Quaternion Rotation - won't go past 90 degrees

Scripting
1

Hi

What am I doing wrong here?

My transform rotates on all 3 axis but the X axis (pulling the ship’s nose up or pushing it down) stops at 90 degrees in either direction. When it reaches 90 it stops and just spins on the other axis. I thought this was fairly simple and I’m not sure where it’s going wrong. Any ideas?

Transform player;
    public float movementSpeed = 5f;
    public int invert = -1;
    float tiltSpeed = 100f;
    float rollSpeed = 300f;
    public float tiltAngle = 30f;
  

    // Start is called before the first frame update
    void Start()
    {
        player = GetComponent<Transform>();
    }

    // Update is called once per frame
    void Update()
    {
        // Get left/right/up/down
        float horizontal = Input.GetAxis("Horizontal");
        float vertical = Input.GetAxis("Vertical");

        // Update ship position
        //transform.Translate(transform.forward * Time.deltaTime, Space.Self);

        // Update ship rotation
        Quaternion lookTowards;
        if (horizontal != 0 || vertical != 0)
        {
            float rotationX = transform.rotation.eulerAngles.x;
            float rotationY = transform.rotation.eulerAngles.y;
            float rotationZ = transform.rotation.eulerAngles.z;

            float hTurn = horizontal * tiltSpeed * Time.deltaTime;
            float vTilt = vertical * tiltSpeed * Time.deltaTime;
            float roll = horizontal * rollSpeed * Time.deltaTime;

            rotationX += vTilt;
            rotationY += hTurn;
            rotationZ -= roll;

            rotationZ = ClampAngle(rotationZ, -75, 75);
            lookTowards = Quaternion.Euler(rotationX, rotationY, rotationZ);
            transform.rotation = Quaternion.RotateTowards(transform.rotation, lookTowards, Mathf.Deg2Rad * 45f);
        } else
        {
            lookTowards = Quaternion.Euler(transform.rotation.eulerAngles.x, transform.rotation.eulerAngles.y, 0);
            transform.rotation = Quaternion.RotateTowards(transform.rotation, lookTowards, Mathf.Deg2Rad * 45f);
        }
    }

Cheers
Dan

2

You’re doing individual x, y, z axis rotation calculations so you’re essentially creating your own gimbal lock problem.

Instead you can simply rotate the underlying transform in individual local space:

    void Update ()
    {
        float roll = -Input.GetAxisRaw( "Horizontal");
        float pitch = Input.GetAxisRaw( "Vertical");
        float yaw = 0;
        if (Input.GetKey( KeyCode.Alpha1)) yaw = -1;
        if (Input.GetKey( KeyCode.Alpha2)) yaw =  1;

        transform.Rotate( pitch, yaw, roll, Space.Self);
    }

Slap that on your first person camera floating in your world and use the arrow keys and 1/2 to control roll, pitch and yaw, respectively.

NOTE: the above is super-simple; I didn’t even use a speed or Time.deltaTime. You should use both.

2 Likes
3

I see. That works better, thanks.

I was trying to use Quaternions to avoid gimble locks. Is transform.Rotate safe from gimbal lock, or does gimbal lock just arise from trying to assign individual axis calculations?

4

Gimbal lock arise when you assing axis rotations one by one and one axis interflows with another. After that, you can rotate your object aroud 2 axis only instead of 3, like this

780×740 81.1 KB

That’s essentialy the gimbal lock problem. Quaternions are build using complex numbers to avoid this problem. Transform.Rotate creates a quaternion and assigns it to the transform instance, therefore it is free from the gimbal lock.

1 Like