CODEWITHSUNDEEP
c#unity-game-engineoculus
Photunix
Photunix

Reputation: 227

How to fetch a rotation of a object while twisting it in Unity?

I am currently implementing a radio in Unity for Oculus. Player can twist the knob to change volume. However, either eulerangle or rotation cannot return a unique value while turning in 360 degrees.

And below code has the same problem with eulerangle.

void Start ()
{
    oldRight = Vector3.right;
    angle = 0.0f;
}

void Update ()
{
    Vector3 right = transform.right;
    float tempAngle = Vector3.SignedAngle(oldRight,right,transform.forward);
    if (right.y < oldRight.y)
    {
        angle += tempAngle;
    }
    else
    {
        angle -= tempAngle;
    }
    oldRight = right;
}

Upvotes: 0

Views: 745

Answers (2)

Galandil
Galandil

Reputation: 4249

First of all, we don't know what's the relation between the radio game object and the knob game object, and that matters.

I'll make an example in order to show how you can get the rotation of the knob regardless of that relation.

In the image below, the radio is the cube, with its transform reset all to 0.

enter image description here

This is the cylinder which acts as the knob:

enter image description here

The important part here is that I rotated and placed the cylinder such that the X axis of the transform is parallel to the X axis of the cube.

And here is the script that rotates the cylinder and reports the angle of such rotation:

using UnityEngine;

public class RotateKnob : MonoBehaviour {
    public float m_Speed;

    void Update() {
        if (Input.GetKey(KeyCode.RightArrow)) {
            transform.Rotate(Vector3.up, Time.deltaTime * m_Speed, Space.Self);
        }

        if (Input.GetKey(KeyCode.LeftArrow)) {
            transform.Rotate(Vector3.down, Time.deltaTime * m_Speed, Space.Self);
        }

        var angle = Vector3.SignedAngle(transform.right, transform.parent.right, transform.up);
        Debug.Log(angle);
    }
}

Notice how the rotation is done relative to the Y axis and Space.Self.

The angle is taken relative to the Y axis of the cylinder (which is the axis around which we rotate the cylinder), thus transform.up as the SignedAngle third parameter, and ofc we measure the angle between the transform.right and the transform.parent.right (the transform.right of the cube that childs the cylinders).

With this code you don't have to worry about the transform of the cube in the world, the result will always be relative to the cube when rotating the cylinder.

Please do remember that the angle will be reported in the range [-180,180] and not [0,360].

Upvotes: 1

Draco18s no longer trusts SE
Draco18s no longer trusts SE

Reputation: 15941

transform.rotation

If you want XYZ angles (and not a quaternion),

transform.rotation.eulerAngles

Upvotes: 1

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