Unity 实现一个简单的 TPS 相机

效果如下：

代码如下：

1public class TPSCamera : MonoBehaviour
2{
3    /// <summary>
4    /// 目标对象
5    /// </summary>
6    [SerializeField]
7    Transform target = null;
8
9    /// <summary>
10    /// 旋转参数
11    /// </summary>
12    [SerializeField]
13    Vector2 rotate;
14
15    /// <summary>
16    /// 旋转速度
17    /// </summary>
18    [SerializeField]
19    float rotateSpeed = 2;
20
21    /// <summary>
22    /// 视口大小
23    /// </summary>
24    [SerializeField]
25    float viewSize = 30;
26
27    /// <summary>
28    /// 默认角度
29    /// 在目标对象的哪个方向
30    /// </summary>
31    [SerializeField]
32    float defaultAngle = -135;
33
34    /// <summary>
35    /// 离目标对象的距离
36    /// </summary>
37    [SerializeField]
38    float radius = 3;
39
40    /// <summary>
41    /// 离目标对象的高度
42    /// </summary>
43    [SerializeField]
44    float height = 1.5f;
45
46        public bool Aim;
47
48    public bool visiable = false;
49
50    public CursorLockMode lockMode;
51
52    Camera cam;
53
54    /// <summary>
55    /// 绕任意轴旋转的参考点
56    /// 暂时用这个办法替代
57    /// </summary>
58    Transform tr;
59
60    static TPSCamera _inst;
61
62    public static TPSCamera inst
63    {
64        get {
65            return _inst;
66        }
67    }
68
69    void Awake ()
70    {
71        _inst = this;
72    }
73
74    void Start ()
75    {
76        cam = this.GetComponent<Camera> ();
77        tr = new GameObject ().transform;
78    }
79
80    void FixedUpdate ()
81    {
82        rotate.x += Input.GetAxis ("Mouse X") * rotateSpeed;
83        rotate.y += Input.GetAxis ("Mouse Y") * rotateSpeed;
84        viewSize -= Input.mouseScrollDelta.y * 3;
85
86        //一些约束，不用管
87        if (viewSize < 30)
88        {
89            viewSize = 30;
90        } else if (viewSize > 60)
91        {
92            viewSize = 60;
93        }
94
95        if (rotate.y < -60)
96        {
97            rotate.y = -60;
98        } else if (rotate.y > 45)
99        {
100            rotate.y = 45;
101        }
102
103        cam.fieldOfView = viewSize;
104        Cursor.visible = visiable;
105        Cursor.lockState = lockMode;
106    }
107
108    void LateUpdate ()
109    {
110        Transform self = this.transform;
111        Vector3 targetPos = target.position;
112        targetPos.y += height;
113
114        //旋转y轴，左右滑动
115        Vector2 v1 = IMath.CalcAbsolutePoint (rotate.x, radius);
116        self.position = targetPos + new Vector3 (v1.x, 0, v1.y);
117
118        //相机的观察点
119        Vector2 v2 = IMath.CalcAbsolutePoint (rotate.x + defaultAngle, radius);
120        Vector3 viewPoint = new Vector3 (v2.x, 0, v2.y) + targetPos;
121
122        //计算2点之间的距离
123        float dist = Vector3.Distance (self.position, viewPoint);
124
125        //取中点作为旋转轴
126        Vector3 center = Vector3.MoveTowards (self.position, viewPoint, dist / 2);
127
128        //这里我不知道怎么计算这个任意轴，暂时先用这个方法替代
129        tr.position = center;
130        tr.LookAt (targetPos);
131        tr.eulerAngles += new Vector3 (0, 0, rotate.y);
132
133        //旋转x轴，上下滑动
134        Vector3 temp = tr.right * dist / 2;
135        self.position = tr.position - temp;
136        self.LookAt (tr.position + temp);
137
138    }
139
140}
141
142public static Vector2 CalcAbsolutePoint (float angle, float dist)
143{
144        angle += 90;
145        dist = -dist;
146        float x = dist * Mathf.Cos (-angle * Mathf.PI / 180);
147        float y = dist * Mathf.Sin (-angle * Mathf.PI / 180);
148        return new Vector2 (x, y);
149}