unity CharacterMotor 中按下shift 实现加速

按下shift加速，减速，实际上只是速度的变换。刚开始，我直接在CharacterMotor中修改代码，结果出现一些很奇怪的问题。后来在http://answers.unity3d.com/questions/164638/how-to-make-the-fps-character-controller-run-and-c.html

找到了解决方法。从新写一个脚本，

• usingUnityEngine;
• usingSystem.Collections;
• publicclassRunAndCrouch:MonoBehaviour
• {
• publicfloatwalkSpeed=7;// regular speed
• publicfloatcrchSpeed=3;// crouching speed
• publicfloatrunSpeed=20;// run speed
• privateCharacterMotorchMotor;
• privateTransformtr;
• privatefloatdist;// distance to ground
• // Use this for initialization
• voidStart()
• {
• chMotor=GetComponent<CharacterMotor>();
• tr=transform;
• CharacterControllerch=GetComponent<CharacterController>();
• dist=ch.height/2;// calculate distance to ground
• }
• // Update is called once per frame
• voidFixedUpdate()
• {
• floatvScale=1.0f;
• floatspeed=walkSpeed;
• if((Input.GetKey("left shift")||Input.GetKey("right shift"))&&chMotor.grounded)
• {
• speed=runSpeed;
• }
• if(Input.GetKey("c"))
• {// press C to crouch
• vScale=0.5f;
• speed=crchSpeed;// slow down when crouching
• }
• chMotor.movement.maxForwardSpeed=speed;// set max speed
• floatultScale=tr.localScale.y;// crouch/stand up smoothly
• Vector3tmpScale=tr.localScale;
• Vector3tmpPosition=tr.position;
• tmpScale.y=Mathf.Lerp(tr.localScale.y,vScale,5*Time.deltaTime);
• tr.localScale=tmpScale;
• tmpPosition.y+=dist*(tr.localScale.y-ultScale);// fix vertical position
• tr.position=tmpPosition;
• }
• }