hey guys. i have a camera movement c# script that follows the player and also has mouse orbit. however, the camera goes through the terrain and buildings and i want to fix that. here's the script:

using UnityEngine;

using System.Collections;

public class CameraMovement : MonoBehaviour { public Transform target; public float walkDistance; public float runDistance; public float height; public float xSpeed = 250.0f; public float ySpeed = 120.0f; public float heightDamping = 2.0f; public float rotationDamping = 3.0f;

private Transform _myTransform;
private float _x;
private float _y;
private bool _camButtonDown = false;

void Awake() {
    _myTransform = transform;  
}

// Use this for initialization
void Start () {
    if(target == null)
       Debug.LogWarning("there is no target assigned to the camera");
    else {
       CameraSetUp();
    }


}

void Update() {
    if(Input.GetMouseButtonDown(1)) {   //Use the Input Manager to make this user selectable button
       _camButtonDown = true;
    }
    if(Input.GetMouseButtonUp(1)) {
       _camButtonDown = false;
    }
}

void LateUpdate() {

// _myTransform.position = new Vector3(target.position.x, target.position.y + height, target.position.z - walkDistance); // _myTransform.LookAt(target); if(target != null) { if(_camButtonDown) {
_x += Input.GetAxis("Mouse X") * xSpeed * 0.02f; _y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

//         y = ClampAngle(y, yMinLimit, yMaxLimit);



            Quaternion rotation = Quaternion.Euler(_y, _x, 0);
            Vector3 position = rotation * new Vector3(0.0f, 0.0f, -walkDistance) + target.position;

            _myTransform.rotation = rotation;
            _myTransform.position = position;
       }
       else {

// _myTransform.position = new Vector3(target.position.x, target.position.y + height, target.position.z - walkDistance); // _myTransform.LookAt(target); _x = 0; _y = 0;

         // Calculate the current rotation angles
         float wantedRotationAngle = target.eulerAngles.y;
         float wantedHeight = target.position.y + height;

         float currentRotationAngle = _myTransform.eulerAngles.y;
         float currentHeight = _myTransform.position.y;

         // Damp the rotation around the y-axis
         currentRotationAngle = Mathf.LerpAngle(currentRotationAngle, wantedRotationAngle, rotationDamping * Time.deltaTime);

         // Damp the height
         currentHeight = Mathf.Lerp(currentHeight, wantedHeight, heightDamping * Time.deltaTime);

         // Convert the angle into a rotation
         Quaternion currentRotation = Quaternion.Euler(0, currentRotationAngle, 0);

         // Set the position of the camera on the x-z plane to:
         // distance meters behind the target
         _myTransform.position = target.position;
         _myTransform.position -= currentRotation * Vector3.forward * walkDistance;

         // Set the height of the camera
         _myTransform.position = new Vector3(_myTransform.position.x, currentHeight, _myTransform.position.z);

         // Always look at the target
         _myTransform.LookAt (target);         
       }        

    }

}

public void CameraSetUp() {
    _myTransform.position = new Vector3(target.position.x, target.position.y + height, target.position.z - walkDistance);
    _myTransform.LookAt(target);   
}

}

i know its a long script, but maybe someone can give some code in c# that keeps the camera from going through the terrain. thanks.