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predominant/Car.js

Created Jul 20, 2020
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Legacy Unity Car Controller Code (Javascript)
private var wheelRadius : float = 0.4;
var dragMultiplier : Vector3 = new Vector3(2, 5, 1);
var throttle : float = 0;
private var steer : float = 0;
private var handbrake : boolean = false;
var centerOfMass : Transform;
var frontWheels : Transform[];
var rearWheels : Transform[];
private var wheels : Wheel[];
wheels = new Wheel[frontWheels.Length + rearWheels.Length];
private var wfc : WheelFrictionCurve;
var topSpeed : float = 180;
var numberOfGears : int = 6;
var maximumTurn : int = 20;
var minimumTurn : int = 10;
var resetTime : float = 5.0;
private var resetTimer : float = 0.0;
private var engineForceValues : float[];
private var gearSpeeds : float[];
private var currentGear : int;
private var currentEnginePower : float = 0.0;
private var handbrakeXDragFactor : float = 0.5;
private var initialDragMultiplierX : float = 10.0;
private var handbrakeTime : float = 0.0;
private var handbrakeTimer : float = 1.0;
private var sound : SoundController = null;
sound = transform.GetComponent(SoundController);
private var canSteer : boolean;
private var canDrive : boolean;
class Wheel
{
var collider : WheelCollider;
var tireGraphic : Transform;
var driveWheel : boolean = false;
var steerWheel : boolean = false;
var lastSkidmark : int = -1;
var lastEmitPosition : Vector3 = Vector3.zero;
var lastEmitTime : float = Time.time;
var wheelVelo : Vector3 = Vector3.zero;
var groundSpeed : Vector3 = Vector3.zero;
}
function Start()
{
SetupWheelColliders();
SetupCenterOfMass();
topSpeed = Convert_Miles_Per_Hour_To_Meters_Per_Second(topSpeed);
SetupGears();
initialDragMultiplierX = dragMultiplier.x;
}
function Update()
{
var relativeVelocity : Vector3 = transform.InverseTransformDirection(rigidbody.velocity);
GetInput();
Check_If_Car_Is_Flipped();
UpdateWheelGraphics(relativeVelocity);
UpdateGear(relativeVelocity);
}
function FixedUpdate()
{
var relativeVelocity : Vector3 = transform.InverseTransformDirection(rigidbody.velocity);
CalculateState();
UpdateFriction(relativeVelocity);
UpdateDrag(relativeVelocity);
CalculateEnginePower(relativeVelocity);
ApplyThrottle(canDrive, relativeVelocity);
ApplySteering(canSteer, relativeVelocity);
}
/**************************************************/
/* Functions called from Start() */
/**************************************************/
function SetupWheelColliders()
{
SetupWheelFrictionCurve();
var wheelCount : int = 0;
for (var t : Transform in frontWheels)
{
wheels[wheelCount] = SetupWheel(t, true);
wheelCount++;
}
for (var t : Transform in rearWheels)
{
wheels[wheelCount] = SetupWheel(t, false);
wheelCount++;
}
}
function SetupWheelFrictionCurve()
{
wfc = new WheelFrictionCurve();
wfc.extremumSlip = 1;
wfc.extremumValue = 50;
wfc.asymptoteSlip = 2;
wfc.asymptoteValue = 25;
wfc.stiffness = 1;
}
function SetupWheel(wheelTransform : Transform, isFrontWheel : boolean)
{
var go : GameObject = new GameObject(wheelTransform.name + " Collider");
go.transform.position = wheelTransform.position;
go.transform.parent = transform;
go.transform.rotation = wheelTransform.rotation;
var wc : WheelCollider = go.AddComponent(typeof(WheelCollider)) as WheelCollider;
var wheel = new Wheel();
wheel.collider = wc;
wc.sidewaysFriction = wfc;
wheel.tireGraphic = wheelTransform;
wheelRadius = (wheel.tireGraphic.renderer.bounds.size.y) / 2;
wheel.collider.radius = wheelRadius;
if (isFrontWheel)
{
wheel.steerWheel = true;
wheel.driveWheel = true;
go = new GameObject(wheelTransform.name + " Steer Column");
go.transform.position = wheelTransform.position;
go.transform.rotation = wheelTransform.rotation;
go.transform.parent = transform;
wheelTransform = go.transform;
}
else
{
wheel.driveWheel = true;
}
return wheel;
}
function SetupCenterOfMass()
{
if(centerOfMass != null)
rigidbody.centerOfMass = centerOfMass.localPosition;
}
function SetupGears()
{
engineForceValues = new float[numberOfGears];
gearSpeeds = new float[numberOfGears];
var tempTopSpeed : float = topSpeed;
for(var i = 0; i < numberOfGears; i++)
{
if(i > 0)
gearSpeeds[i] = tempTopSpeed / 4 + gearSpeeds[i-1];
else
gearSpeeds[i] = tempTopSpeed / 4;
tempTopSpeed -= tempTopSpeed / 4;
}
var engineFactor : float = topSpeed / gearSpeeds[gearSpeeds.Length - 1];
for(i = 0; i < numberOfGears; i++)
{
var maxLinearDrag : float = gearSpeeds[i] * gearSpeeds[i];// * dragMultiplier.z;
engineForceValues[i] = maxLinearDrag * engineFactor;
}
}
/**************************************************/
/* Functions called from Update() */
/**************************************************/
function GetInput()
{
throttle = Input.GetAxis("Vertical");
steer = Input.GetAxis("Horizontal");
if(Input.GetButton("Brake"))
{
if(!handbrake)
{
handbrake = true;
handbrakeTime = Time.time;
dragMultiplier.x = initialDragMultiplierX * handbrakeXDragFactor;
sound.Skid(true, 0.8);
}
}
else if(handbrake)
{
sound.Skid(false, 0);
handbrake = false;
StartCoroutine(StopHandbraking(Mathf.Min(5, Time.time - handbrakeTime)));
}
}
function StopHandbraking(seconds : float)
{
var diff : float = initialDragMultiplierX - dragMultiplier.x;
handbrakeTimer = 1;
// Get the x value of the dragMultiplier back to its initial value in the specified time.
