public Vector2 position; // Position of the current node
#endregion Fields
#region Constructors
// Default Constructor
public EnemyNutrientNode()
{
this.fEstimatedCost = 0.0f;
this.fTotalCost = 1.0f;
this.bAccessible = false;
this.parent = null;
}
public Vector2 position; // Position of the current node
#endregion
// Default Constructor
public EnemyNutrientNode()
{
this.fEstimatedCost = 0.0f;
this.fTotalCost = 1.0f;
this.bAccessible = false;
this.parent = null;
}
// Constructor
public EnemyNutrientNode(Vector2 pos)
{
this.fEstimatedCost = 0.0f;
this.fTotalCost = 1.0f;
this.bAccessible = true;
this.parent = null;
this.position = pos;
}
// Constructor
public EnemyNutrientNode(Vector2 pos)
{
this.fEstimatedCost = 0.0f;
this.fTotalCost = 1.0f;
this.bAccessible = true;
this.parent = null;
this.position = pos;
}
// Get the obstacles in the scene
public void GetObstacles()
{
// Initialise the nodes
nodes = new EnemyNutrientNode[nNumOfRows, nNumOfColumns];
int index = 0;
for (int i = 0; i < nNumOfRows; i++)
{
for (int j = 0; j < nNumOfColumns; j++)
{
Vector2 cellPos = GetNodeCenter(index);
EnemyNutrientNode node = new EnemyNutrientNode(cellPos);
nodes[i, j] = node;
index++;
}
}
// Set the position for each obstacle
if (obstacleList != null && obstacleList.Count > 0)
{
foreach (GameObject obstacle in obstacleList)
{
if (obstacle != null)
{
if (IsInBounds(obstacle.transform.position))
{
int indexCell = GetGridIndex(obstacle.transform.position);
int column = GetColumn(indexCell);
int row = GetRow(indexCell);
int range = (int)(obstacle.GetComponent <CircleCollider2D> ().bounds.size.x / fUniversalnodeSize);
// Assign unaccessible area
nodes[row, column].MarkAsUnaccessible();
/*
* for (int i = row - range; i < row + range; i++)
* {
* for (int j = column - range; j < column + range; j++)
* {
* if (i >= 0 && i < nNumOfRows && j >= 0 && j < nNumOfColumns)
* {
* if (nodes[i, j].bAccessible)
* nodes[i, j].MarkAsUnaccessible();
* }
* }
* }
*/
}
}
}
}
}
// Check the neighbouring node. If it is accessible, add the neighbouring node to the neighbour list.
void AssignNeighbour(int row, int column, ArrayList neighbors)
{
if (row >= 0 && column >= 0 && row < nNumOfRows && column < nNumOfColumns)
{
EnemyNutrientNode nodeToAdd = nodes[row, column];
if (nodeToAdd.bAccessible)
{
neighbors.Add(nodeToAdd);
}
}
}
// Get the real path by reversing the path found
private static ArrayList CalculatePath(EnemyNutrientNode node)
{
ArrayList list = new ArrayList();
while (node != null)
{
list.Add(node);
node = node.parent;
}
list.Reverse();
return(list);
}
void FindPath()
{
startPos = startObject.transform;
endPos = goalObject.transform;
// Initialize start and goal node
startNode = new EnemyNutrientNode(MapManager.Instance.GetNodeCenter(MapManager.Instance.GetGridIndex((Vector2)startPos.position)));
goalNode = new EnemyNutrientNode(MapManager.Instance.GetNodeCenter(MapManager.Instance.GetGridIndex((Vector2)endPos.position)));
// Update the size and position of all obstacles in map
MapManager.Instance.GetObstacles ();
// Find a new path between the start and goal node
pathArray = EnemyNutrientAStar.FindPath(startNode, goalNode);
}
void FindPath()
{
startPos = startObject.transform;
endPos = goalObject.transform;
// Initialize start and goal node
startNode = new EnemyNutrientNode(MapManager.Instance.GetNodeCenter(MapManager.Instance.GetGridIndex((Vector2)startPos.position)));
goalNode = new EnemyNutrientNode(MapManager.Instance.GetNodeCenter(MapManager.Instance.GetGridIndex((Vector2)endPos.position)));
// Update the size and position of all obstacles in map
MapManager.Instance.GetObstacles();
// Find a new path between the start and goal node
pathArray = EnemyNutrientAStar.FindPath(startNode, goalNode);
}
// Get the neighouring nodes in 4 cardinal directions
