USER
This is my kart controller script thingy. How can I make it so AI will drive this kart and not be controlled by the player at all? Same animations and all that. But it will follow a path.
using System;
using UnityEngine;
using System.Collections.Generic;
using UnityEngine.VFX;
namespace KartGame.KartSystems
{
public class ArcadeKart : MonoBehaviour
{
[System.Serializable]
public class StatPowerup
{
public ArcadeKart.Stats modifiers;
public string PowerUpID;
public float ElapsedTime;
public float MaxTime;
}
[System.Serializable]
public struct Stats
{
[Header("Movement Settings")]
[Min(0.001f), Tooltip("Top speed attainable when moving forward.")]
public float TopSpeed;
[Tooltip("How quickly the kart reaches top speed.")]
public float Acceleration;
[Min(0.001f), Tooltip("Top speed attainable when moving backward.")]
public float ReverseSpeed;
[Tooltip("How quickly the kart reaches top speed, when moving backward.")]
public float ReverseAcceleration;
[Tooltip("How quickly the kart starts accelerating from 0. A higher number means it accelerates faster sooner.")]
[Range(0.2f, 1)]
public float AccelerationCurve;
[Tooltip("How quickly the kart slows down when the brake is applied.")]
public float Braking;
[Tooltip("How quickly the kart will reach a full stop when no inputs are made.")]
public float CoastingDrag;
[Range(0.0f, 1.0f)]
[Tooltip("The amount of side-to-side friction.")]
public float Grip;
[Tooltip("How tightly the kart can turn left or right.")]
public float Steer;
[Tooltip("Additional gravity for when the kart is in the air.")]
public float AddedGravity;
// allow for stat adding for powerups.
public static Stats operator +(Stats a, Stats b)
{
return new Stats
{
Acceleration = a.Acceleration + b.Acceleration,
AccelerationCurve = a.AccelerationCurve + b.AccelerationCurve,
Braking = a.Braking + b.Braking,
CoastingDrag = a.CoastingDrag + b.CoastingDrag,
AddedGravity = a.AddedGravity + b.AddedGravity,
Grip = a.Grip + b.Grip,
ReverseAcceleration = a.ReverseAcceleration + b.ReverseAcceleration,
ReverseSpeed = a.ReverseSpeed + b.ReverseSpeed,
TopSpeed = a.TopSpeed + b.TopSpeed,
Steer = a.Steer + b.Steer,
};
}
}
public Rigidbody Rigidbody { get; private set; }
public InputData Input { get; private set; }
public float AirPercent { get; private set; }
public float GroundPercent { get; private set; }
public ArcadeKart.Stats baseStats = new ArcadeKart.Stats
{
TopSpeed = 10f,
Acceleration = 5f,
AccelerationCurve = 4f,
Braking = 10f,
ReverseAcceleration = 5f,
ReverseSpeed = 5f,
Steer = 5f,
CoastingDrag = 4f,
Grip = .95f,
AddedGravity = 1f,
};
[Header("Vehicle Visual")]
public List<GameObject> m_VisualWheels;
[Header("Vehicle Physics")]
[Tooltip("The transform that determines the position of the kart's mass.")]
public Transform CenterOfMass;
[Range(0.0f, 20.0f), Tooltip("Coefficient used to reorient the kart in the air. The higher the number, the faster the kart will readjust itself along the horizontal plane.")]
public float AirborneReorientationCoefficient = 3.0f;
[Header("Drifting")]
[Range(0.01f, 1.0f), Tooltip("The grip value when drifting.")]
public float DriftGrip = 0.4f;
[Range(0.0f, 10.0f), Tooltip("Additional steer when the kart is drifting.")]
public float DriftAdditionalSteer = 5.0f;
[Range(1.0f, 30.0f), Tooltip("The higher the angle, the easier it is to regain full grip.")]
public float MinAngleToFinishDrift = 10.0f;
[Range(0.01f, 0.99f), Tooltip("Mininum speed percentage to switch back to full grip.")]
public float MinSpeedPercentToFinishDrift = 0.5f;
[Range(1.0f, 20.0f), Tooltip("The higher the value, the easier it is to control the drift steering.")]
