using UnityEngine;
namespace UnityStandardAssets.Vehicles.Car
{
internal enum CarDriveType
{
FrontWheelDrive,
RearWheelDrive,
FourWheelDrive
}
internal enum SpeedType
{
MPH,
KPH
}
public class CarController : MonoBehaviour
{
[SerializeField] private CarDriveType m_CarDriveType = CarDriveType.FourWheelDrive;
[SerializeField] private WheelCollider[] m_WheelColliders = new WheelCollider[4];
[SerializeField] private GameObject[] m_WheelMeshes = new GameObject[4];
[SerializeField] private WheelEffects[] m_WheelEffects = new WheelEffects[4];
[SerializeField] private Vector3 m_CentreOfMassOffset;
[SerializeField] private float m_MaximumSteerAngle;
[Range(0, 1)] [SerializeField] private float m_SteerHelper; // 0 is raw physics , 1 the car will grip in the direction it is facing
[Range(0, 1)] [SerializeField] private float m_TractionControl; // 0 is no traction control, 1 is full interference
[SerializeField] private float m_FullTorqueOverAllWheels;
[SerializeField] private float m_ReverseTorque;
[SerializeField] private float m_MaxHandbrakeTorque;
[SerializeField] private float m_Downforce = 100f;
[SerializeField] private SpeedType m_SpeedType;
[SerializeField] private float m_Topspeed = 200;
[SerializeField] private static int NoOfGears = 5;
[SerializeField] private float m_RevRangeBoundary = 1f;
[SerializeField] private float m_SlipLimit;
[SerializeField] private float m_BrakeTorque;
private Quaternion[] m_WheelMeshLocalRotations;
private Vector3 m_Prevpos, m_Pos;
private float m_SteerAngle;
private int m_GearNum;
private float m_GearFactor;
private float m_OldRotation;
private float m_CurrentTorque;
private Rigidbody m_Rigidbody;
private const float k_ReversingThreshold = 0.01f;
public bool Skidding { get; private set; }
public float BrakeInput { get; private set; }
public float CurrentSteerAngle{ get { return m_SteerAngle; }}
public float CurrentSpeed{ get { return m_Rigidbody.velocity.magnitude*2.23693629f; }}
public float MaxSpeed{get { return m_Topspeed; }}
public float Revs { get; private set; }
public float AccelInput { get; private set; }
// Use this for initialization
private void Start()
{
m_WheelMeshLocalRotations = new Quaternion[4];
for (int i = 0; i < 4; i++)
{
m_WheelMeshLocalRotations[i] = m_WheelMeshes[i].transform.localRotation;
}
m_WheelColliders[0].attachedRigidbody.centerOfMass = m_CentreOfMassOffset;
m_MaxHandbrakeTorque = float.MaxValue;
m_Rigidbody = GetComponent<Rigidbody>();
m_CurrentTorque = m_FullTorqueOverAllWheels - (m_TractionControl*m_FullTorqueOverAllWheels);
}
private void GearChanging()
{
float f = Mathf.Abs(CurrentSpeed/MaxSpeed);
float upgearlimit = (1/(float) NoOfGears)*(m_GearNum + 1);
float downgearlimit = (1/(float) NoOfGears)*m_GearNum;
if (m_GearNum > 0 && f < downgearlimit)
{
m_GearNum--;
}
if (f > upgearlimit && (m_GearNum < (NoOfGears - 1)))
{
m_GearNum++;
}
}
// simple function to add a curved bias towards 1 for a value in the 0-1 range
private static float CurveFactor(float factor)
{
return 1 - (1 - factor)*(1 - factor);
}
// unclamped version of Lerp, to allow value to exceed the from-to range
private static float ULerp(float from, float to, float value)
{
return (1.0f - value)*from + value*to;
}
private void CalculateGearFactor()
{
float f = (1/(float) NoOfGears);
// gear factor is a normalised representation of the current speed within the current gear's range of speeds.
