/// <summary>
/// Verifies if the target has been reached by the current node.
/// If affirmative, a flag is set, as well as the destination leaf.
/// </summary>
/// <param name="map">Scene map.</param>
/// <param name="current">Current node in question.</param>
/// <param name="target">Target's position.</param>
private void checkFound(Map map, Node current, Map.Pos target)
{
if (current.pos == target)
{
foundTarget = true;
end = current;
}
}
/// <summary>
/// Returns if the given space is empty or not.
/// </summary>
private bool hasWall(Map.Pos space)
{
if (currentScene.map.getSpaceType(space) == Map.SpaceType.Wall)
{
return(true);
}
return(false);
}
/*********************************************************************/
/* Class Methods */
/*********************************************************************/
/// <summary>
/// Calculates and returns, if possible, best route for ghost to reach pacman.
/// </summary>
/// <param name="map">Map used in search algorithm.</param>
/// <param name="pacpos">Pacman's position in map.</param>
public bool calcPathToPac(Map map, Map.Pos pacpos)
{
pathToPac = pathfinder.findBestPath(map, this.pos, pacpos);
if ((pathToPac != null) && (pathToPac.Count != 0))
{
return(false);
}
return(true);
}
private bool hasSomeone(Map.Pos pos)
{
if (currentScene.pacman.pos == pos)
{
return(true);
}
foreach (Ghost ghost in currentScene.ghosts)
{
if (ghost.pos == pos)
{
return(true);
}
}
return(false);
}
/// <summary>
/// Finds and returns the best path to be followed from the origin postion,
/// to the targets position, on the given map.
/// Theoretically, I should only return the first position in the best path,
/// since it is calculated on every change in the scene, but I prefered to leave
/// it this way for now, in case I find a use for it later.
/// </summary>
/// <param name="map">Scene map.</param>
/// <param name="origin">Origin's position.</param>
/// <param name="target">Target's position.</param>
public Stack <Pathfinder.Direction> findBestPath(Map map, Map.Pos origin, Map.Pos target)
{
// Setup visited map
initVisitedMap(map);
// reset pathfinders state
reset();
// Setup root
root.pos = origin;
visitedMap[root.pos.x, root.pos.y] = true;
// performs inital step
step(map, root, target);
// if target is not found in the frist step, enter step loop
Node nextTry;
while (!foundTarget)
{
nextTry = findLowerCost();
if (noSolution)
{
return(null);
}
visitedMap[nextTry.pos.x, nextTry.pos.y] = true;
stepQue.Remove(nextTry);
step(map, nextTry, target);
}
// fill direction stack
fillBestPath();
return(bestPath);
}
/// <summary>
/// Returns a wall texture, taking in account its adjacent sapces.
/// Look, I know im loading the same textures flipped 3 times, but
/// honestly, each one is like 1K, f*****g 1K. I rather load 1K four
/// times, and flip the images in Gimp, than implement a 100 line logic
/// code that does is automatically.
/// </summary>
private Texture2D getWallTexture(SpriteBatch sb, Map.Pos pos)
{
Map.SpaceType a, b, c, d;
a = currentScene.map.getSpaceType(pos - Map.unity);
b = currentScene.map.getSpaceType(pos - Map.unitx);
c = currentScene.map.getSpaceType(pos + Map.unitx);
d = currentScene.map.getSpaceType(pos + Map.unity);
if (a == Map.SpaceType.Empty)
{
if (b == Map.SpaceType.Empty)
{
if (c == Map.SpaceType.Empty)
{
if (d == Map.SpaceType.Empty)
{
return(wallDot);
}
else
{
return(wallSimpleUp);
}
}
else
{
if (d == Map.SpaceType.Empty)
{
return(wallSimpleLeft);
}
else
{
return(wallLDown);
}
}
}
else
{
if (c == Map.SpaceType.Empty)
{
if (d == Map.SpaceType.Empty)
{
return(wallSimpleRight);
}
else
{
return(wallLLeft);
}
}
else
{
if (d == Map.SpaceType.Empty)
{
return(wallLineHorizontal);
}
else
{
return(wallTDown);
}
}
}
}
else
{
if (b == Map.SpaceType.Empty)
{
if (c == Map.SpaceType.Empty)
{
if (d == Map.SpaceType.Empty)
{
return(wallSimpleDown);
}
else
{
return(wallLineVertical);
}
}
else
{
if (d == Map.SpaceType.Empty)
{
return(wallLRight);
}
else
{
return(wallTRight);
}
}
}
else
{
if (c == Map.SpaceType.Empty)
{
if (d == Map.SpaceType.Empty)
{
return(wallLUp);
}
else
{
return(wallTLeft);
}
}
else
{
if (d == Map.SpaceType.Empty)
{
return(wallTUp);
}
else
{
return(wallCross);
}
}
}
}
}
/// <summary>
/// Performs a step, where every adjacent space to the current node is tested to see
/// if it is a plausible candidate for a next direction to be followed in the
/// pathfinding process.
