[游戏开发]Unity学习笔记01-相机跟随方法

类似电视摄影的视角，相机固定在某处，跟随着画面中人物的移动而移动。


根据图上原理，我们可以利用三种属性更新相机位置
1）距离distance
2）水平旋转角度rot
3）竖直旋转角度roll

	//距离
    public float distance = 15;
    private float maxDistance = 22f;
    private float minDistance = 5f;
    public float zoomSpeed = 0.2f;//缩放速度
    //水平旋转
    public float rot = 0;
    public float rotSpeed = 5f;
    //竖直旋转
    public float roll = 30 * Mathf.PI * 2 / 360;
    private float maxRoll = 70 * Mathf.PI * 2 / 360;
    private float minRoll = -10f * Mathf.PI * 2 / 360;
    public float rollSpeed = 2f;

处理水平旋转

public void Rotate()
    {
        float w = Input.GetAxis("Mouse X") * rotSpeed * Time.deltaTime;
        rot -= w;
    }

处理竖直旋转

public void Roll()
    {
        float w = Input.GetAxis("Mouse Y") * rollSpeed * Time.deltaTime;
        roll -= w;
        if (roll > maxRoll)
            roll = maxRoll;
        if (roll < minRoll)
            roll = minRoll;
    }

处理鼠标滚轮缩放距离

public void Zoom()
    {
        if(Input.GetAxis("Mouse ScrollWheel") > 0)
        {
            if (distance > minDistance)
                distance -= zoomSpeed;
        }
        else if(Input.GetAxis("Mouse ScrollWheel") <0)
        {
            if (distance < maxDistance)
                distance += zoomSpeed;
        }
    }

在update函数中依照公式对相机位置进行处理，即可完成相机跟随

		Rotate();
        Roll();
        Zoom();
        Vector3 targetPos = target.transform.position;
        Vector3 cameraPos;
        float d = distance * Mathf.Cos(roll);
        float hegiht = distance * Mathf.Sin(roll);
        cameraPos.x = targetPos.x + d * Mathf.Cos(rot);
        cameraPos.y = targetPos.y + hegiht;
        cameraPos.z = targetPos.z + d * Mathf.Sin(rot);
        Camera.main.transform.position = cameraPos;
        Camera.main.transform.LookAt(target.transform);