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引言：今天突发奇想，想搞一个车的项目，话不多说，直接下载，但是之前对它一无所知。好在通过简单的测试，已经解决。运行效果还不错。上图是运行效果
1、导入游戏资源
1-1 导入标准资源包：
最后一个就是拥有车模型的资源包，而且导入Unity中会自动出现一个Standard Assets:
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标准资源包里面就有车的模型：
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其他资源是我自己下载的：可以加群（Q群：134688909）获取相关资源
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1-2让车能够移动
因为系统自带的车模型，拥有移动功能，而且还不错。所以直接拿来当轮子使用
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再搞一些跟随车辆：显得有竞技效果，此处也是使用系统资源
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2、搭建简单地形：
2-1创建地形
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2-2添加地形：
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2-3最终效果图：
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3、添加游戏对象 - 车
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4、脚本一栏：
namespace UnityStandardAssets.Vehicles.Car
{
//汽车驱动类型
internal enum CarDriveType
{
//四驱
FrontWheelDrive,
//后驱
RearWheelDrive,
//前驱
FourWheelDrive
}
//速度类型
internal enum SpeedType
{
//英里每小时
MPH,
//千米每小时
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];
//重心位置
[SerializeField] private Vector3 m_CentreOfMassOffset;
//最大可转角度
[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
//所有轮胎的扭矩
[SerializeField] private float m_FullTorqueOverAllWheels;
//反向扭矩
[SerializeField] private float m_ReverseTorque;
//最大刹车扭矩
[SerializeField] private float m_MaxHandbrakeTorque;
//最大下压力
[SerializeField] private float m_Downforce = 100f;
//速度单位
[SerializeField] private SpeedType m_SpeedType;
//最高速度
[SerializeField] private float m_Topspeed = 200;
//档位总数
[SerializeField] private static int NoOfGears = 5;
//
[SerializeField] private float m_RevRangeBoundary = 1f;
//最大滑动距离
[SerializeField] private float m_SlipLimit;
//刹车扭矩
[SerializeField] private float m_BrakeTorque;
private Quaternion[] m_WheelMeshLocalRotations;
private Vector3 m_Prevpos, m_Pos;
private float m_SteerAngle;
//当前档位
private int m_GearNum;
//档位因子
private float m_GearFactor;
//上一帧汽车方向
private float m_OldRotation;
//当前扭矩
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 { if(m_Rigidbody == null) return 0;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; }
public Rigidbody CarRigidbody { get{return m_Rigidbody;}}
// Use this for initialization
private void Start()
{
//四个轮胎的自转方向
m_WheelMeshLocalRotations = new Quaternion[4];
for (int i = 0; i < 4; i++)
{
m_WheelMeshLocalRotations[i] = m_WheelMeshes[i].transform.localRotation;
}
//设置重心
m_WheelColliders[0].attachedRigidbody.centerOfMass = m_CentreOfMassOffset;
//设置最大手刹扭矩
m_MaxHandbrakeTorque = float.MaxValue;
m_Rigidbody = GetComponent();
//设置当前扭矩，初始化的扭矩值跟m_TractionControl大小有关，m_TractionControl决定是否有牵引力，如果m_TractionControl
//值为0，则当前扭矩直接就是最大值，如果该值为1，则初始扭矩为0，然后汽车启动慢慢增加扭矩力。
