Unity 实现圆圈调节

需求：旋钮调节,用鼠标操作

思路：鼠标屏幕上位置，求出当前的旋转角度，求出旋转方向。

public class DragAngleTest : MonoBehaviour
{
    [SerializeField] private Transform operationTrans;
    [SerializeField] private Transform onTouchPoint;

    private Vector3 current_pos;
    private Vector3 old_pos;
    private Vector3 startPos;


    // Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButton(0))
        {
            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);


            RaycastHit raycastHit;
            if (Physics.Raycast(ray, out raycastHit))
            {
                operationTrans = raycastHit.transform;

                var screenPos = Input.mousePosition;
                screenPos = new Vector3(screenPos.x, screenPos.y, Mathf.Abs(Camera.main.transform.position.z));
                startPos = Camera.main.ScreenToWorldPoint(screenPos);

                //TODO:测试小球
                onTouchPoint.position = raycastHit.point;

                //Debug.DrawRay(Camera.main.transform.position, raycastHit.point, Color.red);
                GetAngle();
            }
        }
    }


    private void GetAngle()
    {
        current_pos = operationTrans.position - startPos;
        var normalDirection = Vector3.Cross(current_pos, old_pos);
        var angle = Vector2.Angle(current_pos, old_pos);
        if (normalDirection.z > 0)
        {
            operationTrans.Rotate(Vector3.forward, angle);//顺时针
        }
        else
        if (normalDirection.z < 0)
        {
            operationTrans.Rotate(Vector3.forward, -angle);//逆时针
        }
        old_pos = current_pos;
    }
}

效果