Trying to increase a Cubes scale in Unity and then decrease when it reaches a certain number-CodePudding

This is how I'm going about it:

if(transform.localScale.x > 7)
{
    for(int i = 7; i > 1; i--)
    {
        transform.localScale -= new Vector3(1, 1, 1) * Time.deltaTime;
    }
}
else
{
    transform.localScale  = new Vector3(1, 1, 1) * Time.deltaTime;
}

The else statement is executed to increase the scale and when it reaches 7 the if statement should decrease it back to 1 thanks to the for loop which should run for 6 iterations and decrease the scale 6 times. But only the else part works properly when the scale reaches 7 it just gets decreased to 6 and then back to 7 in a second. It doesn't go all the way down to 1.

CodePudding user response：

You know that your entire for loop will be executed immediately within one single frame? and you multiply that by Time.deltaTime which assuming 60 frames per second would be a value around 0.0166666666....

So what you are ding in a loop basically just equals doing

transform.localScale -= Vector3.one * 6 * 0.017f;

Right in the next frame you might already again be lower than 7 => you land in the else case and again increase the scale.

So in the next frame it will already decrease it again etc

From what I understand is you rather want kind of a pin pong effect between two scales.

I would rather use something like

// adjust via the Inspector
public float speed = 1;
public float amplitude = 7f;

private Vector3 originalScale;
private float timePassed;

private void Start()
{
    originalScale = transform.localScale;
}

private void Update()
{
    timePassed  = Time.deltaTime * speed;

    // see https://docs.unity3d.com/ScriptReference/Mathf.PingPong.html
    transform.localScale = originalScale * (1   Mathf.PingPong(timePassed, amplitude - 1));
    // or with ease-in and ease-out
    //transform.localScale = originalScale * (1   (amplitude - 1) * Mathf.SmoothStep(0, 1, Mathf.PingPong(timePassed, 1)));
}

Where Mathf.PingPong

returns a value that will increment and decrement between the value 0 and length.

Or if you actually need a different increase and decrease duration I would rather suggest a Coroutine like

// adjust via the Inspector
public float increaseDuration = 1f;
public float decreaseDuration = 7f;

public float amplitude = 7f;

private IEnuemerator Start()
{
    var originalScale = transform.localScale;
    var maxScale = originalScale * amplitude;

    while(true)
    {
        for(var timePassed = 0f; timePassed < increaseDuration; timePassed  = Time.deltaTime)
        {
            var factor = timePassed / increaseDuration;
            // optinal add ease-in and ease-out
            //factor = Mathf.SmoothStep(0, 1, factor);

            transform.localScale = Vector3.Lerp(originalScale, maxScale, factor);

            yield return null;
        }

        for(var timePassed = 0f; timePassed < decreaseDuration; timePassed  = Time.deltaTime)
        {
            var factor = timePassed / decreaseDuration;
            // optinal add ease-in and ease-out
            //factor = Mathf.SmoothStep(0, 1, factor);

            transform.localScale = Vector3.Lerp(maxScale, originalScale, factor);

            yield return null;
        }
    }
}

CodePudding user response：

You can make an other variable like:

public bool isDecreasing=false;

if(!isDecreasing && transform.localScale.x > 7)
{
   isDecreasing=true
}else if(isDecreasing&&transform.localScale.x==1)
{
   isDecreasing=false
}

if(isDecreasing)
{
   transform.localScale -= new Vector3(1, 1, 1) * Time.deltaTime;
}else
{
   transform.localScale  = new Vector3(1, 1, 1) * Time.deltaTime;
}