m_CurrentTorque = m_FullTorqueOverAllWheels - (m_TractionControl*m_FullTorqueOverAllWheels);
}
//档位更新
private void GearChanging()
{
//这里其实相当于将所有速度进行了划分，f就是指的目前速度处于最大速度的几分之几
//如果NoOfGears是5，那么就把速度分成5段
//1档就是0/5 ~ 1/5,
//2档就是1/5 ~ 2/5，
//3档就是2/5 ~ 3/5,
//4档就是3/5 ~ 4/5，
//5档就是4/5 ~ 5/5,
//每次先看当前档位是几档，然后看当前速度是否匹配当前档位，如果匹配当前档位没啥事，如果不匹配则看当前速度如果小于当前档位
//最小速度则减档，如果大于当前档位最大速度则，加档；
float f = Mathf.Abs(CurrentSpeed/MaxSpeed);
//计算当前档位的速度上限
float upgearlimit = (1/(float) NoOfGears)*(m_GearNum + 1);
//计算当前档位的速度下限
float downgearlimit = (1/(float) NoOfGears)*m_GearNum;
//如果当前档位大于0， 则看当前速度是否小于当前档位，如果小于，则果断降档
if (m_GearNum > 0 && f < downgearlimit)
{
m_GearNum--;
}
//如果当前档位小于最大档位-1档，且当前速度大于当前档位上限，则果断加档
//这里我好奇的是，为什么条件不是"if(f>upgearlimit&&(m_GearNum < NoOfGears))"，干嘛要减一？
//我觉得原因可能是因为这个5档，只是理论速度，故意不达到。。。就像一般汽车为了汽车性能稳定，速度设定可以上200码一样，但是没有人上过。。
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
//非限制版本的插值函数，我刚开始没发现他有啥特别之处，“非限制”怎么体现？直到我发现他的value没有限制0~1的范围才瞬间明白。
private static float ULerp(float from, float to, float value)
{
return (1.0f - value)*from + value*to;
}
//计算档位因子
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.
//我们要让值平滑地想着目标移动，以保证转速不会在变换档位时突然地上高或者降低
//反向差值，通过当前速度的比例值，找当前速度在当前档位的比例位置，得到的值将是一个0~1范围内的值。
var targetGearFactor = Mathf.InverseLerp(f*m_GearNum, f*(m_GearNum + 1), Mathf.Abs(CurrentSpeed/MaxSpeed));
//从当前档位因子向目标档位因子做平滑差值
m_GearFactor = Mathf.Lerp(m_GearFactor, targetGearFactor, Time.deltaTime*5f);
}
//计算转速
private void CalculateRevs()
{
// calculate engine revs (for display / sound)
//计算引擎转速（只用于显示和声音）
// (this is done in retrospect - revs are not used in force/power calculations)
//（我的个人理解：）这个计算是回溯的转速，不能用于力的计算。
//计算在当前档位上的转速因子（决定在当前档位上的转速）
CalculateGearFactor();
//档位因子
var gearNumFactor = m_GearNum/(float) NoOfGears;
//计算在当前档位下的最小速度
var revsRangeMin = ULerp(0f, m_RevRangeBoundary, CurveFactor(gearNumFactor));
//计算在当前档位下的最大速度
var revsRangeMax = ULerp(m_RevRangeBoundary, 1f, gearNumFactor);
//根据当前的转速因子，计算当前的转速
Revs = ULerp(revsRangeMin, revsRangeMax, m_GearFactor);
}
//外部调用的汽车移动控制函数
public void Move(float steering, float accel, float footbrake, float handbrake)
{
Debug.Log ("***************************: " + footbrake + " " + handbrake);
//保持当前的轮胎网格跟随WheelCollider转动
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
//限定输入值范围
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.
//设置前轮转角
//Assuming that wheels 0 and 1 are the front wheels.
//wheels下标为0、1的就是前轮
m_SteerAngle = steering*m_MaximumSteerAngle;
m_WheelColliders[0].steerAngle = m_SteerAngle;
m_WheelColliders[1].steerAngle = m_SteerAngle;
//调用角度辅助助手，
SteerHelper();
//设置加速/刹车信息到WheelCollider
ApplyDrive(accel, footbrake);
//检查速度范围
CapSpeed();
//Set the handbrake.
//设置手刹
//Assuming that wheels 2 and 3 are the rear wheels.
