1 using UnityEngine;
2 using System.Collections;
3
4 public class ShouShi : MonoBehaviour
5 {
6 public Transform centerTra;//围绕旋转的中心
7 public Transform targetTra;//移动目标
8 private Vector2 oldPos;//上一帧位置
9 private float angular;
10 private float speed = 0.1f;//升降速度
11 void Update()
12 {
13 if (Input.GetMouseButtonDown(0))
14 {
15 oldPos = Input.mousePosition;
16 }
17
18 if (Input.GetMouseButton(0))
19 {
20 Vector3 point = Camera.main.WorldToScreenPoint(centerTra.position );//中心点转换为屏幕坐标
21 angular = SignedAngularGap(new Vector2(point.x, point.y), oldPos, Input.mousePosition);
22 print(angular);
23 float y = targetTra.position.y;
24 y += angular * speed * Time.deltaTime;
25 targetTra.position = new Vector3(targetTra.position.x, y, targetTra.position.z);
26 oldPos = Input.mousePosition;
27 }
28 }
29
30 public static float SignedAngle(Vector2 from, Vector2 to)
31 {
32 // perpendicular dot product
33 float perpDot = (from.x * to.y) - (from.y * to.x);
34 return Mathf.Atan2(perpDot, Vector2.Dot(from, to));
35 }
36 // return signed angle in degrees between current finger position and ref positions
37 static float SignedAngularGap(Vector2 center, Vector2 oldPos, Vector2 newPos)
38 {
39 Vector2 refDir = (oldPos - center).normalized;
40 Vector2 curDir = (newPos - center).normalized;
41
42 // check if we went past the minimum rotation amount treshold
43 return Mathf.Rad2Deg * SignedAngle(refDir, curDir);
44 }
45 }
