Unity 3D 簡易制作攝像機圍繞物體隨鼠標旋轉效果

Unity 3D 簡易制作攝像機圍繞物體隨鼠標旋轉效果

梗概:

一. 攝像機圍繞目標物體旋轉, 即攝像機離目標物體有一定的距離且旋轉軸心為該物體的位置.

 

二. 當目標物體被障礙物擋住后, 需要將攝像機移動到障礙物前方能看見目標物體的位置.

思路:

一. 攝像機繞軸心旋轉, 可以在軸心處創建一個空物體, 將攝像機設為該軸心的子物體. 如圖:

 

這樣便可以簡單地實現攝像機旋轉軸心 (注意: 旋轉時應旋轉軸心而不是單獨旋轉攝像機) . 還應注意, 如果攝像機的目標物體可以移動的話, 就應每幀將軸心的坐標設為目標物體的坐標 (盡量不要直接將軸心設為目標物體的子物體! 除非有特別需要) .

二. 當目標物體被障礙物擋住后, 可以在目標物體處發射一條射線, 射線原點就是目標物體的坐標 (也就是軸心) , 射線方向就是從原點到攝像機的方向. 此時射線的碰撞點就是將要把攝像機調整到的位置.

 

三. 當將攝像機移動到后方沒有障礙物的位置時, 就應將攝像機移回至原距離.

 

過程:

1. 創建任意目標物體;

2. 創建一個空物體並命名, 這個空物體就是軸心, 並將其 Tag 設為 "3rdCameraAxle":

   或者將其 Tag 設為你喜歡的一個都可以;

3. 創建攝像機, 將其 Tag 設為 "MainCamera", 並設為剛創建的軸心的子物體;

4. 創建任意障礙物.

代碼:

一. 此時繞物體旋轉攝像機便可簡化為直接旋轉軸心, 代碼也簡化了許多:

1. 定義鼠標靈敏度:

   public float mouseSensitivity = 2;

2. 定義目標物體的  Transform  :

   public Transform targetTrans;

3. 定義軸心  Transform  與軸心旋轉角度:

   Transform thirdPCamAxle;
   Vector3 thirdPCamEuler;

   在  void Start()  下對其賦值:

   void Start () {
       thirdPCamAxle = GameObject.FindGameObjectWithTag("3rdCameraAxle").transform; //括號里的引號中也可以寫上你自己對軸心設的 Tag.
       thirdPCamEuler = thirdPCamAxle.localEulerAngles; //推薦寫 localEulerAngles, 要不之后處理起來會比較麻煩.
   }

4. 定義攝像機:

   Camera thirdPCam;

   在  void Start()  下對其賦值:

   void Start () {
       thirdPCam = Camera.main;
   }

5. 定義並賦值攝像機離物體的最大距離, 攝像機離物體的當前距離:

   float camForwardMaxDistance = 9;
   float camForwardDistance;
   float camBackDistance;

6. 在  void Update()  下寫:

   thirdPCamAxle.position = targetTrans.position; //將攝像機旋轉軸心位置設為目標物體位置
   //定義旋轉量
   float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity; 
   float mouseY = Input.GetAxis("Mouse Y") * mouseSensitivity;
   thirdPCamEuler.y += mouseX; //控制攝像機左右旋轉
   //控制攝像機上下旋轉, 並且上下旋轉范圍不能超過90°或-90°, 此方法適用於 localEulerAngles.
   if (thirdPCamEuler.z < 90 && mouseY > 0) { thirdPCamEuler.z += mouseY; }
   if (thirdPCamEuler.z > -90 && mouseY < 0) { thirdPCamEuler.z += mouseY; }
   thirdPCamAxle.localEulerAngles = thirdPCamEuler; //將旋轉量應用到攝像機上.

至此, 控制攝像機旋轉完成. 此部分代碼如下:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
​
public class ThirdPCamC : MonoBehaviour {
    public float mouseSensitivity = 2;
    public Transform targetTrans;
​
    Transform thirdPCamAxle;
    Vector3 thirdPCamEuler;
​
    Camera thirdPCam;
    float camForwardMaxDistance = 9;
    float camForwardDistance;
    float camBackDistance;
​
    void Start () {
        thirdPCamAxle = GameObject.FindGameObjectWithTag("3rdCameraAxle").transform;
        thirdPCamEuler = thirdPCamAxle.localEulerAngles;
​
        thirdPCam = Camera.main;
    }
    
    void Update () {
        thirdPCamAxle.position = targetTrans.position;
​
        float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity;
        float mouseY = Input.GetAxis("Mouse Y") * mouseSensitivity;
        thirdPCamEuler.y += mouseX;
        if (thirdPCamEuler.z < 90 && mouseY > 0) { thirdPCamEuler.z += mouseY; }
        if (thirdPCamEuler.z > -90 && mouseY < 0) { thirdPCamEuler.z += mouseY; }
        thirdPCamAxle.localEulerAngles = thirdPCamEuler;
    }
}

