unity实现鼠标拖拽缩放功能代码

1. using UnityEngine;
   
2. using System.Collections;
   
3. 
   
4. public class Script_07_11 : MonoBehaviour 
   
5. {
   
6. 
   
7. public Transform target;
   
8. private int MouseWheelSensitivity = 1;
   
9. private int MouseZoomMin = 1;
   
10. private int MouseZoomMax = 5;
    
11. private float normalDistance = 3;
    
12. 
    
13. private Vector3 normalized;
    
14. 
    
15. private float xSpeed = 250.0f;
    
16. private float ySpeed = 120.0f;
    
17. 
    
18. private int yMinLimit = -20;
    
19. private int yMaxLimit = 80;
    
20. 
    
21. private float x = 0.0f;
    
22. private float y = 0.0f;
    
23. 
    
24. private Vector3 screenPoint;
    
25. private Vector3 offset;
    
26. 
    
27. private Quaternion rotation = Quaternion.Euler(new Vector3(30f,0f,0f));
    
28. private Vector3 CameraTarget;
    
29. void Start () 
    
30. {
    
31. 
    
32. CameraTarget = target.position;
    
33. 
    
34. float z = target.transform.position.z - normalDistance;
    
35. transform.position =  rotation * new Vector3(transform.position.x,transform.position.y,z);
    
36. 
    
37. transform.LookAt(target);
    
38. 
    
39. var angles = transform.eulerAngles;
    
40.      x = angles.y;
    
41.      y = angles.x;
    
42. }
    
43. 
    
44. void Update ()
    
45. {
    
46. 
    
47. if(Input.GetMouseButton(1))
    
48. {
    
49.      x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
    
50.          y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
    
51. 
    
52.   y = ClampAngle(y, yMinLimit, yMaxLimit);
    
53. 
    
54.          var rotation = Quaternion.Euler(y, x, 0);
    
55.          var position = rotation * new Vector3(0.0f, 0.0f, -normalDistance) + CameraTarget;
    
56. 
    
57.          transform.rotation = rotation;
    
58.          transform.position = position;
    
59. 
    
60. }else if (Input.GetAxis("Mouse ScrollWheel") != 0)
    
61. {
    
62.      normalized = (transform.position - CameraTarget).normalized;
    
63. 
    
64. if (normalDistance >= MouseZoomMin && normalDistance <= MouseZoomMax)
    
65. {
    
66. normalDistance -= Input.GetAxis("Mouse ScrollWheel") * MouseWheelSensitivity;
    
67. }
    
68. if (normalDistance < MouseZoomMin)
    
69. {
    
70. normalDistance = MouseZoomMin;
    
71. }
    
72. if (normalDistance > MouseZoomMax)
    
73. {
    
74. normalDistance = MouseZoomMax;
    
75. }
    
76. transform.position =    normalized * normalDistance;
    
77. 
    
78. }else if(Input.GetMouseButtonDown(2))
    
79. {
    
80.       screenPoint = Camera.main.WorldToScreenPoint(target.transform.position);
    
81.      offset = target.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
    
82. }
    
83. //unity3d：http://www.unitymanual.com/
    
84. if(Input.GetMouseButton(2))
    
85. {
    
86.    Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
    
87. 
    
88. Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
    
89.   target.transform.position = curPosition;
    
90. }
    
91. transform.LookAt(CameraTarget);
    
92. 
    
93. }
    
94. 
    
95. static float ClampAngle (float angle , float min ,float  max) 
    
96. {
    
97. if (angle < -360)
    
98. angle += 360;
    
99. if (angle > 360)
    
100. angle -= 360;
     
101. return Mathf.Clamp (angle, min, max);
     
102. }
     
103.