public float DriftControl = 10.0f;
[Range(0.0f, 20.0f), Tooltip("The lower the value, the longer the drift will last without trying to control it by steering.")]
public float DriftDampening = 10.0f;
[Header("VFX")]
[Tooltip("VFX that will be placed on the wheels when drifting.")]
public ParticleSystem DriftSparkVFX;
[Range(0.0f, 0.2f), Tooltip("Offset to displace the VFX to the side.")]
public float DriftSparkHorizontalOffset = 0.1f;
[Range(0.0f, 90.0f), Tooltip("Angle to rotate the VFX.")]
public float DriftSparkRotation = 17.0f;
[Tooltip("VFX that will be placed on the wheels when drifting.")]
public GameObject DriftTrailPrefab;
[Range(-0.1f, 0.1f), Tooltip("Vertical to move the trails up or down and ensure they are above the ground.")]
public float DriftTrailVerticalOffset;
[Tooltip("VFX that will spawn upon landing, after a jump.")]
public GameObject JumpVFX;
[Tooltip("VFX that is spawn on the nozzles of the kart.")]
public GameObject NozzleVFX;
[Tooltip("List of the kart's nozzles.")]
public List<Transform> Nozzles;
[Header("Suspensions")]
[Tooltip("The maximum extension possible between the kart's body and the wheels.")]
[Range(0.0f, 1.0f)]
public float SuspensionHeight = 0.2f;
[Range(10.0f, 100000.0f), Tooltip("The higher the value, the stiffer the suspension will be.")]
public float SuspensionSpring = 20000.0f;
[Range(0.0f, 5000.0f), Tooltip("The higher the value, the faster the kart will stabilize itself.")]
public float SuspensionDamp = 500.0f;
[Tooltip("Vertical offset to adjust the position of the wheels relative to the kart's body.")]
[Range(-1.0f, 1.0f)]
public float WheelsPositionVerticalOffset = 0.0f;
[Header("Physical Wheels")]
[Tooltip("The physical representations of the Kart's wheels.")]
public WheelCollider FrontLeftWheel;
public WheelCollider FrontRightWheel;
public WheelCollider RearLeftWheel;
public WheelCollider RearRightWheel;
[Tooltip("Which layers the wheels will detect.")]
public LayerMask GroundLayers = Physics.DefaultRaycastLayers;
// the input sources that can control the kart
IInput[] m_Inputs;
const float k_NullInput = 0.01f;
const float k_NullSpeed = 0.01f;
Vector3 m_VerticalReference = Vector3.up;
// Drift params
public bool WantsToDrift { get; private set; } = false;
public bool IsDrifting { get; private set; } = false;
float m_CurrentGrip = 1.0f;
float m_DriftTurningPower = 0.0f;
float m_PreviousGroundPercent = 1.0f;
readonly List<(GameObject trailRoot, WheelCollider wheel, TrailRenderer trail)> m_DriftTrailInstances = new List<(GameObject, WheelCollider, TrailRenderer)>();
readonly List<(WheelCollider wheel, float horizontalOffset, float rotation, ParticleSystem sparks)> m_DriftSparkInstances = new List<(WheelCollider, float, float, ParticleSystem)>();
// can the kart move?
