result = new Node(source.Loc.X, source.Loc.Y + 1);
break;
case GridFacing.NorthWest:
result = new Node(source.Loc.X - 1, source.Loc.Y - 1);
break;
case GridFacing.West:
result = new Node(source.Loc.X - 1, source.Loc.Y);
break;
case GridFacing.SouthWest:
result = new Node(source.Loc.X - 1, source.Loc.Y + 1);
break;
}
return(result);
}
