// Find the path between start node and goal node using AStar Algorithm
public static ArrayList FindPath(EnemyNutrientNode start, EnemyNutrientNode goal)
{
// Start Finding the path
frontier = new Frontier_ExploredSet(); // Initialize the frontier
exploredSet = new Frontier_ExploredSet(); // Initialize the explored set
frontier.Push(start); // Add the start node to the frontier
start.fTotalCost = 0.0f; // Initialize the total cost for the start node
start.fEstimatedCost = HeuristicEstimateCost(start, goal); // Calculate the heuristic
EnemyNutrientNode node = null; // Initialize a node to use
// While the frontier isnot empty
while (frontier.Length != 0)
{
node = frontier.First(); // Take the first node in the frontier
// If the node is the goal node, then the path is found
// Instead of checking after adding the node to the explored set, we check it when it's first generated
// The purpose is to save time from looking for a more optimal path
if (node.position == goal.position)
{
return(CalculatePath(node));
}
ArrayList neighbours = new ArrayList();
MapManager.Instance.GetNeighbours(node, neighbours);
#region CheckNeighbours
// Get the Neighbours
for (int i = 0; i < neighbours.Count; i++)
{
// Cost between neighbour nodes
EnemyNutrientNode neighbourNode = (EnemyNutrientNode)neighbours[i];
if (!exploredSet.Contains(neighbourNode))
{
// Cost from current node to this neighbour node
float cost = HeuristicEstimateCost(node, neighbourNode);
// Total Cost So Far from start to this neighbour node
float totalCost = node.fTotalCost + cost;
// Estimated cost for neighbour node to the goal
float neighbourNodeEstCost = HeuristicEstimateCost(neighbourNode, goal);
// Assign neighbour node properties
neighbourNode.fTotalCost = totalCost;
neighbourNode.parent = node;
neighbourNode.fEstimatedCost = totalCost + neighbourNodeEstCost;
// Add the neighbour node to the frontier if not already existed in the frontier
if (!frontier.Contains(neighbourNode))
{
frontier.Push(neighbourNode);
}
}
}
#endregion
exploredSet.Push(node); // Add the node to the explored set as it is expanded
frontier.Remove(node); // Remove the node from the frontier
}
// If finished looping and cannot find the goal then return null
if (node.position != goal.position)
{
//Debug.LogError("Goal Not Found");
//Debug.Log ("Last node position:" + node.position);
//Debug.Log ("Goal node position:" + goal.position);
return(null);
}
// Calculate the path based on the final node
return(CalculatePath(node));
}
// Find the path between start node and goal node using AStar Algorithm
public static ArrayList FindPath(EnemyNutrientNode start, EnemyNutrientNode goal)
{
// Start Finding the path
frontier = new Frontier_ExploredSet (); // Initialize the frontier
exploredSet = new Frontier_ExploredSet (); // Initialize the explored set
frontier.Push(start); // Add the start node to the frontier
start.fTotalCost = 0.0f; // Initialize the total cost for the start node
start.fEstimatedCost = HeuristicEstimateCost(start, goal); // Calculate the heuristic
EnemyNutrientNode node = null; // Initialize a node to use
// While the frontier isnot empty
while (frontier.Length != 0)
{
node = frontier.First(); // Take the first node in the frontier
// If the node is the goal node, then the path is found
// Instead of checking after adding the node to the explored set, we check it when it's first generated
// The purpose is to save time from looking for a more optimal path
if (node.position == goal.position)
{
return CalculatePath(node);
}
ArrayList neighbours = new ArrayList();
MapManager.Instance.GetNeighbours(node, neighbours);
#region CheckNeighbours
// Get the Neighbours
for (int i = 0; i < neighbours.Count; i++)
{
// Cost between neighbour nodes
EnemyNutrientNode neighbourNode = (EnemyNutrientNode)neighbours[i];
if (!exploredSet.Contains(neighbourNode))
{
// Cost from current node to this neighbour node
float cost = HeuristicEstimateCost(node, neighbourNode);
// Total Cost So Far from start to this neighbour node
float totalCost = node.fTotalCost + cost;
// Estimated cost for neighbour node to the goal
float neighbourNodeEstCost = HeuristicEstimateCost(neighbourNode, goal);
// Assign neighbour node properties
neighbourNode.fTotalCost = totalCost;
neighbourNode.parent = node;
neighbourNode.fEstimatedCost = totalCost + neighbourNodeEstCost;
// Add the neighbour node to the frontier if not already existed in the frontier
if (!frontier.Contains(neighbourNode))
{
frontier.Push(neighbourNode);
}
}
}
#endregion
exploredSet.Push(node); // Add the node to the explored set as it is expanded
frontier.Remove(node); // Remove the node from the frontier
}
// If finished looping and cannot find the goal then return null
if (node.position != goal.position)
{
//Debug.LogError("Goal Not Found");
//Debug.Log ("Last node position:" + node.position);
//Debug.Log ("Goal node position:" + goal.position);
return null;
}
// Calculate the path based on the final node
return CalculatePath(node);
}
