How to rotate a 2D object by 90 degrees in unity

Question

I need to rotate 2D GameObject by 90 degrees by z axis. So I already tried transform.RotateAround but still rotates in a complete circle:

transform.RotateAround(target.transform.position, new Vector3 (0, 0, -90),
        50f * Time.deltaTime)

I need to stop it by 90. How can I do it?

enter image description here

Answer 1

Create a coroutine that rotates based on deltaTime and keeps track of how far it has rotated, stopping once it hits 90 . Use Mathf.Min to be sure not to rotate past 90.

private isRotating = false;

// speed & amount must be positive, change axis to control direction
IEnumerator DoRotation(float speed, float amount, Vector3 axis)
{
    isRotating = true;
    float rot = 0f;
    while (rot < amount)
    {
        yield return null;
        float delta = Mathf.Min(speed * Time.deltaTime, amount - rot);
        transform.RotateAround(target.transform.position, axis, delta);
        rot += delta;
    }
    isRotating = false;
}

Then when you want to start rotating, start the coroutine if it isnt already rotating:

if (!isRotating)
{
    StartCoroutine(DoRotation(50f, 90f, Vector3.back));
}

---

It's slightly better form to save the Coroutine itself instead of using a flag. This lets you do stuff like stop the rotation at any point.

private Coroutine rotatingCoro;

// speed & amount must be positive, change axis to control direction
IEnumerator DoRotation(float speed, float amount, Vector3 axis)
{
    float rot = 0f;
    while (rot < amount)
    {
        yield return null;
        float delta = Mathf.Min(speed * Time.deltaTime, amount - rot);
        transform.RotateAround(target.transform.position, axis, delta);
        rot += delta;
    }

    rotatingCoro = null;
}

// ...

if (rotatingCoro != null)
{
    rotatingCoro = StartCoroutine(DoRotation(50f, 90f, Vector3.back));
}

// ...

// call to stop rotating immediately
void StopRotating()
{
    if (rotatingCoro != null) 
    {
        StopCoroutine(rotatingCoro);
        rotatingCoro = null;
    }
}