// We smooth towards the 'target' gear factor, so that revs don't instantly snap up or down when changing gear.
var targetGearFactor = Mathf.InverseLerp(f*m_GearNum, f*(m_GearNum + 1), Mathf.Abs(CurrentSpeed/MaxSpeed));
m_GearFactor = Mathf.Lerp(m_GearFactor, targetGearFactor, Time.deltaTime*5f);
}
private void CalculateRevs()
{
// calculate engine revs (for display / sound)
// (this is done in retrospect - revs are not used in force/power calculations)
CalculateGearFactor();
var gearNumFactor = m_GearNum/(float) NoOfGears;
var revsRangeMin = ULerp(0f, m_RevRangeBoundary, CurveFactor(gearNumFactor));
var revsRangeMax = ULerp(m_RevRangeBoundary, 1f, gearNumFactor);
Revs = ULerp(revsRangeMin, revsRangeMax, m_GearFactor);
}
public void Move(float steering, float accel, float footbrake, float handbrake)
{
for (int i = 0; i < 4; i++)
{
Quaternion quat;
Vector3 position;
m_WheelColliders[i].GetWorldPose(out position, out quat);
m_WheelMeshes[i].transform.position = position;
m_WheelMeshes[i].transform.rotation = quat;
}
//clamp input values
steering = Mathf.Clamp(steering, -1, 1);
AccelInput = accel = Mathf.Clamp(accel, 0, 1);
BrakeInput = footbrake = -1*Mathf.Clamp(footbrake, -1, 0);
handbrake = Mathf.Clamp(handbrake, 0, 1);
//Set the steer on the front wheels.
//Assuming that wheels 0 and 1 are the front wheels.
m_SteerAngle = steering*m_MaximumSteerAngle;
m_WheelColliders[0].steerAngle = m_SteerAngle;
m_WheelColliders[1].steerAngle = m_SteerAngle;
SteerHelper();
ApplyDrive(accel, footbrake);
CapSpeed();
//Set the handbrake.
//Assuming that wheels 2 and 3 are the rear wheels.
if (handbrake > 0f)
{
var hbTorque = handbrake*m_MaxHandbrakeTorque;
m_WheelColliders[2].brakeTorque = hbTorque;
m_WheelColliders[3].brakeTorque = hbTorque;
}
CalculateRevs();
GearChanging();
AddDownForce();
CheckForWheelSpin();
TractionControl();
}
private void CapSpeed()
{
float speed = m_Rigidbody.velocity.magnitude;
switch (m_SpeedType)
{
case SpeedType.MPH:
speed *= 2.23693629f;
if (speed > m_Topspeed)
m_Rigidbody.velocity = (m_Topspeed/2.23693629f) * m_Rigidbody.velocity.normalized;
break;
case SpeedType.KPH:
speed *= 3.6f;
if (speed > m_Topspeed)
m_Rigidbody.velocity = (m_Topspeed/3.6f) * m_Rigidbody.velocity.normalized;
break;
}
}
private void ApplyDrive(float accel, float footbrake)
{
float thrustTorque;
switch (m_CarDriveType)
{
case CarDriveType.FourWheelDrive:
thrustTorque = accel * (m_CurrentTorque / 4f);
for (int i = 0; i < 4; i++)
{
m_WheelColliders[i].motorTorque = thrustTorque;
}
break;
case CarDriveType.FrontWheelDrive:
thrustTorque = accel * (m_CurrentTorque / 2f);
m_WheelColliders[0].motorTorque = m_WheelColliders[1].motorTorque = thrustTorque;
break;
case CarDriveType.RearWheelDrive:
thrustTorque = accel * (m_CurrentTorque / 2f);
m_WheelColliders[2].motorTorque = m_WheelColliders[3].motorTorque = thrustTorque;
break;
}
for (int i = 0; i < 4; i++)
{
if (CurrentSpeed > 5 && Vector3.Angle(transform.forward, m_Rigidbody.velocity) < 50f)
{
m_WheelColliders[i].brakeTorque = m_BrakeTorque*footbrake;
}
else if (footbrake > 0)
{
m_WheelColliders[i].brakeTorque = 0f;
