c# - 统一 5 : How to slow down rigidbody naturally instead of sudden stop

Question

我正在使用这个:

void Update(){
    if(leftJoystick){
        rb.AddRelativeForce(0, 0, 400f, ForceMode.Impulse);
    }
}

让我的角色在空中向前移动(使用喷气背包)。当我松开操纵杆时，我的角色立即停止。我想要的是角色在释放操纵杆后继续前进，并随着时间的推移逐渐减速并逐渐停止。我的角色像撞到墙上一样停下来，这看起来很愚蠢。我应该使用什么样的力/速度/变换，以便在我松开操纵杆后物理减慢我的角色？

我的刚体设置:

• 质量:100
• 拖动:0
• 角度阻力:0.05
• 利用重力
• 不是运动学的
• 插值:插值
• 碰撞检测:离散
• 卡住位置:无
• 卡住旋转:全部

角色还有一个胶囊碰撞器，它不是触发器，也没有物理 Material 。

编辑:这是完整的代码，因此您可以查看我的代码中是否存在任何冲突

using UnityEngine;
using System.Collections;
using UnityStandardAssets.CrossPlatformInput;

public class JetpackController : MonoBehaviour{

    Rigidbody rb;

    // controller axes
    [SerializeField]
    public string speedAxis = "Vertical";
    public string rotateAxis = "HorizontalRotate";

    [SerializeField]
    public float forwardSpeed;
    public float upSpeed;
    public float rotateSpeed;
    public float rotationIgnoreZone;
    public float MAX_HEIGHT;

    float speedInput;
    float rotateInput;
    public bool leftJoystick;
    public bool rightJoystick;

    ParticleSystem jetpackFire1;

    Vector3 originalGravity;

    // access Joystick script in Standard assets to detect when right joystick is held down
    Joystick joystick_left;
    Joystick joystick_right;

    void Start () {
        if (GetComponent<Rigidbody> ()) {
            rb = GetComponent<Rigidbody> ();
        } else {
            Debug.LogError ("Player needs to have a rigidbody.");
        }

        // get Joysticks
        if (GameObject.Find ("MobileJoystick_left").GetComponent<Joystick> ()) {
             joystick_left = GameObject.Find ("MobileJoystick_left").GetComponent<Joystick> ();
         } else {
             Debug.LogError ("Either gameobject with name 'MobileJoystick_right' does not exist in the scene or it does not have script called Joystick.cs attached to it.");
        }
        if (GameObject.Find ("MobileJoystick_right").GetComponent<Joystick> ()) {
            joystick_right = GameObject.Find ("MobileJoystick_right").GetComponent<Joystick> ();
        } else {
            Debug.LogError ("Either gameobject with name 'MobileJoystick_right' does not exist in the scene or it does not have script called Joystick.cs attached to it.");
        }

        jetpackFire1 = GameObject.Find("JetpackFire1").GetComponent<ParticleSystem> ();
        jetpackFire1.playbackSpeed = 5.0f;

        originalGravity = Physics.gravity;
    }

    void FixedUpdate () {

        GetInput ();

        // move forward and backward according to left joysticks input
        if(leftJoystick){
            // left joystick held down
            rb.AddRelativeForce(0, 0, forwardSpeed*speedInput, ForceMode.Impulse);
        }

        // if right joystick is used
        if (rightJoystick) {
            jetpackFire1.Play ();

        if (transform.position.y < MAX_HEIGHT) {
            // allow going up
            //rb.AddRelativeForce (0, upSpeed, 0, ForceMode.Impulse);
            rb.AddForce(transform.forward * forwardSpeed);
        } else if (transform.position.y >= MAX_HEIGHT) {
            // prevent player to go any further up and also falling
            Physics.gravity = Vector3.zero; // no gravity to prevent player from falling
            rb.velocity = Vector3.zero;
        }
            // rotate
            // always keep rotating (player can go past look at joystick dir)
            if (rotateInput >= rotationIgnoreZone || rotateInput <= -rotationIgnoreZone) {
                transform.Rotate(Vector3.up * rotateInput, Time.deltaTime * rotateSpeed);
            }
    } else {
            jetpackFire1.Stop ();
            // if right joystick is released
            Physics.gravity = originalGravity; // normal gravity -> player can fall
        }

    } 

public void GetInput(){
    speedInput = CrossPlatformInputManager.GetAxis (speedAxis);
    rotateInput = CrossPlatformInputManager.GetAxis (rotateAxis);
    // access Joystick.cs script to grab wether right joystick is pressed or not
    leftJoystick = joystick_left.leftJoystickPressed;
    rightJoystick = joystick_right.rightJoystickPressed;
}

Answer 1

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正如 J.Small 所说，您可以将速度乘以一个大约 0.95 的数字来慢慢减慢刚体的速度。如果您将乘法放在 Update 方法中，我建议您将 ~0.95 数字与 Time.deltaTime 相乘，所以速度的降低将与耗时成正比。

void Update(){
    if(leftJoystick){
        rb.AddRelativeForce(0, 0, 400f, ForceMode.Impulse);
    }

    if(noJoystick){
        rb.velocity = rb.velocity * 0.95 * Time.deltaTime;
        //Or: rb.velocity.x
    }
}

如果你想以更可配置的方式减慢刚体的速度，你也可以施加少量的力而不是乘以速度(如果你将它放入更新中，该量应该基于 Time.deltaTime - 它被称为一次一帧)，但上面的方法更简单。