bool m_CanMove = true;
List<StatPowerup> m_ActivePowerupList = new List<StatPowerup>();
ArcadeKart.Stats m_FinalStats;
Quaternion m_LastValidRotation;
Vector3 m_LastValidPosition;
Vector3 m_LastCollisionNormal;
bool m_HasCollision;
bool m_InAir = false;
public void AddPowerup(StatPowerup statPowerup) => m_ActivePowerupList.Add(statPowerup);
public void SetCanMove(bool move) => m_CanMove = move;
public float GetMaxSpeed() => Mathf.Max(m_FinalStats.TopSpeed, m_FinalStats.ReverseSpeed);
private void ActivateDriftVFX(bool active)
{
foreach (var vfx in m_DriftSparkInstances)
{
if (active && vfx.wheel.GetGroundHit(out WheelHit hit))
{
if (!vfx.sparks.isPlaying)
vfx.sparks.Play();
}
else
{
if (vfx.sparks.isPlaying)
vfx.sparks.Stop(true, ParticleSystemStopBehavior.StopEmitting);
}
}
foreach (var trail in m_DriftTrailInstances)
trail.Item3.emitting = active && trail.wheel.GetGroundHit(out WheelHit hit);
}
private void UpdateDriftVFXOrientation()
{
foreach (var vfx in m_DriftSparkInstances)
{
vfx.sparks.transform.position = vfx.wheel.transform.position - (vfx.wheel.radius * Vector3.up) + (DriftTrailVerticalOffset * Vector3.up) + (transform.right * vfx.horizontalOffset);
vfx.sparks.transform.rotation = transform.rotation * Quaternion.Euler(0.0f, 0.0f, vfx.rotation);
}
foreach (var trail in m_DriftTrailInstances)
{
trail.trailRoot.transform.position = trail.wheel.transform.position - (trail.wheel.radius * Vector3.up) + (DriftTrailVerticalOffset * Vector3.up);
trail.trailRoot.transform.rotation = transform.rotation;
}
}
void UpdateSuspensionParams(WheelCollider wheel)
{
wheel.suspensionDistance = SuspensionHeight;
wheel.center = new Vector3(0.0f, WheelsPositionVerticalOffset, 0.0f);
JointSpring spring = wheel.suspensionSpring;
spring.spring = SuspensionSpring;
spring.damper = SuspensionDamp;
wheel.suspensionSpring = spring;
}
void Awake()
{
Rigidbody = GetComponent<Rigidbody>();
m_Inputs = GetComponents<IInput>();
UpdateSuspensionParams(FrontLeftWheel);
UpdateSuspensionParams(FrontRightWheel);
UpdateSuspensionParams(RearLeftWheel);
UpdateSuspensionParams(RearRightWheel);
m_CurrentGrip = baseStats.Grip;
if (DriftSparkVFX != null)
{
AddSparkToWheel(RearLeftWheel, -DriftSparkHorizontalOffset, -DriftSparkRotation);
AddSparkToWheel(RearRightWheel, DriftSparkHorizontalOffset, DriftSparkRotation);
}
if (DriftTrailPrefab != null)
{
AddTrailToWheel(RearLeftWheel);
AddTrailToWheel(RearRightWheel);
}
if (NozzleVFX != null)
{
foreach (var nozzle in Nozzles)
{
Instantiate(NozzleVFX, nozzle, false);
}
}
}
void AddTrailToWheel(WheelCollider wheel)
{
GameObject trailRoot = Instantiate(DriftTrailPrefab, gameObject.transform, false);
TrailRenderer trail = trailRoot.GetComponentInChildren<TrailRenderer>();
trail.emitting = false;
m_DriftTrailInstances.Add((trailRoot, wheel, trail));
}
void AddSparkToWheel(WheelCollider wheel, float horizontalOffset, float rotation)
{
GameObject vfx = Instantiate(DriftSparkVFX.gameObject, wheel.transform, false);
ParticleSystem spark = vfx.GetComponent<ParticleSystem>();
spark.Stop();
m_DriftSparkInstances.Add((wheel, horizontalOffset, -rotation, spark));
}
void FixedUpdate()
{
UpdateSuspensionParams(FrontLeftWheel);
UpdateSuspensionParams(FrontRightWheel);
UpdateSuspensionParams(RearLeftWheel);
UpdateSuspensionParams(RearRightWheel);
GatherInputs();
