private static List <GridSpot> backtrack(pGridSpot curr, List <GridSpot> path)
{
if (curr.mark <= 0) //Found start point
{
path.Add(curr);
return(path);
}
else
{
List <pGridSpot> neighbors = getBackTrackNeighbors(curr);
foreach (pGridSpot back in neighbors)
{
if (back == null)
{
}
else
{
path.Add(back);
path = backtrack(back, path);
return(path);
}
}
return(path);
}
}
private static List <pGridSpot> getBackTrackNeighbors(pGridSpot curr)
{
List <pGridSpot> toReturn = new List <pGridSpot>();
toReturn.Add(getBackTrackNeigh(curr, new Vector3(0f, 1f, 0f))); //Up neighbor
toReturn.Add(getBackTrackNeigh(curr, new Vector3(0f, -1f, 0f))); //Down neighbor
toReturn.Add(getBackTrackNeigh(curr, new Vector3(1f, 0f, 0f))); //Right neighbor
toReturn.Add(getBackTrackNeigh(curr, new Vector3(-1f, 0f, 0f))); //Left neighbor
return(toReturn);
}
private static List <GridSpot> waveExpansion(GridSpot curr, GridSpot end, List <GridSpot> path, int marker)
{
if (curr.Coord().Equals(end.Coord())) //Found endpoint
{
path.Add(curr); //End point
return(path);
}
List <pGridSpot> neighbors = getNeighbors(curr);
foreach (pGridSpot neighbor in neighbors)
{
if (neighbor == null)
{
} //No neighbor, collapse the branch
else
{
neighbor.mark = marker;
copyMap.addTile(neighbor); //Add marked tile to the temp map
stack.Add(neighbor); //Add marked tile to the bottom of the stack
}
}
while (stack.Count > 0)
{
marker += 1;
pGridSpot next = stack[0];
stack.Remove(next);
if (next.Coord().Equals(end.Coord()))
{
waveExpansion(next, end, path, marker); //Go one more time
return(path);
}
else
{
waveExpansion(next, end, path, marker);
}
}
return(path);
}
private static pGridSpot getBackTrackNeigh(pGridSpot curr, Vector3 toLook)
{
int x = (int)(curr.Coord().x + toLook.x);
int y = (int)(curr.Coord().y + toLook.y);
if (x < 0 || x >= BoardManager.rows ||
y < 0 || y >= BoardManager.columns)
{
return(null);
}
if (copyMap.getTile(x, y).GetType() == typeof(pGridSpot))
{
if (curr.mark > ((pGridSpot)copyMap.getTile(x, y)).mark)
{
return((pGridSpot)copyMap.getTile(x, y)); //If the next spot mark is less than the current marker
}
}
return(null);
}
public static List <GridSpot> getPath(Board map, GridSpot start, GridSpot end, List <GridSpot> path)
{
//Step 1: Initialization
copyMap = new Board(map);
pGridSpot first = new pGridSpot(start);
first.mark = 0;
copyMap.addTile(first);
path = waveExpansion(start, end, path, 1); //Step 2: Wave expand
pGridSpot goBack = new pGridSpot(end); //Step 3: Backtrace
goBack.mark = int.MaxValue;
path = backtrack(goBack, path);
//Step 5: Clearance
copyMap = null;
return(path);
}
