//find shortest path to nearest coin pile
public static void findClosestCoinPile()
{
GameObject item, tempItem;
int pos, x, y;
int tempMotion, motion = -1;
//clean history before start
shortClose.Clear();
for (y = 0; y < Arena.size; y++)
{
for (x = 0; x < Arena.size; x++)
{
item = Arena.GetGameObject(x, y);
if (item is Coin)
{
start = new Node();
start.f = 0;
start.g = 0;
start.h = 0;
start.x = x;
start.y = y;
start.motion = -1;
open.Add(start);
while (true)
{
//remove first element from open list and add it to close list
current = open[0];
closed.Add(current);
open.RemoveAt(0);
motion = current.motion;
tempMotion = -1;
for (int xT = current.x - 1; xT < current.x + 2; xT++)
{
if (xT < 0 || xT >= Arena.size) //out of bounds
continue;
for (int yT = current.y - 1; yT < current.y + 2; yT++)
{
//ignore current cell and diagonals
if (!(xT == current.x ^ yT == current.y))
continue;
if (yT < 0 || yT >= Arena.size) //out of bounds
continue;
tempItem = Arena.GetGameObject(xT, yT);
if (tempItem is StoneWall || tempItem is BrickWall || tempItem is Water ||
(tempItem is Tank && ((Tank)tempItem).name != Tank.current_player_name))
//obstacle or another tank! ignore
continue;
temp = new Node();
temp.x = xT;
temp.y = yT;
temp.g = current.g + Math.Abs(xT - current.x) + Math.Abs(yT - current.y);
//determine motion direction
//add extra cost if direction must be changed
if (xT > current.x)
{
if (motion != -1 && motion != RIGHT)
temp.g++;
tempMotion = RIGHT;
}
if (xT < current.x)
{
if (motion != -1 && motion != LEFT)
temp.g++;
tempMotion = LEFT;
}
if (yT > current.y)
{
if (motion != -1 && motion != DOWN)
temp.g++;
tempMotion = DOWN;
}
if (yT < current.y)
{
if (motion != -1 && motion != UP)
temp.g++;
tempMotion = UP;
}
temp.h = Math.Abs(xT - myself.x) + Math.Abs(yT - myself.y);
temp.f = temp.g + temp.h;
pos = open.IndexOf(temp);
if (pos >= 0 && open[pos].g > temp.g)
{
open[pos].g = temp.g;
open[pos].f = open[pos].g + open[pos].h;
}
else if (closed.IndexOf(temp) < 0)
{
temp.motion = tempMotion;
open.Add(temp);
}
}
}
//quit if nothing found
if (open.Count == 0)
break;
//sort open list
open.Sort(CompareNodes);
//exit condition
if (closed[closed.Count - 1].x == myself.x && closed[closed.Count - 1].y == myself.y)
break;
}
}
//is current closed list the shortest?
if (closed.Count > 0 && (shortClose.Count > closed.Count || shortClose.Count == 0))
{
shortClose = new List<Node>(closed);
}
//clean up before next iteration
open.Clear();
closed.Clear();
}
}
}
//comparator for non-increasing sort order
private static int CompareNodes(Node n1, Node n2)
{
return n1.f - n2.f;
}
//find and return my tank in Node form (for AI)
public static void findMe()
{
GameObject item;
myself = null;
myTank = null;
for (int y = 0; y < Arena.size; y++)
{
for (int x = 0; x < Arena.size; x++)
{
item = Arena.GetGameObject(x, y);
if (item is Tank && ((Tank)item).name == Tank.current_player_name)
{
//Get Current Tank
myTank = (Tank)item;
myself = new Node();
myself.x = x;
myself.y = y;
myDirection = ((Tank)item).direction;
return;
}
}
}
}