public void GetNeighbours(EnemyNutrientNode node, ArrayList neighbours)
{
Vector2 neighbourPos = node.position;
int neighborIndex = GetGridIndex(neighbourPos);
int row = GetRow(neighborIndex);
int column = GetColumn(neighborIndex);
// Top
int leftNodeRow = row + 1;
int leftNodeColumn = column;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom
leftNodeRow = row - 1;
leftNodeColumn = column;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Left
leftNodeRow = row;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Right
leftNodeRow = row;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Top left
leftNodeRow = row + 1;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Top right
leftNodeRow = row + 1;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom left
leftNodeRow = row - 1;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom right
leftNodeRow = row - 1;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
}
// Override the class CompareTo function for sorting
// Applied when calling Sort.Sort from ArrayList
// Compare using the estimated total cost between two nodes
public int CompareTo(object obj)
{
EnemyNutrientNode node = (EnemyNutrientNode)obj;
if (this.fEstimatedCost < node.fEstimatedCost)
{
return(-1);
}
if (this.fEstimatedCost > node.fEstimatedCost)
{
return(1);
}
return(0);
}
void Start()
{
// GetComponent on the gameObject
thisRB = GetComponent <Rigidbody2D> ();
pathfindingManager = GetComponent <EMNutrientPathfindingManager> ();
// Initialization
currentNode = null;
nextNode = null;
fSpeed = Random.Range(.4f, .8f);
bIsAbsorbed = false;
fAbsorbSpeed = Random.Range(1f, 2f);
fAbsorbTime = 1f;
// Not using A* by default
bCanFindPath = false;
// Call the PauseAStar function for initial movement
StartCoroutine(PauseAStar());
}
// Draw the path found
void OnDrawGizmos()
{
if (pathArray == null)
{
return;
}
if (pathArray.Count > 0)
{
int index = 1;
foreach (EnemyNutrientNode node in pathArray)
{
if (index < pathArray.Count)
{
EnemyNutrientNode nextNode = (EnemyNutrientNode)pathArray[index];
Debug.DrawLine(node.position, nextNode.position, Color.green);
index++;
}
}
;
}
}
void Update()
{
// Destroy the nutrient if enemy main cell is invisible
if (!EMHelper.Instance().IsEnemyVisible)
{
Destroy(this.gameObject);
}
// Absorb behaviour
if (bIsAbsorbed)
{
Absorb();
}
else
{
// A* pathfinding
if (bCanFindPath)
{
// Set the target to the next node
if (pathfindingManager.pathArray != null)
{
if (pathfindingManager.pathArray.Count > 1)
{
nextNode = (EnemyNutrientNode)pathfindingManager.pathArray [1];
currentNode = nextNode;
}
}
else
{
nextNode = null;
}
// Move to the target node
if (currentNode != null)
{
thisRB.velocity = (currentNode.position - (Vector2)this.gameObject.transform.position) * fSpeed;
}
}
}
}
// Add the node to the frontier and sort all nodes based on the estimated total cost
public void Push(EnemyNutrientNode node)
{
this.nodes.Add(node);
this.nodes.Sort();
}
// Remove the node from the frontier and sort the rest based on the estimated total cost
public void Remove(EnemyNutrientNode node)
{
this.nodes.Remove(node);
this.nodes.Sort();
}
// Remove the node from the frontier and sort the rest based on the estimated total cost
public void Remove(EnemyNutrientNode node)
{
this.nodes.Remove(node);
this.nodes.Sort();
}
// 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);
}
void Update()
{
// Destroy the nutrient if enemy main cell is invisible
if (!EMHelper.Instance().IsEnemyVisible)
Destroy (this.gameObject);
// Absorb behaviour
if (bIsAbsorbed)
Absorb ();
else
{
// A* pathfinding
if (bCanFindPath) {
// Set the target to the next node
if (pathfindingManager.pathArray != null) {
if (pathfindingManager.pathArray.Count > 1) {
nextNode = (EnemyNutrientNode)pathfindingManager.pathArray [1];
currentNode = nextNode;
}
