//Check that a node can be created here
private int GetTerrainCost(int x, int y)
{
//Check the boundary
if (!_boundary.Contains(x, y))
{
return(-1);
}
TerrainPoint node = _terrain.Get(x, y);
if (node.IsEmpty)
{
return(0);
}
return(-1);
}
//Add a node to a parent node, ignoring if impassable or already closed,
//adding if new, updating if new and better route
private void AddAdjacentNode(int dx, int dy, int cost, RouteNode parent)
{
int x = parent.X + dx;
int y = parent.Y + dy;
int newCost = parent.MovementCost + cost;
//Get terrain cost. -1 is not passable, 0 no cost, 1,2,3 etc higher cost
int terraincost = GetTerrainCost(x, y);
if (terraincost == -1)
{
return;
}
//Check if item has been added to the grid already
RouteNode existing = _grid.Get(x, y);
if (existing != null)
{
if (!existing.Closed && newCost < existing.MovementCost)
{
existing.MovementCost = newCost;
existing.TotalCost = newCost + existing.Heuristic;
existing.Parent = parent;
if (_movementList.Contains(existing))
{
_movementList.Update(existing);
}
else
{
_openList.Update(existing);
}
}
return;
}
//Create a new node
RouteNode node = new RouteNode();
node.X = x;
node.Y = y;
//Set the parent after the location so that the Direction can be set correctly
node.Parent = parent;
node.MovementCost = newCost; //Add the cost to the parent cost
node.Heuristic = GetHeuristic(node);
node.TotalCost = newCost + node.Heuristic;
PushNode(node);
//Add to the grid
_grid.Add(x, y, node);
}