// apply our powerups to create our finalStats
TickPowerups();
// apply our physics properties
Rigidbody.centerOfMass = transform.InverseTransformPoint(CenterOfMass.position);
int groundedCount = 0;
if (FrontLeftWheel.isGrounded && FrontLeftWheel.GetGroundHit(out WheelHit hit))
groundedCount++;
if (FrontRightWheel.isGrounded && FrontRightWheel.GetGroundHit(out hit))
groundedCount++;
if (RearLeftWheel.isGrounded && RearLeftWheel.GetGroundHit(out hit))
groundedCount++;
if (RearRightWheel.isGrounded && RearRightWheel.GetGroundHit(out hit))
groundedCount++;
// calculate how grounded and airborne we are
GroundPercent = (float) groundedCount / 4.0f;
AirPercent = 1 - GroundPercent;
// apply vehicle physics
if (m_CanMove)
{
MoveVehicle(Input.Accelerate, Input.Brake, Input.TurnInput);
}
GroundAirbourne();
m_PreviousGroundPercent = GroundPercent;
UpdateDriftVFXOrientation();
}
void GatherInputs()
{
// reset input
Input = new InputData();
WantsToDrift = false;
// gather nonzero input from our sources
for (int i = 0; i < m_Inputs.Length; i++)
{
Input = m_Inputs[i].GenerateInput();
WantsToDrift = Input.Brake && Vector3.Dot(Rigidbody.velocity, transform.forward) > 0.0f;
}
}
void TickPowerups()
{
// remove all elapsed powerups
m_ActivePowerupList.RemoveAll((p) => { return p.ElapsedTime > p.MaxTime; });
// zero out powerups before we add them all up
var powerups = new Stats();
// add up all our powerups
for (int i = 0; i < m_ActivePowerupList.Count; i++)
{
var p = m_ActivePowerupList[i];
// add elapsed time
p.ElapsedTime += Time.fixedDeltaTime;
// add up the powerups
powerups += p.modifiers;
}
// add powerups to our final stats
m_FinalStats = baseStats + powerups;
// clamp values in finalstats
m_FinalStats.Grip = Mathf.Clamp(m_FinalStats.Grip, 0, 1);
}
void GroundAirbourne()
{
// while in the air, fall faster
if (AirPercent >= 1)
{
Rigidbody.velocity += Physics.gravity * Time.fixedDeltaTime * m_FinalStats.AddedGravity;
}
}
public void Reset()
{
Vector3 euler = transform.rotation.eulerAngles;
euler.x = euler.z = 0f;
transform.rotation = Quaternion.Euler(euler);
}
public float LocalSpeed()
{
if (m_CanMove)
{
float dot = Vector3.Dot(transform.forward, Rigidbody.velocity);
if (Mathf.Abs(dot) > 0.1f)
{
float speed = Rigidbody.velocity.magnitude;
return dot < 0 ? -(speed / m_FinalStats.ReverseSpeed) : (speed / m_FinalStats.TopSpeed);
}
return 0f;
}
else
{
// use this value to play kart sound when it is waiting the race start countdown.
return Input.Accelerate ? 1.0f : 0.0f;
}
}
void OnCollisionEnter(Collision collision) => m_HasCollision = true;
void OnCollisionExit(Collision collision) => m_HasCollision = false;
void OnCollisionStay(Collision collision)
{
m_HasCollision = true;
m_LastCollisionNormal = Vector3.zero;
float dot = -1.0f;
foreach (var contact in collision.contacts)
{
if (Vector3.Dot(contact.normal, Vector3.up) > dot)
m_LastCollisionNormal = contact.normal;
}
}
void MoveVehicle(bool accelerate, bool brake, float turnInput)
{
float accelInput = (accelerate ? 1.0f : 0.0f) - (brake ? 1.0f : 0.0f);
// manual acceleration curve coefficient scalar
float accelerationCurveCoeff = 5;
Vector3 localVel = transform.InverseTransformVector(Rigidbody.velocity);
bool accelDirectionIsFwd = accelInput >= 0;
bool localVelDirectionIsFwd = localVel.z >= 0;
// use the max speed for the direction we are going--forward or reverse.
