AI : #6 – Braking

In this episode we are going to make our AI car to apply breaks on some certain points or sectors on the map.

Script that was modified in this episode.

AICarScript

var centerOfMass : Vector3;
var path : Array;
var pathGroup : Transform;
var maxSteer : float = 15.0;
var wheelFL : WheelCollider; 
var wheelFR : WheelCollider;
var wheelRL : WheelCollider; 
var wheelRR : WheelCollider;
var currentPathObj : int;
var distFromPath : float = 20;
var maxTorque : float = 50;
var currentSpeed : float;
var topSpeed : float = 150;
var decellarationSpeed : float = 10;
var breakingMesh : Renderer;
var idleBreakLight : Material;
var activeBreakLight : Material;
var isBreaking : boolean;
var inSector : boolean;

function Start () {
rigidbody.centerOfMass = centerOfMass;
GetPath();
}

function GetPath (){
var path_objs : Array = pathGroup.GetComponentsInChildren(Transform);
path = new Array();

for (var path_obj : Transform in path_objs){
 if (path_obj != pathGroup)
  path [path.length] = path_obj;
}
}


function Update () {
GetSteer();
Move();
BreakingEffect ();
}

function GetSteer(){
var steerVector : Vector3 = transform.InverseTransformPoint(Vector3(path[currentPathObj].position.x,transform.position.y,path[currentPathObj].position.z));
var newSteer : float = maxSteer * (steerVector.x / steerVector.magnitude);
wheelFL.steerAngle = newSteer;
wheelFR.steerAngle = newSteer;

if (steerVector.magnitude <= distFromPath){
currentPathObj++;
if (currentPathObj >= path.length)
currentPathObj = 0;
}

}

function Move (){
currentSpeed = 2*(22/7)*wheelRL.radius*wheelRL.rpm * 60 / 1000;
currentSpeed = Mathf.Round (currentSpeed);
if (currentSpeed <= topSpeed && !inSector){
wheelRL.motorTorque = maxTorque;
wheelRR.motorTorque = maxTorque;
wheelRL.brakeTorque = 0;
wheelRR.brakeTorque = 0;
}
else if (!inSector){
wheelRL.motorTorque = 0;
wheelRR.motorTorque = 0;
wheelRL.brakeTorque = decellarationSpeed;
wheelRR.brakeTorque = decellarationSpeed;
}
}

function BreakingEffect (){
if (isBreaking){
breakingMesh.material = activeBreakLight;
}
else {
breakingMesh.material = idleBreakLight;
}

} 

Script that was created in this episode.

BrakingSectorScript

#pragma strict
var maxBreakTorque : float;
var minCarSpeed : float;


function OnTriggerStay (other : Collider){

if (other.tag == "AI"){
var controlCurrentSpeed : float = other.transform.root.GetComponent(AICarScript).currentSpeed;
if (controlCurrentSpeed >= minCarSpeed){
other.transform.root.GetComponent(AICarScript).inSector = true;
other.transform.root.GetComponent(AICarScript).wheelRR.brakeTorque = maxBreakTorque;
other.transform.root.GetComponent(AICarScript).wheelRL.brakeTorque = maxBreakTorque;
}
else {
other.transform.root.GetComponent(AICarScript).inSector = false;
other.transform.root.GetComponent(AICarScript).wheelRR.brakeTorque = 0;
other.transform.root.GetComponent(AICarScript).wheelRL.brakeTorque = 0;
}
other.transform.root.GetComponent(AICarScript).isBreaking = true;
}
}

function OnTriggerExit (other : Collider){
if (other.tag == "AI"){
other.transform.root.GetComponent(AICarScript).inSector = false;
other.transform.root.GetComponent(AICarScript).wheelRR.brakeTorque = 0;
other.transform.root.GetComponent(AICarScript).wheelRL.brakeTorque = 0;
other.transform.root.GetComponent(AICarScript).isBreaking = false;
}
}