while(dragMultiplier.x < initialDragMultiplierX && !handbrake)
{
dragMultiplier.x += diff * (Time.deltaTime / seconds);
handbrakeTimer -= Time.deltaTime / seconds;
yield;
}
dragMultiplier.x = initialDragMultiplierX;
handbrakeTimer = 0;
}
function Check_If_Car_Is_Flipped()
{
if(transform.localEulerAngles.z > 80 && transform.localEulerAngles.z < 280)
resetTimer += Time.deltaTime;
else
resetTimer = 0;
if(resetTimer > resetTime)
FlipCar();
Debug.Log(resetTimer);
}
function FlipCar()
{
transform.rotation = Quaternion.LookRotation(transform.forward);
transform.rotation.eulerAngles.x = 0;
transform.position += Vector3.up * 0.5;
rigidbody.velocity = Vector3.zero;
rigidbody.angularVelocity = Vector3.zero;
resetTimer = 0;
currentEnginePower = 0;
}
var wheelCount : float;
function UpdateWheelGraphics(relativeVelocity : Vector3)
{
wheelCount = -1;
var groundWheel = 0;
for(var w : Wheel in wheels)
{
wheelCount++;
var wheel : WheelCollider = w.collider;
var wh : WheelHit = new WheelHit();
if(wheel.GetGroundHit(wh))
{
// First we get the velocity at the point where the wheel meets the ground, if the wheel is touching the ground
groundWheel++;
w.wheelVelo = rigidbody.GetPointVelocity(wh.point);
w.groundSpeed = w.tireGraphic.InverseTransformDirection(w.wheelVelo);
w.tireGraphic.Rotate(Vector3.right * (w.groundSpeed.z / wheelRadius) * Time.deltaTime * Mathf.Rad2Deg);
}
}
if( groundWheel == 0 )
resetTimer += Time.deltaTime;
else
resetTimer = 0;
}
function UpdateGear(relativeVelocity : Vector3)
{
currentGear = 0;
for(var i = 0; i < numberOfGears - 1; i++)
{
if(relativeVelocity.z > gearSpeeds[i])
currentGear = i + 1;
}
}
/**************************************************/
/* Functions called from FixedUpdate() */
/**************************************************/
function UpdateDrag(relativeVelocity : Vector3)
{
var relativeDrag : Vector3 = new Vector3( -relativeVelocity.x * Mathf.Abs(relativeVelocity.x),
-relativeVelocity.y * Mathf.Abs(relativeVelocity.y),
-relativeVelocity.z * Mathf.Abs(relativeVelocity.z) );
dragMultiplier.x *= 50;
var drag = Vector3.Scale(dragMultiplier, relativeDrag);
dragMultiplier.x /= 50;
if(initialDragMultiplierX > dragMultiplier.x) // Handbrake code
{
drag.x /= (relativeVelocity.magnitude / (topSpeed / ( 1 + 2 * handbrakeXDragFactor) ) );
drag.z *= (1 + Mathf.Abs(Vector3.Dot(rigidbody.velocity.normalized, transform.forward)));
drag += rigidbody.velocity * Mathf.Clamp01(rigidbody.velocity.magnitude / topSpeed);
}
else // No handbrake
{
drag = Vector3.Scale(dragMultiplier, relativeDrag);
drag.x *= topSpeed / relativeVelocity.magnitude;
}
if(Mathf.Abs(relativeVelocity.x) < 5 && !handbrake)
drag.x = -relativeVelocity.x * dragMultiplier.x;
rigidbody.AddForce(transform.TransformDirection(drag) * rigidbody.mass * Time.deltaTime);
}
function UpdateFriction(relativeVelocity : Vector3)
{
var sqrVel : float = relativeVelocity.x * relativeVelocity.x;
// Add extra sideways friction based on the car's turning velocity to avoid slipping
if( !handbrake )
{
wfc.extremumValue = Mathf.Clamp(300 - sqrVel, 0, 300);
wfc.asymptoteValue = Mathf.Clamp(150 - (sqrVel / 2), 0, 150);
}
for(var w : Wheel in wheels)
{
if( !handbrake )
w.collider.sidewaysFriction = wfc;
w.collider.forwardFriction = wfc;
}
}
function CalculateEnginePower(relativeVelocity : Vector3)
{
if(throttle == 0)
{
currentEnginePower -= Time.deltaTime * 200;
}
else if( HaveTheSameSign(relativeVelocity.z, throttle) )
{
var normPower = (currentEnginePower / engineForceValues[engineForceValues.Length - 1]) * 2;
currentEnginePower += Time.deltaTime * 200 * EvaluateNormPower(normPower);
}
else
{
currentEnginePower -= Time.deltaTime * 300;
}
if(currentGear == 0)
