使用方法如下：
1、把脚本直接连到汽车车身网格上，车身要有Rigidbody Component，要有四个轮子网格做子物体。 要想有声音的话还要有AudioSource Component。
2、打开Inspector，选择汽车脚本，把四个轮子连接到相对应的Transform参数上。设置wheelRadius参数为你轮子网格的大小。WheelCollider是自动生成的，所以无需手动添加。这样就能保证运行了，其他的声音和灰尘可以再添加。
脚本源代码如下：
view plainprint?
#pragma strict
//maximal corner and braking acceleration capabilities
var maxCornerAccel=10.0;
var maxBrakeAccel=10.0;
//center of gravity height - effects tilting in corners
var cogY = 0.0;
//engine powerband
var minRPM = 700;
var maxRPM = 6000;
//maximum Engine Torque
var maxTorque = 400;
//automatic transmission shift points
var shiftDownRPM = 2500;
var shiftUpRPM = 5500;
//gear ratios
var gearRatios = [-2.66, 2.66, 1.78, 1.30, 1.00];
var finalDriveRatio = 3.4;
//a basic handling modifier:
//1.0 understeer
//0.0 oversteer
var handlingTendency = 0.7;
//graphical wheel objects
var wheelFR : Transform;
var wheelFL : Transform;
var wheelBR : Transform;
var wheelBL : Transform;
//suspension setup
var suspensionDistance = 0.3;
var springs = 1000;
var dampers = 200;
var wheelRadius = 0.45;
//particle effect for ground dust
var groundDustEffect : Transform;
private var queryUserInput = ***e;
private var engineRPM : float;
private var steerVelo = 0.0;
private var brake = 0.0;
private var handbrake = 0.0;
private var steer = 0.0;
private var motor = 0.0;
//private var skidTime = 0.0;
private var onGround = false;
private var cornerSlip = 0.0;
private var driveSlip = 0.0;
private var wheelRPM : float;
private var gear = 1;
//private var skidmarks : Skidmarks;
private var wheels : WheelData[];
private var wheelY = 0.0;
private var rev = 0.0;
//Functions to be used by external scripts
//controlling the car if required
//===================================================================
//return a status string for the vehicle
function GetStatus(gui : GUIText) {
gui.text="v="+(rigidbody.velocity.magnitude * 3.6).ToString("f1") + " km/h/ngear= "+gear+"/nrpm= "+engineRPM.ToString("f0");
}
//return an information string for the vehicle
function GetControlString(gui : GUIText) {
gui.text="Use arrow keys to control the jeep,/nspace for handbrake.";
}
//Enable or disable user controls
function SetEnableUserInput(enableInput)
{
queryUserInput=enableInput;
}
//Car physics
//===================================================================
//some whee calculation data
class WheelData{
var rotation = 0.0;
var coll : WheelCollider;
var graphic : Transform;
var maxSteerAngle = 0.0;
var lastSkidMark = -1;
var powered = false;
var handbraked = false;
var originalRotation : Quaternion;
};
function Start () {
//setup wheels
wheels=new WheelData[4];
for(i=0;i<4;i++)
wheels = new WheelData();
wheels[0].graphic = wheelFL;
wheels[1].graphic = wheelFR;
wheels[2].graphic = wheelBL;
wheels[3].graphic = wheelBR;
wheels[0].maxSteerAngle=30.0;
wheels[1].maxSteerAngle=30.0;
wheels[2].powered=***e;
wheels[3].powered=***e;
wheels[2].handbraked=***e;
wheels[3].handbraked=***e;
for(w in wheels)
{
if(w.graphic==null)
Debug.Log("You need to assign all four wheels for the car script!");
if(!w.graphic.transform.IsChildOf(transform))
Debug.Log("Wheels need to be children of the Object with the car script");
//shift to first
gear=1;
}
//update wheel status
function UpdateWheels()
{
//calculate handbrake slip for traction gfx
handbrakeSlip=handbrake*rigidbody.velocity.magnitude*0.1;
if(handbrakeSlip>1)
handbrakeSlip=1;
totalSlip=0.0;
onGround=false;
for(w in wheels)
{
//rotate wheel
w.rotation += wheelRPM / 60.0 * -rev * 360.0 * Time.fixedDeltaTime;
