public void addNeighbor(MGraphNode n)
{
if (n == null)
return;
neighbors.Add (n);
}
public void build(Position origin, int[,] movementArray)
{
int width, height; //map size
width = movementArray.GetLength (0);
height = movementArray.GetLength (1);
nodeArray = new MGraphNode[width,height];
//Populating nodeArray
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
//if movement cost is 5, we can't walk there, so we don't add it to the graph
if (movementArray [x, y] == 5)
continue;
nodeArray [x, y] = new MGraphNode (new Position(x, y), movementArray [x, y]);
}
}
MGraphNode curr;
//Now we add the edges
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
curr = nodeArray [x, y];
if (curr == null)
continue;
//Maybe I could create methods for each of these?
//Maybe I don't even need a graph?
//top
if ((y + 1) < height) curr.addNeighbor(nodeArray[x,y+1]);
//right
if((x+1) < width) curr.addNeighbor(nodeArray[x+1,y]);
//bottom
if(y > 0) curr.addNeighbor(nodeArray[x, y-1]);
//left
if(x > 0) curr.addNeighbor(nodeArray[x-1, y]);
}
}
//Last step: get the origin node
this.origin = nodeArray [origin.x, origin.y];
}
public void Run(MovementGraph graph)
{
Stopwatch s = new Stopwatch();
s.Start ();
List<MGraphNode> Q = new List<MGraphNode>(); //Set of unvisited nodes
dist = new Dictionary<MGraphNode, int>(); //Distances to each node, from the origin
prev = new Dictionary<MGraphNode, MGraphNode>(); //Previous node to each node on the path
foreach(MGraphNode v in graph.nodeArray) //initializing sets
{
if (v == null)
continue;
dist [v] = int.MaxValue;
prev [v] = null;
Q.Add (v);
}
dist [graph.origin] = 0; //distance cost from the origin to the origin
MGraphNode u;
int alt;
while (Q.Count > 0) {
u = getLowestDistance (Q); //origin will be selected first
Q.Remove (u); //equivalent to visiting the node u
foreach (MGraphNode v in u.neighbors) {
if (!Q.Contains (v)) continue; //We dont want neighbors that have already been visited
alt = dist [u] + v.moveCost;
if(alt < dist[v]) //New shortest path to v was found
{
dist [v] = alt;
prev [v] = u;
}
}
}
s.Stop ();
UnityEngine.Debug.Log ("Dijkstra's algorithm just finished taking " + s.ElapsedMilliseconds + " ms");
origin = graph.origin;
goal = graph.goal;
}