float maxSpeed = localVelDirectionIsFwd ? m_FinalStats.TopSpeed : m_FinalStats.ReverseSpeed;
float accelPower = accelDirectionIsFwd ? m_FinalStats.Acceleration : m_FinalStats.ReverseAcceleration;
float currentSpeed = Rigidbody.velocity.magnitude;
float accelRampT = currentSpeed / maxSpeed;
float multipliedAccelerationCurve = m_FinalStats.AccelerationCurve * accelerationCurveCoeff;
float accelRamp = Mathf.Lerp(multipliedAccelerationCurve, 1, accelRampT * accelRampT);
bool isBraking = (localVelDirectionIsFwd && brake) || (!localVelDirectionIsFwd && accelerate);
// if we are braking (moving reverse to where we are going)
// use the braking accleration instead
float finalAccelPower = isBraking ? m_FinalStats.Braking : accelPower;
float finalAcceleration = finalAccelPower * accelRamp;
// apply inputs to forward/backward
float turningPower = IsDrifting ? m_DriftTurningPower : turnInput * m_FinalStats.Steer;
Quaternion turnAngle = Quaternion.AngleAxis(turningPower, transform.up);
Vector3 fwd = turnAngle * transform.forward;
Vector3 movement = fwd * accelInput * finalAcceleration * ((m_HasCollision || GroundPercent > 0.0f) ? 1.0f : 0.0f);
// forward movement
bool wasOverMaxSpeed = currentSpeed >= maxSpeed;
// if over max speed, cannot accelerate faster.
if (wasOverMaxSpeed && !isBraking)
movement *= 0.0f;
Vector3 newVelocity = Rigidbody.velocity + movement * Time.fixedDeltaTime;
newVelocity.y = Rigidbody.velocity.y;
// clamp max speed if we are on ground
if (GroundPercent > 0.0f && !wasOverMaxSpeed)
{
newVelocity = Vector3.ClampMagnitude(newVelocity, maxSpeed);
}
// coasting is when we aren't touching accelerate
if (Mathf.Abs(accelInput) < k_NullInput && GroundPercent > 0.0f)
{
newVelocity = Vector3.MoveTowards(newVelocity, new Vector3(0, Rigidbody.velocity.y, 0), Time.fixedDeltaTime * m_FinalStats.CoastingDrag);
}
Rigidbody.velocity = newVelocity;
// Drift
if (GroundPercent > 0.0f)
{
if (m_InAir)
{
m_InAir = false;
Instantiate(JumpVFX, transform.position, Quaternion.identity);
}
// manual angular velocity coefficient
float angularVelocitySteering = 0.4f;
float angularVelocitySmoothSpeed = 20f;
// turning is reversed if we're going in reverse and pressing reverse
if (!localVelDirectionIsFwd && !accelDirectionIsFwd)
angularVelocitySteering *= -1.0f;
var angularVel = Rigidbody.angularVelocity;
// move the Y angular velocity towards our target
angularVel.y = Mathf.MoveTowards(angularVel.y, turningPower * angularVelocitySteering, Time.fixedDeltaTime * angularVelocitySmoothSpeed);
// apply the angular velocity
Rigidbody.angularVelocity = angularVel;
// rotate rigidbody's velocity as well to generate immediate velocity redirection
// manual velocity steering coefficient
float velocitySteering = 25f;
// If the karts lands with a forward not in the velocity direction, we start the drift
if (GroundPercent >= 0.0f && m_PreviousGroundPercent < 0.1f)
{
Vector3 flattenVelocity = Vector3.ProjectOnPlane(Rigidbody.velocity, m_VerticalReference).normalized;
if (Vector3.Dot(flattenVelocity, transform.forward * Mathf.Sign(accelInput)) < Mathf.Cos(MinAngleToFinishDrift * Mathf.Deg2Rad))
{
IsDrifting = true;
m_CurrentGrip = DriftGrip;
m_DriftTurningPower = 0.0f;
}
}
// Drift Management
if (!IsDrifting)
{
if ((WantsToDrift || isBraking) && currentSpeed > maxSpeed * MinSpeedPercentToFinishDrift)
{
IsDrifting = true;
m_DriftTurningPower = turningPower + (Mathf.Sign(turningPower) * DriftAdditionalSteer);
m_CurrentGrip = DriftGrip;
ActivateDriftVFX(true);
}
}
if (IsDrifting)
{
float turnInputAbs = Mathf.Abs(turnInput);
if (turnInputAbs < k_NullInput)
