How to keep object from going off screen

Questions & Answers
1

var moveDirection = Vector3(Input.GetAxis(“Horizontal”),Input.GetAxis(“Vertical”), 0);
rigidbody.MovePosition(transform.position + moveDirectionmoveSpeedTime.deltaTime);

here is my movement script and i want to make it so the character can ply move if he is within the bounds of the screen.

    #pragma strict
    
    var moveSpeed : float = 1.0;
    var Health : int = 20;
    private var Ammo : GameObject;
    
    var bullet : GameObject;
    var bomb : GameObject;
    var misile : GameObject;
    var sheild : GameObject;
    var PowerParticles : GameObject[];
    
    var bulletSpeed : float = 1.0;
    var shootDelay : float = 0.2;
    
    public var Fire : AudioClip;
    public var Hurt : AudioClip;
    public var Power : AudioClip;
    var HealthText : GameObject;
    var number : int = 1;
    
    private var canShoot : boolean = true;
    private var i : int = 0;
    private var e : int = 0;
    
    function Start(){
    Ammo = bullet;
    }	
    
    function FixedUpdate (){
    	HealthText.GetComponent(TextMesh).text = (Health.ToString());
    	if (Health <= 0){
    		Playerdie();
    	}				
    	var moveDirection = Vector3(Input.GetAxis("Horizontal"),Input.GetAxis("Vertical"), 0);
    	rigidbody.MovePosition(transform.position + moveDirection*moveSpeed*Time.deltaTime);
    	if ((Input.GetAxis("FireHorizontal") != 0.0f || Input.GetAxis("FireVertical") != 0.0f) && canShoot){
    		audio.PlayClipAtPoint(Fire, Vector3 (0, 0, 0));
    		var shootDirection = Vector3(Input.GetAxis("FireHorizontal"),Input.GetAxis("FireVertical"), 0).normalized;
    		var AmmoInstance = Instantiate(Ammo,transform.position,Quaternion.LookRotation(shootDirection));
    		Destroy (AmmoInstance, 10);
    		AmmoInstance.rigidbody.AddForce(shootDirection*bulletSpeed,ForceMode.VelocityChange);
    		canShoot = false;
    		Invoke("ShootDelay", shootDelay);
    	}
    }
    
    function OnCollisionEnter(collision : Collision) {
    	rigidbody.velocity = Vector3.zero;
    	if (collision.gameObject.tag == "Enemy"){
    		Damage();
    	}
        if (collision.gameObject.tag == "Health"){
        var Healthp = Instantiate(PowerParticles[0], transform.position, transform.rotation);
        Destroy (Healthp, 1);
        audio.PlayClipAtPoint(Power, Vector3 (0, 0, 0));
        	Heal();
        	Destroy(collision.gameObject,0);
        }
        if (collision.gameObject.tag == "Machinegun"){
        var MachineP = Instantiate(PowerParticles[1], transform.position, transform.rotation);
        Destroy (MachineP, 1);
        audio.PlayClipAtPoint(Power, Vector3 (0, 0, 0));
        Destroy(collision.gameObject,0);
        shootDelay = 0;
        yield WaitForSeconds(1);
        shootDelay = 0.2;
        }
        if (collision.gameObject.tag == "Bomb"){
        var Bombp = Instantiate(PowerParticles[2], transform.position, transform.rotation);
        Destroy (Bombp, 1);
        audio.PlayClipAtPoint(Power, Vector3 (0, 0, 0));
        Destroy(collision.gameObject,0);
        Ammo = bomb;
        yield WaitForSeconds(1);
        Ammo = bullet;
        }
        if (collision.gameObject.tag == "Seekingmissile"){
        var Missilep = Instantiate(PowerParticles[3], transform.position, transform.rotation);
        Destroy (Missilep, 1);
        audio.PlayClipAtPoint(Power, Vector3 (0, 0, 0));
        Destroy(collision.gameObject,0);
        Ammo = misile;
        yield WaitForSeconds(1);
        Ammo = bullet;
        }
        if (collision.gameObject.tag == "Shield"){
        audio.PlayClipAtPoint(Power, Vector3 (0, 0, 0));
        Destroy(collision.gameObject,0);
        Shield();
        }
    }
    
    function Shield(){
    	var	currentshield = Instantiate(sheild, transform.position, transform.rotation);
    	currentshield.transform.parent = transform;
    	Destroy (currentshield, 1.5);
    }
    	
    function OnCollisionExit(collision : Collision){
    	rigidbody.velocity = Vector3.zero;
    }
    
    function ShootDelay(){
    	canShoot = true;
    }
    
    function Damage(){
    	if (Health > 0){
    		audio.PlayClipAtPoint(Hurt, Vector3 (0, 0, 0));
    		Health--;
    	}
    }
    
    function Heal(){
    	if (Health < 40){
    		Health++;
    	}
    }
    
    function Playerdie(){
    	yield WaitForSeconds(1);
    	Application.LoadLevel("menu");
    }
2

You can clamp the object’s position using Mathf.Clamp():

transform.position = new Vector3(
    Mathf.Clamp(transform.position.x, cameraRect .xMin, cameraRect .xMax),
    Mathf.Clamp(transform.position.y, cameraRect .yMin, cameraRect .yMax),
    transform.position.z);

You could then check the clamped position against the position before it was clamped and play a pushing animation or something.

Getting the world Rect of a Camera is done like so:

var bottomLeft = camera.ScreenToWorldPoint(Vector3.zero);
var topRight = camera.ScreenToWorldPoint(new Vector3(
    camera.pixelWidth, camera.pixelHeight));

var cameraRect = new Rect(
    bottomLeft.x,
    bottomLeft.y,
    topRight.x - bottomLeft.x,
    topRight.y - bottomLeft.y);