AI for following paths.
This AI is the default movement script which comes with the A* Pathfinding Project. It is in no way required by the rest of the system, so feel free to write your own. But I hope this script will make it easier to set up movement for the characters in your game. This script is not written for high performance, so I do not recommend using it for large groups of units.
This script will try to follow a target transform, in regular intervals, the path to that target will be recalculated. It will on FixedUpdate try to move towards the next point in the path. However it will only move in the forward direction, but it will rotate around it's Y-axis to make it reach the target.
Quick overview of the variables
In the inspector in Unity, you will see a bunch of variables. You can view detailed information further down, but here's a quick overview.
The repathRate determines how often it will search for new paths, if you have fast moving targets, you might want to set it to a lower value.
The target variable is where the AI will try to move, it can be a point on the ground where the player has clicked in an RTS for example. Or it can be the player object in a zombie game.
The speed is self-explanatory, so is turningSpeed, however slowdownDistance might require some explanation. It is the approximate distance from the target where the AI will start to slow down. Note that this doesn't only affect the end point of the path but also any intermediate points, so be sure to set forwardLook and pickNextWaypointDist to a higher value than this.
pickNextWaypointDist is simply determines within what range it will switch to target the next waypoint in the path.
forwardLook will try to calculate an interpolated target point on the current segment in the path so that it has a distance of forwardLook from the AI
Below is an image illustrating several variables as well as some internal ones, but which are relevant for understanding how it works. Note that the forwardLook range will not match up exactly with the target point practically, even though that's the goal.
This script has many movement fallbacks. If it finds a NavmeshController, it will use that, otherwise it will look for a character controller, then for a rigidbody and if it hasn't been able to find any it will use Transform.Translate which is guaranteed to always work.
- Deprecated:
- Use the AIPath class instead. This class only exists for compatibility reasons.
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| bool | closestOnPathCheck = true |
| | Do a closest point on path check when receiving path callback.
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| float | forwardLook = 1 |
| | Target point is Interpolated on the current segment in the path so that it has a distance of forwardLook from the AI.
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| bool | alwaysDrawGizmos |
| | Draws detailed gizmos constantly in the scene view instead of only when the agent is selected and settings are being modified.
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| bool | canMove = true |
| | Enables or disables movement.
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| bool | canSearch = true |
| | Enables or disables searching for paths.
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| float | endReachedDistance = 0.2F |
| | Distance to the end point to consider the end of path to be reached.
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| float | pickNextWaypointDist = 2 |
| | Determines within what range it will switch to target the next waypoint in the path.
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| float | repathRate = 0.5F |
| | Determines how often it will search for new paths.
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| float | rotationSpeed = 360 |
| | Rotation speed.
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| float | slowdownDistance = 0.6F |
| | Distance from the target point where the AI will start to slow down.
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| float | speed = 3 |
| | Maximum velocity.
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| Transform | target |
| | Target to move towards.
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| float | centerOffset = 1 |
| | Offset along the Y coordinate for the ground raycast start position.
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| Vector3 | gravity = new Vector3(float.NaN, float.NaN, float.NaN) |
| | Gravity to use.
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| LayerMask | groundMask = -1 |
| | Layer mask to use for ground placement.
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| override void | Awake () |
| | Initializes reference variables.
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| Vector3 | CalculateTargetPoint (Vector3 p, Vector3 a, Vector3 b) |
| | Calculates target point from the current line segment.
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| Vector3 | CalculateVelocity (Vector3 currentPosition) |
| | Calculates desired velocity.
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| void | RotateTowards (Vector3 dir) |
| | Rotates in the specified direction.
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| override void | Update () |
| | Called every frame.
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| float | XZSqrMagnitude (Vector3 a, Vector3 b) |
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| override void | MovementUpdate (float deltaTime) |
| | Called during either Update or FixedUpdate depending on if rigidbodies are used for movement or not.
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| virtual void | OnEnable () |
| | Run at start and when reenabled.
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| override int | OnUpgradeSerializedData (int version) |
| | Handle serialization backwards compatibility.
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| IEnumerator | RepeatTrySearchPath () |
| | Tries to search for a path every repathRate seconds.
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| virtual void | Start () |
| | Starts searching for paths.
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| void | ApplyGravity (float deltaTime) |
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| Vector2 | CalculateDeltaToMoveThisFrame (Vector2 position, float distanceToEndOfPath, float deltaTime) |
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| virtual Vector3 | ClampToNavmesh (Vector3 position) |
| | Constrains the character's position to lie on the navmesh.
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| virtual void | FixedUpdate () |
| | Called every physics update.
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| void | Move (Vector3 position3D, Vector3 deltaPosition) |
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| virtual void | OnDrawGizmos () |
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| Vector3 | RaycastPosition (Vector3 position, float lastElevation) |
| | Find the world position of the ground below the character.
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| virtual void | RotateTowards (Vector2 direction, float maxDegrees) |
| | Rotates in the specified direction.
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| bool closestOnPathCheck = true |
Do a closest point on path check when receiving path callback.
Usually the AI has moved a bit between requesting the path, and getting it back, and there is usually a small gap between the AI and the closest node. If this option is enabled, it will simulate, when the path callback is received, movement between the closest node and the current AI position. This helps to reduce the moments when the AI just get a new path back, and thinks it ought to move backwards to the start of the new path even though it really should just proceed forward.
Public Member Functions inherited from AIPath
1.8.2 