w.rotation = Mathf.Repeat(w.rotation, 360.0);
w.graphic.localRotation= Quaternion.Euler( w.rotation, w.maxSteerAngle*steer, 0.0 ) * w.originalRotation;
//check if wheel is on ground
if(w.coll.isGrounded)
onGround=***e;
var hit : WheelHit;
var c : WheelCollider;
c = w.coll;
if(c.GetGroundHit(hit))
{
//if the wheel touches the ground, adjust graphical wheel position to reflect springs
w.graphic.localPosition.y-=Vector3.Dot(w.graphic.position-hit.point,transform.up)-w.coll.radius;
//create dust on ground if appropiate
if(slip>0.5 && hit.collider.tag=="Dusty")
{
groundDustEffect.position=hit.point;
groundDustEffect.particleEmitter.worldVelocity=rigidbody.velocity*0.5;
groundDustEffect.particleEmitter.minEmission=(slip-0.5)*3;
groundDustEffect.particleEmitter.maxEmission=(slip-0.5)*3;
groundDustEffect.particleEmitter.Emit();
}
//and skid marks
/*if(slip>0.75 && skidmarks != null)
w.lastSkidMark=skidmarks.AddSkidMark(hit.point,hit.normal,(slip-0.75)*2,w.lastSkidMark);
else
w.lastSkidMark=-1; */
}
// else w.lastSkidMark=-1;
}
totalSlip/=wheels.length;
}
//Automatically shift gears
function AutomaticTransmission()
{
if(gear>0)
{
if(engineRPM>shiftUpRPM&&gear<gearRatios.length-1)
gear++;
if(engineRPM<shiftDownRPM&&gear>1)
gear--;
}
}
//Calculate engine acceleration force for current RPM and trottle
function CalcEngine() : float
{
//no engine when braking
if(brake+handbrake>0.1)
motor=0.0;
//if car is airborne, just rev engine
if(!onGround)
{
engineRPM += (motor-0.3)*25000.0*Time.deltaTime;
engineRPM = Mathf.Clamp(engineRPM,minRPM,maxRPM);
return 0.0;
}
else
{
AutomaticTransmission();
engineRPM=wheelRPM*gearRatios[gear]*finalDriveRatio;
if(engineRPM<minRPM)
engineRPM=minRPM;
if(engineRPM<maxRPM)
{
//fake a basic torque curve
x = (2*(engineRPM/maxRPM)-1);
torqueCurve = 0.5*(-x*x+2);
torqueToForceRatio = gearRatios[gear]*finalDriveRatio/wheelRadius;
return motor*maxTorque*torqueCurve*torqueToForceRatio;
}
else
//rpm delimiter
return 0.0;
}
}
//Car physics
//The physics of this car are really a trial-and-error based extension of
//basic "Asteriods" physics -- so you will get a pretty arcade-like feel.
//This may or may not be what you want, for a more physical approach research
//the wheel colliders
function HandlePhysics () {
var velo=rigidbody.velocity;
wheelRPM=velo.magnitude*60.0*0.5;
rigidbody.angularVelocity=new Vector3(rigidbody.angularVelocity.x,0.0,rigidbody.angularVelocity.z);
dir=transform.TransformDirection(Vector3.forward);
flatDir=Vector3.Normalize(new Vector3(dir.x,0,dir.z));
flatVelo=new Vector3(velo.x,0,velo.z);
rev=Mathf.Sign(Vector3.Dot(flatVelo,flatDir));
//when moving backwards or standing and brake is pressed, switch to reverse
if((rev<0||flatVelo.sqrMagnitude<0.5)&&brake>0.1)
gear=0;
if(gear==0)
{
//when in reverse, flip brake and gas
tmp=brake;
brake=motor;
motor=tmp;
//when moving forward or standing and gas is pressed, switch to drive
if((rev>0||flatVelo.sqrMagnitude<0.5)&&brake>0.1)
gear=1;
}
engineForce=flatDir*CalcEngine();
totalbrake=brake+handbrake*0.5;
if(totalbrake>1.0)totalbrake=1.0;
brakeForce=-flatVelo.normalized*totalbrake*rigidbody.mass*maxBrakeAccel;
flatDir*=flatVelo.magnitude;
flatDir=Quaternion.AngleAxis(steer*30.0,Vector3.up)*flatDir;
flatDir*=rev;
diff=(flatVelo-flatDir).magnitude;
cornerAccel=maxCornerAccel;
if(cornerAccel>diff)cornerAccel=diff;
cornerForce=-(flatVelo-flatDir).normalized*cornerAccel*rigidbody.mass;
cornerSlip=Mathf.Pow(cornerAccel/maxCornerAccel,3);