m_WheelColliders[i].motorTorque = -m_ReverseTorque*footbrake;
}
}
}
private void SteerHelper()
{
for (int i = 0; i < 4; i++)
{
WheelHit wheelhit;
m_WheelColliders[i].GetGroundHit(out wheelhit);
if (wheelhit.normal == Vector3.zero)
return; // wheels arent on the ground so dont realign the rigidbody velocity
}
// this if is needed to avoid gimbal lock problems that will make the car suddenly shift direction
if (Mathf.Abs(m_OldRotation - transform.eulerAngles.y) < 10f)
{
var turnadjust = (transform.eulerAngles.y - m_OldRotation) * m_SteerHelper;
Quaternion velRotation = Quaternion.AngleAxis(turnadjust, Vector3.up);
m_Rigidbody.velocity = velRotation * m_Rigidbody.velocity;
}
m_OldRotation = transform.eulerAngles.y;
}
// this is used to add more grip in relation to speed
private void AddDownForce()
{
m_WheelColliders[0].attachedRigidbody.AddForce(-transform.up*m_Downforce*
m_WheelColliders[0].attachedRigidbody.velocity.magnitude);
}
// checks if the wheels are spinning and is so does three things
// 1) emits particles
// 2) plays tiure skidding sounds
// 3) leaves skidmarks on the ground
// these effects are controlled through the WheelEffects class
private void CheckForWheelSpin()
{
// loop through all wheels
for (int i = 0; i < 4; i++)
{
WheelHit wheelHit;
m_WheelColliders[i].GetGroundHit(out wheelHit);
// is the tire slipping above the given threshhold
if (Mathf.Abs(wheelHit.forwardSlip) >= m_SlipLimit || Mathf.Abs(wheelHit.sidewaysSlip) >= m_SlipLimit)
{
m_WheelEffects[i].EmitTyreSmoke();
// avoiding all four tires screeching at the same time
// if they do it can lead to some strange audio artefacts
if (!AnySkidSoundPlaying())
{
m_WheelEffects[i].PlayAudio();
}
continue;
}
// if it wasnt slipping stop all the audio
if (m_WheelEffects[i].PlayingAudio)
{
m_WheelEffects[i].StopAudio();
}
// end the trail generation
m_WheelEffects[i].EndSkidTrail();
}
}
// crude traction control that reduces the power to wheel if the car is wheel spinning too much
private void TractionControl()
{
WheelHit wheelHit;
switch (m_CarDriveType)
{
case CarDriveType.FourWheelDrive:
// loop through all wheels
for (int i = 0; i < 4; i++)
{
m_WheelColliders[i].GetGroundHit(out wheelHit);
AdjustTorque(wheelHit.forwardSlip);
}
break;
case CarDriveType.RearWheelDrive:
m_WheelColliders[2].GetGroundHit(out wheelHit);
AdjustTorque(wheelHit.forwardSlip);
m_WheelColliders[3].GetGroundHit(out wheelHit);
AdjustTorque(wheelHit.forwardSlip);
break;
case CarDriveType.FrontWheelDrive:
m_WheelColliders[0].GetGroundHit(out wheelHit);
AdjustTorque(wheelHit.forwardSlip);
m_WheelColliders[1].GetGroundHit(out wheelHit);
AdjustTorque(wheelHit.forwardSlip);
break;
}
}
private void AdjustTorque(float forwardSlip)
{
if (forwardSlip >= m_SlipLimit && m_CurrentTorque >= 0)
{
m_CurrentTorque -= 10 * m_TractionControl;
}
else
{
m_CurrentTorque += 10 * m_TractionControl;
if (m_CurrentTorque > m_FullTorqueOverAllWheels)
{
m_CurrentTorque = m_FullTorqueOverAllWheels;
}
}
}
private bool AnySkidSoundPlaying()
{
for (int i = 0; i < 4; i++)
{
if (m_WheelEffects[i].PlayingAudio)
{
return true;
}
}
return false;
}
}
}