///<summary>
///use to add the eight neighboring edges of a graph node that
///is positioned in a grid layout
///</summary>
///<param name="graph"></param>
///<param name="row"></param>
///<param name="col"></param>
///<param name="numCellsX"></param>
///<param name="numCellsY"></param>
public static void AddAllNeighborsToGridNode(
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 neighbor
if (!ValidNeighbor(nodeX, nodeY, numCellsX, numCellsY))
continue;
//calculate the distance to this node
Vector2 posNode =
graph.GetNode(row*numCellsX + col).Position;
Vector2 posNeighbour =
graph.GetNode(nodeY*numCellsX + nodeX).Position;
float dist = (posNode - posNeighbour).Length();
//this neighbor is okay so it can be added
NavGraphEdge newEdge =
new NavGraphEdge(
row*numCellsX + col,
nodeY*numCellsX + nodeX,
dist);
graph.AddEdge(newEdge);
//if graph is not a digraph, an edge needs to be added going
//in the other direction
if (graph.IsDigraph)
continue;
NavGraphEdge newReverseEdge =
new NavGraphEdge(
nodeY*numCellsX + nodeX,
row*numCellsX + col,
dist);
graph.AddEdge(newReverseEdge);
}
}
}