二. 攝像機避開障礙物, 並在后方沒有障礙物時移回原距離 (原距離可通過設置對  camForwardMaxDistance  的賦值來改變):

在   void Update()   下寫:

Ray camForwardRay = new Ray(thirdPCam.transform.position, thirdPCam.transform.forward); //在攝像機處發射一條向前的射線, 用來檢測攝像機當前離目標的距離 (此處不必擔心射線碰撞處是障礙物的情況).
RaycastHit forwardRayHit; //定義射線碰撞.
if (Physics.Raycast(camForwardRay, out forwardRayHit)) //當射線有碰撞物時 (也就是目標物體), 
{
    camForwardDistance = Vector3.Distance(thirdPCam.transform.position, forwardRayHit.point); //計算從攝像機到碰撞點的距離 (碰撞點也可以改為目標物體的位置).
}
​
Vector3 dir = thirdPCam.transform.position - targetTrans.position; //定義從目標物體到攝像機的方向.
dir = dir.normalized; //將方向單位化.
Ray ray = new Ray(targetTrans.position, dir); //在目標物體處發射一條射線, 方向即為剛剛定義的向量.
RaycastHit hit; //定義射線碰撞.
if (Physics.Raycast(ray, out hit)) //當該射線有碰撞, 即目標物體被障礙物擋住時, 
{
    thirdPCam.transform.position = hit.point; //將攝像機位置設為碰撞點位置.
}
else //如果沒有碰撞, 即目標物體沒有被障礙物擋住, 
{
    if (camForwardDistance < camForwardMaxDistance) //並且當前距離沒有超過最大距離時, 
    {
        thirdPCam.transform.Translate(Vector3.back * Time.deltaTime * 5); //將攝像機緩慢后移至最大距離.
    }
}

全部代碼如下:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
​
public class ThirdPCamC : MonoBehaviour {
    public float mouseSensitivity = 2;
    public Transform targetTrans;
​
    Transform thirdPCamAxle;
    Vector3 thirdPCamEuler;
​
    Camera thirdPCam;
    float camForwardMaxDistance = 9;
    float camForwardDistance;
    float camBackDistance;
​
    void Start () {
        thirdPCamAxle = GameObject.FindGameObjectWithTag("3rdCameraAxle").transform;
        thirdPCamEuler = thirdPCamAxle.localEulerAngles;
​
        thirdPCam = Camera.main;
    }
    
    void Update () {
        thirdPCamAxle.position = targetTrans.position;
​
        float mouseX = Input.GetAxis("Mouse X") * mouseSensitivity;
        float mouseY = Input.GetAxis("Mouse Y") * mouseSensitivity;
        thirdPCamEuler.y += mouseX;
        if (thirdPCamEuler.z < 90 && mouseY > 0) { thirdPCamEuler.z += mouseY; }
        if (thirdPCamEuler.z > -90 && mouseY < 0) { thirdPCamEuler.z += mouseY; }
        thirdPCamAxle.localEulerAngles = thirdPCamEuler;
​
        Ray camForwardRay = new Ray(thirdPCam.transform.position, thirdPCam.transform.forward);
        RaycastHit forwardRayHit;
        if (Physics.Raycast(camForwardRay, out forwardRayHit))
        {
            camForwardDistance = Vector3.Distance(thirdPCam.transform.position, forwardRayHit.point);
        }
​
        Vector3 dir = thirdPCam.transform.position - targetTrans.position;;
        dir = dir.normalized;
        Ray ray = new Ray(targetTrans.position, dir);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit))
        {
            Debug.DrawLine(ray.origin, hit.point, Color.green);
            thirdPCam.transform.position = hit.point;
        }
        else
        {
            if (camForwardDistance < camForwardMaxDistance)
            {
                thirdPCam.transform.Translate(Vector3.back * Time.deltaTime * 5);
            }
        }
    }
}

最終效果圖:

希望本篇教程能夠幫到大家!

源碼: [GitHub](https://github.com/JadMax/Unity3D-Miscellaneous/blob/master/ThirdpersonCameraController.cs)