m_DriftTurningPower = Mathf.MoveTowards(m_DriftTurningPower, 0.0f, Mathf.Clamp01(DriftDampening * Time.fixedDeltaTime));
// Update the turning power based on input
float driftMaxSteerValue = m_FinalStats.Steer + DriftAdditionalSteer;
m_DriftTurningPower = Mathf.Clamp(m_DriftTurningPower + (turnInput * Mathf.Clamp01(DriftControl * Time.fixedDeltaTime)), -driftMaxSteerValue, driftMaxSteerValue);
bool facingVelocity = Vector3.Dot(Rigidbody.velocity.normalized, transform.forward * Mathf.Sign(accelInput)) > Mathf.Cos(MinAngleToFinishDrift * Mathf.Deg2Rad);
bool canEndDrift = true;
if (isBraking)
canEndDrift = false;
else if (!facingVelocity)
canEndDrift = false;
else if (turnInputAbs >= k_NullInput && currentSpeed > maxSpeed * MinSpeedPercentToFinishDrift)
canEndDrift = false;
if (canEndDrift || currentSpeed < k_NullSpeed)
{
// No Input, and car aligned with speed direction => Stop the drift
IsDrifting = false;
m_CurrentGrip = m_FinalStats.Grip;
}
}
// rotate our velocity based on current steer value
Rigidbody.velocity = Quaternion.AngleAxis(turningPower * Mathf.Sign(localVel.z) * velocitySteering * m_CurrentGrip * Time.fixedDeltaTime, transform.up) * Rigidbody.velocity;
}
else
{
m_InAir = true;
}
bool validPosition = false;
if (Physics.Raycast(transform.position + (transform.up * 0.1f), -transform.up, out RaycastHit hit, 3.0f, 1 << 9 | 1 << 10 | 1 << 11)) // Layer: ground (9) / Environment(10) / Track (11)
{
Vector3 lerpVector = (m_HasCollision && m_LastCollisionNormal.y > hit.normal.y) ? m_LastCollisionNormal : hit.normal;
m_VerticalReference = Vector3.Slerp(m_VerticalReference, lerpVector, Mathf.Clamp01(AirborneReorientationCoefficient * Time.fixedDeltaTime * (GroundPercent > 0.0f ? 10.0f : 1.0f))); // Blend faster if on ground
}
else
{
Vector3 lerpVector = (m_HasCollision && m_LastCollisionNormal.y > 0.0f) ? m_LastCollisionNormal : Vector3.up;
m_VerticalReference = Vector3.Slerp(m_VerticalReference, lerpVector, Mathf.Clamp01(AirborneReorientationCoefficient * Time.fixedDeltaTime));
}
validPosition = GroundPercent > 0.7f && !m_HasCollision && Vector3.Dot(m_VerticalReference, Vector3.up) > 0.9f;
// Airborne / Half on ground management
if (GroundPercent < 0.7f)
{
Rigidbody.angularVelocity = new Vector3(0.0f, Rigidbody.angularVelocity.y * 0.98f, 0.0f);
Vector3 finalOrientationDirection = Vector3.ProjectOnPlane(transform.forward, m_VerticalReference);
finalOrientationDirection.Normalize();
if (finalOrientationDirection.sqrMagnitude > 0.0f)
{
Rigidbody.MoveRotation(Quaternion.Lerp(Rigidbody.rotation, Quaternion.LookRotation(finalOrientationDirection, m_VerticalReference), Mathf.Clamp01(AirborneReorientationCoefficient * Time.fixedDeltaTime)));
}
}
else if (validPosition)
{
m_LastValidPosition = transform.position;
m_LastValidRotation.eulerAngles = new Vector3(0.0f, transform.rotation.y, 0.0f);
}
ActivateDriftVFX(IsDrifting && GroundPercent > 0.0f);
}
}
}
ASSISTANT
To have your kart be driven by AI instead of player inputs while maintaining all existing animations and behaviors, you can follow these steps:
1. **Define a Path for the AI to Follow**
2. **Create an AI Controller to Generate Inputs**
3. **Integrate the AI Controller with Your `ArcadeKart` Script**
4. **Disable or Remove Player Input Components**
Below is a detailed guide for each step, including example code snippets to help you implement the AI driving functionality.
---
### 1. Define a Path for the AI to Follow
First, you need to create a path that the AI will follow. This can be done using waypoints or a spline system. For simplicity, we'll use waypoints here.