/// Is the node in a given direction is empty and has not been visited, it will
/// be added to the the stepQue, as well as the main tree.
/// If the target is reached in one of the directions adjacent to the current Node,
/// the target is set as 'found'.
/// </summary>
/// <param name="map">Scene map.</param>
/// <param name="current">Current node in question.</param>
/// <param name="target">Target's position.</param>
private void step(Map map, Node current, Map.Pos target)
{
// Test all adjacent nodes.
// Left
if ((map.getSpaceType(current.pos - Map.unitx) == Map.SpaceType.Empty) &&
(!visitedMap[current.pos.x - 1, current.pos.y]))
{
Node left = new Node();
left.pos.x = current.pos.x - 1;
left.pos.y = current.pos.y;
left.currentCost++;
left.totalCost = left.currentCost + calcPathCost(left.pos, target);
addTreeNode(current, left, Direction.Left);
checkFound(map, left, target);
if (!foundTarget)
{
addQueNode(left);
}
else
{
return;
}
}
// Right
if ((map.getSpaceType(current.pos + Map.unitx) == Map.SpaceType.Empty) &&
(!visitedMap[current.pos.x + 1, current.pos.y]))
{
Node right = new Node();
right.pos.x = current.pos.x + 1;
right.pos.y = current.pos.y;
right.currentCost++;
right.totalCost = right.currentCost + calcPathCost(right.pos, target);
addTreeNode(current, right, Direction.Right);
checkFound(map, right, target);
if (!foundTarget)
{
addQueNode(right);
}
else
{
return;
}
}
// Up
if ((map.getSpaceType(current.pos - Map.unity) == Map.SpaceType.Empty) &&
(!visitedMap[current.pos.x, current.pos.y - 1]))
{
Node up = new Node();
up.pos.x = current.pos.x;
up.pos.y = current.pos.y - 1;
up.currentCost++;
up.totalCost = up.currentCost + calcPathCost(up.pos, target);
addTreeNode(current, up, Direction.Up);
checkFound(map, up, target);
if (!foundTarget)
{
addQueNode(up);
}
else
{
return;
}
}
// Down
if ((map.getSpaceType(current.pos + Map.unity) == Map.SpaceType.Empty) &&
(!visitedMap[current.pos.x, current.pos.y + 1]))
{
Node down = new Node();
down.pos.x = current.pos.x;
down.pos.y = current.pos.y + 1;
down.currentCost++;
down.totalCost = down.currentCost + calcPathCost(down.pos, target);
addTreeNode(current, down, Direction.Down);
checkFound(map, down, target);
if (!foundTarget)
{
addQueNode(down);
}
else
{
return;
}
}
}
/// <summary>
/// Returns the Manhattan distance between two positions.
/// </summary>
/// <param name="origin">Origin position.</param>
/// <param name="dest">Destination position.</param>
private int calcPathCost(Map.Pos origin, Map.Pos dest)
{
return(Math.Abs(origin.x - dest.x) + Math.Abs(origin.y - dest.y));
}
