Example AstarAI.cs

Full source for the simple AI written in the get started guide .

get started guide .It should be attached to a GameObject with a Seeker and a CharacterController also attached.

using UnityEngine;
// Note this line, if it is left out, the script won't know that the class 'Path' exists and it will throw compiler errors
// This line should always be present at the top of scripts which use pathfinding
using Pathfinding;

public class AstarAI : MonoBehaviour {
public Transform targetPosition;

private Seeker seeker;
private CharacterController controller;

public Path path;

public float speed = 2;

public float nextWaypointDistance = 3;

private int currentWaypoint = 0;

public float repathRate = 0.5f;
private float lastRepath = float.NegativeInfinity;

public bool reachedEndOfPath;

public void Start () {
seeker = GetComponent<Seeker>();
// If you are writing a 2D game you can remove this line
// and use the alternative way to move sugggested further below.
controller = GetComponent<CharacterController>();
}

public void OnPathComplete (Path p) {
Debug.Log("A path was calculated. Did it fail with an error? " + p.error);

// Path pooling. To avoid unnecessary allocations paths are reference counted.
// Calling Claim will increase the reference count by 1 and Release will reduce
// it by one, when it reaches zero the path will be pooled and then it may be used
// by other scripts. The ABPath.Construct and Seeker.StartPath methods will
// take a path from the pool if possible. See also the documentation page about path pooling.
p.Claim(this);
if (!p.error) {
if (path != null) path.Release(this);
path = p;
// Reset the waypoint counter so that we start to move towards the first point in the path
currentWaypoint = 0;
} else {
p.Release(this);
}
}

public void Update () {
if (Time.time > lastRepath + repathRate && seeker.IsDone()) {
lastRepath = Time.time;

// Start a new path to the targetPosition, call the the OnPathComplete function
// when the path has been calculated (which may take a few frames depending on the complexity)
seeker.StartPath(transform.position, targetPosition.position, OnPathComplete);
}

if (path == null) {
// We have no path to follow yet, so don't do anything
return;
}

// Check in a loop if we are close enough to the current waypoint to switch to the next one.
// We do this in a loop because many waypoints might be close to each other and we may reach
// several of them in the same frame.
reachedEndOfPath = false;
// The distance to the next waypoint in the path
float distanceToWaypoint;
while (true) {
// If you want maximum performance you can check the squared distance instead to get rid of a
// square root calculation. But that is outside the scope of this tutorial.
distanceToWaypoint = Vector3.Distance(transform.position, path.vectorPath[currentWaypoint]);
if (distanceToWaypoint < nextWaypointDistance) {
// Check if there is another waypoint or if we have reached the end of the path
if (currentWaypoint + 1 < path.vectorPath.Count) {
currentWaypoint++;
} else {
// Set a status variable to indicate that the agent has reached the end of the path.
// You can use this to trigger some special code if your game requires that.
reachedEndOfPath = true;
break;
}
} else {
break;
}
}

// Slow down smoothly upon approaching the end of the path
// This value will smoothly go from 1 to 0 as the agent approaches the last waypoint in the path.
var speedFactor = reachedEndOfPath ? Mathf.Sqrt(distanceToWaypoint/nextWaypointDistance) : 1f;

// Direction to the next waypoint
// Normalize it so that it has a length of 1 world unit
Vector3 dir = (path.vectorPath[currentWaypoint] - transform.position).normalized;
// Multiply the direction by our desired speed to get a velocity
Vector3 velocity = dir * speed * speedFactor;

// Move the agent using the CharacterController component
// Note that SimpleMove takes a velocity in meters/second, so we should not multiply by Time.deltaTime
controller.SimpleMove(velocity);

// If you are writing a 2D game you may want to remove the CharacterController and instead modify the position directly
// transform.position += velocity * Time.deltaTime;
}
}