**a. Create Waypoints:**
1. **Create an Empty GameObject:** Name it `AIPath`.
2. **Add Child GameObjects:** Each child represents a waypoint. Position them along the track in the order you want the AI to follow.
3. **Script to Manage Waypoints:** Create a script to manage the list of waypoints.
**Example:**
```csharp
using UnityEngine;
using System.Collections.Generic;
public class AIPath : MonoBehaviour
{
public List<Transform> waypoints = new List<Transform>();
private void Awake()
{
foreach (Transform child in transform)
{
waypoints.Add(child);
}
}
public Transform GetWaypoint(int index)
{
if (waypoints.Count == 0) return null;
return waypoints[index % waypoints.Count];
}
public int WaypointCount => waypoints.Count;
}
```
**b. Assign Waypoints:**
1. Attach the `AIPath` script to the `AIPath` GameObject.
2. Add waypoint children to the `AIPath` in the scene.
---
### 2. Create an AI Controller to Generate Inputs
Next, create an AI controller script that calculates the necessary inputs (`Accelerate`, `Brake`, `TurnInput`) based on the current position relative to the waypoints.
**Example: AI Controller Script**
```csharp
using UnityEngine;
using KartGame.KartSystems;
public class AIController : MonoBehaviour, IInput
{
public AIPath aiPath;
public float detectionRadius = 10f;
public float maxSteerAngle = 1f;
public float targetSpeed = 10f;
private int currentWaypoint = 0;
private ArcadeKart kart;
private Rigidbody rb;
private void Awake()
{
kart = GetComponent<ArcadeKart>();
rb = GetComponent<Rigidbody>();
}
private void Update()
{
if (aiPath == null || aiPath.WaypointCount == 0) return;
Transform targetWaypoint = aiPath.GetWaypoint(currentWaypoint);
Vector3 direction = (targetWaypoint.position - transform.position).normalized;
// Calculate direction relative to the kart's forward vector
float angle = Vector3.SignedAngle(transform.forward, direction, Vector3.up);
// Determine turn input
float turnInput = Mathf.Clamp(angle / 45f, -1f, 1f); // Normalize based on a max angle (e.g., 45 degrees)
// Determine acceleration or braking based on distance to waypoint
float distance = Vector3.Distance(transform.position, targetWaypoint.position);
bool accelerate = distance > detectionRadius / 2;
bool brake = distance <= detectionRadius / 2;
// Assign inputs
this.Accelerate = accelerate;
this.Brake = brake;
this.TurnInput = turnInput;
// Advance to next waypoint if close enough
if (distance < 2f)
{
currentWaypoint = (currentWaypoint + 1) % aiPath.WaypointCount;
}
}
// Implementation of IInput interface
public bool Accelerate { get; private set; }
public bool Brake { get; private set; }
public float TurnInput { get; private set; }
}
```
**Notes:**
- **`AIPath` Reference:** Assign the `AIPath` GameObject to the `aiPath` field in the `AIController` script via the Inspector.
- **Waypoint Detection:** The AI advances to the next waypoint once it’s within a certain distance.
- **Turning Logic:** The AI calculates the angle between its forward direction and the direction to the waypoint to determine the `TurnInput`.
**Implement the `IInput` Interface:**
Ensure that your `ArcadeKart` script can accept inputs from the `AIController`. If `ArcadeKart` already uses the `IInput` interface for player inputs, the AI controller can implement the same interface.
If your `IInput` interface looks like this:
```csharp
public interface IInput
{
bool Accelerate { get; }
bool Brake { get; }
float TurnInput { get; }
}
```
Then the `AIController` already correctly implements this interface.
---
### 3. Integrate the AI Controller with Your `ArcadeKart` Script
Assuming that your `ArcadeKart` script gathers inputs from multiple `IInput` sources, you can use the `AIController` alongside or instead of player input scripts.
**Modify `GatherInputs` Method:**
Ensure that `ArcadeKart` correctly aggregates inputs from the `AIController`.
