Unity3D bird flying back and forth - unity3d

Question

I'm trying to create a bird moving across screen along x axis.
bird.transform.position = Vector3.Lerp (pos1, pos2, (Mathf.Abs(speed * Time.time) + 1.0f) / 2.0f);
Using this in Update() the bird flies only once. I want that after it flies to the right, it should wait 2-3 seconds and then fly back with a different sprite.
transform.translate doesn't work like this. Any help will be appreciated.

Answer 1

you would need to put in another LERP for going the other direction and have a variable for which way the bird is flying so roughly:
bool goleft;
if(goleft)
{
if(transform.position != pos2)
{
transform.position = Vector3.Lerp (pos1, pos2, (Mathf.Abs(speed * Time.time) + 1.0f) / 2.0f);
}
else
{
goleft = false;
//change the direction the bird is facing here
}
}
else
{
if(transform.position != pos1)
{
transform.position = Vector3.Lerp (pos2, pos1, (Mathf.Abs(speed * Time.time) + 1.0f) / 2.0f);
}
else
{
goleft = true;
//change the direction the bird is facing here
}
}
Hope that helps

Answer 2

Not tested but i would start here:
Vector3[] posts;
int current = 0;
float speed = 5.0f;
float threshold = Single.Epsilon;
float delay = 2.0f;
public void Update() {
if(!waiting && posts.Length > 0)
{
if(!Mathf.Approximately((posts[current].position - transform.position).sqrMagnitude, threshold)
{
float step = speed * Time.deltaTime;
transform.position = Vector3.MoveTowards(transform.position, posts[current].position, step);
}
else StartCoroutine("Next");
}
}
IEnumerator Next() {
waiting = true;
yield return new WaitForSeconds(delay);
current = (current + 1) % posts.Length;
waiting = false;
}
This will also allow you to have as many posts as you want to have, and all your movement dynamics can be handled in Next(), whereas, if you want him to go from post 0...1...2...3...0...1.. or 0...1...2...3...2...1...
If you want the latter you just change current = (current + 1) % posts.Length; to Mathf.PingPong(current + 1, posts.Length);

Answer 3

I'd go a bit like this:
float flipCooldown
float defaultFlipCooldown = 2.0f;
bool isGoingRight;
Vector2 pos1;
Vector2 pos2;
void Start() {
flipCooldown = defaultFlipCooldown;
isGoingRight = true;
pos1 = new Vector2(0, 0);
pos2 = new Vector2(5, 0); // whatever floats your boat
}
void Update()
{
Vector2 initialPosition = null;
Vector2 finalPosition = null;
if (flipCooldown <= 0) {
isGoingRight = !isGoingRight
flipCooldown = defaultFlipCooldown;
ChangeSprite();
}
if (isGoingRight) {
initialPos = pos1;
finalPos = pos2;
} else {
initialPos = pos2;
finalPos = pos1;
}
bird.transform.position = Vector3.Lerp (initialPos, finalPos, (Mathf.Abs(speed * Time.time) + 1.0f) / 2.0f);
flipCooldown -= Time.deltaTime;
}
What you want to get is that the Time.deltaTime is decreasing the cooldown for the bird to turn. You can easily change the cooldown in the defaultFlipCooldown variable. When it's done going one way, it'll just flip the position and the Lerp function will do the rest of the work. The ChangeSprite function will be just a GetComponent<SpriteRenderer>().sprite change.
If you don't want fix positions, you can calculate how much it'll fly, define the final position and just change the pos1 and pos2.
It's also important to note that WaitForSeconds will just work with Coroutines that is a concept for working with threads, never in a method like Update. You can learn more about Coroutines in Unity's manual: http://docs.unity3d.com/Manual/Coroutines.html