Unity3D研究院之鼠标拉近旋转拖拽模型（六十）

using UnityEngine;
using System.Collections;

public class Script_07_11 : MonoBehaviour 
{

	public Transform target;
	private int MouseWheelSensitivity = 1;
	private int MouseZoomMin = 1;
	private int MouseZoomMax = 5;
	private float normalDistance = 3;

	private Vector3 normalized;

	private float xSpeed = 250.0f;
	private float ySpeed = 120.0f;

	private int yMinLimit = -20;
	private int yMaxLimit = 80;

	private float x = 0.0f;
	private float y = 0.0f;

	private Vector3 screenPoint;
	private Vector3 offset;

	private Quaternion rotation = Quaternion.Euler(new Vector3(30f,0f,0f));
	private Vector3 CameraTarget;
	void Start () 
	{

		CameraTarget = target.position;

		float z = target.transform.position.z - normalDistance;
		transform.position =	 rotation * new Vector3(transform.position.x,transform.position.y,z);

		transform.LookAt(target);

		var angles = transform.eulerAngles;
    	x = angles.y;
    	y = angles.x;
	}

	void Update ()
	{

		if(Input.GetMouseButton(1))
		{
			    x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
        		y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

 				y = ClampAngle(y, yMinLimit, yMaxLimit);

        		var rotation = Quaternion.Euler(y, x, 0);
        		var position = rotation * new Vector3(0.0f, 0.0f, -normalDistance) + CameraTarget;

        		transform.rotation = rotation;
        		transform.position = position;

		}else if (Input.GetAxis("Mouse ScrollWheel") != 0)
		{
		    normalized = (transform.position - CameraTarget).normalized;

			if (normalDistance >= MouseZoomMin && normalDistance <= MouseZoomMax)
			{
				normalDistance -= Input.GetAxis("Mouse ScrollWheel") * MouseWheelSensitivity;
			}
			if (normalDistance < MouseZoomMin)
			{
				normalDistance = MouseZoomMin;
			}
			if (normalDistance > MouseZoomMax)
			{
				normalDistance = MouseZoomMax;
			}
				transform.position =	   normalized * normalDistance;

		}else if(Input.GetMouseButtonDown(2))
		{
	    	screenPoint = Camera.main.WorldToScreenPoint(target.transform.position);
    		offset = target.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
		}

		if(Input.GetMouseButton(2))
		{
 			 Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);

			Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
			 target.transform.position = curPosition;
		}
			transform.LookAt(CameraTarget);

	}

	static float ClampAngle (float angle , float min ,float  max) 
	{
		if (angle < -360)
			angle += 360;
		if (angle > 360)
			angle -= 360;
		return Mathf.Clamp (angle, min, max);
	}
}