//------------ Helper_AddAllNeighboursToGridNode ------------------
//
// use to add the eight neighboring edges of a graph node that
// are positioned in a grid layout
//------------------------------------------------------------------------
public static void Helper_AddAllNeighboursToGridNode(SparseGraph graph,
int row,
int col,
int NumCellsX,
int NumCellsY)
{
for (int i = -1; i < 2; ++i)
{
for (int j = -1; j < 2; ++j)
{
int nodeX = col + j;
int nodeY = row + i;
//skip if equal to this node
if ((i == 0) && (j == 0))
{
continue;
}
//check to see if this is a valid neighbour
if (ValidNeighbour(nodeX, nodeY, NumCellsX, NumCellsY))
{
//calculate the distance to this node
Vector2D PosNode = graph.GetNode(row * NumCellsX + col).Pos;
Vector2D PosNeighbour = graph.GetNode(nodeY * NumCellsX + nodeX).Pos;
double dist = PosNode.Distance(PosNeighbour);
NavGraphEdge NewEdge;
//this neighbour is okay so it can be added
NewEdge = new NavGraphEdge(row * NumCellsX + col,
nodeY * NumCellsX + nodeX,
dist);
graph.AddEdge(NewEdge);
//if graph is not a diagraph then an edge needs to be added going
//in the other direction
if (!graph.isDigraph())
{
NewEdge = new NavGraphEdge(nodeY * NumCellsX + nodeX,
row * NumCellsX + col,
dist);
graph.AddEdge(NewEdge);
}
}
}
}
}
public static void Helper_WeightNavGraphNodeEdges(SparseGraph graph, int node, double weight)
{
//make sure the node is present
Debug.Assert(node < graph.NumNodes(), "Node can not exist in graph!");
//set the cost for each edge
SparseGraph.EdgeIterator EdgeItr = new SparseGraph.EdgeIterator(graph, node);
while (EdgeItr.MoveNext())
{
//calculate the distance between nodes
double dist = Vector2D.Vec2DDistance(graph.GetNode(EdgeItr.Current.From).Pos,
graph.GetNode(EdgeItr.Current.To).Pos);
//set the cost of this edge
graph.SetEdgeCost(EdgeItr.Current.From, EdgeItr.Current.To, dist * weight);
//if not a digraph, set the cost of the parallel edge to be the same
if (!graph.isDigraph())
{
graph.SetEdgeCost(EdgeItr.Current.To, EdgeItr.Current.From, dist * weight);
}
}
}