currentEnginePower = Mathf.Clamp(currentEnginePower, 0, engineForceValues[0]);
else
currentEnginePower = Mathf.Clamp(currentEnginePower, engineForceValues[currentGear - 1], engineForceValues[currentGear]);
}
function CalculateState()
{
canDrive = false;
canSteer = false;
for(var w : Wheel in wheels)
{
if(w.collider.isGrounded)
{
if(w.steerWheel)
canSteer = true;
if(w.driveWheel)
canDrive = true;
}
}
}
function ApplyThrottle(canDrive : boolean, relativeVelocity : Vector3)
{
if(canDrive)
{
var throttleForce : float = 0;
var brakeForce : float = 0;
if (HaveTheSameSign(relativeVelocity.z, throttle) && (throttle != 0))
{
if (!handbrake)
throttleForce = Mathf.Sign(throttle) * currentEnginePower * rigidbody.mass;
}
else if(throttle != 0)
brakeForce = Mathf.Sign(throttle) * engineForceValues[0] * rigidbody.mass;
rigidbody.AddForce(transform.forward * Time.deltaTime * ((throttleForce + brakeForce)));
}
}
function ApplySteering(canSteer : boolean, relativeVelocity : Vector3)
{
if(canSteer)
{
var turnRadius : float = 3.0 / Mathf.Sin((90 - (steer * 30)) * Mathf.Deg2Rad);
var minMaxTurn : float = EvaluateSpeedToTurn(rigidbody.velocity.magnitude);
var turnSpeed : float = Mathf.Clamp(relativeVelocity.z / turnRadius, -minMaxTurn / 10, minMaxTurn / 10);
transform.RotateAround( transform.position + transform.right * turnRadius * steer,
transform.up,
turnSpeed * Mathf.Rad2Deg * Time.deltaTime * steer);
var debugStartPoint = transform.position + transform.right * turnRadius * steer;
var debugEndPoint = debugStartPoint + Vector3.up * 5;
Debug.DrawLine(debugStartPoint, debugEndPoint, Color.red);
if(initialDragMultiplierX > dragMultiplier.x) // Handbrake
{
var rotationDirection : float = Mathf.Sign(steer) * 5; // rotationDirection is -1 or 1 by default, depending on steering
if(steer == 0)
{
if(rigidbody.angularVelocity.y < 1) // If we are not steering and we are handbraking and not rotating fast, we apply a random rotationDirection
rotationDirection = Random.Range(-1.0, 1.0);
else
rotationDirection = rigidbody.angularVelocity.y; // If we are rotating fast we are applying that rotation to the car
}
// -- Finally we apply this rotation around a point between the cars front wheels.
transform.RotateAround( transform.TransformPoint( ( frontWheels[0].localPosition + frontWheels[1].localPosition) * 0.5),
transform.up,
rigidbody.velocity.magnitude * Mathf.Clamp01(1 - rigidbody.velocity.magnitude / topSpeed) * rotationDirection * Time.deltaTime * 2);
}
}
}
/**************************************************/
/* Utility Functions */
/**************************************************/
function Convert_Miles_Per_Hour_To_Meters_Per_Second(value : float) : float
{
return value * 0.44704;
}
function Convert_Meters_Per_Second_To_Miles_Per_Hour(value : float) : float
{
return value * 2.23693629;
}
function HaveTheSameSign(first : float, second : float) : boolean
{
if (Mathf.Sign(first) == Mathf.Sign(second))
return true;
else
return false;
}
function EvaluateSpeedToTurn(speed : float)
{
if(speed > topSpeed / 2)
return minimumTurn;
var speedIndex : float = 1 - (speed / (topSpeed / 2));
return minimumTurn + speedIndex * (maximumTurn - minimumTurn);
}
function EvaluateNormPower(normPower : float)
{
if(normPower < 1)
return 10 - normPower * 9;
else
return 1.9 - normPower * 0.9;
}
function GetGearState()
{
var relativeVelocity : Vector3 = transform.InverseTransformDirection(rigidbody.velocity);
var lowLimit : float = (currentGear == 0 ? 0 : gearSpeeds[currentGear-1]);
return (relativeVelocity.z - lowLimit) / (gearSpeeds[currentGear - lowLimit]) * (1 - currentGear * 0.1) + currentGear * 0.1;
}
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