} else
nextNode = null;
// Move to the target node
if (currentNode != null)
thisRB.velocity = (currentNode.position - (Vector2)this.gameObject.transform.position) * fSpeed;
}
}
}
void Start()
{
// GetComponent on the gameObject
thisRB = GetComponent<Rigidbody2D> ();
pathfindingManager = GetComponent<EMNutrientPathfindingManager> ();
// Initialization
currentNode = null;
nextNode = null;
fSpeed = Random.Range (.4f, .8f);
bIsAbsorbed = false;
fAbsorbSpeed = Random.Range (1f, 2f);
fAbsorbTime = 1f;
// Not using A* by default
bCanFindPath = false;
// Call the PauseAStar function for initial movement
StartCoroutine (PauseAStar ());
}
// Get the neighouring nodes in 4 cardinal directions
public void GetNeighbours(EnemyNutrientNode node, ArrayList neighbours)
{
Vector2 neighbourPos = node.position;
int neighborIndex = GetGridIndex(neighbourPos);
int row = GetRow(neighborIndex);
int column = GetColumn(neighborIndex);
// Top
int leftNodeRow = row + 1;
int leftNodeColumn = column;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom
leftNodeRow = row - 1;
leftNodeColumn = column;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Left
leftNodeRow = row;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Right
leftNodeRow = row;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Top left
leftNodeRow = row + 1;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Top right
leftNodeRow = row + 1;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom left
leftNodeRow = row - 1;
leftNodeColumn = column - 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
// Bottom right
leftNodeRow = row - 1;
leftNodeColumn = column + 1;
AssignNeighbour(leftNodeRow, leftNodeColumn, neighbours);
}
// Get the obstacles in the scene
public void GetObstacles()
{
// Initialise the nodes
nodes = new EnemyNutrientNode[nNumOfRows, nNumOfColumns];
int index = 0;
for (int i = 0; i < nNumOfRows; i++)
{
for (int j = 0; j < nNumOfColumns; j++)
{
Vector2 cellPos = GetNodeCenter(index);
EnemyNutrientNode node = new EnemyNutrientNode(cellPos);
nodes[i, j] = node;
index++;
}
}
// Set the position for each obstacle
if (obstacleList != null && obstacleList.Count > 0)
{
foreach (GameObject obstacle in obstacleList)
{
if (obstacle != null)
{
if (IsInBounds (obstacle.transform.position))
{
int indexCell = GetGridIndex(obstacle.transform.position);
int column = GetColumn(indexCell);
int row = GetRow(indexCell);
int range = (int)(obstacle.GetComponent<CircleCollider2D> ().bounds.size.x / fUniversalnodeSize);
// Assign unaccessible area
nodes[row, column].MarkAsUnaccessible();
/*
for (int i = row - range; i < row + range; i++)
{
for (int j = column - range; j < column + range; j++)
{
if (i >= 0 && i < nNumOfRows && j >= 0 && j < nNumOfColumns)
{
if (nodes[i, j].bAccessible)
nodes[i, j].MarkAsUnaccessible();
}
}
}
*/
}
}
}
}
}
// Get the real path by reversing the path found
private static ArrayList CalculatePath(EnemyNutrientNode node)
{
ArrayList list = new ArrayList();
while (node != null)
{
list.Add(node);
node = node.parent;
}
list.Reverse();
return list;
}
// Calculate the estimated Heuristic cost to the goal node
private static float HeuristicEstimateCost(EnemyNutrientNode currentNode, EnemyNutrientNode goalNode)
{
Vector2 vecCost = currentNode.position - goalNode.position;
return(vecCost.magnitude);
}
// Add the node to the frontier and sort all nodes based on the estimated total cost
public void Push(EnemyNutrientNode node)
{
this.nodes.Add(node);
this.nodes.Sort();
}
// 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));
}
// Calculate the estimated Heuristic cost to the goal node
private static float HeuristicEstimateCost(EnemyNutrientNode currentNode, EnemyNutrientNode goalNode)
{
Vector2 vecCost = currentNode.position - goalNode.position;
return vecCost.magnitude;
}