Unity - How can I add or subtract a chosen number of degrees from an angle?

Question

I was wondering if there's a way to add (in my case) 120 degrees everytime I push 'ButtonA', and subtract 120 degrees everytime I push 'ButtonB', from the Z-axis rotation of a 2d sprite (prefab).

This is the code I'm using at the moment, but it only rotates once left, and once right:

function TouchOnScreen ()
{
    if (Input.touchCount > 0)
    {
        var touch = Input.touches[0];
        if (touch.position.x < Screen.width/2)
        {
            var RSpeed = 10.0f
            transform.rotation = Quaternion.Lerp ( transform.rotation,Quaternion.Euler(0,0,120), Time.deltaTime*RSpeed);
            Debug.Log("RotateRight");
        }
        else if (touch.position.x > Screen.width/2)
        {
            var LSpeed = 10.0f
            transform.rotation = Quaternion.Lerp ( transform.rotation,Quaternion.Euler(0,0,-120), Time.deltaTime*LSpeed);
            Debug.Log("RotateLeft");
        }
    }
}

Thanks in advance!

Note: Please use unityscript if you can, I'm pretty new to coding and unityscript is all I know so far.

score 0 · Answer 1 · answered Sep 10 '14 at 23:20

From the online documentation it is shown that the signature of the function is

static function Lerp(from: Quaternion, to: Quaternion, t: float): Quaternion;

that means the second parameter is the new rotation of the object not the rotation offset

you should use something of the sort

function TouchOnScreen ()
{
if (Input.touchCount > 0)
{
    var touch = Input.touches[0];
    if (touch.position.x < Screen.width/2)
    {
        var RSpeed = 10.0f
        transform.rotation = Quaternion.Lerp ( transform.rotation,transform.rotation + Quaternion.Euler(0,0,120), Time.deltaTime*RSpeed);
        Debug.Log("RotateRight");
    }
    else if (touch.position.x > Screen.width/2)
    {
        var LSpeed = 10.0f
        transform.rotation = Quaternion.Lerp ( transform.rotation,transform.rotation + Quaternion.Euler(0,0,-120), Time.deltaTime*LSpeed);
        Debug.Log("RotateLeft");
    }
}
}

note the second parameter is transform.rotation + Quaternion.Euler(0,0,120) (current rotation + offset to the right)

I'm not an expert on unity engine (I only started toying with the free version yesterday, literally)

Thanks for your answer @workoverflow, but I'm getting this error: BCE0051: Operator '+' cannot be used with a left hand side of type 'UnityEngine.Quaternion' and a right hand side of type 'UnityEngine.Quaternion'. — Bartvb98, Sep 11 '14 at 13:44

score 0 · Answer 2 · answered Sep 11 '14 at 06:27

0

Try this one

function TouchOnScreen ()
{
if (Input.touchCount > 0)
{
    var touch = Input.touches[0];
    if (touch.position.x < Screen.width/2)
    {
        var RSpeed = 10.0f
        transform.Rotate(0,0,120);
        Debug.Log("RotateRight");
    }
    else if (touch.position.x > Screen.width/2)
    {
        var LSpeed = 10.0f
        transform.Rotate(0,0,-120);
        Debug.Log("RotateLeft");
    }
}
}

If this not works try with Gameobject. I didn't check this

answered Sep 11 '14 at 06:27

Rasa Mohamed

882
1
6
14

Thanks for your answer @Rasa Mohamed , but the problem with this script is, is that the rotation isn't smoothly. It snaps from point A to point B in one frame. I want it so that the rotation is visible. – Bartvb98 Sep 11 '14 at 13:47

Unity - How can I add or subtract a chosen number of degrees from an angle?

2 Answers2