// This generates the successors to the given Node. It uses a helper function called
// AddSuccessor to give the successors to the AStar class. The A* specific initialisation
// is done for each node internally, so here you just set the state information that
// is specific to the application
public bool GetSuccessors(AStarPathfinder aStarSearch, MapSearchNode parentNode)
{
Vector2Int parentPos = new Vector2Int(0, 0);
if (parentNode != null)
{
parentPos = parentNode.nodeIndex;
}
if (pathfinder.volume > 0)
{
AddNeighbourNodeOfAttachVolume(1, 0, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(-1, 0, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(0, 1, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(0, -1, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(1, -1, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(-1, 1, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(1, 1, parentPos, aStarSearch);
AddNeighbourNodeOfAttachVolume(-1, -1, parentPos, aStarSearch);
}
else
{
// push each possible move except allowing the search to go backwards
AddNeighbourNode(-1, 0, parentPos, aStarSearch);
AddNeighbourNode(0, -1, parentPos, aStarSearch);
AddNeighbourNode(1, 0, parentPos, aStarSearch);
AddNeighbourNode(0, 1, parentPos, aStarSearch);
AddNeighbourNode(1, -1, parentPos, aStarSearch);
AddNeighbourNode(-1, 1, parentPos, aStarSearch);
AddNeighbourNode(1, 1, parentPos, aStarSearch);
AddNeighbourNode(-1, -1, parentPos, aStarSearch);
}
return(true);
}
void AddNeighbourNode(int xOffset, int yOffset, Vector2Int parentPos, AStarPathfinder aStarSearch)
{
if (ValidNeigbour(xOffset, yOffset) &&
!(parentPos.x == nodeIndex.x + xOffset && parentPos.y == nodeIndex.y + yOffset))
{
Vector2Int neighbourPos = new Vector2Int(nodeIndex.x + xOffset, nodeIndex.y + yOffset);
//Debug.Log("neighbourPos:" + neighbourPos);
MapSearchNode newNode = pathfinder.AllocateMapSearchNode(neighbourPos);
aStarSearch.AddSuccessor(newNode);
}
}
public Vector2Int[] GetPath(Vector2Int start, Vector2Int end, AStarPathfinder pathfinder) => PathFinder.Pathfind(this, start, end, pathfinder).ToArray();
/// <summary>
///
/// </summary>
/// <param name="grid"></param>
/// <param name="startPos"></param>
/// <param name="goalPos"></param>
/// <param name="pathfinder"></param>
/// <returns></returns>
public static List <Vector2Int> Pathfind(Grid grid, Vector2Int startPos, Vector2Int goalPos, AStarPathfinder pathfinder = null)
{
// Reset the allocated MapSearchNode pointer
if (pathfinder == null)
{
pathfinder = new AStarPathfinder(grid);
}
pathfinder.InitiatePathfind();
// Create a start state
MapSearchNode nodeStart = pathfinder.AllocateMapSearchNode(startPos);
// Define the goal state
MapSearchNode nodeEnd = pathfinder.AllocateMapSearchNode(goalPos);
// Set Start and goal states
pathfinder.SetStartAndGoalStates(nodeStart, nodeEnd);
// Set state to Searching and perform the search
AStarPathfinder.SearchState searchState = AStarPathfinder.SearchState.Searching;
uint searchSteps = 0;
do
{
searchState = pathfinder.SearchStep();
searchSteps++;
}while (searchState == AStarPathfinder.SearchState.Searching);
// Search complete
bool pathfindSucceeded = (searchState == AStarPathfinder.SearchState.Succeeded);
if (pathfindSucceeded)
{
// Success
List <Vector2Int> newPath = new List <Vector2Int>();
int numSolutionNodes = 0; // Don't count the starting cell in the path length
// Get the start node
MapSearchNode node = pathfinder.GetSolutionStart();
newPath.Add(node.nodeIndex);
++numSolutionNodes;
// Get all remaining solution nodes
for (; ;)
{
node = pathfinder.GetSolutionNext();
if (node == null)
{
break;
}
++numSolutionNodes;
newPath.Add(node.nodeIndex);
}
;
// Once you're done with the solution we can free the nodes up
pathfinder.FreeSolutionNodes();
return(newPath);
//System.Console.WriteLine("Solution path length: " + numSolutionNodes);
//System.Console.WriteLine("Solution: " + newPath.ToString());
}
else if (searchState == AStarPathfinder.SearchState.Failed)
{
// FAILED, no path to goal
Debug.LogError("Pathfind FAILED!");
}
return(null);
}
public MapSearchNode(AStarPathfinder _pathfinder)
{
nodeIndex = Vector2Int.zero;
pathfinder = _pathfinder;
}
void AddNeighbourNodeOfAttachVolume(int xOffset, int yOffset, Vector2Int parentPos, AStarPathfinder aStarSearch)
{
int src_xOffset = xOffset;
int src_yOffset = yOffset;
bool flag = true;
int volume = aStarSearch.volume;
if (src_xOffset != 0)
{
xOffset += ((xOffset >= 0) ? volume : -volume);
for (int y = -volume; y <= volume; y++)
{
flag = ValidNeigbour(xOffset, y + src_yOffset);
if (flag == false)
{
return;
}
}
}
if (src_yOffset != 0)
{
yOffset += ((yOffset >= 0) ? volume : -volume);
for (int x = -volume; x <= volume; x++)
{
flag = ValidNeigbour(x + src_xOffset, yOffset);
if (flag == false)
{
return;
}
}
}
if (flag && !(parentPos.x == nodeIndex.x + src_xOffset && parentPos.y == nodeIndex.y + src_yOffset))
{
Vector2Int neighbourPos = new Vector2Int(nodeIndex.x + src_xOffset, nodeIndex.y + src_yOffset);
MapSearchNode newNode = pathfinder.AllocateMapSearchNode(neighbourPos);
aStarSearch.AddSuccessor(newNode);
}
}
public MapSearchNode(Vector2Int pos, AStarPathfinder _pathfinder)
{
nodeIndex = new Vector2Int(pos.x, pos.y);
pathfinder = _pathfinder;
}