//Wheel下标是2、3就是后轮
if (handbrake > 0f)
{
//设置手刹值到后轮，达到减速目的
var hbTorque = handbrake*m_MaxHandbrakeTorque;
m_WheelColliders[2].brakeTorque = hbTorque;
m_WheelColliders[3].brakeTorque = hbTorque;
}
//计算转速
CalculateRevs();
//改变档位
GearChanging();
//施加下压力
AddDownForce();
//检查轮胎
CheckForWheelSpin();
//牵引力控制系统
TractionControl();
}
//控制车速
private void CapSpeed()
{
float speed = m_Rigidbody.velocity.magnitude;
switch (m_SpeedType)
{
case SpeedType.MPH:
//将速度m/s转换为mile/h，以便比较
speed *= 2.23693629f;
if (speed > m_Topspeed)
m_Rigidbody.velocity = (m_Topspeed/2.23693629f) * m_Rigidbody.velocity.normalized;
break;
case SpeedType.KPH:
//将速度m/s转换为km/h，以便比较
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
//假如轮子离地，就不用调整汽车角度了
}
// this if is needed to avoid gimbal lock problems that will make the car suddenly shift direction
//这个是为了避免万向锁问题的，万向锁问题会导致汽车突然变换方向（我直到万向锁问题，但不理解下面是怎么避免问题的，我只知道四元数的使用
//就是为了避免万向锁问题）
//下面这个If函数的效果就是，假如上一次车体Y方向角度比这次小于十度，就根据相差的度数乘以系数m_SteerHelper
//计算出这个偏移角度的四元数，然后将刚体速度直接旋转这个偏倚度数，
//根据代码开头m_SteerHelper的定义，这个做法相当于做了一个角度辅助，不完全凭借WheelCollider物理效果
//而直接操控速度方向，对车角度进行调整。
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
//检查轮胎是否旋转
// 1) emits particles
//检查是否发射尾气粒子
// 2) plays tiure skidding sounds
//播放滑行音
// 3) leaves skidmarks on the ground
//去掉刹车印
// these effects are controlled through the WheelEffects class
//这些特效都是通过WheelEffects类控制的
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
//轮胎滑行距离是否超出阈值
if (Mathf.Abs(wheelHit.forwardSlip) >= m_SlipLimit || Mathf.Abs(wheelHit.sidewaysSlip) >= m_SlipLimit)
{
//超出则发射烟雾粒子
m_WheelEffects[i].EmitTyreSmoke();
// avoiding all four tires screeching at the same time
//避免四个轮胎都同时播放滑行声音
// if they do it can lead to some strange audio artefacts
//如果那样的话会导致某些奇怪的音效
if (!AnySkidSoundPlaying())
{
m_WheelEffects[i].PlayAudio();
}
continue;
}
// if it wasnt slipping stop all the audio
//假如没有超出阈值，还没有停止音效，则停止音效
if (m_WheelEffects[i].PlayingAudio)
{
m_WheelEffects[i].StopAudio();
}
// end the trail generation
//停止烟雾生成
m_WheelEffects[i].EndSkidTrail();
}
}
// crude traction control that reduces the power to wheel if the car is wheel spinning too much
//如果汽车轮胎过度滑转，牵引力系统可以控制减少轮胎动力
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)
{
//当向前滑动距离超过阈值后，就说明轮胎过度滑转，则减少牵引力，以降低转速。
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;
}
void Update()
{
//这两段If分别用来控制汽车X轴/Z轴上汽车不会过度翻转，导致汽车游戏性差。
if (transform.rotation.eulerAngles.x > 60 && transform.rotation.eulerAngles.x < 300) {
Quaternion temp = transform.rotation;
if (transform.rotation.eulerAngles.x < 180) {
temp.eulerAngles = new Vector3(60f, transform.rotation.eulerAngles.y, transform.rotation.eulerAngles.z);
}
else {
temp.eulerAngles = new Vector3(300f, transform.rotation.eulerAngles.y, transform.rotation.eulerAngles.z);
}
transform.rotation = temp;
}
if (transform.rotation.eulerAngles.z > 25 && transform.rotation.eulerAngles.z < 335) {
Quaternion temp = transform.rotation;
if (transform.rotation.eulerAngles.z < 180) {
temp.eulerAngles = new Vector3(transform.rotation.eulerAngles.x, transform.rotation.eulerAngles.y, 25);
}
else
{
temp.eulerAngles = new Vector3(transform.rotation.eulerAngles.x, transform.rotation.eulerAngles.y, 335);
}
transform.rotation = temp;
}
}
}
}