If condition true, but code is not executed in Unity

Question

I have a script which triggers a movement when a rotation is completed. The script casts the Euler angle of a transform to an int. If it is true, the condition is executed. For some weird reason, the code in the if condition does not execute, even if the condition is true. I have confirmed the condition is true through both my compiler and the debug log.

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Here is my code:

if(rotationInitiate)
{
    transform.eulerAngles = Vector3.Slerp(transform.eulerAngles, 
        new Vector3(0, 0, angleOfRotation), Time.deltaTime * speedOfRotation);

    Debug.Log(transform.eulerAngles.z);

    if((int)transform.eulerAngles.z == 180)
    {
        Debug.Log("Hurray we have successfully executed the if statement");

        // More rotation stuff
    }
}

As you can see by my log, the angle returns an exact value of 180, but does not enter the if statement to perform the second log output:

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Why might my if statement not be executing?

Answer 1

The problem is that Debug.Log(transform.eulerAngles.z); printing 180 does not mean that z has the value 180. It means it has a floating point value very close to 180, but that could be for instance 179.999969482421875.

This means that the if((int)transform.eulerAngles.z == 180) test will not work, because casting 179.999969482421875 to int yields 179, not 180.

A possible solution is to round the value: if (Math.Round(transform.eulerAngles.z) == 180.0).

Answer 2

I copy pasted your code into a coroutine:

private IEnumerator TestCoroutine()
{
    GameObject newGameObject = new GameObject();

    while (true)
    {
        newGameObject.transform.eulerAngles = Vector3.Slerp(
            newGameObject.transform.eulerAngles, 
            new Vector3(0, 0, 180), Time.deltaTime * 10);

        Debug.Log(newGameObject.transform.eulerAngles.z);

        if ((int)newGameObject.transform.eulerAngles.z == 180)
        {
            Debug.Log("Hurray we have successfully executed the if statement");
        }

        yield return null;
    }
}

I ran it, and it worked:

Answer 3

Since you are using a slerp and casting to int, your rotation doesn't actually ever hit 180, since casting cuts off anything after the comma (179.999999999999.. => 179). The Debug.Log rounds instead, so if you want the behavior to be the same try Mathf.Round instead of the int cast.

It is better to use the solution Wondra posted in the comment above though, this is just to make it clear why it broke before.