using UnityEngine;  
using System.Collections;  
  
  
public class CubeScale : MonoBehaviour {  
  
    private Touch oldTouch1;  //上次触摸点1(手指1)    
    private Touch oldTouch2;  //上次触摸点2(手指2)    
    
    void Start()    
    {  
          
    }  
  
    void Update () {    
          
    
        //没有触摸    
        if ( Input.touchCount <= 0 ){    
            return;    
        }    
    
        //单点触摸， 水平上下旋转    
        if( 1 == Input.touchCount ){    
            Touch touch = Input.GetTouch (0);    
            Vector2 deltaPos = touch.deltaPosition;             
            transform.Rotate(Vector3.down  * deltaPos.x , Space.World);     
            transform.Rotate(Vector3.right * deltaPos.y , Space.World);    
        }    
    
        //多点触摸, 放大缩小    
        Touch newTouch1 = Input.GetTouch (0);    
        Touch newTouch2 = Input.GetTouch (1);    
            
        //第2点刚开始接触屏幕, 只记录，不做处理    
        if( newTouch2.phase == TouchPhase.Began ){    
            oldTouch2 = newTouch2;    
            oldTouch1 = newTouch1;    
            return;    
        }    
            
        //计算老的两点距离和新的两点间距离，变大要放大模型，变小要缩放模型    
        float oldDistance = Vector2.Distance(oldTouch1.position, oldTouch2.position);    
        float newDistance = Vector2.Distance(newTouch1.position, newTouch2.position);    
    
        //两个距离之差，为正表示放大手势， 为负表示缩小手势    
        float offset = newDistance - oldDistance;    
    
        //放大系数  
        float scaleFactor = offset / 100f;    
        Vector3 localScale = transform.localScale;    
        Vector3 scale = new Vector3(localScale.x + scaleFactor,    
                                    localScale.y + scaleFactor,     
                                    localScale.z + scaleFactor);    
    
        //最小缩放到 0.1 倍    
        if (scale.x > 0.1f && scale.y > 0.1f && scale.z > 0.1f) {    
            transform.localScale = scale;    
        }    
    
        //记住最新的触摸点，下次使用    
        oldTouch1 = newTouch1;    
        oldTouch2 = newTouch2;    
    }    
    
}

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