angry bird aim

Questions & Answers
1

hi my friends.
one body tell me how I can to make an aim for my 2d game like angry bird ?!
thanx.

2

You need to break it down into a couple of small steps. What you want to do is to limit the area of how far you can stretch the object before release, use that area to see where the position of the object is on release and shoot it towards the initial center with physics.

#pragma strict

/* 	Slingshot physics by save
	Description: Put this script on the slingshot object.
	Creation date: 2012-12-10
	Last updated: 2012-12-10
*/

static var power : float = 20.0; //Additional power to shot
static var radius : float = 2.0; //Radius of clamp circle
static var sensitivity : float = .2; //Sensitivity of movement

private var myTransform : Transform; //Cached component
private var myRigidbody : Rigidbody; //Cached component
private var initPos : Vector3; //Initial position of slingshot object
private var shot : boolean = false; //Is the object shot?
private var resting : boolean = true; //Is the object resting?

function Start () {
	myTransform = transform;
	myRigidbody = rigidbody;
	myRigidbody.isKinematic = true;
	initPos = myTransform.position;
}

function Update () {
	CheckInput();
}

function CheckInput () {
	if (shot) return;
	if (Input.GetAxis("Fire1")) {
		var inputAxis : Vector2 = Vector2(Input.GetAxis("Mouse X")*sensitivity, Input.GetAxis("Mouse Y")*sensitivity);
		var newPos : Vector3 = Vector3(myTransform.position.x+inputAxis.x, myTransform.position.y+inputAxis.y, initPos.z);
		myTransform.position = CircleClamp(newPos, initPos, radius);
	} else {
		if (!shot && !resting) {
			myRigidbody.isKinematic = false;
			myRigidbody.AddForce((initPos-myTransform.position)*power, ForceMode.Impulse);
			shot = true;
		} else {
			myTransform.position = Vector3.Lerp(myTransform.position, initPos, 10*Time.deltaTime);
		}
	}
}

function CircleClamp (pos : Vector3, center : Vector3, rad : float) : Vector3 {
	var offset : Vector2 = pos - center;
	var distance : float = offset.magnitude;
	if (distance<rad*.2) {
		resting = true;
	} else {
		resting = false;
	}
	if (rad<distance) {
		var direction : Vector2 = offset/distance;
		pos = center+direction*rad;
	}
	return pos;
}

@script RequireComponent(Rigidbody)