```csharp
void GatherInputs()
{
// Reset input
Input = new InputData();
WantsToDrift = false;
// Gather input from all input sources (player inputs, AI controllers, etc.)
for (int i = 0; i < m_Inputs.Length; i++)
{
var inputSource = m_Inputs[i].GenerateInput();
Input.Accelerate = Input.Accelerate || inputSource.Accelerate;
Input.Brake = Input.Brake || inputSource.Brake;
Input.TurnInput += inputSource.TurnInput; // Assuming multiple inputs can affect turning
WantsToDrift = WantsToDrift || (inputSource.Brake && Vector3.Dot(Rigidbody.velocity, transform.forward) > 0.0f);
}
// Clamp TurnInput to ensure it stays within [-1, 1]
Input.TurnInput = Mathf.Clamp(Input.TurnInput, -1f, 1f);
}
```
**Notes:**
- The AI controller and any player input scripts will both provide inputs.
- If you want **only** the AI to control the kart, **remove or disable** all player input components.
---
### 4. Disable or Remove Player Input Components
To ensure that the player does not control the kart at all, you need to remove or disable any player input components attached to the kart.
**a. Remove Player Input Components:**
1. Select the kart GameObject in the Hierarchy.
2. In the Inspector, look for components that handle player inputs (scripts implementing `IInput` for player controls).
3. Remove or disable these components.
**b. Ensure Only AI Controller is Active:**
- Ensure that only the `AIController` (or other AI-related input sources) are active and providing inputs to the `ArcadeKart`.
---
### Additional Enhancements
To make the AI more robust and efficient, consider implementing the following features:
1. **Path Prediction:** Predict upcoming turns and adjust speed accordingly.
2. **Obstacle Avoidance:** Detect and navigate around obstacles on the track.
3. **Dynamic Difficulty:** Adjust the AI’s speed and aggressiveness based on game difficulty settings.
4. **Lap Management:** Track laps and handle behavior when completing a lap (e.g., reset waypoints).
**Example: Enhanced AI Controller with Path Prediction**
```csharp
public class EnhancedAIController : MonoBehaviour, IInput
{
public AIPath aiPath;
public float detectionRadius = 10f;
public float maxSteerAngle = 1f;
public float targetSpeed = 10f;
private int currentWaypoint = 0;
private ArcadeKart kart;
private Rigidbody rb;
private void Awake()
{
kart = GetComponent<ArcadeKart>();
rb = GetComponent<Rigidbody>();
}
private void Update()
{
if (aiPath == null || aiPath.WaypointCount == 0) return;
Transform targetWaypoint = aiPath.GetWaypoint(currentWaypoint);
Vector3 direction = (targetWaypoint.position - transform.position).normalized;
// Predict future position
Vector3 futurePosition = transform.position + rb.velocity * 1.0f; // 1 second ahead
Vector3 futureDirection = (targetWaypoint.position - futurePosition).normalized;
// Calculate direction relative to the kart's forward vector
float angle = Vector3.SignedAngle(transform.forward, futureDirection, Vector3.up);
// Determine turn input
float turnInput = Mathf.Clamp(angle / 45f, -1f, 1f);
// Determine acceleration or braking based on distance to waypoint
float distance = Vector3.Distance(transform.position, targetWaypoint.position);
bool accelerate = distance > detectionRadius / 2;
bool brake = distance <= detectionRadius / 2;
// Assign inputs
this.Accelerate = accelerate;
this.Brake = brake;
this.TurnInput = turnInput;
// Advance to next waypoint if close enough
if (distance < 2f)
{
currentWaypoint = (currentWaypoint + 1) % aiPath.WaypointCount;
}
}
// Implementation of IInput interface
public bool Accelerate { get; private set; }
public bool Brake { get; private set; }
public float TurnInput { get; private set; }
}
```
---
### Summary
By defining a clear path with waypoints, creating an AI controller to generate appropriate inputs, integrating this controller with your existing `ArcadeKart` script, and removing any player input components, you can have your kart driven entirely by AI. This setup maintains all visual effects and animations since the physics and rendering remain unchanged; only the source of input has been switched from the player to the AI.
If you need further customization or encounter specific issues during implementation, feel free to ask!